The Effects of Progressive Water Stress On Soybean Plants.

Water stress affects the entire plant physiology, affects water status of the plant, leaf water potential, stomatal conductance and  leaf photosynthesis. Drought reduces the yield of soybean crop by 40%  affecting all stages of plant development and reducing the quality of seeds. The aim of this experiment was to evaluate the effect of water stress (WS) on soybeans by using three progressive water stress points. The evaluation was conducted using 2Day (2D), 4Day (4D) and 6 Day (6D) irrigation as three WS points, in which soybean RR resistant cultivars DK 4968 and Pioneer Y9570 were investigated for signs of stress. The study revealed physical evidence of the stress in the DK 4968 and Pioneer Y9570 under progressive water stress. The 2D (WS) soybean plants reveal little stress factors, while 6D (WS) revealed extreme stress factors in both soybean cultivars. Chlorophyll conductance and stomatal conductance were measured to evaluate the effect of water stress on the above parameters. Fresh weight and the dry weight was measured to calculate the biomass of the plants undergoing progressive water stress. Based on our results, there was significant decrease in the biomass of plants in water stressed plants. There was significant effect on the stomatal conductance as well, however, chlorophyll concentration increased in water stressed plants compared to 2D watered plants in response to stress.