MARCH
186
CORNELL UNIVERSITY
AGRIC"LT'ORAL EXPERIMENT STATION
EFFECTS OF~ME ENVIRONMENTAL FACTORS
ON GROWTH AND COLOR OF CARROTS
W. C. BARNES
'\
.
ITHACA, NEW YORK
PUBLJSH1£D BY THE UNIVERSITY
Rt'celvell
roJ' publication July 24, ~
CO.K1'ENTR
l'AOl!
Objcm. oHlIo pre.q(,llt Ilxpl.l1imentK .......... , .••••• • • ............ .. ............... 3
J.IIlatezials Ilnd lIIethOlls ulIl'rL . .. .• . . . . . . . . • . . . . . . . . . . . . . . . . . . . . • • . • . • . . . • . • . • • • • • 4
IIistury and importance Ilf rltrot CllO. . . . . . . . . . . . . . . . . . . . . . . . • • . . . . . . . . . . . . . . . . . . . • I)
ExpClrimentall't'lSultR. • . . . . . . . . . . . . . . • . . . . . . . . . . . . . • . . . . . . . . . . . . • . . . . . . . . . . • . . . . (i
Effect of cnvirrmmcnfnl ftictofH un I!;rowth nlllll'llluf of r!~rrots. . . . . . . . . . .. . . .. . . . (}
Temper6ture find HOillnoisture. . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . • . . . . . . • . (}
Tcmpcratuf('. ....... ........ ..........................••.•.......... 13
Temperatnre, soil moisture, lind lougf.h tlf uu.y. . . . . . . . . . . . . . . . . . . . . . . • . . . . . Iii
Length of rillY. . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . • . . . . • . . . . . . . • . . • . • . • • • • • • til
of plnllt.nutricnt.q Oil p;rllwth IUld "nlur IIC (lurrot.s.. .. . . . . • . • . . . • . • • • • . • • • • 19
~f[l!Ct
.-
~,:~:n;~:: :::::::::: :::: :::::: :::::: ::::: ::: :::: ::::::::::::::::::: ~
Copper 6111£lltO. • • • • •• • • • • • • • • • • • • . . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Other nlim·mts. . . .. . . . . • . . . . . . . . . . . . . . . . . . . . . . • • . . . . • . . . . . • • . • . • . • . • • •
Vlilft'oot of ago oC plaut on type of gt'O\\'th nnd on color of carrota. . . . . . • . . . . . . . . • .•
...compMil!oJl of 1l0JnlloflH,ion of Cafe auel or cortex ....•............. " ....•••
DovelopnJl"nt of llblmu""J ,; lUld other pil!:mcllt~ ... , .........•........•... " • "
Effect ot stllrage te;l.pl!rlliure IUld-a!ll' of root, all 1'1uLIlg1ls in color and chemical
cuntpoNitioll ot cllrr()t~. . . . . . . ........... " ...............•..•...•.....•••
Flpl~rlua!'S' u.wl eliRP,UH~inn. .. . . . . . . . . . . . . . . • • . • . • . . . • . • • • . . . • . • • • . • • • • • • • • • • • . • ••
. "lteflll'enll~ citt'(l. . . . . . . . . . . . . . . .. ....... .................••.•.•......•..•...•
23
23
24
<J:1
29
29
a2
36
EFFECTS OF SOME ENVIRONMENTAL FACTORS ON
GROWTH AND COLOR OF CARROTS 1
W. O.
BARNES
Carrots grown in various parts of the United States frt;quently fail
to develop a desirable shape and a good color. This is particularly true
of carrots growll in some parts of the South during wintel' and spring.
'rhe fact that a strain will develop gooo. shape and good color in a. given
l'egion under some conditions and not under othel's indieates that
environment must be involved. Prior to the beginning of the studieR
l'eported in this paper, little experimental wOl'k had bef'n undertaken
to determine the effects 01 variou$ environmental factors on the habit
o,j' growth and on the development of color in carrots.
'fhe color desil'ed in carrots is a deep orange 01' an ol'auge-l'ed in
all parts of the root. Camlers demand a uniform prolluci of a deep
orange color, and a well-colored earrot i~' referretl aiRO on the general
market. Large quantities of carrot!! g own in some regions of the
South fail to meet federal grade!! beeaus of poor color. With the discovery that carotene, the coloring pigment o.f earrots, is pro-vi1amin A,
an interest in color Irom the nutritional standpoint has developed.
In New York State, large quantities o.f carrots are put in storage in
the fall for sale later in the seaBOll. These carrots, as a rule, are well
colored at harvest time, and the question arises as to wht'ther or not
any color is lost during storage.
OBJECT OF THE PRESENT EXPERIMENTS
In the llum.erous researches on the effect of environmental factors on
plant growth, it has been clearly demonstrated that different 'Plants vary
widely in the type of response to the saro.e factor. It has beell $hown
also that often there is an interrelation of the influence of these various
Iaetors on plant growth, At the time when these studies were begun
thoro was little or no evidence available on the effect of environmental
factors on growth and on color of earrots. Studies were initiated,
therefore, to determine: (1) the influence of (a) temperature, (b)
soil moisture, (0) length of day, and (d) the interl'e1ation of these
factGts, on growth and color of carrots; (2) the influenee of the various
nutrient elements on growth and color; (3) the influence of the age
of the plant on type of growth and on color; (4) the interrelated
influence
age of root and of storage temperature on eolor,
or
il;'aper no: 185, Department of V{'getable Crops, Cornell Unlvl>rslty Ithaca, New ~
Also preAen tl'd to tbe Faculty of the Graduate Behnol of Cornell Uiih'e:rAit~, J1lt)e 19811'
as a major theala In partial fulfillment of the rO(1ull'l!llIents tol' tho degree jI'- doetor of
philosophy, 1
•
/
ACItNOWLmDGMltll'l'lJ.
The author wishes t.o ackno'lYledge,.... h1s lnl'lebtedn,e..
to Profess r n. A. McGinty, AS81.lllnt Dean and Dll'l'etor of the South Carolina mspm.
ment eta lon, t01" suggesting this problem. He glnQI:v acknowlPdgu ha Intlehteckl... ta
the vano s ml'mbera of the Department ot Vegetable Cropl! at Wml1ll trntve;r 'Wlio
have a111 d in these studleA, He 18 particularly grateful to nt'. :8, C. Thomll
whotl8 dll'ectlon the studIes were conducted, for valuable s(lv1ce and COllBtriie l'e/Cl!!
clams K\ven throrurhout the course ot the investlgatiolls, anll to 'Or. Ran. Plat-.fUe'lI!
his vaI\lahle aRsilllllnco in the ehemlcal ana1Y81)8 and In 'i)!'11 pl'Sparlttun of 'tbe m u.
Icrlpt.,' Thanks are due also to 01'. O. F. Curti., of the nl'PIUt:instlt tl lJotany at c.nonen
Unlvers!t;r, fOr advice ~n interpreHng the pbyslo1oglclll al1f1l111ea.nee O'tthe ttit(l.. "rS
A'Il'rHOi'
' 11!
3
4
w. C.
BARNES
:MATERIALS AND METHODS USED
The experiments were conducted in the grcenhouscl:4 and gardens of
the Department of Vegetable Crops at Cornell University, and in the
garden of the Long Island Vegetable Research Farm at RiverltcR{l,
New York. The storage experiments were conducted in the experimental
cold-storage rooms, and the chemical analyses were macle in the chemical
laboratory, of this department at Cornell University.
In all of the experiments, a good strain of RE'd Coreu ChantenRY,
which had been tested previously for trueness to type, was l:Iown directly
in the container or in the field in which the experiments were to be
conducted. During the first year of the experimcnts, the plants were
grown in greenhouse benches containing about ]0 inches of soil. Fot"
the remaining greenhouse experiments, 2-gallon glazed croclts were Ul:ICU
as containers. .A. composted garden soil was used in all O! the experiments except those dealing with nutrients, in whil.lh a 8aucly loam soil
low ill llutrients WIIS used. Soil moisture was lIlaintained in tlH:~ g)'ccnhouse beds by watering as neeued and by weekly determination ()f the
percentage of soil moistul·e. The pots were brought up to weight
weekly, and water was added as needed between weighill~ in order
to keep the soil-moisture content as uniform as possible.
The greenhouse!:!, heated by steam, w~re maintained at tour different
ranges of temperature: 40 0 to 50 0 F., 500 to 60 0 , 60° to 70(1, Ilnd 70° to
80°. Records of aetnal temperatures were obtained by means of ihcrmographs. The light duratioll was vaden by the Will of electric light
and by covering the plants with black cloth.
In all of the greenhouse experiments and ill some of the fiold experiments, the following weighings and measurements of individual plauts
were made: length of top, weight of top, length and diameter of root,
diameter of core, and weight of root. Root (liameter nnd core diamoter
were ascertained by slicing the root into equal portions llnd measuring
at the point of greatest magnitude. Photographs wuro macle oI the
plants selected, to show an nearly I:IS possible the typical shapa and
size of top and of root for the particular treatment. Odds wore calculated by Fisher's Method II, Livermore's table of otltls being used for
"t" values.
When the roots were sliced for core-diameter measurement, the two
halves of each root were placed in separate lots. The halves in the lot.
for dry-weight and sugar determination were sliced into thin sections
and were thoroughly mixed, and 100 grams WI.I.S weigbed. out for
dry-weight and another 100 grams for sugar deter.rnination. The dryweight sample was placed in a ventilated oven at 551) C. after having
.~ held at 100 0 C. for one hour to iUR<ltivate the enzymes. The
sample £.91' sugar determination was placed ill a fruit jar with Buffteient
95-per-cent alcohol to make a final concentration of 75 per cent, was
boiled for fifteen nlinutes, and was then scaled and stored at 821;) F.
until the analyses were made.
~
In some preliminary work, carotene waR measured by! extracting
the dry materilll with alcohol in a reflux condenser extract r. According to I:Schertz,1. this method is l.mreliable because of o:s::idat~on resulting
from heating and the use of alcohol, and therefore it was aba.ndoned.
, From porsonal C!U'l.'espoadenCl! with
]l',
M. Sehel'tll.
GROWTH AND COLOR OF CARROTS
5
In all the work reported in this paper, the method or extraction was
essentially that of :::lchcrtz (1928), which is as follows. The sample was
shredded very fille with a small vegetable rohredder. Duplicate 25-gram
samples were weighed out arter the material had bt>en thoroughly mixed.
