Seasonal variations of carbohydrates in Pueraria lobata related to growth and phenology

摘要

The seasonal changes of non-structural carbohydrates (NSCs), water-soluble carbohydrates (WSCs) and starch concentrations were examined in Pueraria lobata throughout its life cycle in order to elucidate the potential points in the seasonal growth and phenological cycles for its improved control. The study was carried out at two different habitat zones with distinct soil conditions in the riparian zone of the Tama River, Tokyo, Japan. One zone, with sandy soil, had lower levels of available nitrogen and phosphorous, while the second zone contained high levels of organic matter and nutrients. The highest and lowest concentrations of the NSC pools in the roots of P. lobata were observed in December and August, respectively, at both study sites. The lowest NSC reserves were attained at the end of the vegetative stage, with the highest NSC reserves found at the end of the reproductive stage. The WSCs gradually decreased from April to August in the roots and then increased until February. The starch concentrations of all the plant organs followed the same pattern as for the WSCs. The stems and leaves did not show the same pattern as did the roots. The total carbohydrate concentrations and pools did not show significant variation between the two sites, suggesting that the soil conditions had very little effect on carbohydrate production in the different organs of the plant. The study suggests that to control P. lobata effectively, the above-ground biomass should be removed at any date between the end of August and early September.