Six wheat (Triticum aestivum L.) varieties with different phosphorus (P) efficiency, selected according to their relative yield in P-deficient soil to that in P sufficient soil, were used to compare their responses to...Six wheat (Triticum aestivum L.) varieties with different phosphorus (P) efficiency, selected according to their relative yield in P-deficient soil to that in P sufficient soil, were used to compare their responses to P deficiency in growth, root and shoot P content and P concentration in leaf phloem exudates in solution culture. Results showed that P deficiency repressed shoot growth, whereas stimulated root growth. Accordingly, root-shoot dry weight ratio of the P deficient plants was relatively larger than that of the P-sufficient plants. Comparing with P-inefficient varieties, the growth rate of shoot and roots of P-efficient varieties was relatively low both under P-sufficient and -deficient conditions. Phosphorus deficiency also resulted in decrease in shoot and root P content. The rate of decrease in shoot was faster than in root. Difference in P partitioning in shoot and root between P-efficient and -inefficient varieties could not be observed. However, a negative relationship between P concentration in leaf phloem exudates of nine-day-old seedlings of these wheat varieties and their degrees of P efficiency were found under the P-sufficient condition, with higher in P-inefficient varieties but lower in P-efficient varieties. The reduce rate of P concentration in leaf phloem exudates of P-efficient varieties was rather slower than that of P-inefficient varieties, showing higher relative P concentration in leaf phloem exudates. The relative P concentration in leaf phloem exudates under P deficiency ranged from 35.9% of the P-sufficient controls in P-inefficient varieties to 59.0% in P-efficient varieties on the 10th day after the treatments.展开更多
文摘Six wheat (Triticum aestivum L.) varieties with different phosphorus (P) efficiency, selected according to their relative yield in P-deficient soil to that in P sufficient soil, were used to compare their responses to P deficiency in growth, root and shoot P content and P concentration in leaf phloem exudates in solution culture. Results showed that P deficiency repressed shoot growth, whereas stimulated root growth. Accordingly, root-shoot dry weight ratio of the P deficient plants was relatively larger than that of the P-sufficient plants. Comparing with P-inefficient varieties, the growth rate of shoot and roots of P-efficient varieties was relatively low both under P-sufficient and -deficient conditions. Phosphorus deficiency also resulted in decrease in shoot and root P content. The rate of decrease in shoot was faster than in root. Difference in P partitioning in shoot and root between P-efficient and -inefficient varieties could not be observed. However, a negative relationship between P concentration in leaf phloem exudates of nine-day-old seedlings of these wheat varieties and their degrees of P efficiency were found under the P-sufficient condition, with higher in P-inefficient varieties but lower in P-efficient varieties. The reduce rate of P concentration in leaf phloem exudates of P-efficient varieties was rather slower than that of P-inefficient varieties, showing higher relative P concentration in leaf phloem exudates. The relative P concentration in leaf phloem exudates under P deficiency ranged from 35.9% of the P-sufficient controls in P-inefficient varieties to 59.0% in P-efficient varieties on the 10th day after the treatments.