Each sample was ground in a mortar with quartz sand, to aid in crushing the tissues. After the material had been thoroughly gl'ound, a. small
quan1 ity 01 ('oM acetone was added, and grinding was continued until
all particles lIad been crushed. The entire mass of lllaterial was transferred 1CI a 500-cc beaker, th{' mortar was washed with acetone, and
the washings were add{'d to the beaker. Aeetone was added to make
the benker about two-thirds J:ull. The mixture was allowed to rotand
for a minute, and the liquid was th('u filtered through glass wool into
a sepal'atory funnel. More acetone wa~ added to the material in the
beaker, aud thil:l was again filtered off as soon as it had reached the
saturlltiou point. This proceros was repeateu until all of the carotene had
been ('xirncted from the samplc, usually about 1 liter of aCE'tone boing
requit'eu per Humple. To the acetone solution ot carotene in the separatory funnel, about 1130 co of petroleum ether (b.p. 40 0 to 60 0 C.), and
suffici('ut ~niurated soclium-chloride solution to cause the two layers
to separate, were added. The colorless solutioll of aCE'tone aud water
was then drained off. Moro of the sodium-chloride solution was added
and the eolo1'1(,88 solution drained off, after which the petrolcunl-ether
solutiou was washed thrE'c or four times with water to illsure removal
of all of the M('1one. '!'he petroleum-ether s()lution was then filtered
through anbyul'()US sodiuUl sulfate into a 200-oc volumetric flask, and
the sodium rouHaie was warohpd with petroleum ether to remove all
traces of carotene. After maldng up to volume and mixing, the
unknown solution was compared in the colorimeter with O.2-per-cent
potassium.dichromate standa.rd, which, aooording to Will2tiitter and
Mieg (1907), is equivalent to 0.0268 gram of carotene per liter. ThE'
results nre reported as milligrams of carotelle per 10 grams oJ: fresh
material or per 10 grams of dry material.
Reducing and non-reducing sugars were determined by the MunsonWalker method (Association of Official Agricultural Chemists, 1925),
and the amount of reduced copper was measured by the potassiumpermanganate method (Sullivan, 1931). Total nitrogen was determined.
by the Gunning method (Association of Official Agricultural Chemists,
1925).
HISTORY AND IMPORTANOE OF CAROTENE
Wackenroder (1831) first isolated carotene .from carrots, and named
it "carotin. H Arnaud (1886) :first established the fact that carotene
is a hydrocarbon, assigned it the formula ClloH88, and named it "caro.
tene." Kohl (1902) published an extellsive monograph on carotene,
reviewing hundreds ot articles which had been published on this and
related pigments priOl' to that date. From 1886 to 1907, Arnaud's
fQl!iiula (C2oH88) was apcepted .eor this pigment, but in 1907 Will•
• tlttter and Mieg proposed the formula C4oH Go , which is aceopted a.t
the present time. .
Carotene has been detected in varying amount£' in nearly all p1a:Q.1B.
'Ptlmer and Eckles (1914, a, b, and e) establisl1cd the fact that the
y ulow coloring matter of the milk of cows andJhumlUl8, a.nd also the
6
W. C.
BARNES
yellow coloring matter in parts of their bodies, is carotene, and that this
carotene is derived from the plant food which they consume. Palmer
(1934) published a revised nomenclature for the carotenoid pigments,
based on the recent findings in the field, and proposed that the principal
pigment be named "cal'otene" instead of "carotin" as it had been
previously.
In spite of the extensive investigations on carotene, its r61e in nature
remained unknown until 1919, when Steenbock and his co-workers found
a relationship between the fat-soluble vitamin .A and the yellow pigments of plants (Steenbock and Boutwell, 1920). Since 1919 it hM
been demonstrated that carotene may be fed as the plant pigment or
as tho chemically Ipure pigment, and it is converted into vitamin A in
the liver of the animal. Vitamin-A deficiency results in discases of
the eye and in breakdown of the tissues of the respiratory tract which
may result in secondary infections with a number of differcnt kinds
of disease organisms. The same types of deficiency have heen found
in all animals investigated, and they can be prevented by feeding
carotene as the plant pigment or as the pure chemical dissolved in some
carrier.
Color in carrots is of importance in determining their appearance
and therefore their value on the market. It:is of importance also from
Ithe nutritional standpoint, since it is largely carotene which has been
found to be pro-vitamin A. These were tho main reasons lor making
this study of the factors affecting the formation of this pigment in. the
carrot.
EXPERIMENTAL RESULTS
EFFECT OF ENVIRONMENTAL FA.CTORS ON GROWTn AND COl.OR Oli' CARROTS
Four experiments were conducted to study the effect of environmental
factors on the growth and color 01 carrots. These experiments were
eonducted during the winter aeasons of 1931-32, 1932-33, und 1933-34.
The plan of the experiments was to grow plants throughout the season under va.rious (londitions of temperature; soil-moisture content, and
length of clay. Since the plan and the conduct of the various e'xperjments differed somewhat, it seems desirable to discuss each one separately.
Temperatwre ana soiZ moisturo
In the fall of 1932, an. experiment was started to study the efIect of
temperature and soil moisture on the growth and eolor of carrots. On
November 5, 92 of the 2-gallon pots used in the studies were fined with
composted garden soil which was watel"ed and allowed to settle for a
week. This soil had a water-holding qapaeity of 45 to 47 per cent, and
,. pH of 5.6. The pots were divided into three lots {).L 80 pots each. The
three lots were placed in three respective greenhouSes, in which the
following temperature ranges, respectively, were maintained: 50° to
.600 F., 60 Q to 70°, and 70° to 80°. The remaining 2 pots were kept
at 40° to 50° F. The seasonal averages of these temperature ranges
were, respectively, 57.2°, 66.P, 75.8°, and 46.0°, The seed was sown
on November 13, and the plants were thinned to six to u pot after ge1'mination. The pots in each greenhouse were subdivided into three lots
. of 10 pots each. One, lot was maintained M nearly as possible at It,w ,
7
GROWTH AND COLOR OF C.A:RROTS
sl1il moisture" (18 per cent), the hecond lot at medium soil moistu~e
(26 per cent), and the third lot at high soil moi~ture (34 per cent)
The pots were systematIcally arranged and rotated on the gref'nbouse
benches so as to eliminate ddrerences in light exposure. The plants were
harvested from April 11 to April 13, 1933
Each 10 degrpes difference 1U temperatul'e made a difference of two
days in time of germmation, f'xcept at 40° to 50°, where the germination
war, so &low that the pots were transferred to a higher temperature until
aft cr gf'rmmntion Although the seed in the highest temperature wa~
the first to germinate, and growth of the plants in that temperature
WM the mO'it ~apid hi the begInning, thi'i lead was later lost, as is sllown
by the average height of the plants on February 8 (table 1). The differTABf.;Rl 1
Eli':['J:Cl'
or
Tm[l'ERA'l'URD AIm SOIL MOISTURE ON HCIGltT OF CARROT
Px..\N~ ON FDBRUAl\Y 8, 1933
SOII·molsture content
Temperature (r)
r ow
I
Medium
I
IIJih
IIelght of plaute. ID cenbrnet8l'll
40° to 50·
50" to 61)6
60" to'tOO
70° to 800
- =-...-
1100
1848
17 17
S 25
1773
Z1 75
2S 70
1900
29 70
27112
-===--_ =- -====-_- ===-====,---,=='--=-= _-=====-==
FlGUM
L
GBOW'l'K OF CUUt0W/ AT 4.0· 'l.'O flJo lI'.
(p)!.otog&phed on Mt.rllb
1988)
,Ji'
8
W. C.
BARNES
ence in growth between theo low- and the IIledium-soil-moisture lots was
greater at this stage than that between the medium- and the high-soilmoie.ture lots.
The plants grown at 40° to 50° made practically no growth until
the temprrature began to rise above 50 0 as spring approached. In
figure I, made from a photograph taken on March 25, it is seen that
growth had begun. As the temperature increased, the plants grew
rapidly, but they all produced seed-stalks without producing the normal
storage Not.
AB the season progressed, the plants at the extremely high temperature
contInued to loe.e their lead, and at harvest time these plants had the
smallest roots and the second smallest tops (figure 2 and table 2). The
type of top growth was influenced mOl.'e by temperature than by moisture, as IS indicatt>d by a comparison or thE' average weight and length
of tops under the various treatments (table 2, and figures 2 and 3).
9
GROWTH AND COLOR OF CARROTS
'l'AJlLE 2.
EFll'ECT
Oli' TEHPERAo.TUlIE AND SOIL MOISTtlRJIl ON GROWTH OF CARROTS,
1932-33
..
TemlJerature ....•
...
AoilllloJsturr .
top
(rt'ntillletel'8)
AvnagB top
Average
(gmm~)
"
1i00 to 6oo F.
lellgth
..
..weight
•••••
.
FIGURE 3.
70· to 80" F.
Low
JlIedillm
High
Low
Medilllll
Big:h
13.1
224-
294
221
32.6
38
13.6
236
66
22.1
98
06
6.3
3,7
43
15
581
43
root length
(centlmrters). . • •• •
78
Averallll root diameter
(cBlltillll't ora) • ... •
2.1i
AverAAe rnre diameter
(oentimeters).. . . •. .
08
Average roo1; weight
(crams) ........... 187
4.9
Root-top raUo .••...
Average
60" to 70" F •
-- ---- -Low
MPdlulIl
High
37.7
21.2
30:2
33.1
33.0
50
14.2
23.8
7.8
8.S
4.6
0.'
5.7
80
4.6
5.1
2.2
3.3
3.6
1.8
1.1
2.1
2.4
00
1.6
1.0
77.3
3.3
256
S.D
76 1
34
100.4
3.0
111
2.2
29 5
2 1
38.0
1.8
ICII'PEC'l' 01' SOIL YOIS'1'tJII.'81 ON GROW'l'H 01'
(,PbotogrllPhlld at hal'l"eat, 1938)
From lelt to l'l&ht, plants ilfOwn iulow, medium, Bud hlah toll IIlOill>')llrB,
W. O.
10
BARNES
Increasing the soil moisture resulted in a greater increase i~ top weight
than did incl'eaRiulJ' the temperature. Root shape was modrfied more by
temJlerature than by moisture, as is shown in figurc 4.
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Ell'lI'JIlCT Oil' TEMPJilRATURE AND qOIL MOIS1"17ruB ON
SHAPE 01' nOOTA, l032-3:i
A. Low rom-ture. B. Medium moisture. C. High molstnre
The m~ium temperature (60 0 to 70°) produced a i'oot of more nearly
normal sha)!,;1e for the variety t.han llid either of the other temperatures.
