WATER TABLE EFFECTS ON SUGARCANE ROOT AND SHOOT DEVELOPMENT
D.R. Morris and P.Y.P. Tai
USDA, ARS, Sugarcane Field Station, 12990 U.S. Hwy 441. Canal Point, FL 33438.
ABSTRACT
Microbial oxidation of organic soils in the Everglades Agricultural Area (EAA) is
resulting in a decrease in soil depth. Raising water tables reduces oxidation rates, but often
reduces sugarcane (interspecific hybrids of Saccharum spp.) yields. An experiment was
conducted to determine the interrelationships between shoot yield and root morphology due to
water-table depths. Twelve sugarcane genotypes were grown outside in 38-L plastic pots with
water-table depths of 0, 15, and 30 (drained) cm established after 2 months of growth. At 10
months, sugarcane shoots and roots in the upper (0-15 cm) and lower (15-30 cm) layers were
harvested. Shoot dry matter was reduced with high water table, but root dry matter within each
soil layer was not affected by water-table depth. About 74 % of the total root dry weight and
length were confined to the upper soil layer regardless of water table. More than 50 % of the
total root length was less than 0.5-cm diameter in both soil layers. A greater percentage of root
lengths in the 2.5- to 4.5-mm root diameter class, in the upper soil layer, were related to shoot
yields. In the lower soil layer, root lengths in the 0- to 1.0-mm root diameter class were most
related to shoot yield. Our data show that sugarcane tolerance of water tables <30 cm includes
increased root mass and length and reduced root diameter near the soil surface. The percentages
of root lengths in various root diameter classes also may serve as indicators for increased
sugarcane dry yields.
INTRODUCTION
About 80 % of the organic soils in the EAA are planted to sugarcane (Izuno et al., 1999).
The common practice of cropping is lowering the water table to at least 61 cm for optimum cane
yield (Snyder et al., 1978). However, microbial oxidation, which results in soil subsidence,
increases as depth of water table increases. Current estimates of soil loss are 1.4 cm yr-1 (Shih et
al., 1998). The best way to reduce soil oxidation is to raise water tables. But, high water tables
may reduce the soil volume for root exploration and change soil nutrient availability, which
could affect root and shoot growth differently (Kozlowski and Pallardy, 1984; Russell, 1977).
Aung (1974) reviewed the literature on shoot/root relationships and indicated that when soil
nutrients are not sufficient for roots and shoots, the requirements of the roots are met first at the
expense of the shoots; when photosynthate is limiting, the requirements of the shoots are met
first at the expense of the roots.
Sugarcane roots are usually located in the upper soil surfaces with 60 % in the 0- to 30-cm
depth, but may penetrate to 180 cm in well-drained soils (Gascho and Shih, 1983; Paz-Vergara et
al., 1980). One morphological change of sugarcane roots growing in high water table is a greater
proportion of fibrous to thick roots in the soil layer above the water table (Eavis, 1972; Webster
and Eavis, 1972). The reason is probably an adaptation to lower O2 levels. A thin root has a
41
Journal American Society Sugar Cane Technologists, Vol. 24, 2004
smaller path-length for O2 diffusion to respiring tissue than a thicker root (Eavis, 1972).
Growth of roots is a heritable characteristic (Dillewijn, 1952). Rahman et al. (1986) tested
four sugarcane genotypes in flooded and drained pots. They found that genotypes more tolerant
to flood had less reduction in root mass than non-tolerant genotypes. Rostron (1974) grew two
cultivars of sugarcane outside in soil from two field sites. He reported that both cultivars
produced a similar distribution of roots in soil with favorable nutrient levels, while one cultivar
produced a deeper root system than the other cultivar under less favorable nutrient conditions.
Total root and shoot mass responses to high water table have not been consistent among
experiments, and root dry matter production may not be associated with rooting depth. Juang and
Uehara (1972) grew sugarcane at water-table depths from 30 to 80 cm and indicated that greater
water-table depths increased the depth of rooting, not the total mass of roots. Andreis (1976)
grew two cultivars of sugarcane under 51- and 89-cm water-table depths in the field and reported
greater root mass and less shoot dry matter with the 51-cm water table. Webster and Eavis
(1972) grew sugarcane in lysimeters and found no significant differences in root masses when 5month old sugarcane was flooded for 1, 4, 14, or 30 days, which they attributed to the ability of
the cultivar to recover fully after flooding. They reported the same results for shoot mass.
Sugarcane genotypes usually show differential tolerance to high water tables based on
shoot dry matter. Glaz et al. (2002) grew nine sugarcane cultivars under 15- and 38-cm watertable depths. They reported a mean yield reduction at the 15-cm water table of 8.3 %, but two
cultivars had similar yields at both water tables, and yield of one cultivar was reduced by 25 % at
the 15-cm water table. Deren and Raid (1997) tested four cultivars of sugarcane for flood
tolerance. Three days after planting, fields were flooded for 10 days. Over a 2-yr period, yield
reductions ranged from 12 to 16 % when flooded fields were compared to non-flooded fields.
Root mass was not reported in either experiment.
Information on the relationship between plant shoot and root morphology characteristics
under high-water stress conditions is limited, and those results available are contradictory. A
better understanding of those relationships should aid in finding ways to improve plant
adaptability to high water tables. An experiment was conducted to determine the
interrelationships between shoot yield and root morphology due to water-table depths.
