Combined effects of resource heterogeneity and simulated herbivory on plasticity of clonal integration in a rhizomatous perennial herb
Combined effects of resource heterogeneity and simulated herbivory on plasticity of clonal integration in a rhizomatous perennial herb
复制标题
资源异质性和模拟食草对根茎多年生草本植物克隆整合可塑性的综合影响
DOI：
10.1111/plb.12122
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发表时间：
2014-07-01
期刊：
影响因子：
3.9
通讯作者：
Wang, L.
中科院分区：
文献类型：
--
作者：
Gao, Y.;Wang, D.;Wang, L.
先前的研究假设克隆整合具有潜在优势，但通常忽略了其在复杂异质环境中的可塑性。克隆植物适应性地响应非生物异质性（不均匀的资源分布）和食草诱导的异质性（分株性能的克隆内异质性），但迄今为止，人们对资源异质性和模拟食草性如何共同影响克隆的整体性能知之甚少。食草引起的克隆内的部分损伤可能会在资源同质环境中产生食草诱导的异质性，并且还可能在资源异质条件下减少或增加异质性的程度。我们进行了一项温室实验，其中对均质或异质营养处理中的羊草片段的目标分株进行修剪（0％或75％芽去除）。在养分利用率高（9:9）的同质环境中，完整或切断根茎的羊草分株生物量为0.70或0.69 g。相反，在养分利用率中等（5：5）和低（1：1）的均质环境中，具有完整根茎的目标分株生物量明显低于切断的目标分株。高资源可用性和食草动物的存在可以分别通过提供丰富的资源或产生食草动物引起的异质性来减轻同质条件下根茎连接的负面影响。在异质条件下，具有连接根茎的克隆片段的食草耐受性高于具有切断根茎的片段。这些发现证实了在资源异质性和模拟食草的共同影响下，克隆整合在繁殖上具有绝对的优势。此外，我们的结果清楚地表明了资源异质性和模拟食草对克隆整合的成本和收益的协同交互作用。这无疑将增进我们对复杂环境条件下克隆整合可塑性的理解。
Previous lines of investigation assuming potential advantage of clonal integration generally have neglected its plasticity in complex heterogeneous environments. Clonal plants adaptively respond to abiotic heterogeneity (patchy resource distribution) and herbivory-induced heterogeneity (within-clone heterogeneity in ramet performance), but to date little is known about how resource heterogeneity and simulated herbivory jointly affect the overall performance of clones. Partial damage within a clone caused by herbivory might create herbivory-induced heterogeneity in a resource-homogeneous environment, and might also decrease or increase the extent of heterogeneity under resource-heterogeneous conditions. We conducted a greenhouse experiment in which target-ramets of Leymus chinensis segments within homogeneous or heterogeneous nutrient treatments were subject to clipping (0% or 75% shoot removal). In homogeneous environments with high (9: 9) nutrient availability, ramet biomass of L. chinensis with intact or severed rhizomes is 0.70 or 0.69 g. Conversely, target-ramet biomass with intact rhizomes is obviously lower than that of the severed target-ramets in the homogeneous environments with medium (5: 5) and low (1: 1) nutrient availability. High resource availability and the presence of herbivory can alleviate negative effects of rhizome connection under homogeneous conditions, by providing copious resource or creating herbivory-induced heterogeneity respectively. Herbivory tolerance of clonal fragments with connected rhizomes was higher than that of fragments with severed rhizomes under heterogeneous conditions. These findings confirmed the unconditional advantage of clonal integration on reproduction under the combined influence of resource heterogeneity and simulated herbivory. Moreover, our results made clear the synergistically interactive effects of resource heterogeneity and simulated herbivory on costs and benefits of clonal integration. This will undoubtedly advance our understanding on the plasticity of clonal integration under complex environmental conditions.