Pakistan Journal of Biological Sciences, 2 (1): 45-52, 1999
Research Article
Development of Chloroplast in the Mesophyll Cells of Satsuma Mandarin Foliar
Sprayed with Urea
Socorro E. Aguja, Pear Mohammad and Masaya Shiraishi*
The United Graduate School of Agriculture Sciences, *Citriculture Laboratory,
Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan
Abstract
The development of chloroplasts in the mesophyll cells of control and urea-applied satsuma mandarin leaves were studied.
At 20 days after budding (DAB) active differentiation of chloroplasts in urea-applied trees was evident. However, on a length
times width basis, chloroplasts were small in both palisade (1.99 × 0.70 µm2) and spongy (2.78 × 1.50 µm2) layers that
contained few small (0.53 - 0.72 × 0.39 - 0.57 µm2) starch grains. The thylakoid layers per chloroplast were lesser (2.80)
in this treatment compared to control (3.72). At 40 DAB, both control and urea-applied trees reached chloroplast maturity,
but control trees had bigger chloroplast (4.87 × 2.39 µm2) in the palisade layer cells which contained extremely large and
numerous starch grains with few dilated thylakoid layers. Degenerating chloroplasts in the spongy layer cells of control trees
were characterized by the disappearance of the outer membrane. While urea-applied trees had smaller chloroplast (4.56 ×
2.39 µm2) in the palisade layer. Further, few small starch grains, thylakoid-filled stroma and many lipid droplets were found.
Moreover, thylakoid layers were about to dilate but outer membrane of the chloroplasts remained intact in both palisade and
spongy layer cells. Compared to the palisade layer cells, chloroplasts in the spongy were bigger (5.32 x 1.95 µm2).
Introduction
applied trees.
The verification of chloroplast development in a particular
growth stage of citrus will provide us a more comprehensive
information on the reaction mechanisms between nitrogen
and chloroplast and the subsequent development of other
organelles in the leaf tissues.
The present study was conducted in an effort to describe
the developmental stages of chloroplast in the mesophyll
cells of satsuma mandarin leaves foliar sprayed with urea at
20 and 40 days after budding.
Plastids are probably the most metamorphic and ubiquitous
DNA-containing organelles present in plant cells. These
organelles carry out numerous metabolic functions including
photosynthesis, starch synthesis and steps in lipid,
terpenoid, amino acid, tetrapyrrole and plant hormone
biosynthesis (Mullet, 1993; Harrak et al., 1995). The
various important functions of plastids complimented the
need for meticulous investigations of these organelles.
Generally, the development of leaves is derived from
meristematic cells of shoots that contain proplastids.
Subsequently, as these meristematic cells develop into leaf
cells, proplastids differentiate into chloroplasts. As a result,
the number of chloroplasts increases dramatically during
mesophyll cell expansion producing large population of
chloroplasts in each mature mesophyll cells (Pyke and
Leech, 1992) or simply, chloroplasts develop from
proplastids through a process that involves an increase in
volume and membrane expansion (Reiter et al., 1994).
Although chloroplast differentiation appears to start very
early during plant development (Leon et al., 1998), the
stages of chloroplast differentiation at various ages of plants
or leaf tissues in a variety of species are not yet well
established. It can also be asserted that the chloroplast
development could be dependent on plant species,
environmental factors and different growing conditions.
