Root phosphatase activity of sorghum genotypes grown with organic and inorganic sources of phosphorus 1 |
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| Authors: | A M C Furlani R B Clark J W Maranville W M Ross |
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| Institution: | 1. Department of Agronomy , University of Nebraska , Lincoln, NE, 68583;2. Instituto Agronomico , C.P. 28, Campinas, Sao Paulo, 13,100, Brazil;3. U.S. Department of Agriculture, Agricultural Research Service , University of Nebraska , Lincoln, NE, 68583 |
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| Abstract: | Abstract Relatively insoluble sources of phosphorus (P) may require solubilization, and organic P (Po) may require hydrolysis to inorganic P (Pi) before P can be readily absorbed by plants roots. The mechanisms for these processes, however, are unknown. Root phosphatase (Pase) activity was measured to assess its relationships to P uptake by seven sorghum Sorghum bicolor (L.) Moench] genotypes grown with Po (ethylammonium phosphate, glycerophosphate, and phenylphosphate) and Pi (KH2PO4, calcium tribasic phosphate, calcium pyrophosphate, aluminum phosphate, and ferric phosphate) in nutrient solutions in a greenhouse. Plants grown with Po had lower root Pase activities than plants grown with Pi NB9040 and SC369–3–1JB (tolerant to low levels of P) had lower root Pase activities than CK60‐Korgi and SC33–9–8‐E4 (sensitive to low levels of P), with the other genotypes having intermediate root Pase activities. Higher root Pase activity was associated with lower root P concentrations, but Pase activity was not related to dry matter yield of roots. In experiments where genotypes were grown three weeks with KH2PO4 before being transferred to other sources of P, within four days root Pase activity patterns were similar to those for plants grown initially in the particular Po or Pi compound. Root Pase activity of sorghum plants appeared to be an indicator of P status or P deficiency stress in the plants, and not associated with making Po or Pi compounds more available for plant use. |
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| Keywords: | Phosphorus nutrition efficiency and deficiency Mineral nutrition Nutrient solutions |
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