Influence of desiccation and associated metabolic changes during seed germination in Corypha umbraculifera Linn

Corypha umbraculifera L. is a monocarpic palm, which usually flowers after 30-60 years of growth. In C. umbraculifera seeds are the only propagating unit, but the germination rate is very low and seeds are highly recalcitrant. In this context, it was imperative to investigate the desiccation sensitivity, physiological and biochemical changes accompanying the desiccation and germination in C. umbraculifera seeds. Therefore, to make a detailed study, freshly collected C. umbraculifera seeds were desiccated at room temperature for a period of 35 d and physiological and biochemical changes during desiccation and germination were monitored at an interval of 7 d. It was observed that there was a sharp decline in the moisture content of the seed as desiccation proceeded. As the desiccation period progressed, the germination percentage decreased which was below 50% after 35 d. The dry weight percentage of the embryo and endosperm increased with the desiccation period and the increase in dry weight of embryo was significant in comparison with the endosperm. Total protein content of embryo was more compared to that of the endosperm. Peroxidase activity in the embryo was increased up to 28 d of desiccation and decreased further. The endosperm registered a gradual reduction of peroxidase activity during desiccation. In contrast, SOD activity in the embryo was comparatively higher in the fresh seeds and further declined during desiccation, while that of the endosperm remained almost unaltered. The results give a strong indication that desiccation in C. umbraculifera is accompanied by abundant activity of peroxidase in embryo, thereby viability is retained up to 35 days. Whereas, feeble activity of SOD is not seen to be linked with seed viability of C. umbraculifera.