In some monocot species, a more or less thorough
investigation on chloroplast development has been done
particularly in C4 plants where further chloroplast
differentiation concurrent with mesophyll differentiation in
the bundle sheath has been reported (Nelson and Langdale,
1989). But in citrus, information regarding chloroplast
development is very limited particularly with nitrogen foliar-
Materials and Methods
The experiment was conducted in the Citriculture
Laboratory, Faculty of Agriculture, Ehime University during
spring 1998. Three-year-old satsuma mandarin (Citrus
unshiu Marc. cv. Okitsu Wase) trees of similar vigor were
planted in potted sandy soil mixed with granite and
maintained in plastic house conditions. Light intensity of
approximately 60,000 lux and temperature range of
23-26EC were maintained in the plastic house. Heavy
pruning was done by removing the old shoots and leaves on
April 14, 1998. Spring flushes were allowed to grow for
about 3-5 cm before spraying. Three sprayings of urea
(Wako Pure Chemicals Industries Ltd., Osaka, Japan) at
2,000 ppm were applied to two sets of 3 potted trees 11
set for 20 DAB and another set for 40 DAB at 33 ml/tree in
the morning of April 28, 30 and May 2. The same number
of trees were sprayed with tapwater which served as the
control. Pots were covered with polyethylene bags to
prevent entry of spray solution into the soil. Leaf sampling
for 20 and 40 days after budding were done on May 3 and
23, 1 and 20 days after the last spray application,
respectively.
45
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
Ecological data such as leaf length, width, mesophyll
thickness and leaf color were recorded. Moreover,
chlorophyll content determined by MINOLTA-SPAD 501
reading values and nitrogen content by Kjeldahl analysis
were also included. Prior to nitrogen analysis, samples for
electron microscopy were prepared by cutting the central
portion of the leaf blades into small pieces (1 mm x 2 mm)
and were fixed in paraformaldehyde-glutaraldehyde for
24 hrs at 10EC, postfixed in 1 percent osmiun tetroxide for
2 hrs at room temperature, dehydrated in a graded alcohol
series and embedded in epoxy resin. Ultrathin sections were
cut with diamond knife using the ultramicrotome (UT-1000)
and double stained with uranyl acetate and lead citrate.
Sections were examined and photographed under HITACHI
H-7100 transmission electron microscope at 100 kV.
A total of 130 photomicrographs (x10,000) were
considered for investigations on the different chloroplast
features. Chloroplast and starch grain areas were traced
from approximately 25 photomicrographs and were
measured using leaf area meter MK2. Cell, chloroplast and
starch grain sizes were measured on a length (L) and width
(W) basis and the number of starch grain and thylakoid layer
per chloroplast were directly counted from the
photomicrographs. Means of these parameters were
analyzed using the Duncan's Multiple Range Test (DMRT).
cell size, chloroplast area and size, starch grain area and
size, number of starch grains and thylakoid layers per
chloroplast (Tables 2a and 2b). Apparently, urea applied
trees had bigger cell size than the control (Table 2b). The
chloroplast area as well as the size, the starch grain area
and the number of starch grains per chloroplast were
greater in palisade layer 3 and spongy layers 1-2 but
smallest in palisade layer 1 of control trees (Table 2a). The
starch grain size was bigger in palisade layer 3 and spongy
layers 1-3 than in the palisade layers 1 and 2, while the
number of thylakoid layer per chloroplast was more in the
spongy layers 1-3. At this particular phase, 20 DAB,
different stages of chloroplast were observed, however,
each mesophyll layer was dominated by a certain
chloroplast stage. The chloroplast developmental stages in
palisade layers 1-3 were generally featured with the
formation of lamellar system (Figs. 1 A, C and E). Spongy
layers 1-3 had similar plastid developmental stages where
formation of stroma and grana lamellae were at an
advanced phases and were almost at the full grown stage
of chloroplast (Figs. 1 G, I and K).
Table 2b represents the urea-applied trees where chloroplast
area and size, starch grain area, size and number per
chloroplast and number of thylakoid layer per chloroplast
were bigger and numerous in spongy layers 1-3, and least
in palisade layers 1 and 2. Bigger cell size and more
thylakoid layer per chloroplast in the mesophyll cells were
observed in this treatment compared to the control trees.
Majority of the chloroplasts in palisade layers 1 and 2 were
at the developing stage of forming internal lamellar system
(Figs. 1 B and D). The palisade layer 3 cells had chloroplasts
mostly in the stage of forming stroma lamellae (Fig. 1 F).
Spongy layer 1 had chloroplasts generally forming grana
(Fig. 1 H) and the spongy layers 2 and 3 mostly contained
chloroplasts forming both grana and stroma lamellae (Figs.
