Dinitrogen-fixing Acacia species from phosphorus-impoverished soils resorb leaf phosphorus efficiently

作者：He Honghua^*; Bleby Tim M; Veneklaas Erik J; Lambers Hans

来源：Plant, Cell and Environment, 2011, 34(12): 2060-2070.

DOI：10.1111/j.1365-3040.2011.02403.x

• desert shrub
• legume
• N2-fixation
• N : P ratio
• soil nutrient patchiness

Nitrogen (N) and phosphorus (P) resorption from senescing leaves were studied, and the contribution of N and P cycling through litterfall to soil nutrient patchiness was investigated for four Acacia species in the Great Sandy Desert in north-western Australia. N and P concentrations of mature and recently shed leaves were analysed and compared; soils under the canopies of the shrubs and soils in gaps (open areas) between the shrubs were also analysed and compared for N and P concentrations. Mature leaf P concentrations of the plants were considerably lower than the global average values, and N : P ratios of mature leaves were high. Plants derived 075% of their leaf N from symbiotic N2-fixation. N-resorption efficiency was between 0 and 43%, and P-resorption efficiency was between 32 and 79%; all plants were more efficient at P resorption than at N resorption, and litter N : P ratios were significantly higher than mature leaf N : P ratios. Soils of the study sites were P-impoverished. Total soil N and P concentrations were higher under the canopy than in gaps, but bicarbonate-extractable P concentration was higher in gaps. Nutrient cycling through litterfall results in soil nutrient patchiness and forms islands of fertility under the canopies of the shrubs.

• 出版日期2011-12