| Abstract: | Growth parameters and auxin metabolism of developing cotton(Gossypium hirsutum L., cv. Sankar 5) fibre were studied inplants grown in the field. Fibre length and dry weight wereplotted against boll age and fitted to the best-fit curves bycomputer curvilinear regression analysis. Based on this analysis,fibre development was divided into four phases: (i) initiation,(ii) elongation, (iii) secondary thickening, and (iv) maturation.Changes in IAA oxidase and peroxidase activity showed that IAAcatabolism was low during the elongation phase, while duringthe phase of secondary thickening it was very high (four-foldincrease). It is suggested that the level of IAA may regulatethe termination of primary wall extension and the initiationof cellulose deposition in cotton fibre. |
