INCORPORATION OF [C-14] GLUCOSE INTO CRYSTALLINE CELLULOSE IN ABERRANT FIBERS OF A COTTON MUTANT

Ligon lintless-1 is a dominant simply inherited mutant of cotton (Gossypium hirsutum L.) containing markedly short cotton fibers with extensively thickened secondary walls. The incorporation of [C-14]glucose into crystalline cellulose in the primary and secondary walls was studied to determine the relation between the extent of crystalline cellulose microfibril formation and the pattern of microfibril deposition to the aberrant growth and developmental pattern in the mutant cotton. The results show that the rate of crystalline cellulose formation in the primary walls of the mutant fibers correlates with the reduced rate of fiber elongation and primary wall formation. There is a five-fold increase in the rate of crystalline cellulose formed per millimeter of fiber length during secondary wall formation in the mutant fibers compared to the rate in the wild-type fibers. The Ligon lintless-1 gene mutation affects the growth and development of the cotton fibers with accompanying changes in the rate of formation of crystalline cellulose microfibrils in the primary and secondary walls. This increase in crystalline cellulose microfibrils in secondary walls is most likely due either to an increase in synthetic activity of the individual cellulose synthase complexes or to an increase in number of synthetic complex sites per unit of fiber length in the mutant.