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.

研究背景。雌全异株（gynodioecy）是一种二态性生殖系统，即植株要么为雌性，要么为雌雄同株（hermaphroditic），目前已在不足1%的被子植物（angiosperm）物种中被报道。该生殖系统的罕见性表明，雌全异株仅能在一系列受限条件下才能演化并维持。确定此类约束条件的一种可行路径，是识别与雌全异株相关联的表型性状与生态因子——此类性状或因子可推动该生殖系统的演化与存续。

研究方法。我们构建了覆盖全球被子植物（angiosperm）类群的雌全异株物种数据库，并基于该数据库检验雌全异株是否与两类表型性状/生态因子存在关联：草本生长型与温带地理分布。首先通过物种水平分析确认，雌全异株物种以草本类群和温带分布类群为主；随后开展科水平分析，检验某演化支系中若存在草本或温带分布物种，是否更易孕育雌全异株物种。

关键结果。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株物种中显著富集。同时，包含草本或温带分布物种的植物科，其内部出现雌全异株物种的概率显著更高。

研究结论。本研究证实雌全异株与草本生长型及温带分布显著相关，提示草本习性与温带生境可助力雌全异株的演化或存续。此外，本研究结果显示，雌全异株与亲缘关系密切的另一生殖系统——雌雄异株（dioecy）所关联的表型性状/生态因子存在显著差异。由此可见，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的演化支系的生长型与地理分布特征。