Lowe:ring fhe'\temperature below this range produced a longer and much
more slender r~t, while raising the temperature ubove this range produced a. relativelx, Rhorter and thicker root. There was little difference
between the shape (),( roots grown in high nneI in medium soil moisture,
but those grown in lo~ soU moisture were slightly mor~ pointed. Total
11
GROWTH .AND COLOR OJ!' CARROTS
growth of roots was probably influenced more by moist\tre than by
temperature, although the diifel'enct's were statistically significant for
both moisturc and temperature. This means that ·under the conditions
of this experiment the differences iu weight 01 rout are statistically
sib"D.ificant betwecll 60° to 70° nnd 70° to 1:10°, between 60° to 70° and
{iOo to 60°, and between 50° to 60° and 70° 10 80°, for a given soilmoisture content. Also, the differences in root weight are statistically
significant between high and medium soil moisture anel between mediulll
and low soil moisture, at each of the temperature ranges.
The root-top ratio (table 2), obtained by dividing the weight of roots
by the weight of tops, also throws some 'light on the effect of temperature
and of moisture on growth. The higher the root-top ratio, the greater
is the proportion of root to top, 01', expressed in a different manuel',
the more efficient is each unit of foliage in producing root. With an
increase in moisture or an increase in temperature, there was a decrease
in root-top ratio. This sugges1s that the lower the temperature and
the moisture, the 1ll0rE' efficient is the foliage, and therefore one would
expect that the growth would be gl'eater, but it was not. Increased
efficiency per unit or top is, 110 doubt, a factor. Howevel', the data
show clearly that tht' l'OOt-top ratio is not necessarily cOl'fPlated with
either total plant growth or total l'oot gl·owth.
On the dry-weight basis, therl' is little difference in eal'lltl'nc content
between the plants at 50° 10 60° and those at 60° to 70 n ; but ill the
plants at 70° to 80° the carotene (.'ontent is much lower lban in the
plants at either of the other two temperature ranges, as is shown in
table 3. Differcncps due tl) soil moistUl'e are incollsistent and not of
'l:ABl.E
3.
EFIl'mOT
OF TEMl'UATU.l\E AJ.IlD SOIL MOISTURE ON COLOR .AND CHEMIOAL
COMPOSITION OF CARROTS, 1032-33
I
Temperature ..••.
GO" to 80" F.
SoilJXIoieture. •••
I.ow I Medillm 1 High
Carotene (mUlIgrama per 10
grams Of root).
3.70
Glucose rer oent) 2.86
Suorose ~ cent) 3.01
Dry 1M ter (per
cent) ......... 14.34
8.00
60· to 70° F.
70a to 80" F,.
\
Low I Medium I nigh
Freall"I!Ieip;ht baais
Low I Medium I Hiah
2.46
2.Jl9
2.69
2.23
2.S3
3.61
2.61
2.82
3.3!!
2.02
2.10
281
1.76
2.24
ViS
UI8
3.38
2.36
11.71
11.46
14.31
11.41
11.20
14.64
12.36
Dry.weight baala
Carotene (mUllIl'ame )!er 1tl
grllms or root) .. 20.2
Glucose ef oantl 19.9
Suorose per cent 20.11
i:
25.8
20.1
22.1
2S.&
19.4
20.8
25.2
18.2
10.7
29.7
17.7
18.4
25.1
1117
20.0
I
17.2
13.5
!I).I
2.33
1.49
2.11
1.73
2.JlG
I
I
11.1
J3.9
20.6
1 11 •88
i"--
.
•
19.8
111.61
18.3
-
any great importance. Decreasing the tem.perature in{!reased the glucose
content, while sucrose was not influenced greatly by ehanges in te;m.pera.
ture. Soil moisture had little effect on sugar content. Total nitrogen
showed only small, inconsistent differences, and the data are omitted
in this and in all of the other tables. Temperat'ire had littJe effect on
the percentage of dey matter, while soil moistul'C<! altered th; percentage
very greatly, The percentage of dry matter wail highest in the plants
12
W. C.
BARNES
grown ill low soilmoistnre j ill the plants grown in medinm soil moisture,
the drY-llla1ter content was small but was COllRif.ltenily high('r llUlll ill the
plants grown in high soil moisture.
Expressed all the fresh-weight basis the results appear very dill'E'l'ent
from what they do when expressed on the dry-weight basis, owing to thiH
marked influence of soil mOi!ltUl'e on the percentage dry w(·ight. From
a commercial standpoint, 1he influence of these various fuctorl:l if! of lllorC:!
importallce as exprcssE'd on 111e fresh-weight hal-lil:l than as I:'xpreHse(l all
the dry-weight basis. ]'01' Lhis reason, in thiH and all subsequcnt oxperiments reported in this IJapel' primary cOllHidel'uiiol1 is given to differences on tile fresh-weight basis. l.As is shown in table 3 and in figure 1;,
3.8
_-..,...---r--_-..,...---,r----.---,.---,
FIUURE 5. EFFECT OF T1!JMPI'lRATURE AND SOIL MOISTURE ON THE
COLOR AND THE CHEMICAL COMPOSITION OF CARROTS, ]032-33
HUll moisture: L. t low; M., medium: H., high
Thr figures at the left reprpsent: for CI\rotellel milligramR per 10 graIns of
root; for glucoselllnd 8uoroae, per oeuL. All 011 tne
fresh-wright blUl!s
it is evident that both temperature and moiHture iufluence color a!:!
measured by carotene content expl'esscd on tIle Cresh-weight basis. 'j'he
hilt!! ~mperatur6 reduced the total amount of Cllrotene markedly,
s'1i'd ah,~ reduced the variation in color caused by difference's in soilmoisture ,content. It is doubtfuL that the differences between the temperatures''{)oo to 70 0 and 50° to 60° are significant so fur as total carotene content is concerned, The roots at 50° to 60 0 , however, were
lighter-co]orcll'on the surface than those at 60° to 70 0 • Careful examination showecl that this light color was due to the absence of pigment
from a few cells ,011 the outer part of tho carrot. Increasing the soil
moisture decreaseq the carotene content, and the increase from a low
to a mediUln soil moisture gavc a greater reduction than did the increase
from a medium to a ~igh soil moisture except in the case of the 600 _
to-70° lot.
Reducing sugar, eypressed as glucose, ()n the fresh-weight buis
decreased as the perce.ntnge of soil moisture increased and also as the
GROWTH AND COLOR OF CARROTS
13
temperature was raised. Non.reducing sugar, expressed as sucrose,
on the fresh-weight basis also decreased as soil moisture increased,
except at 60 0 to 70 0 where at high moisture the percentage of sucrose
was slightly higher than at mediuu\ moisture.. Suerose content is not
affected by telllperuture in the IlRme way as is glucose. GLUcose decreased
us tho temperat ure increas('d, while suel'ose decreased from. low to
nlf'uinm tempel'atttre but iucreaseu from llledium to high temperature. ,
Tcmpcratt£,-e
Since the experiment reported above showed a marked relation between
growth and color, and temperature, it was decided to eonduct further
experiments. In 1933, 30 pots were prepared and planted as in the
preceding year. All of these pots were placed at 60° to 70° F., because
this had proved to he the most favorahle temperature ill the previous
experiment. .As SOOll as the plants were thinned to five to a pot, 10 of the
potb were shif1!'cl to the 40 0 .10-50° house at about 6 p.m. and back to
thtl 60 0 -to-70o houl'lf' at about 7 a.m. ThLs \Vas an attempt to duplicate
growiup: conditionl:! in the South during the winter months, when the
nights are ('old and the days arc relatively Wllrm. To serve as a check,
10 of the pots were left at 60 0 to 70 0 until harvest. The remaining
10 pots w<'rl' lE'ft at 60° to 70 0 until root formation had begun, and were
then shiited to 400to 50 0 for the rest of 1he seasoIi. This was an attempt
to (lnplicntl' conditions whpl'e plants are started iu the fall and make
flome growth before cold checks the growth, and also to spe whether
furth,.r lowI·ring of the temperature below 50 0 to 60 0 would give more
of 1hE' wllHE'uillg of roots 011 the outside which was obtained in the previous experiment. Soil- and air-tpmpel'ature readings were made over
a period of 1(311 days during the middle of March, These readings were
made at approximlLtely two-hour intervals throughout the day 8.l'ld the
night. Accurate thermometers, such as are nsed in chemical work, were
plunged into thE" soil or suspended above the pots. The averages of
these r€'adings are recorded in graphic form in figure 6.
Tempet..turG
;....----....-----r----...,.---.......,
(F.)
70'
40·~----~~~~----~~----~
6 p.m.
Ht p.m.
8 lI.m.
l'
FIGURm
6.
BOlL AND Ala '1'lD:MPE1U.'1't1Rll1S J
mum:RIKIIIJ.II'I."
14
W. C.
BARNES
The 60°-1 ()..700 lot :is referred to hereinafter as the U check," the lot
kept at 60° to 70° during the day and at 40° to 50° during the night
as the "daily shift," and the lot kept at 60 0 to 70° until root formation
and at 40° to 50° for the remainder of the season as the "Reasonal
shift." The carrot& in the check lot wer(' about normal ill Rhapt', while
thoo;e in the daily shift were longer and more slt'nder than is typical
of Chantenay, as i<g shown in figure 7 and in table 4.
iaUD
7.
EI'lI'JiICT Oll"TEMPERA-TUam ON aRO'W'.1'll: OF OAlUtO'I.'IJ, 1933-34
t len kept at 600 to 700 F. untll root. formatlOli. then at 4QO
')D
(lseaione.lllhdtl
to 50° until the end
enter kept at 60 to 70· dunnl[ the dM'. 40° to 500 durin. the nlaht (dady aluft)
'1ht kept at 60· to 700 thr0ll8hDut ilie leason (oheok)
~ift
produced very poorly shaped roots, these being
end somewhat in the normal manner but at the
'8 like a fieshy taproot than a storage root. As the
\~ecreased, the average length and weight of top
.f the seasonal-shift plants grew very little after
ecoid tempera-ture, although they must have
~er
GR()W'l'Il AND (lor..oR 011' CARROTS
15
TABLE 4. F.lFFEVl' O~' 'J'nMPIol8ATUtw. ON GactWTIl 01' CAlIlI.OTS, ID33-34
-
---=.-:.,
00· to 'TO" F.
GO" to 711° I'.
40"
(Chl'rJ..)
A;'eroge top length (olllltimeters)
•••• •
Avomge top WPlght (ltrIlDlY)....
• ....
Average root Ipnllth CI"'nlIDl!'tl'ra) • •
•
Avernge root dlRDlotl'l' (rlllltIllIPtc>ral •••••
Average cora dlllDletor (rrnlimateral
.,.
