Stuefer Josef F, Huber Heidrun
Department of Plant Ecology and Evolutionary Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands e-mail:
Oecologia. 1998 Nov;117(1-2):1-8. doi: 10.1007/s004420050624.
Plant species from open habitats often show pronounced responses to shading. Apart from a reduction in growth, shading can lead to marked changes in morphology and architecture, and it may affect the rate of plant development. Natural shade comprises two basically different features, a reduction in light quantity (amount of radiation) and changes in the spectral light quality. The first aspect represents changes in resource availability, while the latter acts as a source of information for plants and can prompt morphogenetic responses. A greenhouse experiment was carried out to study the effects of changes in light quality and quantity on the growth, morphology and development of two stoloniferous Potentilla species. Individual plants were subjected to three light treatments: (1) full daylight (control); and two shade treatments, in which (2) light quantity (photon flux density) and (3) light spectral quality (red/far-red ratio) were changed independently. Plant development was followed throughout the study. Morphological parameters, biomass and clonal offspring production were measured at the end of the experiment. Morphological traits such as petiole length, leaf blade characteristics and investment patterns into spacers showed high degrees of shade-induced plasticity in both species. With a few exceptions, light quality mainly affected morphological variables, while production parameters were most responsive to changes in light quantity. Potentilla anserina allocated resources preferentially to established rosettes at the cost of stolon growth and branching, while in P. reptans, all parameters related to development and allocation were slowed down to the same extent by light limitation. Light quality changes also positively affected biomass production via changes in leaf allocation. Changes in the spectral light quality had major effects on the size of modular structures (leaves, ramets), whereas changes in light quantity mainly affected their numbers.
来自开阔生境的植物物种通常对遮荫表现出明显的反应。除了生长减缓外，遮荫还会导致形态和结构发生显著变化，并且可能影响植物的发育速度。自然遮荫包括两个基本不同的特征，即光量（辐射量）的减少和光谱光质的变化。第一个方面代表资源可用性的变化，而后者则作为植物的信息来源，并可引发形态发生反应。进行了一项温室实验，以研究光质和光量变化对两种匍匐委陵菜属植物的生长、形态和发育的影响。对单株植物进行了三种光照处理：（1）全日照（对照）；以及两种遮荫处理，其中（2）光量（光子通量密度）和（3）光谱光质（红/远红比率）被独立改变。在整个研究过程中跟踪植物的发育情况。在实验结束时测量形态参数、生物量和克隆后代的产生情况。叶柄长度、叶片特征和间隔物投入模式等形态特征在两种植物中均表现出高度的遮荫诱导可塑性。除了少数例外情况，光质主要影响形态变量，而生产参数对光量变化最为敏感。鹅绒委陵菜优先将资源分配给已形成的莲座叶丛，以匍匐茎生长和分支为代价，而在匐枝委陵菜中，与发育和分配相关的所有参数都因光照限制而减缓到相同程度。光质变化还通过叶片分配的变化对生物量生产产生积极影响。光谱光质的变化对模块化结构（叶片、分株）的大小有主要影响，而光量变化主要影响其数量。
