Effect of drought stress on water relation traits of four soybean genotypes

Abstract

An experiment was conducted in a venyl house at the environmental stress site of Bangabandhu Sheikh Mujibur Rahman Agricultural University during September to December 2012 to know the internal water status under drought stress in soybean genotypes, viz. Shohag, BARI Soybean-6, BD2331 (relatively stress tolerant) and BGM2026 (susceptible). Drought (water) stress reduced the leaf water potential in all the genotypes though was more negative in tolerant genotypes than in susceptible ones. The lowest leaf water potential was obtained from BARI Soybean-6 (-1.58 MPa) and the highest in BGM2026 (-1.2 MPa). Relative water content (RWC) decreased remarkably in all the genotypes and reduction was more in susceptible than tolerant genotypes. At 8.00 am, RWC of stressed plants decreased by 9.58, 9.02, 8.90 and 13.90% in the genotype Shohag,, BARI Soybean-6, BD2331 and BGM2026 at vegetative stage, respectively. Drought stress decreased the exudation rate in all the genotypes of soybean and it was 24, 27, 22 and 12 mg h -1 in the genotype Shohag, BARI Soybean-6, BD2331 and BGM2026 at vegetative stage, respectively. Leaf temperatures in drought stressed plant were higher than in well-watered plants. Shohag, BARI Soybean-6, BD2331 and BGM2026 showed 4.7, 4.5 5.2 and 11.07% increase in leaf temperature due to water stress. At drought stressed treatment reduction in leaf water potential, relative water content, exudation rate and water retention capacity were noticed at the three growth stages in all the genotypes with a concurrent increase in leaf temperature. Genotypes BARI Soybean-6, Shohag and BD2331 showed considerably less reduction in relative water content, exudation rate and water retention capacity, high reduction in leaf water potential and less increase in leaf temperature during drought were considered as drought tolerant. However genotype BGM2026 showed considerably high reduction in relative water content, exudation rate and water retention capacity, low reduction in leaf water potential and high increase in leaf temperature was considered as drought susceptible.Keywords: Drought, stress, soybean, genotypes INTRODUCTION Water is absolutely necessary for the functioning of protoplasm of cell. Water deficit stress affects water status in plant. Thus adequacy and inadequacy of water are the limiting factors for life both in land and water environment (Onwugbuta-Enyi, 2004). Several methods are used to characterize plant water status under water stress conditions. Determination of water relation components in whole plant or cellular level is important for determination of tolerance genotypes to environmental stresses especially to water deficit stress. It may be possible to improve the water stress tolerance of soybean by understanding the water relation parameters that are associated with high productivity. Among the several methods used to characterize internal plant water status under water stress conditions, relative water content and leaf water potential are used as the indicators of degree of water stres...

Morphophysiological and biochemical response of mungbean [<i>Vigna radiata</i> (L.) Wilczek] varieties at different developmental stages under drought stress

“…It was observed that drought conditions have negative impact on water balance, and hence decrease the water potential of leaves. Therefore, RWC indicates the degree of drought stress, as previous studies have reported that higher decreases in water potential were observed in drought-susceptible varieties than in drought-tolerant varieties (Parvin et al, 2015; Chowdhury et al, 2017) .…”

“…It was observed that drought conditions have negative impact on water balance, and hence decrease the water potential of leaves. Therefore, RWC indicates the degree of drought stress, as previous studies have reported that higher decreases in water potential were observed in drought-susceptible varieties than in drought-tolerant varieties (Parvin et al, 2015;Chowdhury et al, 2017). In this study, the highest percentage decrease in RWC was observed in varieties TARM-1 (19.52%) and PDM-139 (16.6%); the lowest percentage decrease in RWC was recorded in varieties MCV-1 (1.82%) and V. sublobata (1.5%) during the vegetative and reproductive stages, respectively.…”

Effects of seed priming treatments on the germination and development of two rapeseed (Brassica napus L.) varieties under the co-influence of low temperature and drought

“…A previous study supports the results presented here, where unprimed control seeds recorded the highest value; whereas, the seeds primed with SA had the lowest recorded value in maize [ 31 ]. An increase in electrolyte leakage, which reflects a loss in the ability of biological membranes to regulate the transport of ions, has been reported in soybeans under drought stress [ 82 ]. Seeds primed with phenylalanine or calcium nitrate had the lowest electrical conductivity readings, suggesting lower degrees of cell injury [ 31 ].…”

Screening of Mungbean Genotypes under Polyethylene Glycol (PEG) Induced Drought Stress Condition

“…Reducing the size of the cells is a very common anatomical variation found in leaves under water stress condition [28]. Lowest reduction of water in genotypes of soybean namely Shohag and BARI Soybean-6 which indicate their tolerance capability under water stress phenomenon [29]. Faster the establishment potential of the mungbean genotypes, the greater the germination co-efficient.…”