Average root \\eljl'ht (WaDl'l) . • • • • • •
Root-top rllIIO. ••
.. ... .... ... •
=====-::-:::--_._-_-___,- _-
60· to 70· F
40· to 50· F'
(80lI8011&1 ahlft)
to III)" ].1'.
(Daily
~hlft)
:10 11
:10.7
7.4
4 rrfl
an.lI
7H 1!!
nil
q fi
:I KJ
276
0.0
OJ.R
280
3'.
2342
12.K
2 11\
1.42
:1M
1.07
4117
200
-=-=--=-.:._-
-
canied 011 phOt()SYlltlH'~i!l, ~illC!l roots were fOl'lned during that period.
The weight ot the roots of tho llhN~k plants was siguificanlly greater
than that of ('itlWf of' tIIP other two lntH, und the weight of thp roots of
the dl1ilY-l'Ihift Jllltllt.~ wn~ significlLlltly gl'(lUt{,l' than tIle wt'ight of the
rootA of thc scnsollul..f.hift plantl'l. 'J.1JliR Aubstantiates th(, relmlts obtained
in previolls eXVl:'l'imenbl on tIll' ('iTE'<'t of t('mperaturc 011 growth.
• As shown hy thE' C'UJ'OiP1H' determinations giV(lll ill table 5, the temperature holow that ill [he llrevions exp(\rimE'nt resultt'd ill It r(.'duction
in ('01 or. Not 01l1y was there II. difiE'rencp in the total {'olot', but there
was an in('reaR(.' ill tIlt> amount of colorless tissue on the surface of the
roots, as was th(' ('aRe at the low tempcratnr(.'o in tho previous E'xperiment.
In the previou'l oxperiment only a. f{'\V cons or the ontoI' part were
devoid of tho pigment, bllt bere tho number of Mlleh OE'US \V8.$ increased
by the daily I:Ihift and tho effect was extended E'veu farther into the
rootR hy 1he souRonnl shiit.
TAnLE D.
lUFFEC'T OJ!' TJIlMl'BBATUBE ON COLOn ANI! CUICMIC'A.L C(rMPOB1'l'ION OD'
-
CARnOO'S, Ul33-34
80" to 70· F.
(Cbeok)
------ - --
I
80" to '1QO P.
40° to aD· F.
(De.1Iy IIhlft)
Fraah-welih ~ blllili.
Carotene (mi1lillrams per 10 Illl1ma of root) ...
OlU0Cl88 (per oent). • .....................
Burrose (par cent) ........................
Dry ma.t.ter (per oent) .....................
-
<"'arotene (m.lUlgrallUl per 10 I1'Doma of root) ••
GIUII098 &ar cont) .. • .. ... • ....... .. ..
Suorose per cent) ........................
1.156
2.04
1.82
1M3
3.3
8 II
12 140
11.78
Dry-welllht. bllllia
111.7
18.8
29.0
I
11.B
20.2
28.1
I
600 to 70· F.
40· to 00· li'.
(Selllonai llhift)
I
I
085
233
4.11
18.110
63
19.8
8& 3
Glucose was lowest in the check plants and highest in the dai1y~shift
plants, while sucrose was lowest in the daily..shift plants. and highest in
the seasonal·shift plants. The per.centage of dry matter was only
slightly decreased by the dailyRshift treatment, while the seasonal
shift produced an increase in dry matter, as compared with the"check
plants,
Temperature, Boil moiBture, and length of ilay
In the fall of 1981, an experiment was set up to determine the e1fect
of Boil moisture, temperature, and lengllh of
dFW, on.
growth and color
16
W. C.
BARNES
of carrots. The plan of the experiment was similar to that used in
the first experiment of this series, except that the plants were grown
in rai~ed greenhouse benches containing about 10 inches of soil. The
experiment was conducted under three ranges of temperature-500 to
600 F., 60 0 to 70°, and 70° to 80°. 'fwo benches in each of the three
greenhouses were divided into three plots, with a. 6-inch space between
the plots. The plants in one bench in each house were grown under
the normal length or day, while those in the other benah were grown
under additional light until 10 p.m. each night. The average length of
day for the two lots was approximately 10~ hours and 14 houl'll,
respectively. Each plot was planted to five rows of carrots, spaced 7
inches apart and the plants thinned to eighteen to the row. At harvest
time the plants of the two outside rows, and the three end plants in the
center rows, were discarded. It was planned to maintain one plot in
each hench at low soil moisture, one at medium, and one at high, bllt,
owing to difficulties in rlet('rmining the aciual amount of water to be
applied, no definite percentage or soil moisture could be maintainec.l..
Difficulty with red spillers was encountered in the 70 0·to·800 hOllse, mid
many of the plants were injured in attempts to control these spiderK.
F()r this reason the data for this temperature range are not considered
very reliable and therefore they are omitted here. The method nsed
in making the carotene determination in connection with this experi.
ment was later found to bEl unreliable for determining actual quantities,
although the results obtained by it do SllOW relative quantities.
A -comparison of the data given in tablo 6 and ill table 2 shows that
the di:fferences in growth due to soil moisture and to temperature are
not so gl'cat in this experiment as in the first experiment. It is believed
that the difference in results between the two experiments is due to the
fact that the plants were more crowded in this experiment than in
the first. There is a possibility also that the actual differences in soil
moisture between the different moisture treatments in this experiment
were not so great as in the first experiment. All treatmonts involving
these two factors show the Rame type of response in both experiments,
and therefore they are not discussed here. At the medium temperature
(60 0 to 70°), the effect of additional light on root growth was insignificant. At 50° to 60° the additional light produced a statistically
significant difference in root weight at the low soil·moisture content. At
the medium soil·inoisture <lontent the difference was on the border line
of significance, while at the high soil.moisture content the difference
was not significant. As is shown in table 6, additional light produced
a greater length of t()P in every case, but the increase in weight was
not ill proportion to the increase in length.
l' , The data. givon in table 6 suggest that the greatest responso in growth
of roots from additional light was obtained under the least favorable
conditions for growth, namely, at a temperature of 50° to 60° and at
low moisture.
\ The data on 'bhe effect of S()il moisture and temperature on color and
chemical composition of earrots agree with those from the first experi·
ment and therefore are not presented here. .Although the method used
was not reliable for determining actual quantities of carotene, the
GROWTH AND COLOB OF CABBOTS
i
e
S
.8...,.., ~
:.!
",,,,oo~~I);1~
~ti~~"';!8"';
~"!~~~"!~
:;I!~Ct.I,...,~fO't
.§IGOQo>~!i;oo~
p.j
;;s·oic:im~
~
11~0!"'~~"!~
...... '"
.E
~
j
~
t"IQ~~.-t"""1""'I
i
"I"'tDO~;iP"li:
~ ~
j
~.Q~~"';c;l"';
...
l1li
"'Q"'~S;",~
giaO";c.io~c.i
it ~~O::~~":~
~:!~CQ"",:;!
9
~
.8 1
........ ~
....
Q"'<CIEl~~~
~~";cio~c.i
!1~~~~ilI!~~
p.j
8l"'<CI0<C:>~'"
~
..
11C!~C'!~~~~
tIl ~~""'CII"'~'"
Q
~
j
S
~
!' :a
", ... "",t;~",s
~aO";c.i0C7i"
~~oi
.,..co ...
! .o.o";c.ici";'-;
...
...
,
:
"1
.....
:: "' .
....
·
)
. ·
·t
;
I
••••
•
t
....
.. ..
..'. ...
. ..
...
: : :: :
"'
, .....
:.,:. ,
'i
~Uij ~
liNi):
i
H~
:.
-1JI1
Hl· .~.~~
! .1 .UUUl
ii 111!i!! I
I
i'-
17
18
W. C.
BARNES
relative values obtained indicate that additional light had no effect 011
color. With the exception of an increase in sncrose at 50 0 to 60 n and
low soil moisture, there was very little change in chemical composition
produced by additional light. ,
Length of day
Garner and Allard (1920) roportefl a marImd re!lponsc in gl'owth
and color of carrots to different lengths of day. After the improved
method of carotene determination was work<>d out, it wa~ drcided to
repeat this phase of the study and to uf'le a greater variation in longth
of day than had been used in the preceding experimeut. In the fall of
1933, 30 pots were prepared alld planted as in the first experiment of
the series except that ouly five plants were left in eltch pot. The soil
in all of these pots was maiutaiu('d at optimum soil momturc and the
plants were grown at 60 0 to 700 F. Of the 30 pots, 10 rec(livetl only
9 hours of light, 10 received normal daylight (averllg'tl about 10%
hours), and 10 received additional light until 10 p.m. (avol'!1gl~ about
14 hours). The data from this experiment are given ill tablc 7.
TABLE 7. EFF1!:C'l'
O]!'
L'ENGTU
OF PU<YrOPERlOD ON GROW'l:lt OF CAlU«lTS, 19a3-:~4
101·hour lIn~'
9-hour day
l4-hnur dny
-li7.1" .- 42.l-
A'\I"eI'8IIG top ]enl!th (c()IItimetere) .••••.••.••... " .. ~~ ----;;;:-7
Average top weight (grams)............................
27.2
AveraKerootl~llI!th(ilentitnetct8).......................
1.2
AV8l'BllG root diamoter (centimeters). .. • .. .. ... .. .... . . .
4.4
AverBKe core dinmeter (centllnetera). ...................
2.0G
Avereae root weight waDloll) • • • • • • • • • • • • • • • • • • • • • • • • • • •
011.20
Root--top~til).. .....................................
2.M
115.8
7.3
4.0
lI.lli
78.35
3.03
2n.4
6.9
4.4
1.90
011.011
2.'I'l
As is shown in table 7 and ill figure 8, there was practically no
di1Ierellee in size 0)' shape of roots llnder the three treatmentH. The
normal day did produce a slightly larger root than did the othElr two.
treatment.~ but the difference is not statistically significant. As in the
preceding experiment, under the long day the tops Here sligh.tly longer
than under the other treatments, bnt they were more Rlender as is
indicated by comparison of the fresh weight and the length of tops. This
suggests that varying thp. length of light durat.ion unde!' optimum condi.
TABLE 8. Eli'i'ECT Oli' Ll\:lSGTl[ OF PnOTOl'ERIOD O~ COLOB AND CltEKIOA.:L
COlll'OSITION OF CAB'ROTS, 1933-34
lI·hour day
J~~ day !l4.obOUr day
Freah-welght basis
Carotene (p:Ill~ per 10 lP'aJrIB of root) ...............
Gluooae (pel' cent?- ..... " ..... " .....................
Sucrose (Pel' C!IIIt .......................... ~ .........
Dey JIIIItter (per cent) ................................
S.12
2.20
3.20
11.66
!
