Casting off flower buds on assimilation, growth and mineral nutrition of cotton

Abstract

Upland cotton (Gossypium hirsutum L.r. latifolium Hutch) plants were regulary disbudded and compared at 88 and 107 days after germination, with plants allowed to flower normally. There were significant increases in the root biomass and shoot biomass, net assimilation rate, leaf absolute and relative growth rate, leaf area duration and photosynthetic potencial at 88 and 107 days in the disbudded plants. Also a marked increase in invertase activity and protein content was observed. Soluble sugar concentration was not affected. However, starch concentration increase at 88 and 107 after germination was almost identical in shoot and root. Even with an increase in protein content, the N content staid unchanged and content of P, K, Ca and Mg were even smaller due to a greater biomass. These results show that flowering and fruiting represent a major modification in the metabolism of the cotton plant, and that in semi-and areas, with unreliable rain fall, the cotton ideotype should have enough vegetative development and root growth, and this can only be obtained by a longer period of flowering.