Nutrient resorption is an important nutrient conservation strategy for plants and is sensitive to environmental changes. It is well-known that plant growth and productivity in terrestrial ecosystems are generally limited by the availability of nitrogen (N) and phosphorus (P). Along with industrialization and increases in agricultural fertilizer application, the atmospheric N deposition received by terrestrial ecosystem is rapidly increasing. In some area of China, the ecosystems also receive P deposition from sandy dust. Our knowledge about the effects of the increases in N and P availability on the nutrition of plants in grassland is relatively limited.
Dr. Xiao-Tao Lü, an ecologist from Institute of Applied Ecology, and his colleagues, investigated the effects of N and P, both single and combined additions, on the nutrient resorption of two dominant plant species in grass land Leymus chinensis and Stipa grandison the long-term experimental platform constructed in Xilinguole Grassland. Their results showed that N addition increased the N content in both mature and senesced leaves but reduced plant N and P resorption during senescence. The effects of N additionon the foliar P concentrations depended on plant species identity. In contrast, P addition had no significant effect on the foliar nutrition. For the whole experiment platform, there was no correlation between N content and P content in mature leaves. However, they were closely and significantly coupled in senesced leaves. Such contrasting results between living and senescing leaves were resulted from the occurrence of nutrient resorption during the leaf senescence. The results from this study indicated that the plants in grassland ecosystem are more sensitive to the changes of N availability than that of P and that the nutrient resorption is an important mechanism in regulate the coupling between N and P under nutrient enriched conditions.
The results were published in Plant and Soil.
Xiao-Tao Lü*, Sasha Reed, Qiang Yu, Xingguo Han. 2016. Nutrient resorption helps drive intra-specific coupling of foliar nitrogen and phosphorus under nutrient-enriched conditions. Plant and Soil, 398:111-120.
Full text URL:Nutrient resorption helps drive intra-specific coupling of foliar nitrogen and phosphorus under nutrient-enriched conditions.
Keywords: ecological stoichiometry, nitrogen addition, nutrient cycling, nutrient retranslocation, phosphorus addition, plant functional traits.
Abstract:Aims Plant biomass growth, storage, and decomposition connect nitrogen (N) and phosphorus (P) cycles, yet we know relatively little about the dynamics of such coupling under nutrient enriched conditions, and our understanding of the interactive relationships between plant N and P in drylands remainsparticularly poor.
MethodsIn a semiarid steppe of northern China, we examined the effects of single and combined N and P additions on soil and plant N and P poolsfor both mature and senesced leaves in two dominant grasses:Leymuschinensis and Stipagrandis.
ResultsNitrogen additions increased N concentrations in mature and senesced leaves for eachplant species, and decreased N and P resorption during leaf senescence. The effects of N additions on foliar P concentrations were species-specific, while P additionshad no effect on any nutrient characteristics examined. Due to treatment effects on N resorption, N and P concentrations were tightly correlated in senesced leaves but not in mature leaves.
Conclusions Taken together, the results suggest plants in this ecosystem are much more responsive to changing N cycles than P cycles and emphasize the significance of nutrient resorption as an important plant control over the stoichiometric coupling of N and P under nutrient enriched conditions.
Publication Name:Xiao-Tao Lü*, Sasha Reed, Qiang Yu, Xingguo Han.
Email:lvxiaotao@gmail.com