MATERIALS AND METHODS
Twelve sugarcane genotypes (US 87-1006, US 94-1059, US 96-1082, US 96-1083, US
96-1098, US 96-1106, US 96-1107, US 96-1112, US 96-1121, ‘CP 65-357', ‘CP 72-2086', and
‘POJ 2725') were arranged in a randomized complete block design with split-plot (water-table
depth) treatment arrangement. Water-table depth treatments (main plots) were 0, 15, and 30
(drained) cm from the soil surface and genotypes were the sub plots. All treatments were
replicated four times. A split-plot arrangement was chosen to facilitate watering of plants. The
sugarcane genotypes exhibited a wide range of genetic background. POJ 2725 is a commercial
cultivar that has some water-logging tolerance (Rege and Mascarenhas, 1956). CP 65-357 is a
42
Morris: Water Table Effects on Sugarcane Root and Shoot Development
commercial cultivar that has some frost tolerance (Tai and Miller, 1996). CP 72-2086 is a
commercial cultivar that is widely used in south Florida (Glaz, 1998; Miller et al., 1983). The
remaining genotypes were cold tolerant genotypes derived from crosses between commercial
cultivars and S. spontaneum or Miscanthus sp (Tai, 1993; Tai and Miller, 1996; P.Y.P. Tai
unpublished data).
Plants were grown outside in 38-L pots that were 30-cm deep. One part quartz sand to
two parts Pahokee muck soil (Euic, hyperthermic Lithic Haplosaprist) (by weight) was mixed
and used to fill the pots. The sand/soil mixture was used to improve water infiltration into the
pots compared to 100 % organic soil. The sand is non-reactive and would not be expected to
affect the chemical properties of the muck soil. Chemical analyses of the sand/soil mixture
revealed a pH (water) of 7.4 (Thomas, 1996), 11 % organic matter (weight loss after combustion;
Nelson and Sommers, 1996) and 13 and 26 mg kg-1 soil of P (NaHCO3 extractable; Kuo, 1996)
and K (ammonium acetate extractable; Helmke and Sparks, 1996), respectively. The high soil
pH is not unusual for cropped organic soils in the EAA since they overlay hard limestone
bedrock (Zelazny and Carlisle, 1974).
Single-budded cuttings (2.5-cm length) were taken in April, 1999 from mature stalks of
each genotype and planted in flats (60 x 30 x 10 (deep) cm) containing the same soil used to fill
the pots. Flats were watered twice daily, and after 1 month, one healthy plant was transplanted to
each plastic pot. Approximately 50 g of slow release fertilizer (14-14-14, Scotts Osmocote,
Sierra Hort. Products, Co., Marysville, OH1) was sprinkled over the soil surface of each
container 1 week after transplanting and after peak tillering. This fertilizing method has been
demonstrated to grow healthy sugarcane plants to tasseling stage by plant breeders at Canal
Point. The slow release fertilizer would reduce leaching of soluble nutrients in the drained pots
compared with the flooded pots.
All plants were grown under well watered but non-flooded conditions during the first two
months to allow the plants to become established in the pots. Soil moisture levels in the pots
were not measured gravimetrically, but water was added twice a day as needed to visually keep
the soil moist. Water-table treatments were then imposed (July) by drilling holes (2.5-cm
diameter) along the side of the pots to correspond to the desired water-table depths (0, 15, or 30
(drained) cm). Fifteen minute drip irrigations (WPC Dripper, part number E-WPC20U, Netafim
USA, Fresno, CA), three times per day, were used throughout the course of this study to
maintain desired water levels. After irrigation, water running from the holes in the pots indicated
the appropriate water table was achieved. The two month delay in establishing water-table
treatments had little effect on root development, because temporary sett roots develop in the first
two months, and more than 94 % of the shoot roots develop after 2 months (Gascho and Shih,
1983).
In the first week of February 2000, stalks were counted and plants were harvested by
1
Mention of a specific proprietary product does not constitute a recommendation by the USDA and does not imply
approval to the exclusion of other suitable products.
43
Journal American Society Sugar Cane Technologists, Vol. 24, 2004
cutting stalks at the soil surface and weighing. Two stalks from each treatment were randomly
selected and dried at 60o C to constant weight to calculate average stalk dry weight. The two
stalks amounted to an average of 25 % of the total stalk counts in the pots and should represent
an adequate sample. Total shoot dry yield was determined from the total number of stalks and
average stalk dry weight.
After stalk removal, the entire soil/root core (volume) was removed from each pot.
Soil/root cores were cut (horizontally) in half to provide an upper (0- to 15-cm) and lower (1530-cm) soil layer. Roots in each layer were carefully washed with a garden hose on a 2.5-cm
screen to remove most of the soil. Roots were cut from the lower stalk (below ground stalk
remaining after stalks were removed) using pruning cutters. The lower stalks were dried,
weighed, and added to the dry weight of stalks. Partially-washed root fresh weight was recorded.
Three root subsamples were randomly pulled by hand from the partially-washed root mass and
composited from each soil layer, weighed (average 115 g), and washed again for 0.3 hr using a
Gillison’s hydropneumatic root elutriation washer with roots collected on a 1-mm screen
(Smucker et al., 1982). Washed root weights were recorded. Non-root material in the washed
roots was removed by hand separation and weighed. Remaining roots were scanned on a root
scanner using WinRhizo software (WinRhizo, 2001) to determine root diameter, length, and
percentage of total root length within 10 root diameter classes (<0.5, 0.5-1.0, 1.0-1.5, 1.5-2.0,
2.0-2.5, 2.5-3.0, 3.0-3.5, 3.5-4.0, 4.0-4.5, and >4.5 mm). Scanning resolution was 7.9 pixels mm1
using a flatbed scanner with a positive film transparency unit. After scanning, roots were dried
to constant weight at 60o C and total root dry weight for each sample was calculated as follows:
TDW=TFW(DS/PS)
where;
TDW=total dry weight of root, g
TFW=total fresh weight of partially washed root, g
PS=fresh weight of partially washed root subsample, g
DS=dry weight of washed root subsample after scanning, g
Percentage of root length within each root diameter class for each sample was calculated by
taking the root length of each root diameter class, dividing by the total root length, and
multiplying by 100.
