Physiological and biochemical changes in relation to seed quality in ageing

Abstract

A study was conducted during 2006–08 to identify physiological (per cent germination, germination rate, seedling vigour index, germination index and standard germination) and biochemical changes (membrane injury, malonaldehyde content, total soluble sugars, amylase, peroxidase and dehydrogenase activity) in relation to seed vigour and viability in fresh and aged bell pepper seeds (Capsicum annum L.). Results showed an overall decrease in germination, vigour and enzyme activity with increase in ageing duration (data). Increased membrane injury (1.2–2.05 times) and lipid peroxidation (1.09–1.38 times) coupled with significant reductions in dehydrogenase (34.5–100%) and amylase activity (42.9–100%) were noticed in accelerated aged (3–15 days) seeds. Peroxidase activity remained unaltered up to 9 days after accelerated ageing but declined significantly at 12 and 15 days after accelerated ageing. Changes in protein and isozymes profiles in aged seeds compared to fresh seeds further indicated that the loss in seed quality might be due to adverse effect of ageing on proteins. The electrophoretic variations in proteins and enzymes noticed in the present study could be used as criteria in assessing the quality of bell pepper seed lots.