Plant-soil associations in a lower montane tropical forest: physiological acclimation and herbivore-mediated responses to nitrogen addition
Plant-soil associations in a lower montane tropical forest: physiological acclimation and herbivore-mediated responses to nitrogen addition
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DOI：
10.1111/j.1365-2435.2010.01731.x
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发表时间：
2010-12-01
影响因子：
5.2
通讯作者：
Dalling, James W.
中科院分区：
文献类型：
--
作者：
Andersen, Kelly M.;Corre, Marife D.;Dalling, James W.
P > 1。土壤养分影响热带森林植物生产力和群落组成。在巴拿马西部低山地热带森林中，在1 ~ 20 km尺度上，林下棕榈物种的分布与土壤氮(N)的差异相关。我们假设土壤氮决定了森林林下幼苗的表现，并可能因此影响物种沿土壤氮梯度的分布。我们通过生物量分配、光合能力、氮利用效率和对草食敏感性的物种特异性差异，探索了氮有效性产生物种-栖息地关联的潜力。将2个亚科4种生境类型的9种棕榈幼苗移栽到低氮基地的补氮和对照地。在21个月的时间里，测定了植株的生长、死亡率、生物量分配、光合作用、叶面氮含量和食草性。施氮后，各树种叶片氮含量均增加（15-68%）。除2种植物光合速率略有下降（5-15%）外，大多数植物的光合速率随N的增加而显著提高（20-200%）。然而，生理性状的变化并没有增加任何物种或氮处理组合的相对生长率或生物量分配的变化。相反，叶片质量的提高有助于与中、高无机氮有效性土壤相关的物种的更高水平的草食。因此，随着N的增加，总体生长的潜在增长被食草性掩盖，导致随着N的增加而没有明显的生长响应。我们认为，对于林下棕榈和其他潜在的山地森林植物来说，分布模式是由生理和食草性对土壤养分有效性的响应共同驱动的。
P>1. Soil nutrients influence plant productivity and community composition in tropical forests. In lower montane tropical forests in western Panama, the distribution of understory palm species over a scale of 1-20 km correlates with differences in soil nitrogen (N). We hypothesized that soil N determines seedling performance in the forest understory, and, may therefore influence species distributions along the soil N gradient.2. We explored the potential for N availability to generate species-habitat associations through species-specific differences in biomass allocation, photosynthetic capacity, N use-efficiency, and susceptibility to herbivory. Seedlings of nine palm species from two sub-families and four habitat types were transplanted into N-addition and control plots at a low N site. Growth, mortality, biomass allocation, photosynthesis, foliar N content and herbivory were measured over 21 months.3. Foliar N increased for all species (15-68%) following N addition. Most species showed strong (20-200%) increases in photosynthetic rates with N addition except two species with marginal decreases in photosynthetic rates (5-15%). However, shifts in physiological traits did not increase relative growth rate or change in biomass allocation for any species or N treatment combination. Rather, increased leaf quality contributed to greater levels of herbivory in species associated with soils of intermediate and high inorganic N availability.4. Thus, potential increases in overall growth with N addition were masked by herbivory, resulting in no apparent growth response with increased N. We suggest that for understory palms, and potentially other montane forest plants, distribution patterns are driven by a combination of physiological and herbivore-mediated responses to soil nutrient availability.