The experiment was analyzed as a randomized complete block design with a split-plot
treatment arrangement (water-table treatment) using PROC ANOVA (SAS, 1990). For
percentage root distributions, arcsin square root transformations were calculated before
performing statistical analyses. However, the analyses for transformed and untransformed data
resulted in similar conclusions, so only untransformed analyses and data are reported.
Correlation analyses of sample means were made using untransformed data (SAS, 1990). Mean
comparisons between soil layers of root total dry weight, total length, and average diameter were
made according to Duncan’s Multiple Range Test (P = 0.05) using the pooled error term for the
root parameter analyses at each soil depth. To plot root length (y-axis) vs. root diameter class (x44
Morris: Water Table Effects on Sugarcane Root and Shoot Development
axis) in Figure 1, the mid-point of each root diameter class was used to represent the x-axis.
RESULTS AND DISCUSSION
Based on visual appearances at harvest, sugarcane shoot and root growth developed in a
normal fashion. Sugarcane stalks grew to heights ranging between 1.5 to 2.3 m. Roots
intertwined and grew sideways and downward with a mix of white and dark roots as appears
under drained field conditions. Roots growing upward were not observed.
Sugarcane total shoot dry matter was significantly (P = 0.05) reduced to 1.0 kg in the
flooded treatment compared with the 30-cm (drained) water-table yield of 1.9 kg (data not
shown). The 15-cm water-table treatment had an average dry yield of 1.8 kg, which was not
significantly different from the 30-cm drained treatment. Interaction of genotype by water table
was not significant for shoot dry weight (Table 1). Root dry yield in the upper soil layer (131 g)
was larger than the root dry yield in the lower soil layer (45 g) (Table 2). Neither the total root
dry weight nor the root dry weight in each soil depth was affected by water table or genotype by
water-table interaction (Table 1). However, the genotype by water-table interaction for root dry
weight in the upper soil layer was borderline significant (P=0.09) due to one genotype (US 961106) showing a smaller root dry weight (94 g) in the 30-cm (drained) treatment compared with
the 0- and 15-cm water-table treatments (average 193 g). Differential response of shoot and root
to water table can also be observed in the correlation analyses (Table 3). Shoot dry matter was
significantly correlated with water-table depth, while root dry matter was not.
Lack of root response to water table may be because sugarcane roots have aerenchyma
tissue. Ray and Sinclair (1999) examined more than 30 sugarcane genotypes and found that all
had aerenchyma whether under hypoxic or non-hypoxic conditions. Aerenchymas are air-filled
tissues that allow transport of O2 from shoots to the roots in many aquatic and flood tolerant
plant species, such as rice (Drew, 1997). Our data conform to those of Gosnell (1972) who grew
one genotype of sugarcane in plastic containers at water-table depths ranging from 25 to 125 cm.
He did not report a significant difference in root dry matter yields.
The reason the shoots showed a decline in dry yield with flooding may have been
decreased nutrient availability due to soil chemical changes or the inhibitory effect of nutrient
uptake mechanisms of roots with low O2 (Kozlowski and Pallardy, 1984). Generally, plant
uptake of N, P, and K decreases when grown in waterlogged soils (Glinski and Stepniewski,
1985). The data suggests that when soil nutrients are in short supply or out of balance, the root
dry yields are not as affected as are the shoots (Aung, 1974). However, none of the plants in our
study showed visual nutrient deficiency symptoms at any water-table depth.
45
Journal American Society Sugar Cane Technologists, Vol. 24, 2004
Table 1. Probability values from the analysis of variance for shoot and root parameters, for the
experiment conducted at Canal Point, Florida in 2000.
Source of
variation
Shoot dry
weight
Total root dry
weight
Total root
length
Avg. root
diameter
Root dry
weight (U)†
------------------------------ Probability > F -------------------------------------Water table
depth (D)
<0.01
0.77
0.87
0.69
0.66
Genotype (G)
<0.01
0.01
0.01
<0.01
<0.01
0.99
0.52
0.56
0.15
0.09
D*G
Continued
Source of
variation
Root length
(U)
Root
diameter (U)
Root dry
weight (L)†
Root
length (L)
Root
diameter (L)
------------------------------ Probability > F -------------------------------------Water table
depth (D)
0.77
0.63
0.92
0.91
0.57
<0.01
0.02
0.40
0.34
0.06
D*G
0.32
0.92
0.82
0.72
U = upper 0- to 15-cm soil layer and L = lower 15- to 30-cm soil layer.
0.03
Genotype (G)
†
46
Morris: Water Table Effects on Sugarcane Root and Shoot Development
Table 2. Shoot and root parameter mean comparisons in soil layers and across sugarcane genotypes.
