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The relationship between proton extrusion by rice wheat roots and phosphate level in medium

Fan Xiaohui, Liu Zhiyu

Nanjing Inst. Soil Sci., Acad. Sin.

Abstract

The effects of roots system on medium pH were related to the levels of phosphate supplied. Medium pH declined obviously, as the level of phosphate supplied decreased. under P deficiency stress, more protons were extruded by roots, However, there was a distinct difference in H super(+)-extrusion rate among the various plant species and cultivars. It was observed that the proton efflux by roots was proportional to light intensity, and had a diurnal change. The main organic acids extruded by roots were malic and citric acids. There was a marked inverse relation between P levels and citric acid efflux, the amount of citric acid extruded by rice roots increasing distinctly under P deficiency. And the extent of solubilization of rock phosphate was negatively proportional to rhizophere pH value.

Key words: Phosphate supply;Rhizosphere;H~(+)-extrusion;Organic acid;Insoluble phosphorus

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Citing This Article：

Fan Xiaohui, Liu Zhiyu. The relationship between proton extrusion by rice wheat roots and phosphate level in medium. Acta Physiol Sin 1991; 43 (2): (in Chinese with English abstract).