Physiological and biochemical changes associated with sink development in cotton seeds. I. Glycosidases and water content.

Three cotton genotypes (Gossypium hirsutum L. H-4, H-6, G. herbaceum V797) varying in their final seed weight were analyzed for the growth and glycosidases activity. Five glycosidases, viz., a-b-galactosidases, a-b-glucosidases and a-mannosidases were estimated in cytoplasmic and wall-bound fractions. Data on dry weight and water content were fitted to polynomial equations and third degree polynomial equation was best-fit. Rate of dry matter accumulation showed closed relationship with water content in all three genotypes. The values for correlation coefficient {r= 0.956(H-4), r= 0.892(H-6) and r= 0.983 (V797)}, were statistically significant. No correlation between ionically wall-bound glycosidases and sink development was observed. In cytoplasmic fraction, the activities were higher during latter phase of dry matter accumulation. Probable role of these enzymes in mobilization of storage products during seed development is discussed.