Effect of Seed Priming on Biochemical Changes in Fresh and Aged Seeds of Cucumber

Abstract

The present investigation was conducted at the laboratory of Seed Science and Technology, Indian Institute of Horticultural Research, Hessaraghatta, and Bangalore, India during March 2014 to September 2014. The objective of the study was to identify effect of seed priming on biochemical changes in cucumber seeds. This study showed that the enhancement in seed viability and vigor in primed seeds was due to low membrane injury coupled with high enzyme activities (dehydrogenase and amylase). The priming with KH₂PO₄ and K₂HPO₄ reduced the electrical conductivity (EC) significantly in seed. With seed priming with KH₂PO₄ 10^-3M there was 44 and 45% lower EC values compared to unprimed. This priming with KH₂PO₄ 10^-3M and K₂HPO₄10^-3M reduced seed leachate values indicating priming initiates the process of repair by stabilizing membrane integrity. priming significantly increased dehydrogenase enzyme in low vigor seeds was noticed. These changes are to the tune of 16 and 21 per cent due to priming with K₂HPO₄10^-3M and KH₂PO₄10^-3M, respectively in cucumber. Similarly, higher amylase activity was noticed upon priming in low vigor seeds These are to the extent of 2.1, 1.94 folds higher due to priming with K₂HPO₄10^-3M and KH₂PO₄10^-3M, respectively, in cucumber and 1.4 & 1.4 folds higher due to priming with K₂HPO₄10^-3M .Alteration in protein profiles in low vigor seeds compared to high vigor seeds was noticed in the crops. The disappearance of some low molecular weight proteins in low vigor seeds might be the reason for lesser performance of these seeds. Seed priming although not restored all the lost proteins, but induced synthesis of some other proteins which probably might helped in restoration of germination ability and vigor. Esterase Isozyme profiles also showed variation in their number and intensity in less vigor seeds. Primed seeds further exhibited tolerance to abiotic stress condition (high temperature and water stress) as evident from higher germination compared to unprimed. Besides these studies, some advanced studies were initiated in the present investigation to identify changes in proteome profiles and isocitratelyase gene expression in high vigor and low vigor seeds during germination.