1 J and L).
At 40 DAB, mesophyll cells of both urea and control plants
have a clearly differentiated palisade and spongy layer cells
which were bigger than those of 20 DAB. Tables 3a and 3b
illustrate that the cell size in the mesophyll of urea-applied
and control trees at 40 DAB did not greatly differ but,
within the 2 palisade and 3 spongy layer cells, differences
were observed. In terms of length, the palisade layer 1 cells
were the longest followed by palisade layer 2 and in terms
of width, spongy layer 3 cells were the widest. The
chloroplast area in the spongy layer 3 cells and the
chloroplast size in palisade layers 1 and 2 were bigger
in control trees (Table 3a) than in urea-applied trees
(Table 3b). The biggest starch grain area and the
largest starch grain were observed in the chloroplasts
located in the palisade layers 1 and 2 respectively, in
control trees (Table 3a). Numerous starch grains were
also found in the chloroplasts of palisade layer 1 cells.
The number of thylakoid layer per chloroplast was
many in the spongy layer 3 cells where the cell size,
chloroplast area, chloroplast size and the number of starch
Results
Comparatively, urea-applied trees had bigger leaves and
thicker mesophyll, higher chlorophyll and nitrogen contents
than the control (Table 1).
Table 1: Ecological data of control and urea-applied satsuma
mandarin leaves 20 and 40 days after budding.
Treatment
-------------------------Control
Urea
20 Days after budding
Length
2.23
Width
0.17
Mesophyll thickness (mm)
0.21
SPAD reading
13.30
Chlorophyll content (mg/100 cm2)
1.20
N-content (%)
2.94
40 Days after budding
Leaf size (mm)
Length
4.57
Width
2.35
Mesophyll thickness (mm)
0.26
SPAD reading
26.70
Chlorophyll content (mg/100 cm2)
2.60
N-content (%)
1.69
Leaf size (mm)
2.41
2.03
0.23
13.47
1.30
3.64
6.09
2.48
0.27
29.53
2.80
2.01
In undifferentiated mesophyll cells 20 days after budding
(20 DAB), the first 3 layers of palisade and spongy cells in
both urea and control trees had remarkable differences in
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
46
15.36a
14.84abc
11.13c
12.65abc
12.97abc
Palisade 2
Palisade 3
Spongy 1
Spongy 2
Spongy 3
7.96
7.63
7.06
5.96
5.27
6.69
W2
3.06d
5.99a
5.87ab
5.73abc
3.77cd
2.55d
Chloroplast
area
(µm2)
2.50c
3.31b
4.71a
2.50cd
1.88d
1.63d
L1
0.98d
1.48bc
1.34cd
2.35a
1.75b
1.34bcd
W2
Chloroplast size
(µm)
0.48abc
1.15ab
0.93abc
1.73a
0.30c
0.10c
Starch
grain
area
(µm2)
47
19.22a
14.85de
16.06cd
18.80ab
10.04f
Palisade 2
Palisade 3
Spongy 1
Spongy 2
Spongy 3
15.21a
8.55b
7.19b
6.10b
6.96b
7.09b
W2
2.53bc
3.03ab
4.53a
2.13bcd
0.64e
0.57a
Chloroplast
area
(µm2)
2.58abcd
2.79ab
2.97a
2.71abe
1.88e
1.37e
L1
1.10bc
1.33bc
2.07a
0.91cd
0.46e
0.72de
W2
Chloroplast size
(µm)
*Means in columns are separated by Duncan's Multiple Range Test at 5% level
1
: length; 2: width; -: no starch grain
18.93ab*
L1
Cell size
(µm)
Palisade 1
Mesophyll
layer
0.39ab
0.49ab
0.83a
0.25b
-
-
Starch
grain
area
(µm2)
0.72abc
0.87ab
0.88a
0.53c
-
-
L1
0.64abc
0.88a
0.61abcd
0.70ab
0.42cde
0.45abc
0.51ab
0.57a
0.39c
-
-
W2
Starch grain size
(µm)
0.71
0.91
0.64
0.75
0.51
0.36e
W2
Starch grain size
(µm)
0.41
L1
Table 2b: Cell and chloroplast structures in urea-applied satsuma mandarin leaves 20 days after budding.
