Comparative nitrogen allocation and partitioning of field-grown gossypium hirsutum and G. barbadense

Abstract

In our previous study, we found that though pima cotton had higher area-based total leaf nitrogen content, pima cotton had lower photosynthetic capacity than upland cotton. The principal aim of this study was to reveal underlying mechanisms contributing to the relationship between leaf nitrogen and photosynthetic capacity in pima cotton and upland cotton. Pima cotton possessed lower light-saturated photosynthetic rate, higher area-based leaf nitrogen content, and consequently lower photosynthetic nitrogen utilization efficiency. Upland cotton partitioned a higher fraction of the photosynthetic nitrogen to carboxylation and bioenergetics. The results illustrated that nitrogen allocation and partitioning were the most important factors underlying the difference in photosynthetic nitrogen utilization efficiency between upland cotton and pima cotton.