2.13
2.12
3.GO
12.22
3.17
11.92
2.20
:1.36
Dey·weiaht baala
Carotene (1I\llllsr1lllllJ per 10 BrlDlll of root) •••••••••••••••
GIUOOII8f:,er centl' . .. .. • .. .. .. .. ... • ................
BllarOIIe er aent ................. • ............... "I
-
18.1
18.9
27.1
17.8
18.0
2lU
17.8
19.3
26.6
19
D'l:GUl\BI
8.
:mJ'l!'lIlCT OJ' Ll!lNGTlI Oll' PUO'rOPIIIRlon O}q' GROWTH
oct
01' OAKHaM J.!f
'1'0 70° 11'. AND A.T 0l'TJ:1II:tTK SOIL
:MOIS'l'l1RBl
Plant .t left riven g.hoUl' day: plant at llcht elVIIII 14·houp day
tiona of temperature and moisture has practically no effect on the
growth of carrots. The effect of length of day on carotene content and
on sugars is shown in table 8.
t The data in table 8 substantia.te the results obtained in the preceding
experiment, and show that there is no- signiftcant effect of length of day,
within the limits USI.'d, on eolor and chemical composition of carrots. \
EFFl!lC'!' OF PLAN'!' NUTItlEN'!'S ON G~Owrn AND COIA1S OF CARROTS
The :Brst exp~riments in this study, on the effect of env}J:QPP"'"
:fa.ctors on growth. and color cf carruts, showed an asaocu. t '
and resp()nlle8 in growth. In commercial production the eh
increasing growth· in humid regions is the use of pIa
E;tperiments were initiated·tc determine tae ejfeet of the vr
W. C.
20
BARNES
ft'rtiIizing ('lements, and somc of thp rare elements, on the growth and
color of carrots. Only one fertilizing element was studied in a. given
experiment, anu where two experiments WE're carrieu out with the
same element the plan of the eJt.periments varied. It seems desirable,
therefore, to discuss these expel'imC'nts separatE'iy.
Nit"ogon
Plants usually respond more to nitrogen than to any 0:1: the other
common nutrients. In the fall of 1933, some sandy 10al11 soil low in
nutrients was thoroughly mixed with commercia} superphosphate and
potaah at the rate of 1 ton of 0-10-5 to the acre. With thi."l soil
~O of the 2-gallon pots used in thcse studies w(,1'e filled, aud t}lelle were
placed in a greenhouse maintained at 60 0 to 70 0 F. Soil moistllre was
maintained liS neal' optimum tiS possible. A fter germination 1ho plants
were thinned to five to a pot. Two weeks after g(,l'lninatioll, the pota
were divined into 1hrpe lot~ of 10 potR each. ThA pots W('1'e systemati·
cally arranged anrl rotated on thE:' gref'lIhouse bpnch so as to overcome any
difforcucPR in light E'XpORlll'e. The first lot of 10 1lotR was given no additional nitrate, the liecond lot waK l!,iVE:'ll sodium nitrate in solution at
the rute of 1.1 grams per pot, and 1he third lot waR given twice this
amount of sodium nitrn.tt>. The applications of nitrogE:'ll wt're repeated
at two-"epks intervals until har\rest time. Tho soil had a pH rE'ading of
5.55 at the beginning 01: the exp<.>l'imellt. At the end of the experiment
this had increased by almost 1 I)II unit in the high.nitro-g('11 sl'ri('s, and
by almOilt OJ; unit in the low-nitrogen series. The increase in pH 0:[ the
low-nitrogE'n series was probably due to the minerals carried ill the tap
water used in lllailltainillg the soil moisture. The increase in pH of the
high.nitrogE:'ll series OVE'r that of the low-nitrogen serif'S was: prohably due
to the sodiunl nitrate added during the experiment. The plants were
harvested on .April 6, 1934. The data are giv('n ill table 9.
TABLE 9. EFFEO'.r
OF NITROGEN ON GnOWTH ()F
Avere.ge top : t h (oentimelers) ......................
A'Y8l'IIII:1I top
ght CRrams) .......... , •.•.••••• """
Average root length (~lttilltElteral. •••. .• • ••••.•••••••
A.varll&8 root dia:meter ~centimeter.) .••••••••••••••••••.
iverage oora dlamet~r centimeters} ....................
"1lrIIlI:8 root weight (grlllD8). ". • ....................
Root-top ratio •.•• , ............. " • • • . .. . • • .. .• • .•• ,
-
OABnOT8, 1933-34
LowN
Medium N
lIigh N
26.11
37.0
39.0
7 46
liS
83
1.4
81 04
4.16
20.64.
6.0
4.0
1.0
60.50
2.46
27./)
6.6
4.1
2.0
l54.1}6
200
..
The Jow-nitrogen plants began to show nitrogen deficiency about the
first of March. Total growth of both tops and roots was increased by
the addition 01 nitrogen. The increase in root weight from the addition
of nitrogen was not statiaticaUy significant in the case of the high over
•.thfl_medium nitrogen, but it was statistically significant in the case of
.... '''i!iu~ and the high over the low nitrogen. Nitrogen had no effect
...t)f growth other than the usual di:fference in color of foliage
g application of nitrogen to a soil deficient in that element.
make carrots vigo: ously vegetative by addition of nitrogen
Ring in compost.1(l soil, similar to the soil used in the first
;»roved unsuccesslul.
21
GROWTH AND COLOR OF CARROTS
. Color ~I the root, a.s measured by. carotene content, was only slightly
hIgher wIth the low mtrogen than wlth the other treatments, as is shown
in table 10. It is doubtful that the diiIer<>nce is of 8ny significance.
')'ABLE 10. ]~FlI'J<lCT OF NITROGEN ON COLOR AND
1033-34
CnEMIOAL COMPOSITION 011' CABlIOTS,
LowN
I
MedlllmN
I
Hi«hN
Ji'rMh-weight basis
Carotene (mIlll,qrams pl'r 1IJ Ilrlllnb of root) ••.••••..••..•.
Glurl)&e (prr rt'nt) ....................................
Huoro\o (per cent) .......•.. , ...•.•.•.•••.•••...•••..
Dry mailer (per rent) ................................
1.981
2,22
3.19
11.66
I
1.688
2.39
2.97
10.57
I
1.690
254
2.U9
10 1i0
Dry-we.ight basie
<Jarott'ul' (mmigram~ prr 10 grllmH or fnut) ............. ,
(lilloose (pet rPJlt) . . • . • • .• . ............. , ............
SucroliC (per rPIII) .. , ...•.•...•...••.•.•••••••..•••• ,
15.8
22.6
2B.1
16.6
10.1
32.8
I
16 I
242
25.6
'rhis SUggt'Hts that, in ot'llinary soil, nitrogen has little or no e:tl:ect on
color of carrotH. 'l'he ]l('l'{'ontage of glucose increased with the addition
of nitrogen, while that of sucrose decreased at about the same rate, so
that the totnllil1gars remained practically unchanged. These results are
in agreement with thm'lc of a preliminary experiment conducted in the
preceding year. \
Phosphorus
Many New York soils are deficient in phosphorus, and therefore it
seemed desirable to determine the effect of this element on the growth
and color of eR1Tots. Some of the same soil as was used in the preceding
experiment was prepared ill the same manner as in that experiment,
except that Ol1e. lot of 10 pots received no phosphorus, one lot received
phosphorus at the rate of 1.1 grams per pot, and oue lot received twice
.this amount of phosphorus. Nitrogen was added as in the mediumrnitrogen series ill the preceding experiment.
The results of this experiment are shown in table 11. Phosphorus
deficiency was evident in the low-phosphorus series earlier than was
nitrogen deficiency in the low-niLrogen sel'ies. .After a period of slow
growth, the tops of the plants in the low-phosphorus series began to grow
again toward the end of the season.
TADLE 11.
E:rrFEOT OF PnOSPIIORUB ON GBOW'l'H Oll' OABROTB,
3~y·"""/
p,
114.2
17.2
6.1
3.4
1.6
31.8
2.19
Average top lenstb (oentimeterlt) ..... , ............... ..
Average top Walght Caramel .......................... ..
Average root len#th (OentlDtetl!rs) ••••••.•••••••••••••••.
Averaae root diameter (centlmeterll) •• , ............... ..
Average oore diameter (oant metal'll) •.••••••••••••••••.
Average root weisht (S.ra.Du!) .......................... .
Jtoo~top ratio ....... , ............................. ..
========================~
The da.ta. in table 11 show an increase in grov
of phosphorus, but the increase frOIn medium
statiatieally BigDiftea;nt. 'rh& type of gr0"Wt\l·
f
1933-34
19.$
11.9
4.1
f
rkl
W. C.
22
BARNES
not markedly ditIerent with the three treatments, except that the roots
of the low-phosphorus plants were slightly more pointed.
Varying the amount of phosphorus did not have any appreciable effect
on the carot<>nn or the glucose content, as is Rhown in table 12, bllt
sncrose appeared to be slightly inCl'eas('d by the addition of phoRllhorlls.
TARLE 12.
F.FFF.CT OF l'nOSl'nORUR ON COLOR AND (Jm~Mrc"\T. COM)'IlI'll'rION OF
CAUlIOTS, lO:l3-!Io1
==-=-==:--=-=- -
- - - - --- - _
1',
I
Carotene Cmilllp;rruus per lUllrnlllS ofluot) ...... .......
2.14
2.03
2.:iS
Glucose (llProcnt).. .............. ... ........... ...
2.48
247
2.6U
fhu:roso (llerrent)....... ............. ................
2.111
320
3.39
Dry matter (por cent~_
•. _•._._. _.•_.•_._._._
.._.:__
.. _.·1 __1_0_.9_O_..!.-_I_I_:_18_...l-_I_I_.2_7_
nry-wfi"ht l).1hi~
1()'6
227
23.0
('arotene (milli~rmns JJP1' 10 I!rllme nf rnot) .••••••••••••••
Blu('ose (per ('ent) .•••••. , •..•••...••••.•.••..••...•.
Rllcrll'lo (ller rpnt) .................................. ..
I
17.8
21.7
211 1
21.1
2:1.0
aO.l
======~-==-=--~==-_=~============~~~===========
In the spring of 1934, one row of can'ots 48% l'eeL long wali planted
on each· of four plots at the Long Island vegetable l'esearl·h .farm on
which phosphorns hall been applieu rE'Rpectively af! £0110"'1'1: Po, PI, Pe,
and Pa. The plots WE're l'eplielltC'd threE' times. Tho PI plot hl1(l )'(llloivcd
57 pounds of P,O.to the acr(' for t('n yeal'S priol' 10 1933, and GO pounds
to the acre siuce that date. 'eba Pn and Pn platH lmtl receivcrl, respectively, two and tlll'ec limes those nmounts. All or tIle plots had received
90 pounds of nitrogen to the acre and 90 'Pounds o£ K.O to the acre prior
to 1933, and 120 pounds of each of these material:, Rince tbat date. The
carrotR were harvE'KtE'd ill the uunching stage. The rf.lHllltl:l nre presented
in table 13.
