Data from: An angiosperm-wide analysis of the correlates of gynodioecy

Premise of research. Gynodioecy, a dimorphic sexual system where individual plants are either female or hermaphroditic, has been documented in ≪1% of plant species. This rarity suggests that gynodioecy can evolve and persist only under a restrictive set of conditions. One approach to determining these conditions is to identify the phenotypic traits and ecological factors that are associated with gynodioecy, as such traits or factors may facilitate the evolution and persistence of the sexual system. Methodology. We assembled an angiosperm-wide database of gynodioecious species and used this database to test whether gynodioecy was associated with two phenotypic traits/ecological factors: an herbaceous growth form and a temperate geographic distribution. Species-level analyses were used to confirm that gynodioecious species are predominately herbaceous and temperate. Family-level analyses were then used to test whether the presence of herbaceous and temperate species in a lineage was associated with the presence of gynodioecious species. Pivotal results. An herbaceous growth form and a temperate geographic distribution were significantly overrepresented in gynodioecious species relative to their frequency in all plant species. Families that contained species with an herbaceous growth form and a temperate geographic distribution were significantly more likely to also contain gynodioecious species. Conclusions. Gynodioecy was associated with an herbaceous growth form and a temperate distribution, suggesting that herbaceousness and temperateness can facilitate the evolution and/or persistence of gynodioecy. In addition, our results suggest that gynodioecy is associated with different phenotypic traits/ecological factors than dioecy, a closely related sexual system. Consequently, whether gynodioecy is a transitional state in the evolution of dioecy may depend on the growth form and geographic distribution of the lineage in which it evolves.

研究前提：雌全异株（gynodioecy）是一种二态性系统，即植株要么为雌性，要么为两性植株，目前仅在远不足1%的植物物种中被报道。该性系统的稀有性表明，雌全异株仅能在一系列严格限定的条件下才能演化并维持。确定此类限定条件的一种方法，是识别与雌全异株相关的表型性状与生态因子，因为此类性状或因子可促进该性系统的演化与维持。
研究方法：我们构建了覆盖全被子植物类群的雌全异物种种数据库，并利用该数据库检验雌全异株是否与两项表型性状/生态因子相关：草本生长型与温带地理分布。首先通过物种水平分析，证实雌全异物种以草本植物为主且多分布于温带区域；随后开展科水平分析，检验某演化支内存在草本与温带分布物种的情况，是否与该支系存在雌全异物种相关联。
核心结果：相较于所有植物物种的整体占比，草本生长型与温带地理分布在雌全异物种中显著富集。同时，包含草本与温带分布物种的植物科，其演化支内存在雌全异物种的概率显著更高。
研究结论：雌全异株与草本生长型及温带分布显著相关，这表明草本习性与温带适应性可促进雌全异株的演化和/或维持。此外，本研究结果显示，雌全异株与亲缘关系密切的雌雄异株（dioecy）性系统所关联的表型性状/生态因子存在差异。因此，雌全异株是否为雌雄异株演化过程中的过渡状态，可能取决于其演化所在类群的生长型与地理分布特征。