Physiological growth analysis of the life-history of calotropis procera (AIT.) AIT. F.

Abstract

Growth of Calotropis procera was analysed by distribution of dry weight throughout the plant at various stages in growth. Dry biomass, leaf area index, specific leaf area, leaf weight ratio, leaf area ratio, net assimilation rate, relative growth rate and crop growth rate were monitored monthly during 1987-1989. In Calotropis storage of assimilates seems to dominate both vegetative and reproductive phases, thus Calotropis does not undergo the developmental phenomenon known as "cutout". Total biomass increased steadily for all three major organs, i.e. leaves, stem and root. LAI increased sharply following the seedling stage and reached 9.0 during the reproductive phase. The amount of biomass packed into a given volume of canopy space was high in Calotropis procera achieved by having leaves with low SLA. LAR and LWR reached a maximum during the seedling phase and thereafter consistently declined. The decreasing value of LAR was due to greater contribution to stem and root dry matter to the total dry matter. Calotropis has alternating peaks of rise and fall in NAR with time until the beginning of the reproductive phase. RGR was highest during the seedling phase and the least during the reproductive phase. CGR continued at a higher level during late vegetative and early reproductive stages. Calotropis has ecophysiological adaptations in its life-cycle which enable it to avoid the consequences of a season unfavourable to active growth. These findings are discussed in relation to the management and control of C. procera.