TABLE 13.
EFFl!'l(,T OF PUOSl'nmtUR ON GnnWTlt ANII COLon OF C,Mtl\()TR, 1934 \
!'I,
Po
PI
1\
1'1
Average top wel(rl!t (I!l'IlI1lS) ••••••••••••••
AV8l'&lP;e toot Weight (grams) ••.••••••••••.
~top ratio .. , .......................
31.3
lili.!
1.76
10.3
28'2
119.
2.07
10.4
34.8
83.6
Dry matter (per cent) ...................
30.S
00.8
1.67
10.2
Carotene (D:dlllgxoalllS per 10 grams of ropt).
GluCOII8
oent? ......................
Ruereee per cent ......................
10.8
164
27.2
1.83
10.3
Dry-w0i3ht buls
.
I=
~s shown' in table
I
10.8
17.3
2li.S
I
12.0
15.4
30.0
-
I
11.6
16.5
31).3
=--
13, there was a. sligb t inBrease in growth from
"\tion of phosphorus. The llgures on carotene, glucose, sucrose,
"l.,atter are averages of the three replications. The data indicate
' 4i1 ..V''' or no ditrer(lnce in color or in chemical composition of
'>t the different treatments. There was as much varia{thin a treatment as there was between treatments,
. bosphorus is a minor factor as far as color and
~arl'ots are concerned.
23
GROWTH .AND C01.OR OF CARROTS
Oopper suZfate
In the spring of 1933, 60 glazed pots were filled with composted soil
such as was used in the first experiment. The pots were divided into
six lots of ]0 pots each, and were given, respectively, the following
applications of copper sulCate to the acre: 0, 100, 200, 300, 400, and 600
pound",. The seed was plantec1 on April 20 and the plants were later
thinned to five to a pot. Harvesting toolc place on August 19, 1933.
'1'!te pots were systematically distributed on the greenhouse benches! and
were rotateu at int~rvals. Temperatures in the greenhouse were usually
high <luring the clay, and the soil-moisture content was extremely difficult
to control.
AS is shown in table 14, the addition or copper sulfate gave a slight
but insignificau1; increasl' in weight of root, and also an increase in the
root-top ratio. The HmaU increase in color dne to the addition of copper
sulfate was 110t sufficil'nt to warrant the extl'a expense of the treatment.
'r.ABI.E 14.
Ell'lI'E(~T Oli' COPPER. Sur.FATE ON GBOWTII AND
-
--Averago top \Vl·jKht (Krll.ms)
Averllge root wright
(grllms) ...............
Root-top ratio .•••••••.•.
Oarotene (mWlgrlUllA Pl'r
10 I!l'I\UIlI of root) .......
Oluoosa (per cent) ........
Sucrose (per oent) ••••••..
Dry mBtttor (per oent) •••.
CHF....'II'tOAL
COMPosmON
OJ!' CAlUlO'l'S, 1033
C11~ck
I I
100 Ills.
CuSO.
200 lb••
OuI:lO.
36.48
30.aG
29.28
82.17
72.54
2.39
78.12
2.67
30.80
72.()4
2.38
34.41
62.80
1.72
72.54
2.10
711.44
2.311
2.50
2.10
3.92
14,.03
2.12
2.20
2.17
2.40
4.18
14.18
2.83
2.20
4.48
14.740
2.85
2.82
3.76
14.66
2.68
11.32
3.74
14.76
19.4
17.84
25.6
18.0
14.58
25.0
(NoOuaQ.)
,1.48
14,.96
I
300Ib~.
CuSOc
Frcsh·\yeight ba~ls
I
400 lba.
CuSO.
I
600 lb,.
OuElO.
Dey-weoll!;ht bubo
Oat'otene (mJUigrams por
10 Ill'Bms of root) ......
01l1I'0II8 (Iler oent) .•••••.
SUcrOBO (per C811t) ........
17.8
15.09
28.0
I I I
18.2
14..74
31.40
IUS
16.90
29.4
19.2
16.96
30.4
In the summer of 1933, plots were laid out in a. commercial planting ol
ca.rrots on muck soil. The plots were 1/16 aere in size, and were sys.
tema.tic!l.Uy arranged in a rectangular form, two plots wide and :five
plots long. The carrots were harvested at the time when the 60mmereial
planting was harveRtcd. No data were obtained oIl yield, and the color
determinations showed, as in the greenhouse experiment, no significfWt
influence of copper sulfate.
Other
tninera~
Preliminary experiments on the effect of manganese filUlfatewma .
nesium sulfate, and potash yielded no results as togro:
color of carrots, and, since previous experiments with 0 er mi
had resulted similarly, no iurther investigations were en ducta}'
this line.
.
6ith$
W. C.
24
BARNES
EFFEOT OF AGE OF PLANT ON TYPE OF GROWTII AND ON COLOR
Ol~
CARltOTS
,In order 10 determine the effect of the age of the plant 011 the Lype of
growth and the ('olor ().l carrots, an expt'riment WitS ('onduetcu. ill 1933.
On May 26, carrot seed was planted in the garden on a mmdy loam Hoil
which had bt'en manured Rnd fertilized with a 5-10-5 iel'1ilizel' at the
rate of 1200 pounds to the acre. During periods of' drought, watel' was
supplied through an overhead irrigation Syst('lU. ffhc 1'11\111.'1 were
thinned in accordance with commercial pro.ctico.
Beginning on July 1, samples were taken at iut('rvals of two wo(·ks
J until the end of the growing season. In ordol' to (lOluplete the flllalysiN
l in one day, it was necessal'y to harvest the ('a1'1'ots at abonl ti (I'dock ill
the morning. On the night bt'fore one of the RfllllpHllA' datI's (All gliNt
24), the1'l:' had been a storm, and it was found hllpohllibl(' to Act the plmltR
dry; therdol'c the percentage of dry mattf'r on thn1. dutt' WUK uot in
agreement with the general trend. The growth duta outuitll'cI f)'Olll thiN
experiment are given ill table J5.
'I
"'ABLE Id.
EFFE('r 01' AC,E OF PLANT ON Hm.\.'I'IYB GHIlW'I'Jl 01" (J<\IUUI'IH,
-
-- =--=--=-......-::::::.Aile "ll>ll\nl (III dnvh)
_--
3U
AVelaRe top length «'81111metel'll)
.
. • • • '1118
Average top \\~il!ht (IIr'II1I<) 1157
.\\ pralle root IImflth (centlmeters)
AverRg,p
root
Q1UIlloior
(..entlmeter,'. • •• . • •
Avelill!8
core
di.!IllPtpr
(oentlmetl'l'II) . "
Average root well-ht (II:rllms) (1078
o 14
lI.oot-top I atlo. ........
..
72
118
-4i- -- ----
68
IS 40
467
...
4678
336
IiO 04
677
7 68
887
o ;>3
:I 06
366
.il' 69
o 15
1 18
14 11
0411
11XI
1113:1
-.:-_--=
---- --- ---
114
128
142
lin 66 70 CIS 612()
1437 11'16 17J II
603 M
fl7 lI8
1CJ 6.1
11 3!1
III ':;1
1.? HI
14 00
471
:; 67
o 61
7.011
8.117
112 U 1111 :;
2 1:;
28'1
:I 116
422
II 2(1
62S
572 121 6 1117 II 2'186 :l/j3 4 ;;02.1
U84
84.
100
2
ilK
1
238
3.44
....
--=--=-=-~
-
--
There was a constant increase in the size of the plant throughout the
season, but the increase in root weight was a1. n. greatt'l' rute tha11 the
increase in top weight, as is indicated by the incrf'asing l'oot-top ratio
shown in table 15. The shape of the root olll.tug(·tj as the plants gl'OW
older, as is shown in figure 9. The young rootR nrl! much more slt'niler
than the older ones.
The percentage 0:[ dry matter rcmaintl(l I.lractil'nlly cOll~1al1.t ihroughout the seaSOll, as is shown in table 16 anll in figure 10. The color, as
measured by carotene content, in(!reast'd al:l thl' l:IeaSOll pI'ogressed. 1'}1e
rrate of increase was much greater ill the early Rtages of growth than in
the latel'stages. It is during the t'arly stagt'fI, however, that most of the
commercial bunching carrots arc harvested. The roots reached t1le
"bunching" stage about the first of August alld the "u'l8hel" stage in
~e latter part of A UgURt, and both these dates wel'e hefore the highest
~otene content was obtained. Total carbohydrates remaint'd about the
." throug~out the season, although the form of sugur changed, as is
'(led by! the decreac.e in glucose and the increase in sucrose as the
~Bed.
25
GaowTn AND COLOR OF CARROTS
,,,, "C.-..--:::-:...~~~"';. : ; , . - .........
/'
"._:: .... -:,. ...4 __ ... "
"
II
\
I
"
"
,
I:"
,'
I
"
I
\
,
I
I
I
\
\
I
II
\ \ I,
II I I
\ \,'
.,'
'.Jt/
'
:
\,
"
\
\
J
\
I
I
I
I
,
"
\
I
I
I
I
I
,
,
I
I
I
\
'
,
,
I
I
,
,
I I
,
\
:
I
\
'-
\
',',
,~
I
,',.;.1
"
I
I
~
I
\
I
,\
I'
"\ \ ,')
J'
"
".......\,',.
o::{lI"
.... ,', "
.... '"""'~ ....
SBDAYS
TADl..ltl 10.
,
I
\
\,
\
\
I
,
I
I
\
I
I
,
I
\
I
,
I
'
\
I
I
FIGURE
, ;-:,..:--.'..... , "
I
I
,
I
I
\
I
"
.. "f::-... -:;...T,"II',_,.· ......
l
I
I
\
,
I
I
I'
I
\
\
,
"
"
"
:
I
\
\
'~O~'\
I I
,
" I
I
I
'
\
\
\
I I
.
"
,
I I
\
'
8SDAYS
9.
EFFECT OF AGE ON BBAl'E OF nOOT, 1933
J~FI!'E(.lT Ol!' .AOI:: O~' PLANT ON COlAlIl. AND CBtM:ICAL COM:POBITION OF
CA1IIl(llfB. 1033
Age of plllllt (in days)
6S
C"rotene (mfUfp;roma 1111r 10
p;rams ohoot)
.... .. .
