Kyllo Damond A, Velez Virginia, Tyree Melvin T
University of Missouri-St. Louis, Department of Biology, 8001 Natural Bridge Rd., St. Louis, Missouri 63121, USA.
Smithsonian Tropical Research Institute, PO Box 2072, Balboa, Panama.
New Phytol. 2003 Nov;160(2):443-454. doi: 10.1046/j.1469-8137.2003.00896.x.
• Root hydraulic conductance (K ) was measured for five understory shrub species of the neotropical moist forest to determine the effects of arbuscular mycorrhizas (AM) for both carbon-rich and carbon-limited host plants. • K was measured using a high pressure flow meter (HPFM) for potted plants grown in a factorial combination of AM fungi (presence/absence) and light (3.5 and 30% of full sun, low/high). • AM colonization improved K for the more shade-tolerant species plants when growing in low light. By contrast, water uptake efficiency of the light-demanding species was significantly decreased by AM fungi in high light. Regardless of AM colonization, light-demanding species had a lower capacity than shade-tolerant species to meet transpirational demands, and they allocated substantially more to fine root production relative to leaf area when colonized. • The differential effects of AM colonization and light on a species' root hydraulic conductance in relation to phylogeny and light adaptation demonstrate that AM fungi may be critical in determining early plant succession and community composition not only due to effects on nutrient uptake, but on water uptake as well.
• 测量了新热带湿润森林中五种林下灌木物种的根系导水率（K），以确定丛枝菌根（AM）对富碳和碳受限宿主植物的影响。
• 使用高压流量计（HPFM）测量了盆栽植物的K，这些盆栽植物生长在AM真菌（存在/不存在）和光照（全日照的3.5%和30%，低/高）的因子组合条件下。
• 对于更耐荫的物种植物，在弱光条件下生长时，AM定殖提高了K。相比之下，在强光条件下，AM真菌显著降低了喜光物种的水分吸收效率。无论是否有AM定殖，喜光物种满足蒸腾需求的能力都低于耐荫物种，并且在定殖时，相对于叶面积，它们分配到细根生产的资源要多得多。
• AM定殖和光照对物种根系导水率的不同影响与系统发育和光适应性有关，这表明AM真菌可能不仅由于对养分吸收的影响，而且对水分吸收的影响，在决定早期植物演替和群落组成方面至关重要。
