Alkalinity induced changes in mobilization efficiency, seedling vigour, alpha -amylase and protease activities in rice genotypes.

摘要

The effects of varying levels of alkalinity on mobilization efficiency, seedling vigour, amylase and protease [proteinase] activities in 3 rice genotypes were studied in a laboratory experiment. Genotype IR-24 (salt susceptible) and genotypes NDR-501 and USAR-1 (salt tolerants) were soaked in distilled water (pH 6.6) or respective sodium bicarbonate solutions (pH 7.2, 8.5, 8.8 and 9.2) in Petri dishes lined with Whatman No.1 filter paper and placed in a seed germinator at 30+or-1 degrees C for germination. The mobilization efficiency of reserve food material and seedling vigour was significantly higher in NDR-501 and USAR-1 than IR-24. Increasing alkalinity induced a progressive inhibition of the activities of both enzymes. IR-24 exhibited the maximum inhibition in protease and amylase activities. The amylase activity in the embryo-axis was strikingly higher than in the endosperm, irrespective of the treatments and genotypes. NDR-501 and USAR-1 with better mobilization efficiency and seedling vigour than IR-24 depicted better effects on protease and alpha -amylase activities and were able to tolerate alkalinity stress in a better way. Seedling vigour and mobilization efficiency may be looked upon as probable indices for rapid screening of rice genotypes for alkali tolerance.