Soil layer
Shoot dry weight†,
kg
Total root dry weight,
g
Total root length,
km
Average root diameter,
mm
Upper (0-15 cm)
-
131 A
2.2 A
0.68 B
Lower (15-30 cm)
-
45 B
0.8 B
0.71 A
Genotype
US 87-1006
1.8 abc
183 abcd
3.6 ab
0.69 bcd
US 94-1059
2.1 ab
155 bcd
3.0 bc
0.63 d
US 96-1082
1.2 cd
189 abcd
2.4 bc
0.73 ab
US 96-1083
1.5 bcd
190 abcd
3.6 ab
0.66 cd
US 96-1098
2.1 ab
238 a
5.0 a
0.63 d
US 96-1106
1.5 bcd
203 abc
3.3 bc
0.77 a
US 96-1107
2.2 a
223 ab
3.1 bc
0.72 abc
US 96-1112
1.5 bcd
188 abcd
3.1 bc
0.69 bc
US 96-1121
1.4 cd
166 abcd
2.7 bc
0.72 abc
CP 65-357
1.3 cd
147 bcd
2.1 bc
0.71 abc
CP 72-2086
1.5 bcd
114 d
1.8 c
0.72 abc
POJ 2725
1.1 d
129 cd
2.3 bc
0.68 bcd
†
Means among soil layers or genotypes followed by the same letter are not significantly different according to Duncan’s Multiple
Range Test (P = 0.05).
47
Journal American Society Sugar Cane Technologists, Vol. 24, 2004
Table 3. Correlations (r) of shoot and root dry weights with water table levels and average root diameters, total root lengths, and root
lengths within ten root diameter classes in the upper (U) 0- to 15 and lower (L) 15- to 30-cm soil layers.
Parameter
Root dry
weight
Water-table depth
0.65 **
-0.15 ns
Total root length
0.49 **
0.84 **
Root diameter, U
†
Shoot dry
weight†
-0.38 *
-0.02 ns
Parameter
Shoot dry
weight
Root dry
weight
-
-
-
Average root diameter
-0.36 *
<0.01 ns
Root diameter, L
-0.25 ns
0.03 ns
Root length, U
0.48 **
0.82 **
Root length, L
0.30 ns
0.61 **
<0.5-mm diam. class, U
0.25 ns
0.19ns
<0.5-mm diam. class, L
0.36 *
0.33 *
0.5- to 1.0-mm diam. class, U
0.09 ns
0.05 ns
0.5- to 1.0-mm diam. class, L
0.36 *
0.35 *
1.0- to1.5-mm diam. class, U
-0.10 ns
-0.12 ns
1.0- to 1.5-mm diam. class, L
0.20 ns
0.47 **
1.5- to 2.0-mm diam. class, U
-0.11 ns
-0.23 ns
1.5- to 2.0-mm diam. class, L
0.11 ns
0.38 *
2.0- to 2.5-mm diam. class, U
-0.35 ns
-0.07 ns
2.0- to 2.5-mm diam. class, L
-0.06 ns
0.19 ns
2.5- to 3.0-mm diam. class, U
-0.41 *
-0.05 ns
2.5- to 3.0-mm diam. class, L
-0.17 ns
0.15 ns
3.0- to 3.5-mm diam. class, U
-0.48 **
-0.04 ns
3.0- to 3.5-mm diam. class, L
-0.19 ns
0.16 ns
3.5- to 4.0-mm diam. class, U
-0.46 **
-0.12 ns
3.5- to 4.0-mm diam. class, L
-0.21 ns
0.17 ns
4.0- to 4.5-mm diam. class, U
-0.39 *
-0.09 ns
4.0- to 4.5-mm diam. class, L
-0.16 ns
0.10 ns
>4.5-mm diam. class, U
-0.28 ns
0.19 ns
>4.5-mm diam. class, L
-0.15 ns
"*” and “**” denotes significance at P < 0.05 and 0.01, respectively, while “ns” denotes non-significance at P > 0.05.
48
0.23 ns
Journal American Society Sugar Cane Technologists, Vol. 24, 2004
The roots in the pots had the potential to explore a greater volume of soil for increased
nutrient uptake, but did not do so as root dry weights in the upper and lower soil layers were
similar across water-table treatments (Table 1). Averaged across water-table treatments, 74 % of
the total root dry weight remained in the upper soil layer (Table 2). Gascho and Shih (1983)
reported that more than 50 % of sugarcane root dry weight was located in the top 20-cm layer of
soil. However, small variations can occur due to external factors such as surface irrigation and
application of fertilizer. Baran et al. (1974) irrigated sugarcane at 1, 2, and 3 wk intervals. In the
top 30-cm soil layer, they found 67 % of the roots with weekly irrigations, as opposed to 50 %
with irrigations every 3 weeks. Also, fertilizer applied to the surface soil encourages extensive
branching and growth of sugarcane roots around nutrient sources (Dillewijn, 1952). Across all
genotype and water-table treatments, sugarcane shoot dry weight was significantly correlated
with root dry weight in the upper (r = 0.49**) and not the lower (r = 0.21) soil layer (data not
shown). A desirable morphological characteristic of sugarcane appears to be one that produces
greater roots in the upper soil depth under <30-cm water tables, but if roots could be genetically
engineered to explore deeper soil layers, a greater volume of soil could be explored to scavenge
extra nutrients to increase crop yields.
Characteristics of sugarcane with increased shoot yield associated with root morphology
in the upper soil layer, based on significant correlation coefficients (P = 0.05), were smaller
average diameter roots and greater total root lengths (Table 3). Finer roots are associated with
younger roots, which are most active in water and nutrient uptake that is needed for increased top
growth (Barber and Silberbush, 1984; and Fageria et al., 1997). Greater root length along with
small root diameter is associated with greater nutrient uptake by roots and increased shoot yield
(Barber and Silberbush, 1984; and Mengel, 1985). Consequently, smaller (finer) average
diameter roots and greater total root lengths would indicate greater capacity for nutrient uptake
and increased shoot yield compared to larger diameter roots and lower total root lengths (Fageria
et al., 1997). Eavis (1972) and Webster and Eavis (1972) also reported smaller diameter roots in
sugarcane under waterlogged compared with drained soil. Eavis (1972) suggested the smaller
diameter root production was an adaptive mechanism to low O2 contents in the soil. He indicated
that a smaller diameter root would have less O2 demand and a lower diffusive path length for O2
compared with a large diameter root. Another desirable root morphology characteristic detected
in the upper soil layer for increased sugarcane yield was lower quantities of root lengths in the
2.5- to 4.5-mm root diameter classes (medium to older aged roots) (Table 3). These larger
diameter roots (older roots) may be less active in nutrient uptake compared with smaller diameter
(younger roots) (Baver et al., 1963).
