Changes in phosphate fractions, growth rate, nodulation and nitrogen₂ fixation of phosphorus-starved soybean plants.

摘要

The objective of this study was to elucidate the effects of phosphorus (P) starvation on the internal P status expressed as P fractions (acid soluble P, sugarP, inorganic P, nucleotide P, and insolubleP) in different plant organs (leaves, roots and nodules), at different plant growth rates and dinitrogen(N₂) fixation rate of soybean plants. The symptoms of P starvation differed during early 10 days and late 28 days of starvation. There were close relationships between nodulation and N₂ fixation rate, and parameters of growth rate and internal P status. Although growth rate and N₂ fixation of P starved plants were reduced their nodules showed ability to accumulate more soluble P in comparison with the leaves. The decreased sugar-P and inorganic P accounted for accumulation of more soluble sugars and starch in the stressed leaves. In contrast, stressed nodules accumulated higher quantities of sugar P, inorganic P, and nucleotide P and had reduced quantities of starch and sucrose. The increased accumulation of phosphorylated sugars in the nodules was regarded as a manifestation of the mechanism of stress tolerance of soybean nodules to P limited nutrition.