Glucose (Per ofnt I ........ .
truorOl:l8 (per 08111) •••••••••
Dry m"tter (per (·ent) .....•
Carotene (millhru.m, per 10
IIfIloXllll of foot) .. • ......
(per aeut) .. , •••••
I:IUDrose (per 08111) .•••••••••
U1UCOllD
I.
72
86
J
841 2.12
1.1Ii I1.
1.18
1.;; 1
2.08
U
1.98
1.36
10.18
8.24
lU
13.3
10.20
100
,9.50
2.95
1.22
2.48
10.42
17.2
18.4
!1l.8
28.3
11.1
23.S
114
1
8.06
1.06
2.81
10.49
128
1
116
3.
098
303
11 19
142
08
1 30.98
•
3.03
10.81
~------~~----~---------------Dry-weipt billie
111.2
1'7.4
20.1
1
29.2
10.1
117.3
129.1
8.1
27.1
I
28.S
9.0
28.0
The roots eontinued to increase in size until the end 01 the season, but
the uhuuges in carbohydra.tes and in color were small alter the middle
o.f September and some of the ;roots began to show "hollow heart" after
that date. This "hollow heart" began in the eenter of the root and
gradually inereased in size as the season progressed. Other parts of the
roots did not show signrt of pitfliness or of breakdown at any Lime. .AI!.
a rule, the tissue surrounding the "hollow heart" was not disCiolored to
any appreciable extent.
26
W. C.
BARNES
-_
72
86
100
114
Age uf plant, in daYB
FmURE
10.
EFFEC1' OF AGEl OF PLANT ON (JOLOn. AND CHEMICAL COMPOSITION OF CAnnOl'S, 1933
The figures at the left roprp,ent: fnr 11Ilrotene. millillrawH pcr 10 Kl'ILlIl~ of root;
for mlucll8e, IIllcrose, anti dry InlLtter, Jler Dont. All on the dry-weillht bllbll>
This experiment was repeated in 1934, and the l'eHultR were c~olltbllly
the same as in 1933 as call be seen by cOmpnl'hlg the data. in tables 16
and 17.
TABLE 17.
EJi'FEC'l' 0);' AGE OF l'LAN'r ON SIZE, COLOR, AND CIllUUCAL COMI'OI-lI'rION OF CAll'ROTS, UJ::l4
AllP of plnnt (ill 111\3'.)
70
-----------------------~--AVBI'IIIe root weight (grams) ..•.•......•.
Carotene (milllgralllll per 10 gI'll.lIIII of root)
Glll.COIIQ (per oent) ..................... .
SIlCU'OIIe (per cant) ..................... .
Dey ma.ttlll' (per C1lllt) ............ " ... .
&
U8
(mWi~ma
per 10 era11l!l of root)
(lfuaoae (per cent) ..................... .
Suo.roIe (per Qent) ..................... .
36.4
0.91
1.811
70.9
1.4(
120.11
!,71
1.62
3.37
1
1.3&
3.10
10. liB
433 8
.
1204.6
l.u4 1 2.26
Dry.weight baws
-------8.9
10.1
n.7
111.0
21).9
146
Fresh-weight basis
2.66
10.28
1],93
-------·I-----~----
Carotene
112
-------.----------------------
13.6
28.2
J
I
111.11
211.3
1.23
lUIS
D.77
19.K
1:.1.6
34..3
l.lll
a.Hl
:O~
--1-~7
lU.6
29.9
A second planting was made in 1933 on July 14, nnd harvested in the
:tirst pa.rt of October. It was observed that hl both the early and the late
pla.ntings there was considerable variation ill size of the root, and particularly in some places where the plants were crowded in the rows.
Samples of large, medium, and small roots from the early plunting, and
of la:rj!re a.nd small roots from the later planting, were selected for
analYSls. The data are given in table 18.
The data in table 18 and in figure 11 show that there was a variation
'~ color and composition with age and also with size. The larger roots
27
GROWTH AND COLOR OF CARROTS
'rABLE 19. EFFJ~OT
__
OF SIZE AND AGE OF Roo'l' ON COLOR.AliD CHEMIOAL
COMPOSITION OF CARnOTS, ]933
I
Old roote
.
Large
-
Ruol weight (grams) ........... , ....
Gllrotrne (llIi1lilmun~ Jlrr 10 1':1'11111... of
ruot) .............................
Gll1oo.~e (per oont) ...........•......
SucrOlio ())rr oent) .. ..•....• • ......
Dry IDtltlcr (ller CI'lIt) ................
353.4
3.3
(1.98
3.U4
11.19
Y01lIl8 roots
arge
I Medium I Sm,all
Fresh-weight bams
163.3
3.3
1.20
2.72
10.95
I
Small
S•. 2 •
73.4
18.7
2.7
1.60
2.70
11.01
1.9
1.7
1.96
2.22
11.64
1.94
2.82
10.69
Dry-weilht basis
ClIl'utl'ne (nJiIJiIP'I\lns ,'er 10 sr~111!1 uf
rnnt) ........................ ·· •..
Gluaoae (per crllt) ..................
,
Suoroso (lJer rl'nLI
-
-
-
..............
- -
-
29 II
8.7
27.1
I I I I
80.1
10.9
24.9
24.2
14.5
24.5
18.1
18.7
21.7
14.7
17.0
19.2
in each eaSH were or a better color than the sma.ller ones, and the older
roots were l)ottel' ill thiFl l'CI,;pect than the younger ones, even though the
RmalleHt uld rootl:l were
smaller thau the largest
young roots. This sug- 80
gests that l)otll age and xize
Ilrf'
of
illlportance
in
determining eulor, but that
age .is the more important.
1~,--t:;:s:~I«~fj;r'/).~~.:::U.:...;'H~-.Iik:-t--I
The small c]iil'Cl'CllCCS ill 24 f\
" "
1\
percentage oi U1'Y matter"
SHALL
1\
aro prohahly of 110 signi!~
1\
jounce so ral' all quulity is
1\ ~
(lollcernl'd. III the case of 18 1\
","
1\
tllO older e8.1·l'ots, th~rc WIl!!
1\
1\
I' 1\
a deCl'eRSf' ill glucose and
1\
1'\
r\ i\
1\ 1\
an increaFle in !.Iucr()se with
1\
1\
r:.. r...
1\ 1'\
size; Lhe younger !lUI'roi 11 12 . ..j,.:f\:lH....:I--l---tmll'l:+-+......Hrr-1k'I1\
showeu })l'a(·tically 110 tlif~ \
~ ~
,~
ferellee in 'theHe sugars on
~ ~
1\ I"
~"
the rrt'sh-weight llasis, and
['..:-,,~
very little on thc dry6 LD
'(JL'1{6
OLD lYOUN6
!f,!nDlYOVAl
weight haxill.
CAII!UITEN.I! RLUClJSE
...Af"nl
The results of a simBal'
"V'"
cxperiment, conducted in FIGURE 11. EFFECT OF SIZE AMD AGE OF ROOT ON
COLOR AND CHJDMICAL COMPOSlTlON OF c..uutOTS,
1934, were essentially the
1933
same as thosA of this
:figures at the left represent.: for 08rotene. mi11l1lf8lIl~
experiment, and therefol'o perThe
10 grams of root: for Iluooae IlIld sucrose. per oeJlt. All
they arc not presented berc. on tho dry-weight bll8is
I
I'"
Oomparison of composition oj oors a,ond of oortS:Ji
.A comparison of the composition of the core and of the cortex in young
and in old ca1'l.'ots was made in 1933. Both lots of roots were sligh~~:v
older than those used in the preceding experiD1Q,~t. It is seen in ta,..
28
TAllLE 10.
W. C.
BARNES
F.FFECT OF AGE O]!' ROOT ON COLOR ANn CIIEMICAL COMPOSITION OF
CORE AND OF CORTEX,
1033
Young roots
Old roots
Whole
root
- I- - - I
Carotene (m.illl,zyams liar
10 grams of root) ••.•.
Gluoose (Per cent) . •• • •.•
Sucrose (per oent) .. . ...
Dry matter (per rent) •.
Carotene (mlJliqrams por
10 granlS of r.lot). .. ..
OllloD'3e (per cpnt). • • . .
SUDrose (Iler Dont) •••••.•
2.89
0.94
3.20
11.10
26.0
8.5
28.8
Cortex
I
I
3.44
104
3.48
11 81
20.1
8.8
29.5
I
I
Wholo
root
Core
I
Cortex
I
3.28
11.81
I
Core
I
1.37
1.08
2.50
10.05
'Fle<.h-weight bllsis
242
n 70
256
007
I
2.19
1 64
2.00
11.28
Dry-wl.'illht btl~lS
24.2
7.0
256
I
104
14 5
2;; 7
-- I
2.40
1.118
20 If
167
27.7
-
I
13.6
10.7
24.9
19 and in figure 12, A, that cal'otl'ne increased with age anu that the
difference in color bptwe!'ll COl'{' anu cortex deCl'<'I1Secl with age. rrhe
differences in sugar coutent bl'twel'n the two ngffi of roots were not so
markeu as in the precl'ding
experiment.
_
WHOLE R()OT
'l1his wus owing 10 the
36~==~~~------~r-----------~~--i
I.I:::D:DI "CJl'fl 1:. A
greater "age of both
r::=:=J CORE
luts ill this experiment as comparE'u
with 1110se ill the pre.
C,leuing olle. The r e
was, however, more
Sl1<'rOSe in the older
carrots than itl the
young!'r ones. The
I! 0 l' t l' X
apparently
maintained a higher
sucrose cnntent than
did the core, and also
A·"3~
S- /934
a. higher percentage
FIOURE 12. EFFECT OF AGE 011' ROOT ON (,OLOR AND CHEMII'AL of dry matter,
COMPOSITION OF CORE AND OF CORTEX IN CA1\ROT8 (0, OJ.D
Another t'xperiment
1\OOTSj Y, YOUNG ROOTS)
was conducted in
The fiallrea at the lett represent: for oa.rotene, milligrams Jler 10 grllms 1934 in which SaInof root; for BlulJ0811 find suorOllle, per cent, All on the dry-wOlght bllllia
l'
t k f
P es were a en rom
a May 26 plllnting on two different dates during the season. The first
lot of samplE's was taken at the bunahing stage, 70 day!! after planting,
and the second was taken 112 days aftE'r planting, whell the carrots were
at a good stage for topping and markE'ting iu bushel baskets. The results
of this study, as shown graphically in figure l2, B, are in agreement
with those of the preceding year.
Microscopic studies made on sections cut with a sliding microtome
. oI;_~om roots 70 days old, revealE'd carotene crystals in only the cortex; oj!
,
....