*Means in columns are separated by Duncan's Multiple Range Test at 5% level.
1
: length; 2: width
15.34ab*
L1
Cell size
(µm)
Palisade 1
Mesophyll
layer
Table 2a: Cell and chloroplast structures in satsuma mandarin leaves 20 days after budding.
1.2be
1.4ab
2.2a
0.5c
0
0
Number of
starch
grain per
chloroplast
1.6abcd
1.9abc
2.0ab
2.2a
0.9bcd
0.3d
Number of
starch
grain per
chloroplast
3.03abc
4.63a
2.81abcd
3.51ab
1.32e
1.51bcde
Number of
thylakoid
layer per
chloroplast
4.03
4.34
4.07
3.84
3.12
2.90
Number of
thylakoid
layer per
chloroplast
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
21.02ab
12.78c
11.97c
13.28c
Palisade 2
Spongy 1
Spongy 2
Spongy 3
15.70a
15.08ab
14.84abc
9.35d
10.63abc
W2
6.35c
9.85abc
9.68abc
13.79ab
14.60a
Chloroplast
area
(µm2)
3.75c
4.23abc
4.98ab
5.12a
4.61abc
L1
1.59bc
2.05ab
1.78b
2.17ab
2.61a
W2
Chloroplast size
(µm)
3.38c
2.94c
5.07bc
8.17ab
11.00a
Starch
grain
area
(µm2)
48
17.88b
12.95bcd
10.52d
17.23bc
Palisade 2
Spongy 1
Spongy 2
Spongy 3
18.43a
13.07bc
13.59b
8.53d
10.84bcd
W2
8.57a
7.67ab
7.70ab
6.67ab
5.58b
Chloroplast
area
(µm2)
5.36ab
5.08abc
5.48a
5.07abc
4.05c
L1
1.46
1.44
1.70b
1.52
1.14
1.34
Starch
grain
area
(µm2)
2.56a
1.60b
1.32b
1.63b
W2
Chloroplast size
(µm)
*Means in columns are separated by Duncan's Multiple Range Test at 5% levell
1
: length; 2: width
23.29a*
L1
Cell size
(µm)
Palisade 1
Mesophyll
layer
0.81cd
0.67d
0.92abc
1.15a
1.03
1.25
1.41
1.14
0.49b
0.57ab
0.65ab
0.60ab
0.71a
W2
Starch grain size
(µm)
1.74abc
1.28c
1.95a
1.91ab
1.07ab
W2
Starch grain size
(µm)
1.64abc
L1
1.14
L1
Table 3b: Cell and chloroplast structures in urea-applied satsuma mandarin leaves 40 days after budding.
*Means in columns are separated by Duncan's Multiple Range Test at 5% levell
1
: length; 2: width
22.72a*
L1
Cell size
(µm)
Palisade 1
Mesophyll
layer
Table 3a: Cell and chloroplast structures in satsuma mandarin leaves 40 days after budding.
1.9abc
2.3a
2.1ab
0.9d
1.0cd
Number of
starch
grain per
chloroplast
1.8c
2.6bc
3.1bc
3.8ab
4.9a
Number of
starch
grain per
chloroplast
9.56a
6.87b
6.97b
6.31 b
7.16b
Number of
thylakoid
layer per
Chloroplast
5.68a
5.42ab
3.19abc
2.29a
3.41abc
Number of
thylakoid
layer per
Chloroplast
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
Fig. 1: Electron micrographs of chloroplast in the mesophyll cells of control and urea-applied satsuma mandarin leaves
20 days after budding, A, C, E: control - palisade layers 1, 2 and 3; B, D, F: urea-applied-palisade layers 1, 2 and
3; G, l, K: control-spongy layers 1, 2 and 3; H, J, L: urea-applied - spongy layers 1, 2 and 3. Chloroplasts of ureaapplied trees were smaller and at early stages of development compared to the control. Bar 0.5 µm.
