Some chemical and agronomic values in tillering stage of rice grown under salty conditions in Thailand

Abstract

Rice (Oryza sativa L.) is the staple food for more than half of the world’s population, especially people in developing countries. However, salinity is one of the most common abiotic stresses causing severe reductions in plant growth and productivity of crops including rice. The objective was to determine the effect of proline and trehalose applications to alleviate salinity stress in rice plant at the tillering stage that plants received the salty conditions at the tillering stage. In each experiment was conducted in 4x4x3 factorial in Completely Randomized Design (CRD). Three factors consisted 4 levles of salinity (sodium chloride; NaCl) [0 mM (0 dS/m), 50 mM (5 dS/m), 100 mM (10 dS/m), and 150 mM (15 dS/m)], four concentrations of proline or trehalose (0 mM, 50 mM, 100 mM, and 150 mM), and three varieties of lowland rice varieties (Chai Nat; CNT 1, Pathum Thani; PT1, and Inpari 35. The result in these two experiments showed a significant negative effect of salinity level starting at 50 mM NaCl in most characteristics, but there is a slight difference between the use of the proline and trehalose. Application of external proline or trehalose started at 50 mM could promote to increase in some characteristics: including RWC, proline content, and soluble sugar in leaves in proline application and on Chlorophyll A and B contents, soluble sugar in the stem, and starch content in leaves, stem, and root in trehalose application. In addition, these characteristics were increased in the order of increasing the concentration of exogenous substances (proline and trehalose) for applying. CNT 1 and PT 1 were susceptible to salinity stress than Inpari 35. Thus, these Thai rice varieties need to be stimulated by external spraying both proline or trehalose to promote both biochemical and agronomic characteristics. effects of exogenous proline or trehalose application on rice plants in the tillering phase on plant height, the percentage of productive tillers per plant formation, and the number of seeds per panicle. However, grain yield per plant could promote only by the application of trehalose.

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