Effect of Water Stress on the Photosynthesis, Productivity and Water Status of Mung Bean (Vigna radiata L. Wilczek)

The effect of water stress and its subsequent recovery on the photosynthesis, productivity and water status, was examined in three mungbean varieties ( Vigna radiata L. Wilczek) i.e. PS 16, P 105 and Pusa Baisakhi. The variety P 105 was found relatively less susceptible to water stress compared to high susceptibility in Pusa Baisakhi and PS 16. The adverse effect of stress was comparatively higher at the post-flowering and pod development stages. It was observed that variety P 105 had inherently maintained higher water status by retaining higher water potential and water content under water stress condition, thereby effectively reducing the water loss. The higher transpiration rate in this variety regulates the flow of water within the plant. This type of regulation of water flow and maintenance of high water status in P 105 helped to resist the adverse effect of water stress on photosynthesis and productivity. Such adaptation mechanism was not observed in varieties PS 16 and Pusa Baisakhi. The recover) mechanism was, however, operated efficiently in susceptible varieties PS 16 and Pusa Baisakhi particularly for recouping the vegetative growth, but its effect could not be retained for reproductive characters, wherein also variety P 105 due to its efficient partitioning system yielded better than other cultivars.