Effect of proline on germination and seedling growth of rice (Oryza sativa L.) under salt stress

The present investigation was carried to study the effect of seed priming with 1mM, 5mM and 10mM proline on germination and seedling growth of rice (Oryza sativa L.) exposed to five level of salinity i.e.0, 50, 100,150 and 200mM NaCl and water. Seeds of ten rice genotypes (IR11, IR12, IR28, USAR2, USAR3, Swarna sub1, IR11T172, IR11T220, IRRI147 and IRRI154) were procured from diverse origin and primed with proline and studied under various salinity levels. The experimental design based on completely randomized design with three replicates and performs at the laboratory of crop physiology, NDUA&T, Kumarganj, Faizabad from July 2015 to Dec. 2015. The exposure of rice seeds to increasing concentration of NaCl had drastically reduced germination (%), seed vigour index and α-amylase activity. It is evident from the result that seed treatment with various concentration of proline significantly increased the germination (%), seed vigour index andα-amylase activity of ten rice genotypes under normal as well as salinity condition. Beneficial effect of seed priming with proline on various traits was more pronounced under salinity than normal condition. Further study has demonstrated that rice seeds pre-treated with proline (1mM, 5mM and 10mM) and grown at different NaCl concentrations counteracted the adverse effect of salt. Pre-treatment of proline at a concentration of 1mM was found to be effective and stimulated cellular activities, whereas 10mM proline was found ineffective to improve germination and biochemical activity under high level of salt (150 and 200mM NaCl). Genotypic variability was observed regarding salt tolerance and response of proline as priming agent to improve efficiency to maintained physiological activity occurred during germination under salt stress condition.