GROW'l'H A.ND
OR OF CARROTS
29
the largt'r cal'rotll. '1.'he core of the larger carrots, and the core and the
cortex 0/ tht' smaller eal'rots, of the same planting, contained carotene in
an amorvhous form but none in crystalline form. As the roots grew
older, crystals illCrCaf.,pd murkedly iu the cortex and also appeared in the
core. At the cnd of the' season, sections wt'l'e made of roots from the
older planting, 1hc>n 175 days old, and also of SODle roots only 95 days
old. In th(.l 95-c1ays-old roots no crystals were found in the core except
near the- ('cuter, and thel'e only a single crystal in an occasional cell.
The cortex contained many more crystals than did the core, but, as in
the core, the young",r cells ncar the cambium layer contained much less
carotene tllall did the older ct'lIs. tfhe core and the cortex of the 175days-oIU canots contained many more crystals than did those of the
young ('nrrots. As with the young carrots, the older cells in the center
of tho core and jn the onter part of the cortex contained many more
crystal!i than did the youngpr cells near 1he cambium.
DEV]!'LOPMEN'l' 011'
OHI,OROPIIYLr~
AND OTInClt PlaMENTS
It was obsl'rved that wliE'n the top of It carrot root was exposed to light
abovo the soil, it became gl'pen. In exposed parts of most fleshy roots,
this grpE'n (lolur, presumably chlorophyll, develops only in the epidermal
layers j but in the carrot it was found throughout the entire part of the
root expQlo,ed above the soil.
Carrot roots in one lot were kt'pt well covered with black paraffin,
black papf'r, and Roil, and WE're fonnd to be free of chlorophyll. In
anoth(,r lot thE.' roo1s were alIowt'd to grow in the usual manner until
they were about lh inch in cliamE'ter at the top, and then the soil was
removed from about two-thirds oi the root. These roots greened throughout down to the level of the soil, the greening being more intense in the
cambium aull e-pidpl'mal regions than in the other parts of the root. Tbis
iudicated that ligh1 was penetrating the ('arrot root, since chlorophyll
does not deve-lop in the absence of light. Preliminary experiments with
glasN filters iuclicah"d 1hat this was true, as those ftlters allowing the
pa~sil.ge of wavp-lpugths of light appareutly similar to those of the
carrllt til*l11C guvP ('hlol'ophyll developmt'nt in the root while those allowing other portions of the spectrum to pa'lS did not give any chlorophyll
developlllt'nt.
.
A smull qnRn1 ily of xlllltllophyll was found to be pl'esent in the carrot
rootH. ThiH pigllll'n1 il'l similar in color to caroten(', and, since the amount
preRent waH small, th€' two pigments Wl'rc not separated when the
analysis Ior color wa,:; made.
Some roots were found to bE' reel to lavender in color on the surface
of the part exposed to lighL. This was found to be a sun-red anthocyanin
pigment, which will devt'lop in the epidermis of any part of the root
exposed to light.
EFFECT OF BTORAGE TEMPERATURE AND A.GE OF ROOT, ON OHANGES IN COLOR
ANI) CHEMIC'At. COMPOSITION OF CARROTS
Carrots of the Ma.y 26 and July 14 plantings made in 1933 were
harvested when 145 and 90 days old, respectively. The roots wete
cRrofully Borted and were placed in 12-quart baskets. Lots of each age of •
W. C.
30
BARNES
.
17M
80
DOol's in ~tDr.lge
FIGURE
13.
Dli'Ji'DCT OF hTORAGD ON ('HANGE;, IN COJ.OR AND IN
l'HEMICAL ('OMPOSITION OF OLD l'AnnO'l'h
The fignreR lit the left rOJ)regent: for cilrotene, milligram. Jl~r 10 p;rlm •• of
root: for giurO'lC and RIl.erosr, per Ol'nt. AU all lh,· ury·wp!ght bl"i,
FZGl1BJ11 14. J!lI'Jl'ECT 07 STORA.GE ON OlUNGES IN
COLOR A.ND IN CHElIIICAL COMPOSITION OB' YOUNG
CA.:aBO'l'S
The figlU'BII at the left repreeent: fat flIM'Otene, mlllisraDl8 Pill' 10 gra.Dl8 of root; for RlllQ(Jlle a.nd IUOl'OIIII, per
oent. .AU on the dry-weight bwa
root W!'l'(, plaeed ill the th('r~
mostatiC'tllly controlled ClOlt1~
storago roomR at 32 0 aud nt
50° F. SampleR Wl'l'e takE'll at
intervals, wit h retmUs as Rhown
in tahle 20 ancl ill fignres 1:1
and 14.
AftI:'r 45 flays the roots at
50° were brgilming to sprout.
A ftel' flO days some of tht' roots
at 50 0 were bE-ginning to decay,
and aft!'r 129 days mOHt of thl'
roots were not ('(lihlo bocauRl'
of decay or OL lOR~ of moisture.
The smaller roots always appearell more will ed than did
the larger rootI!J. ALter 129
days at 32° the smaH roots
were bc.>ginning to show signs
of breakflown, whereas the
largA roots were still in fair
condition after 178 days.
As is shown in the preceding
experiments, the older carrots
GIWWTII ANLo
~
~
co
.....
riJ
!
n
Q
J;-t
~
c::!
Ii§ I~
!:
::
cS
~
!I.
00
2
S
§
8
t.I
.~I;
I>i
t:I
~~~C4t;
-""':S$1
... t;~ .... ~
-· ....
· ..
-.......
~ai:!!
-......
~gi:::
l!!!:Fl~
~=
f!!l
1'"'Icqcqr:-:::i
... lZS ..S
...
oo~t;
"";n~~
:lsi
-..fa
... ~~t:liI
••
,
..
•
I
",
•
I
•
••
•
'.'
t
.....
',' "
.....
~;l:
....i
:::: :
:::: :
til
"a :
~
:j :
Illl1
..
,
'
S:!;;1
! ...;
,
j
.&1
!
~
~
00 ...
.. ~ti
~C"Q=
:
--
" ",..i:::i;:i
.. ~~"!::!I
;
.
i
E-i
-t:i:::
... 1::1«118
-,..4...i"=g
I: -
.11 i
!t
~
CQ.
--
0 ......
a~!:i
1 -.........
19 1
...... 1
6 - j ....- ... g k .......
~
"aqtNaft;:t
- ..-"'
C'ID~''''~
.......
=6!1~
r ~~ ..- ........
..
~firi
~
I
i
Rae:!!
0.100";10"':
~
I
};;~
~S<
~
-.~ri=
. .. =
-.........
::i~~
,... co .....
J
.........
l!!!l!Il.1
l<i~
oQcq~_o
(.)
~
-
. - ..
~
I
... lO!te .. 18
........
co=88aoti
.......
-: .. ~ :
ii
c..>
.. 5!~"....
cqCl)C'lS!!
]
tt
!i...
",,~~R
t:(I"'"==
-
.1
~
~
.oK OF CABROTS
-
co .....
........
===
-........
fI.l .. ~
....
....
...
....
..
.
1
'IS
I
$I
l.
jrill ItI
11 dm
J1I
81
W. C.
.HNES
~ highe): 111 carotene and sUC'l'ose, but lower in glucose, tl1an the
y':su"er _c4Vrats. AU the lots showed a decrease in carote11e as the storage
p~a~nced, up to 80 days, aiter which there was a slight increase, ali
a:Mllj1s In tf.'ble 20 and in figures 13 and 14. The actual cal'otf'ne value!:!
per unit ot root w,ere higher at 50° than at 32°, but if calculated on the
percentage of orilfinal carotene present the results are s.lightly different.
For exam»le, a:l'ter the young roots had beOll in storage for 129 days,
those at 50~ had only 43 per e£.>l1t of their original carotene, while those
at 32° hacl 6~ per cent, or olll'-fifth more, of their original carotene. Old
roots storetl.'I at 32° had slightly more of their carotene after 178 days
than had 'ilJd roots stored at 50" for ouly 129 days. There was a los!l ill
weight tip.it'in carotene c011tent in the roots stored at 32" and at 50°,
The rate of loss ill weight and in carotene content was grett~cr at Glo
than at 3211: The difference between pt'rcf'utagc or CUl'ot('nc Pl'E's£.>ut anu
percentage of original carotene presellt WM flue to the Luct. that the
differcuC'c betw(>cn the rate of watel lost and the l'ail.! of carotl'ue lost
was greater at 50° than at 32°.
During the first stol'age period, the percentuge of bucrose increa&>d
slightly in both young lind old roots stored at 32", while those stored at
50 lost heavily. During the second storage pl'riod, the lORs in sucrose at
320 was very rapid, so that by the end of that period the sucrose level
of the tW() temperatures was about the snmo. At 32" there wac; a slight
incl'ea\le in suc.rose during the last storage period, while at 00° thore was
np increase. During the first storage period, glucose illel'('uSf'd ouly
srIghtly at 32°, while at 50° it increaseu rapidly. During the seeond
period, gluco&e inel'aase(} rapidly at 32° and fllowly at 50 0 • In the last
storage period, glucose decreased in both old alld young roots, but the
loss was at a much mOore rapid rate in the young roots than in the old
roots. r'vhe loss was much less d 320) than at 50° during the last period,
The percentage of dl'y matter ileruained practically constnnt Until the
last storage period, when an iucrf'ase bccnrrec1. All lots at 50 0 increased
in percentage of dry matter moreih!tn did those at 32 0 , and young roots
increased more in this respect than did old roois at oaeh temperatnre.
The differences in loss of weight for the two ages of TOOts r,tored at the
tw~ temperatures is very marked. At 32" the loss in weight o.c the old
roo11s was only about half as much as the losi :i:'Ir'weight ot the young
roots. while at 50° the old roots lost about two-thirds as much as. did the
10ung roots. The rate of loss in dry matter follows...,.ery clos<']y the Joss
ln total weight until the last storage period, when the loss in moisture
was at a grea1 er rate than the loss in dry matter.
0
SUMMARY
Al\D
DISCUSSION
The major aim in the studies here'reported was to determine tho effect
of *ral environm.antal factors on growth and on .color development
:in
ots. Special emphasis was placcd on tompel'atul'e, soil moistnre,
and' ngth of day as -.tfecting tl.fJIIe ch&nlt'lt61'S. Some attention was
given to the effect of "V~
a.Q;1fjand color, and also
to the effect of age ot th
Il'd
~ temperature on
color. The effects of 111 Qf tl!J.e..
en
..ere studied under
. ~ain of Chantenay,
controlled conditions b; t l ·
.ldeh had been prcv~:
t'I tpP, was used in all
:E:*'
lbe atu<tiea.
I.....'