Scheiner Samuel M, Gurevitch Jessica, Teeri James A
Barnes Laboratory, The University of Chicago, 5630 S. Ingleside Avenue, 60637, Chicago, Illinois, USA.
Oecologia. 1984 Sep;64(1):74-77. doi: 10.1007/BF00377546.
Three populations of the grass Danthonia spicata were observed to have different rates of biomass accumulation when grown in common environment treatments. The populations were native to adjacent sites of different successional age and different levels of shading. Twelve individuals from each population were clonally replicated and two replicates were grown in each of two light treatments, 100% and 22% of unshaded sunlight. Following growth in the treatments the populations all exhibited the same mean light-saturated photosynthetic rate of 11.7 μmol ms. This rate is intermediate for published values of sun and shade species and for species from along a successional gradient. There was no difference in photosynthetic rate among treatments. There was significant genetic variation for lightsaturated photosynthetic rate within populations but no significant differences among populations. The populations had similar leaf water potential values of-1.12 MPa in all treatments. There were significant differences among treatments and genotypes for specific leaf weight which resulted in significant differences among treatments and no significant differences among genotypes in light-saturated photosynthetic rate expressed on a leaf weight basis. Lightsaturated photosynthetic rate had a high heritability and low plasticity. We postulate that photosynthetic rate is under strong selection and that the observed rates permit populations of D. spicata to grow in a wide range of habitat light levels.
在共同环境处理条件下生长时，观察到草本植物穗三毛（Danthonia spicata）的三个种群具有不同的生物量积累速率。这些种群原产于不同演替年龄和不同遮荫水平的相邻地点。每个种群选取12个个体进行克隆繁殖，并将两个复制品分别置于两种光照处理下生长，光照强度分别为无遮荫阳光的100%和22%。经过处理生长后，所有种群的平均光饱和光合速率均为11.7 μmol m⁻² s⁻¹。该速率处于已发表的阳生和阴生植物以及沿演替梯度分布的植物的光合速率值之间。各处理间光合速率无差异。种群内光饱和光合速率存在显著的遗传变异，但种群间无显著差异。在所有处理中，这些种群的叶水势值相似，均为 -1.12 MPa。处理和基因型之间的比叶重存在显著差异，这导致以叶重为基础表示的光饱和光合速率在处理间存在显著差异，而基因型间无显著差异。光饱和光合速率具有高遗传力和低可塑性。我们推测光合速率受到强烈选择，并且观察到的速率使穗三毛种群能够在广泛的生境光照水平下生长。
