Physiological and Biochemical Changes Associated with Cotton Fibre Development. IV. Glycosidases and {beta}-1,3-Glucanase Activities

Developing cotton fibre was analysed from 12 days post anthesis(DPA) till maturity for the activity of wall degrading enzymes,ß-galactosidase, ß-glucosidase, -mannosidaseand ß-1,3-glucanase. Each enzyme was estimated inthree different fractions namely cytoplasmic, ionically wall-boundand covalently wall-bound. There was a significant correlationbetween ß-galactosidase and ß-glucosidaseactivities in the covalently bound fraction, and the rate offibre elongation. Similarly, covalently bound ß-1,3-glucanaseactivity showed an increasing trend up to 18 DPA, i.e. aboutthe time when maximum rate of fibre elongation was achieved. The results presented here suggest that covalently wall-boundglycosidases may have an importafit role in cell wall loosening.Earlier reports providing evidence against the involvement ofthese enzymes in elongation growth in intact system, may perhapsbe due to scant attention paid to the subcellular distributionof these enzymes. Gossypium hirsutum, cotton fibre, glucanase, glycosidase, wall-loosening