Exogenous trehalose application in rice to mitigate saline stress at the tillering stage

ABSTRACT Rice (Oryza sativa L.) production is globally impacted by salinity stress, since it is a salt-sensitive plant species. This study aimed to determine the effect of exogenous trehalose to reduce the salinity stress at the tillering stage in three lowland rice varieties: Chai Nat 1 (CNT1), Pathum Thani 1 (PT1) and Inpari 35 (IN35). Salinity stress was induced by watering the plants with four concentrations (0, 50, 100 and 150 mM) of sodium chloride (NaCl). Thereafter, exogenous trehalose with the same concentration was applied through foliar spray to reduce the salinity stress. The induced salinity in the rice plants affected various physiological parameters, such as relative water content, chlorophyll content and chlorophyll a/b ratio. Salinity also affected the levels of soluble sugar, starch content and other eight agronomic traits. At the concentration of 50 mM, the impact of trehalose was significantly observed on the physiological, biochemical and other agronomic traits of the plant. However, the 100-grain weight of the rice did not improve with the use of trehalose, what may have been influenced by the duration of the trehalose exposure during the tillering stage. The physiological, biochemical (excluding starch content) and agronomical traits of the rice plants also varied with the varieties. The salt-tolerant variety (IN35) showed a higher content of relative water (12.98 %), chlorophyll (8.33 %), soluble sugars (12.25 %), reproductive tillers per plant (12.4 %), grains per panicle (18.81 %), 100-grain weight (10.71 %), percentage of filled grains per panicle (22.39 %) and grain yield per plant (23.49 %), in comparison to CNT1 and PT1.