Growth and physiological responses of sugarcane to drought stress at an early growth stage

olic strategies 
for survival. For instance, plants can synthesize 
antioxidants such as ascorbate, glutathione, and 
flavonoids (Medeiros et al., 2013), together 
with increasing the activity of antioxidant 
enzymes including peroxidase, superoxide 
dismutase, and catalases. 
SPAD readings and maximum photochemical 
efficiency (Fv/Fm) 
The maximum photochemical efficiency 
(Fv/Fm) is positively correlated with the 
photosynthesis rate of a plant and thus, is used as 
an important parameter for quantifying a plant’s 
response to drought stress (Silva et al., 2013). 
Maintaining a similar Fv/Fm ratio between plants 
under drought stress and plants under well-
irrigated conditions indicates a high efficiency of 
carbon assimilation and hence, the plant is better 
able to adapt to the stressed conditions (Silva et 
al., 2007). No significant differences in the 
Fv/Fm ratios were found among all the cultivars 
at 100 and 110 DAP. All the cultivars had a 
Fv/Fm ratio of 0.74 to 0.78. However, at 120 
DAP (20 days of withholding water), significant 
differences in the Fv/Fm ratios were observed 
Bui The Khuynh et al. (2019) 
https://vjas.vnua.edu.vn/ 457 
Table 4. SPAD meter readings and Fv/Fm ratios of different sugarcane cultivars before (100 days after planting, DAP), after 10 
days (110 DAP), and after 20 days of drought (120 DAP) 
Treatment 
Fv/Fm SPAD readings 
100 DAP 110 DAP 120 DAP 100 DAP 110 DAP 120 DAP 150 DAP 
ROC10 FC 0.765 0.776 0.742 53.6 43.3 45.5 39.0 
Stressed 0.767 0.764 0.633 51.0 44.2 36.9 44.4 
ROC16 FC 0.791 0.786 0.773 52.2 46.0 44.2 42.8 
Stressed 0.781 0.741 0.679 52.7 45.2 40.1 44.3 
ROC22 FC 0.788 0.784 0.738 50.7 45.7 45.7 42.6 
Stressed 0.786 0.704 0.581 53.5 46.1 40.9 44.9 
QĐ93-
159 
FC 0.780 0.771 0.755 48.3 46.8 43.7 41.7 
Stressed 0.775 0.756 0.550 53.6 46.1 34.0 43.1 
VL06 FC 0.764 0.780 0.752 47.7 44.2 43.9 39.1 
Stressed 0.783 0.701 0.610 52.2 45.3 36.4 42.6 
LSD 0.05C*W 0.211 0.161 0.427 4.5 1.9 2.9 2.1 
Mean ROC10 0.766 0.770 0.687 52.3 43.8 41.2 41.7 
ROC16 0.786 0.763 0.726 52.4 45.6 42.2 43.5 
ROC22 0.787 0.744 0.659 52.1 45.9 43.3 43.8 
QĐ93-159 0.778 0.763 0.653 51.0 46.4 38.9 42.4 
VL06 0.773 0.762 0.681 49.9 44.8 40.2 40.9 
LSD0.05C 0.149 0.114 0.303 3.2 1.4 2.1 1.4 
Mean FC 0.778 0.779 0.752 50.5 45.2 44.6 41.2 
Stressed 0.778 0.742 0.610 52.6 45.3 37.7 43.9 
LSD 0.05W 0.145 0.132 0.191 2.2 0.9 1.3 2.0 
CV% 1.6 1.2 3.7 5.1 2.5 4.2 2.7 
Note: C: cultivar; W: water treatment; FC: field capacity (control); Stressed: drought treatment.
among cultivars. The highest Fv/Fm ratio value 
was found in ROC16 (0.726) while the rest of 
the cultivars had no significant differences. 
Drought stress only led to a significant 
reduction in the Fv/Fm ratio in the stressed 
treatment compared with the control at 120 
DAP (20 days of water withholding). A Fv/Fm 
ratio value of less than 0.75 indicates the 
beginning of stress and, therefore, a reduction 
in the photosynthetic capacity of the plant 
(Maxwell & Johnson, 2010). Low values of the 
Fv/Fm ratio have also been reported by Graca 
et al. (2010) and Silva et al. (2007) in 
sugarcane under severe drought. 
