Cytological and biochemical changes in aged and osmoprimed seeds of chilli

Abstract

Studies Oil seed quality aspects in storage or chilli variety Jwalasakhi and Ujwala were undertaken in the Department of Plant Breeding and Genetics, College of Ilort icult urc, Vel lanikkara during 1997 to 1998 to study the di fferent types of cytological and biochemical changes in aged seeds or chilli, to investigate the effects of osmopriming in chilli seeds and to study the feasihility of osmopriming in overcoming physiological and genetic deterioration of stored seeds. The germination studies conducted during the ten months of storage period revealed that chilli seeds lost viability completely from the nineth month of storage onwards in amhient conditions. Hydroprimed seeds germinated to the tune of 13 and 20 per cent in Jwalasakhi and Ujwala respectively. Under this conditions osmopriming with chemicals PI':(; and Na Cl significantly improved this germination per cent to 40 as observed during the tenth month of storage. The chemical Na Cl with concentration 1.5 MPa and 48 hours duration was found the hest. Among the varieties Ujwala responded bcuer compared to Jwalusukhi. Irrespective of the chemical all osmopriming treatments produced uniform seedlings compared to control and the germination was completed within seven days under ideal conditions. In general vigour index and root shoot ratio also expressed similar results to that of germination. Studies 011 biochemical characteristics revealed a progressive loss of activity of mitochondrial dehydrogenase and soluble protein with ageing. The electrical conducuvity of seed leachate also increased with period of storage revealing the loss of mcmbrune integrity resulting ill leakage of cell contents outside the cell membrane. . Osmopriming treatments were ahle to repair this membrane damage to a good extend and increase the level of dehydrogenase activity and soluhle protein content compared to _ control. In hoth varieties sodium chloride with - 1.5 MPa was found the hest treatment. Among varieties Ujwala responded hetter than lwalasakhi. Cytological studies revealed u reduction in mitotic index values during storage irrespective of the variety. Osmopriming was found to improve the mitotic index values over hydropriming and untreated control. Any type or chromosomal aberration was not

detected during the ten months of ageing period. l lere also sodium chloride with I. S M 1 'a was found to be superior. It can be concluded that I. The loss of viability in chilli seeds is mainly due to biochemical lesions '") Osmopriming was found beneficial after two months of storage in chilli seeds, because chilli seeds could retain the innate capacity to germinate and produce quality seedl ings up to two months of storage period. 3. PHI-ooon and Na Cl C<.I1l be used as an osmoticum for post storage priming treatments in aged chilli seeds. Na Cl can be advocated more economically compared to PLG.