摘要
Aims Nutrient resorption is a crucial component of plant nutrient use strategy,yet the controls on the responses of community-level nutrient resorption to altered nutrient availability remain unclear.Here,we addressed two questions:(1)Did leaf and stem nutrient resorption respond consistently to increased nutrient availability?(2)Was community-level plant nutrient resorption response after nutrient enrichment driven by the intraspecific plasticity in plant nutrient resorption or by altered species composition?Methods We investigated the changes in aboveground biomass,and leaf and stem nutrient resorption of individual species after 3-year nitrogen(N)and phosphorus(P)additions,and assessed community-level nutrient resorption response to 3-year nutrient additions in a graminoid-dominated temperate wetland,Northeast China.Important Findings For both leaves and stems,N and P additions did not affect nutrient resorption efficiency,but they decreased respective nutrient resorption proficiency.Similarly,community-level N and P resorption proficiency declined with respective nutrient addition.Community-level N and P resorption efficiency was reduced by N addition primarily due to altered community composition and declined leaf:stem ratio.These results suggest that leaf and stem nutrient resorption processes exhibit consistent responses to increasing nutrient availability in the temperate wetland.These findings highlight the importance of altered species composition and biomass allocation between leaf and stem in driving community-level nutrient resorption response to nutrient enrichment.
养分回收是植物养分利用策略的一个重要组成部分,但养分有效性的变化如何调控群落尺度上植物养分回收过程仍不清楚。在本研究中,我们提出两个科学问题:(1)叶片和茎养分回收过程对养分有效性增加的响应格局是不是一致?(2)群落尺度上养分富集引起的植物养分回收变化是受物种内养分回收可塑性的影响还是受物种组成变化的调控?本研究以中国东北草本植物占优势的温带湿地为研究对象,利用施肥实验调查了氮和磷添加3年后物种水平上植物地上部分生物量以及叶和茎养分回收的变化趋势,并评价了群落尺度上植物养分回收对3年养分添加的响应。对于植物叶和茎而言,氮和磷添加对养分回收效率(nutrient resorption efficiency)均没有影响,但降低了相应的养分回收度(nutrient resorption proficiency)o同样地,在群落水平上,植物氮和磷养分回收度也随着相应的养分添加而降低。而且,由于植物群落组成变化及其引起的叶茎比降低,氮添加显著降低群落尺度上植物氮和磷的养分回收效率。这些研究结果表明,温带湿地植物叶和茎养分回收过程对养分有效性增加的响应是一致的,而且养分富集引起的物种组成以及叶和茎生物量分配格局变化是驱动群落尺度上植物养分回收动态的重要因素。
基金
Foundation of China(31570479,41171169).
