Data from: Genetic diversity, sexual condition, and microhabitat preference determine mating patterns in Sphagnum (Sphagnaceae) peat-mosses.

In bryophytes, the possibility of intragametophytic selfing creates complex mating patterns not possible in seed plants, but relatively little is known about patterns of inbreeding in natural populations. In the peat-moss genus Sphagnum, taxa are generally bisexual (gametophytes produce both sperm and egg) or unisexual (gametes produced by separate male and female plants). We sampled populations of 14 species, to assess inbreeding variation and inbreeding depression in sporophytes, and to evaluate correlations between sexual expression, mating systems, and microhabitat preferences. We sampled maternal gametophytes and their attached sporophytes at 12-19 microsatellite loci. Bisexual species exhibited higher levels of inbreeding than unisexual species but did generally engage in some outcrossing. Inbreeding depression did not appear to be common in either unisexual or bisexual species. Genetic diversity was higher in populations of unisexual species, compared to populations of bisexual species. We found a significant association between species microhabitat preference and population genetic diversity: species preferring hummocks (high above water table) had populations with lower diversity than species inhabiting hollows (at the water table). We also found a significant interaction between sexual condition, microhabitat preference, and inbreeding coefficients, suggesting a vital role for species ecology in determining mating patterns in Sphagnum populations.苔藓植物（Bryophytes）中，配子体自交（intragametophytic selfing）可形成种子植物（seed plants）无法实现的复杂交配模式，但目前学界对其自然种群的近交（inbreeding）模式仍知之甚少。 泥炭藓属（Sphagnum）的类群通常分为两类：雌雄同株（bisexual，即配子体可同时产生精子与卵细胞）与雌雄异株（unisexual，即由独立的雄株与雌株分别产生雌雄配子）。 本研究对14个物种的种群开展采样，旨在评估孢子体（sporophyte）的近交变异与近交衰退（inbreeding depression），并分析性别表达、交配系统与微生境偏好之间的相关性。 研究团队在12至19个微卫星位点（microsatellite locus）上，对母本配子体及其附着的孢子体样本进行了检测分析。 结果显示，雌雄同株物种的近交水平高于雌雄异株物种，但通常仍会发生一定程度的异交（outcrossing）。 近交衰退在雌雄异株与雌雄同株类群中均不常见。 相较于雌雄同株物种的种群，雌雄异株物种的种群遗传多样性更高。 本研究还发现物种微生境偏好与种群遗传多样性间存在显著关联：偏好泥炭丘（hummock，即高于地下水位的生境）的物种，其种群遗传多样性低于栖息于泥炭洼地（hollow，即处于地下水位处的生境）的物种。 此外，性别状态、微生境偏好与近交系数（inbreeding coefficient）三者间存在显著交互作用，这表明物种的生态学特性在决定泥炭藓种群的交配模式中扮演着关键角色。