Characteristics of sugarcane with increased shoot yield associated with root morphology
in the lower soil layer were not the same as in the upper soil layer (Table 3). Shoot dry weight
was not correlated with total root diameter or length in the lower soil layer. In addition, increased
root length in the <1-mm root diameter class (younger roots) in the lower layer was positively
correlated to shoot yields. Our data suggest there are discrete root sizes, probably related to
function, that affect shoot growth.
49
Morris: Water Table Effects on Sugarcane Root and Shoot Development
Root dry weight was positively correlated with total root length and with root length in the
upper and lower soil layers and was not correlated with average root diameter within either soil
layer (Table 3). Also, root dry weight in the upper soil layer was not correlated with root length
in any root diameter class. But, younger roots (<2.0-mm length) in the lower soil layer were most
associated with root dry weight compared to older roots in the upper or lower soil layers. It
appears that increases in root dry matter yield are related to production of new roots that
penetrate to lower depths for increased soil volume exploration to absorb nutrients needed for
biomass production.
Total root length in the upper and lower soil layers showed responses similar to root dry
weight (Table 2). About 73% of the total root length was located in the upper soil layer
regardless of water-table. But, there were larger diameter roots in the lower soil layer. Generally,
larger diameter roots are characteristic of root growth in aerobic compared to anaerobic soil
(Webster and Eavis, 1972), but in our study, the smaller diameter roots may be a reflection of a
greater number of younger roots in the upper soil layer compared to the lower layer due to a
more favorable environment for water and nutrient uptake in the surface soil. There was a
genotype by water-table interaction for root diameter in the lower soil layer (Table 1). The cause
of this interaction was due to slight variations in root diameters as water-table depth increased
for some genotypes (data not shown). Genotypes US 96-1006 and US 96-1083 tended to have a
larger root diameter (average 0.18 mm increase) in the flood compared to the drained and 15-cm
water-table treatments, while genotypes CP 72-2086 and POJ 2725 tended to have a higher root
diameter (average 0.20 mm increase) in the 15 cm water-table treatment compared to the drained
and flood treatments. All other genotypes had similar root diameters across water-table
treatments.
Analyses of variance for percentage of root lengths within the various root diameter
classes shows that water table was not significant in either soil layer, genotype was significant in
13 out of the 20 root distribution classes of both layers, and genotype by water-table interaction
was significant only in the lower layer in four out of the 10 analyses (Table 4).
Many root and shoot parameters and percentage root lengths within root diameter classes
were affected by genotype (Tables 1 and 4). Genotype US 96-1098 tended to have higher shoot
and root dry weight, greater total length, and smaller root diameters compared with other
genotypes, while genotype US 96 1106 tended to have lower shoot and medium root dry weight,
medium total root length, and large root diameters compared with the other genotypes (Table 2).
There was a trend for these genotypes to conform to significant correlations in the upper and
lower soil layers for percentage root lengths within the root diameter classes. For example, in the
upper soil layer, shoot yields were negatively correlated with percentage root lengths in the 2.5to 4.5-mm root diameter classes (Table 3), and genotype US 96-1098 tended to have the lower
percentage root lengths in those root diameter classes, while the opposite was true for genotype
US 96-1106 (Table 5). In the lower soil layer, shoot yields were positively correlated with the
percentage root lengths in the <1 mm root diameter classes (Table 3), and genotype US 96-1098
tended to have the higher percentages, while genotype US 96-1106 tended to have the lower
50
Journal American Society Sugar Cane Technologists, Vol. 24, 2004
percentages (Table 6). Because the genotypes often affected total root length, average root
diameter, and root length percentage within root diameter classes, this suggests that all the root
characteristics measured are heritable. Furthermore, our data suggest a root subsample taken
from a soil core could be scanned, and the percentage root lengths in the various root diameter
classes could be evaluated for yield potential of sugarcane growing in soil with water tables <30
cm. The entire sugarcane root system may not need to be excavated.
There were some root diameter classes that were non-responsive (no significant effect due
to water table, genotype, or water table by genotype interaction) (Table 4). This occurred in the
upper soil layer (1.0- to 1.5- and 2.0- to 2.5 and >4.5-cm diameters), which corresponds to two
out of the three non-responsive classes in the lower soil layer (<0.5-, 1.0- to 1.5-, and >4.5-cm
diameters) (Tables 5 and 6). The reason for the non-responsiveness of these discrete root sizes
could not be determined from this experiment.
A plot of the distribution of root lengths in the various root diameter classes revealed an
exponential relationship that was similar whether data were partitioned by soil depth, water-table
depth, or genotype (Fig. 1A, 1B, and 1C). Since all genotypes had a similar response, only three
are shown in Fig. 1C. About 85 % of the root lengths were <1-mm diameter. Our data indicate
that if large diameter (>2 mm) roots are collected from a sample and the root lengths measured,
then total root length could be estimated for any root diameter class using the exponential
function. However, additional research is needed to determine if this function would remain
valid for sugarcane growing under different conditions.
