Effect of exogenous methyl jasmonate on growth, gas exchange and chlorophyll contents of soybean subjected to drought

Drought is considered as one of the major constraints to crop production worldwide. Methyl jasmonate (MJ) is a plant-signaling molecule that elicits a wide variety of plant responses ranging from morphological to molecular level. A pot-culture study was undertaken to investigate the possible role of MJ-treatment on growth, gas exchange and chlorophyll contents in soybean (Glycine max L. Merrill.) plants subjected to water stress. The soybean plants were grown under normal water supply conditions till blooming and were then subjected to moisture stress by withholding water followed by foliar application of MJ at the rate of 50 μM. Drought stress severely hampered the growth, leaf gas-exchange attributes as well as the photosynthetic pigment contents. It was evident from the experimental results that, MJ-treatment led to further impairment in growth by inhibiting the leaf gas exchange attributes and chlorophyll contents. It is worth noted that, MJ-treatment also hampered the performance of soybean crop under well-watered conditions. In all, MJ-treatment appeared to arrest the growth, impaired leaf gas-exchange attributes and caused the loss of chlorophyll contents of soybean plants under water deficit conditions.