Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia, Michoacán, México.
Laboratorio Nacional de Análisis y Síntesis Ecológica, Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México, Morelia, Michoacán, México.
PLoS One. 2020 Apr 16;15(4):e0231526. doi: 10.1371/journal.pone.0231526. eCollection 2020.
In tropical dry forests, although seed germination and seedling establishment are in general limited by the seasonal availability of water, high interspecific variability, nonetheless, exists in terms of seedling traits and germination dynamics. Differences among species in seed germination and seedling traits may be related to other plant life-history traits, such that assessing these relationships may increase our understanding of factors influencing plant establishment, which would affect the regeneration pathways of tropical dry forest communities. In this study, taking into consideration the effect species' phylogeny, we evaluated the relationships of seed germination metrics (percentage, lag time, and rate of germination) and seedling types (i.e. cotyledons functional morphology), with plant life-history traits (growth form, seed mass, dispersal syndrome and dispersal phenology) for 110 species in a Neotropical dry forest in Mexico. A total of 92% of the species studied disperse their seeds during the dry season, mainly at the beginning of this season (66%), a strategy mostly associated with autochorous herbs. Seed germination was more frequent in species that dispersed seeds at the end of the dry season. Germination percentage was not related to any of the traits studied. However, germination lag time and rate were negatively related to seed mass, a trait that in turn depended on growth form and dispersal syndrome. The dominant seedling type in the community was phanerocotylar epigeal with foliaceous cotyledons (56%), which was mostly associated with small seed mass and herbaceous growth form. Our results provide evidence that several plant life-history traits explain an important part of the variation in seed germination and seedling characteristics observed among species. Therefore, these plant life-history traits may be useful for grouping species in terms of their establishment strategies and roles on the regeneration of tropical dry communities.
在热带干旱森林中，尽管种子萌发和幼苗建立通常受到季节性水分供应的限制，但在幼苗特征和萌发动态方面，种间存在高度的变异性。种子萌发和幼苗特征在物种间的差异可能与其他植物生活史特征有关，因此评估这些关系可以增加我们对影响植物建立的因素的理解，这将影响热带干旱森林群落的再生途径。在这项研究中，考虑到物种系统发育的影响，我们评估了种子萌发指标（百分比、滞后时间和萌发率）和幼苗类型（即子叶功能形态）与植物生活史特征（生长形式、种子质量、扩散综合征和扩散物候）之间的关系，研究了墨西哥新热带干旱森林中的 110 个物种。研究中 92%的物种在旱季传播种子，主要在旱季开始时（66%），这一策略主要与自播草本植物有关。在旱季末传播种子的物种中，种子萌发更为频繁。萌发百分比与研究中的任何特征都没有关系。然而，萌发滞后时间和速率与种子质量呈负相关，而种子质量又取决于生长形式和扩散综合征。群落中占主导地位的幼苗类型是地上性的真叶胚轴，具有叶片状的子叶（56%），这主要与小种子质量和草本生长形式有关。我们的研究结果提供了证据，表明几种植物生活史特征可以解释观察到的物种间种子萌发和幼苗特征变化的重要部分。因此，这些植物生活史特征可用于根据其建立策略和在热带干旱群落再生中的作用对物种进行分组。