A SPAD chlorophyll meter reading (SCMR) 
is considered a rapid assessment of the 
chlorophyll content in many crops including 
sugarcane, corn, and papaya (Jangproma et al., 
2010). Our results showed that drought 
significantly reduced the SCMRs of plants under 
stressed conditions at the end of the drought 
stress treatment (120 DAP), which was 
consistent with the findings of Silva et al. (2007). 
A drought imposed 90 DAP led to reductions in 
the SCMRs, and more severe reductions were 
recorded in susceptible genotypes. SCMRs, 
therefore, can be used for the identification of 
drought-tolerant genotypes (Silva et al., 2007). 
Significant differences in the SCMRs were 
observed among the five cultivars at the end of 
the drought stress treatment. The highest mean 
SCMR value was recorded in ROC22 (43.8), 
followed by ROC16 (42.2), and was lowest in 
QĐ93-159 (38.6). Under stressed conditions, the 
Growth and Physiological Responses of Sugarcane to Drought Stress at an Early Growth Stage 
458 Vietnam Journal of Agricultural Sciences 
SCMRs were maintained at an average of 40 in 
ROC22 and ROC16, which were significantly 
higher compared to those in ROC10, VL06, and 
QĐ93-159. This suggests a higher capacity of the 
ROC22 and ROC16 plants to conserve their 
photosynthetic pigment content during drought 
stress. According to Silva et al. (2013), a SCMR 
below 40 in sugarcane indicates the start of 
chlorophyll deficiency, which affects the 
photosynthetic activities of the plants. Thus, the 
low SCMRs (below 40) recorded in ROC10, 
VL06, and QĐ93-159 indicate drought stress 
sensitivities. No significant difference in terms of 
the SCMRs was found between the control and 
stressed treatments at 30 days after re-watering 
(150 DAP). 
Plant fresh weight, leaf area (LA), and 
drought tolerance index (DTI) at recovery 
(150 DAP) 
Sugarcane plants exposed to prolonged 
drought have been reported to experience a 
reduction in growth (Jaiphong et al., 2016). Our 
results showed that root, leaf, and stem fresh 
weights, and leaf area were significantly reduced 
in plants under the drought treatment relative to 
the control (Table 5). Fresh root weight was 
reduced by 51.5% compared to the drought stress 
treatment at 150 DAP. This matches with the 
findings in early studies by Medeiros et al. 
(2013), Jaiphong et al. (2016), and Silva et al. 
(2013). Significant differences in root fresh 
weight, leaf fresh weight, stem fresh weight, and 
Table 5. Effects of drought stress at an early stage on the plant fresh weight, leaf area, and drought tolerance index (DTI) of five 
cultivars at 150 DAP 
Treatment 
Root fresh weight 
(g plant-1) 
Leaf fresh weight 
(g plant-1) 
Stem fresh weight 
(g plant-1) 
Leaf area 
(cm2) 
Drought tolerance 
index (DTI) 
ROC10 FC 57.2 158.6 79.3 18.2 - 
Stressed 30.7 76.5 46.1 9.5 0.59 
ROC16 FC 50 188.8 71.2 22.5 - 
Stressed 31.3 78.8 46.2 10.5 0.69 
ROC22 FC 93.1 176.5 96.7 23 - 
Stressed 41.3 115.6 50.6 17.1 0.55 
QĐ93-159 FC 58.1 164.6 80.5 14.9 - 
Stressed 21.2 82.5 46.5 8.8 0.57 
VL06 FC 46.5 91.3 64.7 17.2 - 
Stressed 26.7 54.9 44.4 5.7 0.68 
LSD 0.05C*W 4.1 10.5 4.4 1.9 
Mean ROC10 43.9 117.5 62.7 13.9 
ROC16 40.6 133.8 58.7 16.5 
ROC22 67.2 146.1 73.6 20.1 
QĐ93-159 39.6 123.5 63.5 11.8 
VL06 36.6 73.1 54.5 11.4 
LSD0.05C 2.8 7.4 3.1 1.3 
Mean FC 60.9 155.9 78.5 19.2 
Stressed 30.2 81.6 46.8 10.3 
LSD 0.05W 1.8 4.7 2 0.9 
CV% 5.2 5.2 4.2 7.8 
Note: C: cultivar; W: water treatment; FC: field capacity (control); Stressed: drought treatment.
Bui The Khuynh et al. (2019) 
https://vjas.vnua.edu.vn/ 459 
leaf area were found among sugarcane cultivars. 
The mean values of stem fresh weight ranged 
from 54.5g (in VL06) to 73.6g (in ROC22). 
