不同海拔圆叶天女花的传粉生物学研究

Study on pollination biology of Oyama sinensis at different altitudes

对国家Ⅱ级重点保护野生植物、准四川省特有植物和优先拯救保护的极小种群植物圆叶天女花[Oyama sinensis(Rehder et E.H.Wilson)N.H.Xia et C.Y.Wu]在不同海拔居群[P1(海拔1 758 m)、P2(海拔1 988 m)、P3(海拔2 181 m)和P4(海拔2 397 m)居群]的花部特征、花粉活力和柱头可授性进行了研究,并对其访花昆虫的种类和访花行为进行了观察。结果表明:P2和P3居群圆叶天女花的花朵直径、花被片长和花被片宽总体上显著(P<0.05)大于P1和P4居群,而4个居群间花朵长的差异不显著(P>0.05)。随着海拔升高,圆叶天女花在雄蕊和雌蕊投入上逐渐减少,其雄蕊、雌蕊、花粉和胚珠的数量以及花粉/胚珠比(P/O)总体上呈逐渐减小的趋势。高海拔居群(P3和P4居群)圆叶天女花的花粉活力和柱头可授性明显高于低海拔居群(P1和P2居群),雄蕊和雌蕊的寿命更长。熊蜂(Bombus ningpoensis)、花蚊子(Aedes albopictus)、中华蜜蜂(Apis cerana)、食蚜蝇(Syrphus sp.)和白粉蝶(Pieris rapae)为圆叶天女花的有效传粉昆虫,其中,主要访花昆虫熊蜂的访问高峰期为10:00—14:00。P2和P3居群圆叶天女花花朵的展示效果较好,访花昆虫种类较多(10~11种)。随着海拔升高,圆叶天女花访花昆虫的访问次数逐渐减少。研究结果显示:随着海拔升高,延长花粉和柱头的寿命为圆叶天女花提高传粉效率和增强适应性的有效策略。

Floral characteristics,pollen viability,and stigma receptivity of Oyama sinensis（ Rehder et E.H. Wilson） N. H. Xia et C. Y. Wu（ national class Ⅱ key protected wild plant,quasi endemic species in Sichuan Province,and prior rescue and protection plant with extremely small population） in populations at different altitudes [population P1（ altitude of 1 758 m）,P2（ altitude of 1 988 m）,P3（ altitude of2 181 m）,and P4（ altitude of 2 397 m） ]were studied,and species and visiting behaviors of its flowervisiting insects were observed. The results show that flower diameter,and length and width of tepal of O.sinensis in population P2 and P3 are significantly（ P0. 05） larger than those in population P1 and P4 in general,while there is no significant（ P0. 05） difference in flower length among four populations. With increasing of altitude,input of stamen and pistil of O. sinensis decreases gradually,and numbers of stamen,pistil,pollen and ovule and pollen/ovule ratio（ P/O） show a tendency to gradually decrease in general. Pollen viability and stigma receptivity of O. sinensis in high altitude populations（ population P3 and P4） are evidently higher than those in low altitude populations（ population P1 and P2）,and their stamen and pistil have longer life. Bombus ningpoensis,Aedes albopictus,Apis cerana,Syrphus sp.,andPieris rapae are the effective pollination insects of O. sinensis,in which,the visiting peak period of major flower-visiting insect of B. ningpoensis is 10： 00—14： 00. Exhibition effect of flowers of O. sinensis in population P2 and P3 is relatively good,and number of flower-visiting insect species is relatively large（ 10-11 species）. With increasing of altitude,visiting times of flower-visiting insects of O. sinensis decrease gradually. It is suggested that with increasing of altitude,extending the life of pollen and stigma is an effective strategy to improve pollination efficiency and enhance adaptability of O. sinensis.