叶裂在莲座状草本染料千里光（菊科）对遮荫的伸长反应中的作用。
The role of leaf lobation in elongation responses to shade in the rosette-forming forb Serratula tinctoria (Asteraceae).
作者信息
Semchenko Marina, Zobel Kristjan
机构信息
Institute of Botany and Ecology, University of Tartu, 40 Lai St, 51005 Tartu, Estonia.
出版信息
Ann Bot. 2007 Jul;100(1):83-90. doi: 10.1093/aob/mcm074. Epub 2007 May 11.
BACKGROUND AND AIMS
Lobed leaves are considered selectively advantageous in conditions of high irradiance. However, most studies have involved woody species, with only a few considering the role of leaf lobation in herbaceous rosette species. In this study, it is hypothesized that, in addition to its adaptive value in high light, leaf lobation may add to the function of petioles as vertical spacers in herbaceous species in conditions of strong competition for light.
METHODS
To test this hypothesis, leaf development was examined under seasonally changing natural light conditions and a field experiment was conducted in which light climate was manipulated in a wooded meadow population of Serratula tinctoria.
KEY RESULTS
No changes in leaf lobation were observed in response to experimental shading or different natural light conditions. However, in tall herbaceous vegetation, plants with highly lobed leaves achieved significantly greater vertical elongation than plants with less-lobed leaves. In contrast to herbaceous shade, tree shade had no effect on leaf elongation, suggesting differential responsiveness to competition from neighbouring herbs versus overhead shade. In shading treatments, imposed shade could only be responded to by the elongation of leaves that were produced late in development.
CONCLUSIONS
The results show that extensive leaf lobation can enable greater leaf elongation in response to shade from surrounding herbaceous vegetation. The different morphological responses displayed by Serratula tinctoria to different types of shade demonstrate the importance of critically assessing experimental designs when investigating phenotypic plasticity in response to shade.
背景与目的
裂叶在高光照条件下被认为具有选择优势。然而，大多数研究涉及木本植物，只有少数研究考虑了叶裂在草本莲座状植物中的作用。在本研究中，我们假设，除了在强光下的适应价值外，叶裂可能会增强叶柄在草本植物中作为垂直间隔物的功能，这些草本植物在光照竞争激烈的条件下生长。
方法
为了验证这一假设，我们在季节性变化的自然光条件下研究了叶片发育情况，并在一个有树木的草地上对染料麻花头（Serratula tinctoria）种群进行了光照气候调控的田间试验。
主要结果
在实验遮荫或不同自然光条件下，未观察到叶裂的变化。然而，在高大的草本植被中，叶裂程度高的植株比叶裂程度低的植株实现了显著更大的垂直伸长。与草本植物遮荫不同，树木遮荫对叶片伸长没有影响，这表明对来自邻近草本植物的竞争与上方遮荫的反应存在差异。在遮荫处理中，施加的遮荫只能通过发育后期产生的叶片伸长来响应。
结论
结果表明，广泛的叶裂能够使叶片在受到周围草本植被遮荫时实现更大程度的伸长。染料麻花头对不同类型遮荫表现出的不同形态反应表明，在研究对遮荫的表型可塑性时，严格评估实验设计非常重要。
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