Significant differences in stem fresh weight and 
leaf area were also found among the cultivars 
under drought stress. The highest value of stem 
fresh weight under stressed conditions was 
recorded in ROC22 (50.6g), followed by QĐ93-
159 (46.5g), ROC16 (46.2g), ROC10 (46.1g), 
and VL06 (44.4g). Leaf area also varied among 
the sugarcane cultivars and ranged from 11.4cm2 
in VL06 to 20.1cm2 in ROC22. A reduction in 
plant growth under water deficit conditions can 
be seen as the consequence of the decrease in cell 
elongation caused by the interruption of water 
flow from the xylem to surrounding elongation 
cells, the increase in cell sap concentration, and 
the dehydration of the protoplasm (Nonami, 
1998; Larcher, 2003). Low biomass 
accumulation of sugarcane, when exposed to 
drought stress, can be explained by reductions in 
light interception, plant extension rate, and 
photosynthetic capacity (Koonjah et al., 2006). 
The drought tolerance index (DTI) has been used 
as an important parameter in evaluating the 
tolerance ability of crops. Among the sugarcane 
cultivars, the highest DTI was recorded in 
ROC16, followed by VL06, ROC10, QĐ93-159, 
and ROC22, respectively. 
Conclusions 
Drought stress at an early growth stage (100-
120 DAP) significantly affected the growth and 
physiological characteristics of five sugarcane 
cultivars. A 20-day water withholding treatment 
resulted in reductions in plant height, stalk 
diameter, and leaf number of sugarcane, in 
addition to reductions in photosynthetic pigment 
content, Fv/Fm, and SPAD readings at 120 DAP, 
and in stem, root, and leaf fresh weights, and leaf 
area at 150 DAP (30 days after re-watering). 
Furthermore, drought stress led to reductions in 
stomatal density and increases in stomatal length. 
Variation was also found among the cultivars in 
response to drought stress. The highest value of 
stem fresh weight under stressed conditions was 
recorded in ROC22 (50.6g), followed by QĐ93-
159 (46.5g), ROC16 (46.2g), ROC10 (46.1g), 
and VL06 (44.4g). However, the highest DTI 
was recorded in ROC16, followed by VL06, 
ROC10, QĐ93-159, and ROC22, respectively. 
Conflicts of Interest 
The authors declare no conflicts of interest. 
References 
Amalraj R. S., Selvaraj N., Veluswamy G. K., Rananujan 
R. P., Muthurajan R. & Palaniyandi M. (2010). 
Sugarcane proteomics: Establishment of a protein 
extraction method for 2-DE in stalk tissues and 
initiation of sugarcane proteome reference map. 
Electrophoresis. 31: 1959-1974. 
Arnon D. I. (1949). Copper enzymes in isolated 
chloroplasts, polyphenoxidase in Beta vulgaris. Plant 
Physiology. 24(1): 1-15. 
Ashraf M. & Harris P. J. C. (2013). Photosynthesis under 
stressful environments: An overview. Photosynthetica. 
51(2): 163-190. 
Begcy K., Mariano E. D., Gentile A., Lembke C. G., 
Zingaretti S. M., Souza G. M. & Menossi M. (2012). 
A novel stress-induced sugarcane gene confers 
tolerance to drought, salt and oxidative stress in 
transgenic tobacco plants. PLoS One. 7:e44697. 
Camargo M. A. B. & Marenco R. A. (2011). Density, size 
and distribution of stomata in 35 rainforest tree species 
in Central Amazonia. Acta Amazonia. 41(2): 205-212. 
Chaves M. M., Maroco J. P. & Pereira J. S. (2003). 
Understanding plant responses to drought-from genes 
to the whole plant. Functional Plant Biology. 30: 239-
264. 
Farooq M., Hussain M., Wahid A. & Siddique K. H. M. 
(2012). Drought stress in plants: an overview. In: 
Aroca R. (Eds.) Plant responses to drought stress. 
Springer, Berlin/Heidelberg. 1-33. 
Graça J. P., Rodrigues F. A., Farias J. R. B., Oliveira M. C. 
N., Hoffmann-Campo C. B. & Zingaretti S. M. (2010). 
Physiological parameters in sugarcane cultivars 
submitted to water deficit. Brazilian Journal of Plant 
Physiology. 22: 189-197. 
Hoang D. T., Hiroo T. & Yoshinobu K. (2018). Nitrogen 
use efficiency and drought tolerant ability of various 
sugarcane varieties under drought stress at early 
growth stage. Plant Production Science. 22: 250-261. 
