Efficient and Inefficient Use of Phosphorus by Sorghum1
- J. C. Brown,
- R. B. Clark and
- W. E. Jones2
Twelve (Sorghum bicolor L. Moench) genotypes were grown on acid-Bladen soil (pH 4.3, P stressed or Al toxic), on limed-Bladen soil (pH 5.2, Cu stressed), and on alkaline Quinlan soil (pH 7.5, Fe stressed) to determine the effect of P efficiency on use of these clements by the plants. Under P-stress or Al-toxicity conditions, the most P-efficient sorghum genotypes absorbed more 32P than the most P-inefficient lines and grew normally, while the P-inefficient plants developed P-deficiency symptoms. Under Fe-stress conditions, the most P-efficient genotypes developed Fe chlorosis, while the most P-inefficient plants remained green. Under Cu-stress conditions, one of six genotypes developed severe Cu-deficiency symptoms, characterized by the accumulation of higher P in the lower leaves, and by lower Fe and Ca in upper leaves of Cu-stressed plants as compared with Cu-sufficient plants. Thus, P efficiency in plants may be an asset when P availability limits growth, but it may be a liability when these same plants are subjected to Fe or Cu stress.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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