土壤养分水平影响绢毛匍匐委陵菜匍匐茎生物量投资

 为研究匍匐茎草本植物对基质养分供应水平的生物量分配格局的可塑性，在一盆栽实验中对绢毛匍匐委陵菜(Potentilla reptans var.sericophylla)进行了8种不同的养分处理。绢毛匍匐委陵菜植株生物量、匍匐茎数、分株数以及匍匐茎节间长在中等养分条件下最大。随 土壤养分的降低，绢毛匍匐委陵菜对叶片和叶柄的生物量投资减小，而对根系的生物量投资增加。在中等养分条件下，绢毛匍匐委陵菜对匍匐 茎的生物量投资倾向于最大，而在更高或更低的养分条件下倾向于减少。此生 物量分配格局与de Kroon和Schieving的模型模拟结果相符合， 结果表明在中等资源水平下增加对匍匐茎的生物量投资是克隆植物增加资源获取的对策之一。

NUTRIENT AVAILABILITY AFFECTS BIOMASS ALLOCATION TO STOLONS IN POTENTILLA REPTANS VAR. SERICOPHYLLA

Aims Plasticity in biomass allocation of plants under different growing conditions is often assumed to be adaptive. Biomass allocation patterns in clonal plants are usually different from those in non-clonal plants due to clonal architecture and clonal morphology. de Kroon and Schieving (1991) published a model to predict the likely pattern of biomass allocation to spacers (i.e., stolons or rhizomes) as resource supply varies. The model predicted that under moderate resource levels, clonal plants would allocate more biomass to spacers to efficiently utilize resources. The aim of this study is to experimentally test this prediction. Methods In a greenhouse experiment, Potentilla reptans var. sericophylla plants were subjected to eight levels (i.e., N1 to N8 in decreasing order) of nutrient supply. N1 was equivalent to 600 kg nitrogen as NH4NO3, 240 kg phosphorus as NaH2PO4 and 600 kg K as KCl per ha per year. N2 to N8 were 50%, 25%, 12.5%, 6.25%, 3.13%, 1.57% and 0 of N1, respectively. The experiment started on April 6, 2003 and ended on June 3, 2003. Important findings Potentilla reptans var. sericophylla had greater biomass, produced more stolons and had longer stolon internodes at moderate levels (i.e., N3 and N4 treatments) of nutrient supply. Biomass allocation to different plant organs (roots, stolons, laminae and petioles) responded greatly to nutrient treatments. With decreasing nutrient supply, biomass allocation to laminae and petioles decreased, whereas that to roots increased. Biomass allocation to stolons tended to be the highest at moderate levels (N3, N4) of nutrient supply and became smaller at both lower and higher nutrient conditions. Patterns of biomass allocation to stolons in P. reptans var. sericophylla under different levels of nutrient supply agree with the model prediction of de Kroon and Schieving (1991), suggesting that allocating more biomass to spacers (i.e., stolons or rhizomes) at moderate nutrient levels enables clonal plants to efficiently utilize resources.