Jaiphong T., Tominaga J., Watanabe K., Nakabaru M., 
Takaragawa H., Suwa R., Ueno M. & Kawamitsu Y 
(2016). Effects of duration and combination of drought 
and flood conditions on leaf photosynthesis, growth 
and sugar content in sugarcane, Plant Production 
Science. 19: 427-437. 
Jangpromma N., Thammasirirak S., Jailsil P. & Songsri P. 
(2012). Effects of drought and recovery from drought 
Growth and Physiological Responses of Sugarcane to Drought Stress at an Early Growth Stage 
460 Vietnam Journal of Agricultural Sciences 
stress on above ground and root growth, and water use 
efficiency in sugarcane (Saccharum officinarum L.). 
Australian Journal of Crop Science. 6: 1298-1304. 
Jangpromma N., Songsri P. & Jaisil P. (2010). Rapid 
assessment of chlorophyll content in sugarcane using a 
SPAD chlorophyll meter across different water stress 
conditions. Asian Journal of Plant Science. 9: 368-374. 
Koonjah S. S., Walker S., Singels A., Van Antwerpen R. 
& Nayamuth A. R. (2006). A quantitative study of 
water stress effect on sugarcane 
photosynthesis. Proceedings of the South African 
Sugarcane Technologists’ Association. 80: 148-158. 
Larcher W. (2003). Physiological plant ecology: 
Ecophysiology and stress physiology of functional 
groups (4th ed). Springer-Verlag. 401-416. 
Mafakheri A., Siosemardeh A. & Bahramnejad B. (2010). 
Effect of drought stress on yield, proline and 
chlorophyll contents in three chickpea cultivars. 
Australian Journal of Crop Science. 4: 580-585. 
Maxwell K. & Johnson G. N. (2000). Chlorophyll 
florescence: a practical guide. Journal of Experimental 
Botany. 51: 659-668. 
Meng L., Li L., Chen W., Xu Z. & Liu L. (1999). Effect of 
water stress on stomatal density, length, width and net 
photosynthetic rate in rice leaves. Journal of Shenyang 
Agricultural University. 30: 477-480. 
Medeiros D. B., Silva E. C., Nogueira R. J. M. C., Teixeira 
M. M., Buckeridge M. S. (2013). Physiological 
limitations in two sugarcane varieties under water 
suppression and after recovering. Theoretical and 
Experimental Plant Physiology. 25: 213-222. 
Nonami H. (1998). Plant water relations and control of cell 
elongation at low water potentials. Journal of Plant 
Research. 111: 373-382. 
Robertson M. J., Inman-Bamber N. G., Muchow R. C. & 
Wood A. W. (1999). Physiology and productivity of 
sugarcane with early and mid-season water deficit. 
Field Crop Research. 64: 211-227. 
Reddy T. Y., Reddy V. R. & Anbumozhi V. (2003). 
Physiological response of groundnut (Arachis hypogea 
L.) to drought stress and its amelioration: A critical 
review. Plant Growth Regulation. 41: 75-88. 
Silva M. A., Jifon J. L., Santos C. M., Jadoski C. J. & Silva 
J. A. G. (2013). Photosyntheitc capacity and water use 
efficiency in sugarcane genotypes subject to water 
deficit during early growth phase. Brazilian Archives 
of Biology and Technology. 56: 735-748. 
Silva M. A., Jifon J. L., Silva J. A. G. & Sharma V. (2007). 
Use of physiological parameters as fast tools to screen 
for drought tolerance in sugarcane. Brazilian Journal 
of Plant Physiology. 19: 735-748. 
Silva M. A., Silva J. A. G., Enciso J., Sharma V. & Jifon J. 
(2008). Yield components as indicators of drought 
tolerance of sugarcane. Scientia Agricola. 65: 620-627. 
Smith D. M., Inman-Bamber N. G. & Thorburn P. J. (2005). 
Growth and function of the sugarcane root system. 
Field Crops Research. 92: 169-183. 
Xu Z. & Zhou Z. (2008). Responses of leaf stomatal density 
to water status and its relationship with photosynthesis 
in a grass. Journal of Experimental Botany. 59: 3317-
3325. 
Yang L., Han M., Zhou G. & Li J. (2007). The changes of 
water-use efficiency and stoma density of Leymus 
chinensis along Northeast China Transect. Acta 
Ecologica Sinica. 27: 16-24.