CONCLUSIONS
Sugarcane adaptation to high water tables in the Everglades is an important goal to reduce
soil organic matter oxidation that causes soil subsidence. Sugarcane shoots appear less tolerant
than roots to high water tables. Across genotype and water-table treatments, high shoot dry
yields were related to increased root dry weight, total root length, and small diameter roots.
Genotype US 96-1098 (high dry yield) and US 96 1106 (low dry yield) most closely conformed
to these relationships. Improvements in sugarcane shoot yields were also related to a lower
percentage of root lengths with larger diameters in the upper soil layer, and a higher percentage
of root lengths with smaller diameters in the lower soil layer. Root subsampling using soil cores
to evaluate percentage root lengths in various root diameter classes may be a viable method for
evaluating sugarcane for tolerance to water tables <30 cm. Field studies are needed to confirm
these observations.
51
American Society Sugar Cane Technologists, Vol. 24, 2004
Table 4. Probability values from the analyses of variance for root lengths within root diameter classes.
Upper 0- to 15-cm soil layer
Source of
variation
Root diameter class, mm
<0.5
0.5-1.0
1.0-1.5
1.5-2.0
2.0-2.5
2.5-3.0
3.0-3.5
3.5-4.0
4.0-4.5
>4.5
---------------------------------------------------------- Probability > F ---------------------------------------------------------------Water
table
depth (D)
0.65
0.94
0.70
0.50
0.62
0.99
0.50
0.36
0.45
0.55
Genotype
(G)
<0.01
<0.01
0.09
<0.01
0.06
0.01
0.01
0.02
0.05
0.27
D*G
0.80
0.30
Lower 15- to 30-cm soil layer
0.36
0.94
0.99
0.50
0.98
0.86
0.81
0.79
3.0-3.5
3.5-4.0
4.0-4.5
>4.5
Source of
variation
Root diameter class, mm
<0.5
0.5-1.0
1.0-1.5
1.5-2.0
2.0-2.5
2.5-3.0
---------------------------------------------------------- Probability > F ---------------------------------------------------------------Water
table
depth (D)
0.63
0.43
0.40
0.92
0.77
0.46
0.40
0.33
0.29
0.31
Genotype
(G)
0.08
<0.01
0.07
0.26
0.02
<0.01
0.02
0.05
0.03
0.17
D*G
0.17
0.92
0.37
0.04
0.02
<0.01
0.06
0.07
0.11
0.20
52
Morris: Water Table Effects on Sugarcane Root and Shoot Development
Table 5. Genotype root length as a percentage of total length for different root diameter classes in the upper 0- to 15-cm soil layer.
Root diameter classes, mm†
Genotype
<0.5
0.5-1.0
1.0-1.5
1.5-2.0
2.0-2.5
2.5-3.0
3.0-3.5
3.5-4.0
4.0-4.5
>4.5
--------------------------------------------------- Percentage of total root length --------------------------------------------------US 87-1006
56 abc
26 ab
9.0‡
4.1 cde
2.8‡
1.2 abc
0.62 bcd
0.27 cd
0.12 bc
0.11‡
US 94-1059
59 a
24 bc
8.6
4.1 cde
2.3
0.9 c
0.37 d
0.16 d
0.07 c
0.06
US 96-1082
54 bc
26 ab
9.4
4.4 abcd
3.2
1.6 a
0.88 abc
0.44 abc
0.22 abc
0.29
US 96-1083
59 a
25 abc
8.3
3.6 e
2.4
1.2 abc
0.51 d
0.25 cd
0.10 c
0.09
US 96-1098
59 a
25 abc
8.6
3.8 de
2.3
1.0 bc
0.39d
0.17 d
0.08 c
0.07
US 96-1106
57 ab
23 c
8.7
4.1 cde
3.1
1.7 a
1.01 a
0.51 a
0.30 a
0.83
US 96-1107
52 c
27 a
9.9
5.1 a
3.0
1.3 abc
0.61 bcd
0.29 bcd
0.13 bc
0.15
US 96-1112
53 bc
26 ab
9.5
4.6 abc
3.3
1.7 a
0.88 abc
0.43 abc
0.27 ab
0.35
US 96-1121
53 bc
27 a
8.9
4.2 bcde
3.2
1.7 a
0.93 ab
0.50 ab
0.26 ab
0.46
CP 65-357
55 abc
26 ab
8.9
4.3 bcde
3.0
1.5 ab
0.69 abcd
0.34 abcd
0.18 abc
0.25
CP 72-2086
53 bc
26 ab
10.2
4.9 ab
2.8
1.2 abc
0.58 cd
0.26 cd
0.12 bc
0.12
POJ 2725
57 ab
25 abc
8.8
4.1 cde
2.7
1.3 abc 0.70 abcd
0.34 abcd 0.17 abc
0.24
Means of percentage root lengths within each column followed by the same letter are not significantly different according to
Duncan’s Multiple Range Test (P = 0.05).
‡
There were no statistically significant differences among genotype means (P < 0.05).
†
53
American Society Sugar Cane Technologists, Vol. 24, 2004
Table 6. Genotype root length as a percentage of total length for different root diameter classes in the lower 15- to 30-cm soil layer.
