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...

本研究针对东南亚地区优势且分布广泛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）与分层贝叶斯分析（hierarchical Bayesian analyses），对花粉扩散核（pollen dispersal kernel）、雄性繁殖力（male fecundity）及自花花粉亲和性（self-pollen affinity）的相关参数进行估算。我们提出如下研究假说：若母树接收到充足花粉，部分自交不亲和（partial self incompatibility）与/或近交衰退（inbreeding depression）会减少自交种子的数量；而在花粉供应量较低的情况下，繁殖保障（reproductive assurance）机制则会增加自交种子的数量。通过对比未受干扰的高密度原生林与经选择性采伐的低密度林的自花花粉亲和性估算参数，结果显示前者存在自花花粉的选择性交配排除现象，该现象可能归因于种子成熟前的部分自交不亲和或近交衰退。通过估算两种林分中每株母树的自花花粉亲和性，自花花粉量更高的母树其...具有显著意义。