Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
Ann Bot. 2010 Dec;106(6):979-88. doi: 10.1093/aob/mcq195. Epub 2010 Sep 29.
Plant functional traits are assumed to be adaptive. As selection acts on individuals and not on traits, interpreting the adaptive value of a trait not may be straightforward. For example, productive leaves are associated with fertile environments. However, it is not clear if productive leaves confer an advantage in these habitats, or if they are an advantage as part of a suite of coordinated traits.
Genotypes of Arabidopsis thaliana were grown in high and low nutrient treatments and low, neutral and high pH treatments. Nutrient availability is reduced in acidic or basic soils relative to neutral pH soils. pH treatments were used to alter the availability of resources rather than the amount of resources.
Leaf function (specific leaf area, SLA) and life history (size at reproduction, age at reproduction) were variable across genotypes and were plastic. High nutrient availability induced higher SLA and larger size at reproduction. Genotypes that reproduced at large size in high nutrient conditions at neutral pH had the greatest fruit production. SLA was only indirectly related to fruit production through a causal relationship with rosette size; in high nutrient conditions, plants with high SLA were large at reproduction and had higher fruit production. In high nutrient and high pH treatments, plants were large at reproduction, but large size at reproduction was associated with low fecundity. This suggests that large size is adaptive under high nutrient availability.
Interpreting the adaptive value of functional traits will sometimes only be possible when these traits are considered as a suite of correlated and coordinated traits. Leaf functional traits may be important in defining adaptive strategies in A. thaliana but only through how they affect plant life history. Finally, manipulating soil pH can be a valuable tool in assessing adaptive plasticity on nutrient gradients.
植物功能性状被认为是适应性的。由于选择作用于个体而不是性状，因此解释一个性状的适应性价值可能并不简单。例如，生产性叶片与肥沃的环境有关。然而，目前尚不清楚生产性叶片在这些栖息地是否具有优势，或者它们是否是一系列协调性状的优势。
拟南芥（Arabidopsis thaliana）的基因型在高养分和低养分处理以及低、中、高 pH 值处理中生长。与中性 pH 值土壤相比，酸性或碱性土壤中的养分可用性降低。pH 值处理用于改变资源的可用性，而不是资源的数量。
叶片功能（比叶面积，SLA）和生活史（繁殖时的大小，繁殖时的年龄）在基因型之间是可变的，并且具有可塑性。高养分可用性诱导更高的 SLA 和更大的繁殖时大小。在中性 pH 值的高养分条件下繁殖时体型较大的基因型具有最大的果实产量。SLA 仅通过与莲座叶大小的因果关系间接与果实产量相关；在高养分条件下，SLA 较高的植物在繁殖时体型较大，并且果实产量较高。在高养分和高 pH 值处理中，植物在繁殖时体型较大，但繁殖时的体型较大与较低的繁殖力有关。这表明在高养分可用性下，大体型是适应性的。
只有当这些性状被视为一系列相关和协调的性状时，才能解释功能性状的适应性价值。叶片功能性状可能在定义拟南芥的适应性策略方面很重要，但仅通过它们如何影响植物的生活史。最后，操纵土壤 pH 值可以成为评估养分梯度上适应性可塑性的有价值工具。