Root diameter classes, mm†
Genotype
<0.5
0.5-1.0
1.0-1.5
1.5-2.0
2.0-2.5
2.5-3.0
3.0-3.5
3.5-4.0
4.0-4.5
>4.5
--------------------------------------------------- Percentage of total root length --------------------------------------------------US 87-1006
52‡
27 ab
10.3‡
4.5‡
2.9 bc
1.4 bc
0.77 bc
0.41 b
0.23 bc
0.37‡
US 94-1059
56
26 b
9.7
4.2
2.5 c
1.1 c
0.56 c
0.26 b
0.11 c
0.14
US 96-1082
51
26 b
10.5
4.9
3.5 ab
1.8 ab
0.98 ab
0.50 ab
0.22 bc
0.21
US 96-1083
54
25 bc
9.5
4.4
2.9 bc
1.4 bc
0.81 bc
0.43 b
0.23 bc
0.43
US 96-1098
56
26 b
9.0
4.1
2.5 c
1.3 bc
0.61 c
0.31 b
0.14 bc
0.23
US 96-1106
52
23 c
9.9
5.0
3.8 a
2.3 a
1.25 a
0.73 a
0.46 a
0.83
US 96-1107
49
29 a
10.9
4.9
3.0 bc
1.4 bc
0.70 bc
0.38 b
0.18 bc
0.25
US 96-1112
54
26 b
9.5
4.4
2.8 bc
1.4 bc
0.61 c
0.31 b
0.17 bc
0.23
US 96-1121
54
26 b
8.9
4.2
2.9 bc
1.5 bc
0.80 bc
0.43 b
0.21 bc
0.39
CP 65-357
54
25 bc
9.7
4.7
3.1 abc
1.7 b
0.87 bc
0.42 b
0.26 bc
0.34
CP 72-2086
51
27 ab
9.6
4.9
3.3 ab
1.7 b
0.90 abc
0.48 ab
0.30 ab
0.38
POJ 2725
55
25 bc
9.0
4.4
2.8 bc
1.4 bc
0.70 bc
0.41 b
0.22 bc
0.27
Means of percentage root lengths within each column followed by the same letter are not significantly different according to
Duncan’s Multiples Range Test (P = 0.05).
‡
There were no statistically significant differences among genotype means (P < 0.05).
†
54
Morris: Water Table Effects on Sugarcane Root and Shoot Development
55
American Society Sugar Cane Technologists, Vol. 24, 2004
REFERENCES
1.
Andreis, H.J. 1976. A water table study on an Everglades peat soil: effects of sugar cane
and on soil subsidence. Sugar J. 39(6):8-12.
2.
Aung, L.H. 1974. Root-shoot relationships. Pages 29-61. In: The Plant Root and Its
Environment, E.W. Carson, ed. Univ. Press Virginia, Charlottesville, VA.
3.
Baran, R., D. Bassereau, and N. Gillet. 1974. Measurement of available water and root
development on an irrigated sugar cane crop in the Ivory Coast. Proc. Int. Soc. Sugar
Cane Technol. 15(2):726-735.
4.
Barber, S.A., and M. Silberbush. 1984. Plant root morphology and nutrient uptake. Pages
65-87. In: Roots, Nutrients and Water Influx, and Plant Growth, S.A. Barber and D.R.
Bouldin, eds. ASA Spec. Publ. 49. Madison, WI.
5.
Baver, L.D., H.W. Brodie, T. Tanimoto, and A.C. Trouse. 1963. New approaches to the
study of cane root systems. Proc. Int. Soc. Sugar Cane Technol. 11:248-253.
6.
Deren, C.W., and R.N. Raid. 1997. Yield components of sugarcane subjected to flood at
planting. J. Am. Soc. Sugar Cane Technol. 17:28-37.
7.
Dillewijn. C.V. 1952. Botany of Sugarcane. The Chronica Botanica Co. Waltham, MA.
8.
Drew, M.C. 1997. Oxygen deficiency and root metabolism: Injury and acclimation under
hypoxia and anoxia. Ann. Rev. Plant Physiol. and Plant Mol. Biol. 48:223-250.
9.
Eavis, B.W. 1972. Effects of flooding on sugarcane growth 2. Benefits during subsequent
drought. Proc. Int. Soc. Sugar Cane Technol. 14:715-721.
10.
Fageria, N.K., V.C. Baligar, and R.J. Wright. 1997. Soil environment and root growth
dynamics of field crops. Rec. Res. Devel. Agron. 1:15-57.
11.
Gascho, G. J., and S. F. Shih. 1983. Sugarcane. Pages 445-479. In: Crop-Water Relations
I.D. Teare and M.M. Peet, eds. John Wiley & Sons. New York.
12.
Glaz, B. 1998. Sugarcane variety census: Florida 1998. Sugar y Azucar. 93(12):30-34,
36-37.
13.
Glaz, B., S.J. Edme, J.D. Miller, S.B. Milligan, and D.G. Holder. 2002. Sugarcane
cultivar response to high summer water tables in the Everglades. Agron. J. 94:624-629.
56
Morris: Water Table Effects on Sugarcane Root and Shoot Development
14.
Glinski, J., and W. Stepniewski. 1985. Soil Aeration and Its Role for Plants. CRC Press,
Inc. Boca Raton, FL.
15.
Gosnell, J.M. 1972. Some effects of a water table level on the growth of sugarcane. Proc.
Int. Soc. Sugar Cane Technol. 14:841-849.
16.
Helmke, P.A., and D.L. Sparks. 1996. Lithium, sodium, potassium, rubidium, and
cesium. Pages 551-601. In: Methods of Soil Analysis, Part 3. Chemical Methods, D.L.
Sparks, A.L. Page, P.A. Helmke, R.H. Leoppert, P.N. Soltanpour, M.A. Tabatabai, C.T.
Johnston, and M.E. Sumner, eds. SSSA No. 5. Madison, WI.
17.
Izuno, F.T., R.W. Rice, and L.T. Capone. 1999. Best management practices to enable the
coexistence of agriculture and the Everglades environment. Hort. Sci. 34:27-33.