49
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
Fig. 2: Electron micrographs of chloroplast development in the mesophyll cells of control and urea-applied satsuma
mandarin leaves 40 days after budding. A: Control - palisade layer; B: urea-applied - palisade layer; C: control
spongy layer; D urea-applied - spongy layer. The outer membrane of chloroplasts in control start to disappear.
Bar = 1 µm.
in the chloroplasts of spongy layer cells than in the palisade.
The number of thylakoid layer was numerous chloroplasts
located in the spongy layer 3 cells where the chloroplast
area was biggest and starch grain was srnalle Chloroplasts
in this group were ellipsoidal, have more li droplets and
thylakoid-filled strorna. Although thylakoid observed
were about to dilate, the outer membrane was intact in
both palisade and spongy layer cells. Chloroplast in the
spongy cells were bigger compared to those palisade
(Figs. 2 B and D).
grain per chloroplast were least. Chloroplasts at this stage
(40 DAB) have already reached advanced maturity phase for
both control and urea-applied trees. Chloroplasts found in
palisade layers 1 and 2 were similar in structure and so with
the chloroplasts in the spongy layer cells. In control trees,
palisade layers 1 and 2 were indicated with chloroplasts
that were irregularly globular with extremely large and
numerous starch grains and with few dilated thylakoid
layers (Fig. 2 A). Spongy layers 1-3 were identified with
smaller chloroplasts that were ellipsoidal, containing less
starch grains but more thylakoid layers than the
choloroplasts in the palisade layer accompanied with a sign
of degenerating chloroplast characterized by the
disappearance of the outer membrane (Fig. 2 C).
Table 3b shows the starch grain area and chloroplast size
of urea-applied trees that were almost similar in any
mesophyll layer cells. Fewer starch grains were contained
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
Discussion
Present study indicated that the nitrogen content in the
leaves of urea-applied trees was higher than in control
However, the accumulation of nitrogen in the leaves
decreased to about 16 percent at 40 days after budding.
This phenomenon has been revealed in the studies
50
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
deficiency is assumed in these non-active chloroplasts.
Similar studies in different plant species have been observed
in this regard (Thomson and Weier, 1962; Whatley, 1971;
Chonan et al., 1977), reflecting large starch grains in the
chloroplasts of nitrogen deficient plants. In the present
study, it seems that the size of chloroplast is directly
affected by the continuous accumulation of starch grains.
As these starch grains increase in size and become
enlarged, the walls of the chloroplasts are being pushed in
order to accommodate the starch grains without breaking
the seemingly elastic chloroplast membrane. Degradative
enzymes for starch grains in these chloroplasts are
suspected to be lacking due to the low nitrogen content.
Moreover, starch accumulation decreases photosynthetic
activities in plants (Makino and Osmond, 1991; Nii et al.,
1993, Wykoff et al., 1998) and may disrupt chloroplast
organizations (Carmi and Shomer, 1979). Thus, as reflected
in the present results, the accumulation of starch was
accompanied by the destruction and disorientation of grana
and thylakoids (Figs. 2 A and C).
An appealing observation of outer membrane disappearance
in the spongy chloroplast of control trees implies a
degenerating chloroplast (Fig. 2C). This could be attributed
to nitrogen deficiency resulting in a premature senescence
of leaves (Possingham, 1980). This chloroplast stage has
not been observed in urea-applied trees. Although
chloroplasts in this group were smaller compared to palisade
chloroplast of control trees, a well-developed chloroplast
ultrastructures were evident, which contained less and
smaller starch grains, lamellae-filled stroma and more lipid
droplets (Figs. 2 B and D). A similar observation was noted
by Kirchanski (1975) on nutrient-applied, Zea mays, where
mature chloroplast ultrastructure possessed numerous lipid
droplets.
