Physiological and biochemical changes associated with cotton fiber development. VIII. Wall components

Fibers of three cotton cultivars (Gossypium hirsutum L.) H-4, H-8 and (G. arboreum) G. Cot-15, which shows variation in staple length were analyzed for growth in terms of fiber length and fresh and dry mass. From the growth analysis cotton fiber development is divided in four distinct phases i.e. (i) initiation (ii) elongation (iii) secondary thickening and (iv) maturation. Rate of fiber elongation and rate of water content shows close parallelism. Highly esterified and less esterified pectic fraction along with high and low molecular weight xyloglucan fractions were estimated from fiber walls of all the three cotton genotypes. Xyloglucans were fractioned in to high and low molecular weight by alkali treatment, 1 M and 4 M KOH respectively. Xyloglucan content shows inverse correlation with fiber elongation. Role of water content and wall components in determination of staple length in cotton genotypes is discussed.