18.
Juang, T.C., and G. Uehara. 1972. Effects of ground-water table and soil compaction on
nutrient element uptake and growth of sugarcane. Proc. Int. Soc. Sugar Cane Technol.
14:679-687.
19.
Kozlowski, T.T., and S.G. Pallardy. 1984. Effect of flooding on water, carbohydrate, and
mineral nutrition. Pages 165-193. In: Flooding and Plant Growth, T. T. Kozlowski, ed.
Academic Press, Inc. New York.
20.
Kuo, S. 1996. Phosphorus. Pages 869-920. In: Methods of Soil Analysis, Part 3.
Chemical Methods, D.L. Sparks, A.L. Page, P.A. Helmke, R.H. Leoppert, P.N.
Soltanpour, M.A. Tabatabai, C.T. Johnston, and M.E. Sumner, eds. SSSA No. 5.
Madison, WI.
21.
Mengel, K. 1985. Dynamics and availability of major nutrients in soils. Adv. Soil Sci.
2:67-131.
22.
Miller, J.D., P.Y.P. Tai, B. Glaz, J.L. Dean, and M.S. Kang. 1983. Registration of CP 722086 sugarcane. Crop Sci. 24:210.
23.
Nelson, D.W., and L.E. Sommers. 1996. Total carbon, organic carbon, and organic
matter. Pages 961-1010. In: Methods of Soil Analysis, Part 3. Chemical Methods, D.L.
Sparks, A.L. Page, P.A. Helmke, R.H. Leoppert, P.N. Soltanpour, M.A. Tabatabai, C.T.
Johnston, and M.E. Sumner, eds. SSSA No. 5. Madison, WI.
24.
Paz-Vergara, J.E., A. Vasquez, W. Iglesias, and J.C. Sevilla. 1980. Root development of
the sugarcane cultivars H32-8560 and H57-5174, under normal conditions of cultivation
and irrigation in the Chicama valley. Proc. Int. Soc. Sugar Cane Technol. 17(1):534-540.
25.
Rahman, A.B.M.M., F.A. Martin, and M.E. Terry. 1986. Growth response of Saccharum
spp. to flooding. Proc. Int. Soc. Sugar Cane Technol. 19(1):236-244.
57
American Society Sugar Cane Technologists, Vol. 24, 2004
26.
Ray, J.D., and T.R. Sinclair. 1999. Sugarcane transpiration response to drying soil. Sugar
Cane International. Aug:5-8.
27.
Rege, R.D. and J.P. Mascarenhas. 1956. Studies on the influence of floods on cane
growth and quality in the Pamba River Valley. Proc. Int. Soc. Sugar Cane Technol.
9(1):375-388.
28.
Rostron, H. 1974. Radiant energy interception, root growth, dry matter production and
the apparent yield potential of two sugarcane varieties. Proc. Int. Soc. Sugar Cane
Technol. 15(2):1001-1010.
29.
Russell, R.S. 1977. Plant Root Systems: Their Function and Interaction with the Soil.
McGraw-Hill Book Co. New York.
30.
SAS. 1990. SAS/STAT User’s Guide, vol. 1 and 2. Ver 6. 4th Edition. SAS Institute, Inc.
Cary, NC.
31.
Shih, S.F., B. Glaz, and R.E. Barnes, Jr. 1998. Subsidence of organic soils in the
Everglades Agricultural Area during the past 19 years. Soil Crop Sci. Soc. Florida Proc.
57:20-29.
32.
Smucker, A.J.M., S.L. McBurney, and A.K. Srivastava. 1982. Quantitative separation of
roots from compacted soil profiles by the hydropneumatic elutriation system. Agron. J.
74:500-503.
33.
Snyder, G.H., H.W. Burdine, J.R. Crockett, G.J. Gascho, D.S. Harrison, G. Kidder, J.W.
Mishoe, D.L. Myhre, F.M. Pate, and S.F. Shih. 1978. Water table management for
organic soil conservation and crop production in the Florida Everglades. Univ. Florida
Agr. Exp. Stat. Bull. 801. Gainesville, FL.
34.
Tai, P.Y.P. 1993. Low temperature preservation of F1 pollen in crosses between noble or
commercial sugarcane and Saccharum spontaneum L. Sugar Cane. 5:8-11.
35.
Tai, P.Y.P., and J.D. Miller. 1996. Field test for leaf cold tolerance in sugarcane. J. Am.
Soc. Sugar Cane Technol. 16:39-49.
36.
Thomas, G.W. 1996. Soil pH and soil acidity. Pages 475-490. In: Methods of Soil
Analysis, Part 3. Chemical Methods, D.L. Sparks, A.L. Page, P.A. Helmke, R.H.
Leoppert, P.N. Soltanpour, M.A. Tabatabai, C.T. Johnston, and M.E. Sumner, eds. SSSA
No. 5. Madison, WI.
37.
Webster, P.W.D., and B.W. Eavis. 1972. Effects of flooding on sugarcane growth 1.
Stage of growth and duration of flooding. Proc. Int. Soc. Sugar Cane Technol. 14:708714.
58
Morris: Water Table Effects on Sugarcane Root and Shoot Development
38.
WinRhizo. 2001. Basic, Regular, and Pro for Washed Root Measurement. v. 2002a.
Regent Instruments, Inc. Montreal, Canada.
39.
Zelazny, L.W., and W.H. Carlisle. 1974. Physical, chemical, elemental and oxygencontaining functional group analysis of selected Florida Histosols. Pages 63-78. In:
Histosols, R.C. Dinauer, ed. Special Publ. No. 6, SSSA. Madison, WI.
59