Sánchez-Gómez David, Valladares Fernando, Zavala Miguel A
Instituto de Recursos Naturales, Centro de Ciencias Medioambientales, C.S.I.C., Serrano 115 dpdo, Madrid E-28006, Spain.
New Phytol. 2006;170(4):795-806. doi: 10.1111/j.1469-8137.2006.01711.x.
The aim of the study was to assess the potential importance for Mediterranean plants of trade-offs in the response to irradiance and water availability at the regeneration stage. Survival and growth patterns across an experimentally imposed irradiance gradient (1, 6, 20 and 100% sunlight) were studied in seedlings of eight Mediterranean woody species, together with the impact of a simulated summer drought. We found evidence of some of the trade-offs previously reported for non-Mediterranean plant communities, such as between survival in the shade and relative growth rate (RGR) at high light, but no evidence for others, such as between shade and drought tolerances. The impact of drought on survival and RGR was stronger in high light than in deep shade. The observed species-specific differences in performance provide a mechanistic basis for niche differentiation at the regeneration stage, contributing to possible explanations of species coexistence in Mediterranean ecosystems.
本研究的目的是评估在地中海地区植物的更新阶段，权衡光照和水分可利用性响应的潜在重要性。我们对8种地中海木本植物的幼苗，研究了在实验设定的光照梯度（1%、6%、20%和100%阳光）下的存活和生长模式，以及模拟夏季干旱的影响。我们发现了一些先前报道的非地中海植物群落权衡的证据，例如在弱光下的存活与强光下的相对生长速率（RGR）之间的权衡，但没有发现其他权衡的证据，例如耐荫性和耐旱性之间的权衡。干旱对存活和RGR的影响在强光下比在深荫下更强。观察到的物种特异性表现差异为更新阶段的生态位分化提供了一个机制基础，有助于解释地中海生态系统中物种共存的可能原因。