Collectively, present results indicated that the
developmental stages of chloroplasts in control and
urea-applied satsuma mandarin leaves collected at 20 and
40 days after budding (DAB) differed. A more active
differentiation of chloroplasts in urea-applied trees were
evident at 20 DAB thus, chloroplasts in this treatment were
smaller with few and small starch grains and with lesser
thylakoid layers per chloroplast as compared to the control.
Chloroplast maturity was attained in both control and
urea-applied trees at 40 DAB. Although similar
developmental stages of chloroplast were observed in the
mesophyll tissues for both treatments, control had
extremely large and numerous starch grains with few dilated
thylakoids. Chloroplasts found in the spongy layer cells
were degenerating characterized by the disappearance of
outer membrane which could be considered a sign of
senescence. Urea-applied trees had smaller chloroplasts in
palisade layer cells with few and small starch grains,
thylakoid-filled stroma and contained many lipid droplets.
Chloroplasts in this treatment had thylakoid layers that were
almost to dilate but the outer membrane remained intact.
Therefore, urea application prevented an early degeneration
Embleton et al. (1973) and Feigenbaum et al. (1987),
indicative. that the nitrogen concentration of citrus leaves
tends to decline with age. Although both control and ureaapplied trees had similar mesophyll differentiation at 20 and
40 DAB, differences in terms of nitrogen and chlorophyll
contents and subsequently, the chloroplast ultrastructures
were observed in both treatments.
The bigger cell size exhibited by urea-applied trees could be
considered a positive indication of nitrogen effect on the
growth of leaves at an early stage. The different
developmental stages of chloroplast observed in the
mesophyll cells of both control and urea-applied trees at 20
DAB is considered to be a consequential event related to the
early stage of leaf development where differentiation of
plastids occur. An interesting feature of smaller chloroplasts
observed in the urea-applied trees is not to be regarded
as being due to slow or non-growing chloroplasts but
rather can be viewed as developing plastids which have
resulted from an active division of preexisting chloroplasts
triggered by the application of nitrogen (Possingham, 1980).
Whereas, the control trees, which had bigger chloroplasts,
can be considered as the same chloroplasts that preexisted
in the cell and continued to develop but were not actively
dividing unlike those of urea-applied trees. Thomson and
Whatley (1980) however, reported that during the early
stages of cellular differentiation, differences in plastid
size apparently become established as
a result of
differential expansion of the plastids prior to division and as
some cells become fully differentiated, plastids undergo
dedifferentiation to an eoplast state similar to some of the
chloroplasts found in urea-applied trees, which were usually
small (Figs. 1 B, D and F). Some of these small chloroplasts
were dumbbell-shaped suggestive that these were in the
early stage of plastid division (Pyke and Page, 1998).
Based from the dominating chloroplast ultrastructure per
mesophyll layer cells observed, palisade and spongy layer
cells in control trees had chloroplasts which were at
advanced stages of development compared to the ureaapplied trees. This phenomenon could have been the result
of an active division and redifferentiation of plastids in ureaapplied trees. Consequently, the formation of these early
developmental stages of chloroplast could have been the
result from prolonged juvenile stages of chloroplast that
occurred in urea-applied trees.
The cell sizes of both control and urea-applied plants at 40
DAB were almost similar. This similarity could be attributed
to their capacity to have reached the full size or maturity
stage (Figs. 2 C and D). However, the chloroplasts with
smaller and lesser starch grain and more thylakoid layers in
urea-applied trees need to be considered in elaborating its
differences with the control trees.
The accumulation of extremely large and numerous starch
grains in the chloroplasts of control trees in both palisade
and spongy layers is indicative of non-active chloroplasts.
Negative starch degradation process due to the absence
of necessary degradative enzymes caused by nitrogen
51
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
Aguja et al.: Chloroplast development, foliar spray, satsuma mandarin, urea.
of chloroplasts at 40 DAB, where clear differentiation and
fully developed mesophyll cells were reached.
