Glycinebetaine alleviates water deficit stress in indica rice using proline accumulation, photosynthetic efficiencies, growth performances and yield attributes

We investigated the role of GlyBet (100 mM) applied exogenously in alleviating water-deficit induced stress in indica rice cv. Pathumthani 1 (PT1). Exogenous GlyBet increased proline concentration in the leaf tissues of water deficit stressed plants depend on a degree of soil water content (SWC), especially at severe water deficit (25% SWC). Foliar GlyBet (100 mM) significantly enhanced chlorophyll a (Chla) and total chlorophyll (TC) content in the leaf tissues of water stressed plants (25% SWC) and stabilized total carotenoids (Cx+c) in 25 and 36% SWC better than those in controlled plant. A positive correlation was observed between Chla and maximum quantum yield of PSII (Fv/Fm), and TC and photon yield of PSII (PSII). In contrast to control plants, where Fv/Fm and PSII and net photosynthetic rate (Pn) declined, Glybet pre-treated plants maintained a high level of Fv/Fm, PSII and Pn even under 25% SWC. Even at the harvest stage, plant height and yield traits such as panicle length and weight, fertility percentage and onehundred grain weight of GlyBet pre-treated plants were better than those in the control plants when exposed to water stress. The study concludes that exogenous application of GlyBet significantly alleviates water-deficit in indica rice and maintains grain yield.