Abstract
Seeds from two varieties of spring barley (Prisma and Camorgue) were grown axenically in water. After 14 days, the culture solutions contained organic P substances (about 4 μg P per plant) derived from root exudation, representing about 3% of the total P found in the seed. Gel filtration, separated the organic P into two well defined peaks, one with a high molecular weight (>45000 daltons) and the other with a low molecular weight (<500 daltons). The bioavailability of the soluble organic P released was assessed enzymatically and chemically. At the optimum pH of 5.0, phytase and acid phosphatase hydrolysed about 80% and 65%, respectively of the organic P in the exudate after 24 h whereas at the optimum pH of 9.8, alkaline phosphatase hydrolysed up to 40% P after the same length of time. In a pH 5.0 buffer, up to 10% of the organic P was hydrolysed compared with up to 45% in a pH 9.8 buffer. The high molecular weight organic P fraction recovered from the G-75 Sephadex behaved similarly.
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Pant, H.K., Vaughan, D. & Edwards, A.C. Molecular size distribution and enzymatic degradation of organic phosphorus in root exudates of spring barley. Biol Fert Soils 18, 285–290 (1994). https://doi.org/10.1007/BF00570630
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DOI: https://doi.org/10.1007/BF00570630