Mullet, J.E., 1993. Dynamic regulation of chloroplast
transcription. Plant Physiol., 103: 309-313.
Nelson, T. and J.A. Langdale, 1989. Patterns of leaf
development in C4 plants. Plant Cell, 1: 3-13.
Nii, N., M. Kato, Y. Hirano and T. Funaguma, 1993. Starch
accumulation and photosynthesis in leaves of young
peach trees grown under different levels of nitrogen
application. J. Jpn. Soc. Hortic. Sci., 62: 547-554.
Possingham, J.V., 1980. Plastid replication and
development in the Life cycle of higher plants. Ann.
Rev. Plant Physiol., 31: 113-129.
Pyke, K.A. and A.M. Page, 1998. Plastid ontogeny during
petal development in Arabidopsis. Plant Physiol.,
116: 797-803.
Pyke, K.A. and R.M. Leech, 1992. Chloroplast division and
expansion is radically altered by nuclear mutations in
Arabidopsis thaliana. Plant Physiol., 99: 1005-1008.
Reiter, R. S., S.A. Coomber, T.M. Bourett, G.E. Bartley and
P.A. Scolnik, 1994. Control of leaf and chloroplast
development by the Arabidopsis gene Pale cress. Plant
Cell, 6: 1253-1264.
Thomson, W.W. and J.M. Whatley, 1980. Development
of nongreen plastids. Ann. Rev. Plant Physiol.,
31: 375-394.
Thomson, W.W. and T.E. Weier, 1962. The fine structure
of chloroplasts from mineral-deficient leaves of
Phaseolus vulgaris. Am. J. Bot., 49: 1047-1055.
Whatley, J.M., 1971. Ultrastructural changes in
chloroplasts of Phaseolus vulgaris during development
under conditions of nutrient deficiency. New Phytol.,
70: 725-742.
Wykoff, D.D., J.P. Davies, A. Melis and A.R. Grossman,
1998. The regulation of photosynthetic electron
transport during nutrient deprivation in Chlamydomonas
reinhardtii. Plant Physiol., 117: 129-139.
References
Carmi, A. and I. Shomer, 1979. Starch accumulation and
photosynthetic activity in primary leaves of bean
(Phaseolus vulgaris L.). Ann. Bot., 44: 479-484.
Chonan, N., H. Kawahara and T. Matsuda, 1977. Effect
of nitrogen application on ultrastructure of the
chloroplasts in rice plants. Jpn. J. Crop Sci.,
46: 387-392.
Embleton, T.W., W.W. Jones, C.K. Labanauskas and
W. Fleuther, 1973. Leaf Analysis as a Disagnostic Tool
and Guide to Fertilization. In: Citrus Industry, (Reuther,
W.J. (Ed.). Vol. 3, University of California, California,
pp: 183-211.
Feigenbaum, S., H. Bielorai, Y. Erner and S. Dasberg, 1987.
The fate of 15N labeled nitrogen applied to mature
citrus trees. Plant Soil, 97: 179-187.
Harrak, H., T. Lagrange, C. Bisanz-Seyer, S. Lerbs-Mache
and R. Mache, 1995. The expression of nuclear genes
encoding plastid ribosomal proteins precedes the
expression of chloroplast genes during early phases of
chloroplast development. Plant Physiol., 108: 685-692.
Kirchanski, S.J., 1975. The ultrastructural development of
the dimorphic plastids of Zea mys L. Am. J. Bot.,
62: 695-705.
Leon, P., A. Arroyo and S. Mackenzie, 1998. Nuclear
control of plastid and mitochondrial development in
higher plants. Ann. Rev. Plant Biol., 49: 453-480.
Makino, A. and B. Osmond, 1991. Effects of nitrogen
nutrition on nitrogen partitioning between chloroplasts
and mitochondria in pea and wheat. Plant Physiol.,
96: 355-362.
Pak. J. Biol. Sci., 2 (1): 45-52, 1999
52