State Key Laboratory of Grassland and Agroecosystems, School of Life Science, Lanzhou University, Lanzhou, P.R. China.
State Key Laboratory of Grassland and Agroecosystems, School of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, P.R. China.
PLoS One. 2014 Jun 3;9(6):e98601. doi: 10.1371/journal.pone.0098601. eCollection 2014.
Seed germination is a crucial stage in the life history of a species because it represents the pathway from adult to offspring, and it can affect the distribution and abundance of species in communities. In this study, we examined the effects of phylogenetic, life history and environmental factors on seed germination of 134 common species from an alpine/subalpine meadow on the eastern Tibetan Plateau. In one-way ANOVAs, phylogenetic groups (at or above order) explained 13.0% and 25.9% of the variance in germination percentage and mean germination time, respectively; life history attributes, such as seed size, dispersal mode, explained 3.7%, 2.1% of the variance in germination percentage and 6.3%, 8.7% of the variance in mean germination time, respectively; the environmental factors temperature and habitat explained 4.7%, 1.0% of the variance in germination percentage and 13.5%, 1.7% of the variance in mean germination time, respectively. Our results demonstrated that elevated temperature would lead to a significant increase in germination percentage and an accelerated germination. Multi-factorial ANOVAs showed that the three major factors contributing to differences in germination percentage and mean germination time in this alpine/subalpine meadow were phylogenetic attributes, temperature and seed size (explained 10.5%, 4.7% and 1.4% of the variance in germination percentage independently, respectively; and explained 14.9%, 13.5% and 2.7% of the variance in mean germination time independently, respectively). In addition, there were strong associations between phylogenetic group and life history attributes, and between life history attributes and environmental factors. Therefore, germination variation are constrained mainly by phylogenetic inertia in a community, and seed germination variation correlated with phylogeny is also associated with life history attributes, suggesting a role of niche adaptation in the conservation of germination variation within lineages. Meanwhile, selection can maintain the association between germination behavior and the environmental conditions within a lineage.
种子萌发是物种生活史中的一个关键阶段，因为它代表了从成年到后代的途径，并且可以影响物种在群落中的分布和丰度。在这项研究中，我们检查了系统发育、生活史和环境因素对青藏高原东部高山/亚高山草甸 134 种常见物种种子萌发的影响。在单向方差分析中，系统发育组（在或高于等级）分别解释了萌发百分比和平均萌发时间方差的 13.0%和 25.9%；生活史特征，如种子大小、扩散模式，分别解释了萌发百分比方差的 3.7%和 2.1%，平均萌发时间方差的 6.3%和 8.7%；环境因子温度和生境分别解释了萌发百分比方差的 4.7%和 1.0%，平均萌发时间方差的 13.5%和 1.7%。我们的结果表明，高温会导致萌发百分比显著增加和萌发加速。多因素方差分析表明，导致高山/亚高山草甸种子萌发百分比和平均萌发时间差异的三个主要因素是系统发育属性、温度和种子大小（分别独立解释萌发百分比方差的 10.5%、4.7%和 1.4%；独立解释平均萌发时间方差的 14.9%、13.5%和 2.7%）。此外，系统发育组与生活史特征之间以及生活史特征与环境因素之间存在强烈的关联。因此，萌发的变异主要受到群落中系统发育惯性的限制，与系统发育相关的种子萌发变异也与生活史特征相关，这表明在谱系内保持萌发变异的生态位适应作用。同时，选择可以维持谱系内萌发行为与环境条件之间的关联。
