不同海拔狼毒种群花性状变异及交配系统特征的研究

Study on flower traits variation and mating system characteristics of populations of Stellera chamaejasme at high and low altitude

选择高海拔和低海拔2个不同地理分布的狼毒(Stellera chamaejasme)自然种群,通过对花性状测定和人工辅助授粉,探究了狼毒的花性状变异程度及其交配系统特征。结果表明:2个狼毒种群花性状变异幅度较大,低海拔种群花性状变异系数为9.25%~105.27%,高海拔种群为4.32%~80.05%。狼毒花各性状的变异在不同种群内表现一致,单株丛花序数变异系数最大,单花序小花数变异次之,株高变异相对较小,冠口直径、花筒长和花序头直径变异系数最小,而且同一花性状均值在不同种群间存在极显著差异(P<0.01)。人工辅助授粉结果表明,在低海拔种群和高海拔种群中,自然授粉和人工异交处理下的结实率之间无显著差异(P>0.05),自交、自主自交和无融合结实处理下的结实率均与自然授粉和人工异交处理存在显著差异(P<0.05)。综合表明,两狼毒种群花性状存在变异,且繁殖器官(除单株丛花序数和单花序小花数)的变异程度小于营养器官,其交配系统均为自交不亲和。

In this study,two natural populations of Stellera chamaejasme were selected which were from different geographical distributions at high and low altitudes.The degree of variation in floral traits and the characteristics of its mating system were explored by the measurement of floral traits and the treatment of artificial assisted pollination.The results showed that the two S.chamaejasme population had a large variation in floral traits,and the coefficient of variation(CV)ranged from 9.25%to 105.27%in low-altitude population and from 4.32%to 80.05%in high-altitude population.The variation in all traits of S.chamaejasme was consistent in different populations.The CV of the number of inflorescence per plant was the largest,followed by the number of flowers per inflorescence,the CV of plant height was relatively small,and the CV of corolla diameter,cylinder length and inflorescence head diameter were the smallest;the mean values of the same flower traits were significantly different between two populations(P<0.001).The results of artificial assisted pollination showed that there was no significant difference in the seed-setting rate between natural pollination and artificial cross-pollination treatment in low-altitude population and high-altitude population(P>0.05),while the seed-setting rate under self-pollination,autonomous self-fertilization and apomixis were significantly different from that under natural pollination and artificial cross-pollination treatment(P<0.05).In conclusion,there was variation in floral traits of two populations of S.chamaejasme,the degree of variation in the reproductive organs(except the number of inflorescence per plant and the number of flowers per inflorescence)was less than that of the vegetative organs,and their mating system were self-incompatibility.