Data from: Mixed mating system are regulated by fecundity in Shorea curtisii (Dipterocarpaceae) as revealed by comparison under different pollen limited conditions

The maintenance of mixed mating was studied in Shorea curtisii, a dominant and widely distributed dipterocarp species in Southeast Asia. Paternity and hierarchical Bayesian analyses were used to estimate the parameters of pollen dispersal kernel, male fecundity and self-pollen affinity. We hypothesized that partial self incompatibility and/or inbreeding depression reduce the number of selfed seeds if the mother trees receive sufficient pollen, whereas reproductive assurance increases the numbers of selfed seeds under low amounts of pollen. Comparison of estimated parameters of self-pollen affinity between high density undisturbed and low density selectively logged forests indicated that self-pollen was selectively excluded from mating in the former, probably due to partial self incompatibility or inbreeding depression until seed maturation. By estimating the self-pollen affinity of each mother tree in both forests, mother trees with higher amount of self-pollen indicated significance of self-pollen affinity with negative estimated value. The exclusion of self-fertilization and/or inbreeding depression during seed maturation occurred in the mother trees with large female fecundity, whereas reproductive assurance increased self-fertilization in the mother trees with lower female fecundity.

本研究针对东南亚地区优势且广布的龙脑香科树种肖氏娑罗双（Shorea curtisii）的混合交配系统维持机制展开探究。研究采用父本分析（paternity analysis）与分层贝叶斯（hierarchical Bayesian）分析方法，对花粉扩散核（pollen dispersal kernel）、雄性育性（male fecundity）及自花花粉亲和性（self-pollen affinity）的相关参数进行估算。本研究提出如下假说：当母树接收充足花粉时，部分自交不亲和性（self incompatibility）与/或近交衰退（inbreeding depression）会降低自交种子的数量；而在花粉供应量较低的情境下，繁殖保障（reproductive assurance）则会提升自交种子的占比。通过对比未受干扰的高密度林分与经择伐的低密度林分（selectively logged forests）的自花花粉亲和性参数估算结果，发现前者存在自花花粉的交配选择性排除现象，该现象大概率归因于种子成熟阶段的部分自交不亲和性或近交衰退。在两类林分中分别估算每株母树的自花花粉亲和性后可知，自花花粉亲和性估计值为负值的母树，其自花花粉亲和性效应显著。雌性育性（female fecundity）较高的母树在种子成熟过程中存在自交受精排除与/或近交衰退现象，而雌性育性较低的母树则通过繁殖保障提升了自交受精比例。