Rethinking the role of many plant phenolics - protection from photodamage not herbivores?
Rethinking the role of many plant phenolics - protection from photodamage not herbivores?
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DOI：
10.1034/j.1600-0706.2002.990117.x
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发表时间：
2002-10-01
期刊：
影响因子：
3.4
通讯作者：
McArthur, C
中科院分区：
文献类型：
--
作者：
Close, DC;McArthur, C
酚类化合物一直被认为是保护植物免受食草动物侵害的经典防御化合物，因为植物次生代谢产物被认为是出于这个原因而进化的。资源可用性和碳-养分平衡假说提出，植物物种之间和内部酚类水平的变化反映了环境中养分和光照的可用性，并代表了植物在生长和防御食草动物方面的分配权衡。与这些概念相反，我们认为：（1）许多植物酚类物质的主要作用可能是保护叶子免受光损伤，而不是草食动物：（2）它们可以通过充当抗氧化剂来实现这一点：（3）它们的水平可能会随着环境条件的变化而变化，以抵消这种潜在的光损伤。因此我们认为酚类物质的含量。通常用于支持在资源可用性方面在生长和草食动物防御之间进行权衡的概念，实际上可能反映了光损害的不同风险。我们认为，在某些环境条件下，许多酚类化合物的水平很低，不是因为生产它们的资源有限，而仅仅是因为光损伤的风险很低，不需要它们。如果我们的光损伤假说是正确的，需要重新评估植物防御理论中许多酚类化合物的生态和进化作用。
Phenolics have been considered classic defence compounds for protecting plants from herbivores, ever since plant secondary metabolites were suggested to have evolved for that reason. The resource availability and carbon-nutrient balance hypotheses proposed that variation in phenolic levels between and within plant species reflects environmental availability of nutrients and light, and represents a trade-off in allocation by plants to growth and defence against herbivores. In contrast to these concepts, We Suggest that (1) the main role of many plant phenolics may be to protect leaves from photodamage, not herbivores: (2) they can achieve this by acting as antioxidants: and (3) their levels may vary with environmental conditions in order to counteract this potential photodamage. We therefore suggest that patterns in phenolic levels. often used to support the concept of trade-off between growth and herbivore defence in relation to resource availability, may actually reflect different risks of photodamage. We suggest that the level of many phenolics is low under some environmental conditions, not because resources to produce them are limited, but simply because the risk of photodamage is low and they are not required. If our photodamage hypothesis is correct, a reassessment of the ecological and evolutionary role of many phenolics in plant defence theory is required.