高山植物甘青铁线莲花冠下垂现象适应性意义  

The adaptive significances of downward orientation flowers in alpine species Clematis tangutica

作　　者：孙坤[1] 范宝强[1] 侯勤正[1] 王思源[1] 张世虎[1] SUN Kun;FAN Bao-qiang;HOU Qin-zheng;WANG Si-yuan;ZHANG Shi-hu(College of Life Science,Northwest Normal University,Lanzhou 730070,Gansu,China)

机构地区：[1]西北师范大学生命科学学院,甘肃兰州730070

出　　处：《西北师范大学学报（自然科学版）》2018年第1期55-60,76,共7页Journal of Northwest Normal University(Natural Science)

基　　金：国家自然科学基金资助项目(31270429)

摘　　要：以分布于高海拔地区的甘青铁线莲(Clematis tangutica(Maxim.)Korsh.)为研究对象,通过对其花朝向改变(花朵上举),研究花粉数量和质量、访花昆虫、结籽率以及种子特征的变化,从传粉者和非传粉者因素等角度探讨甘青铁线莲花期花冠下垂现象的适应意义.结果显示,花朵人工上举后,在模拟雨水冲刷条件下甘青铁线莲花粉数量和花粉萌发率显著下降,而在阳光直射条件下甘青铁线莲花粉萌发率显著下降,表明花冠下垂可以通过减缓雨水对花粉的冲刷和避免阳光直射对花粉的破坏而起到雄性生殖器官的保护作用,进而提高其雄性适合度;花朵人工上举后,甘青铁线莲的单花结籽率和种子萌发率都显著降低,表明花朵朝向改变会降低其雌性适合度;甘青铁线莲的主要传粉者为熊蜂和中华蜜蜂,在花朵人工上举后,两种传粉者的访花频率和单花停留时间与自然状态下(下垂)相比并没有差异,说明甘青铁线莲花朵朝向的变化不会影响到其主要访花昆虫对其繁殖成功的贡献.研究结果表明,甘青铁线莲花期花朵下垂现象对有效传粉昆虫的影响不大,但可以显著提高植物雄性适合度和雌性适合度,并作为一种有效的适应策略保障了其繁殖成功.This study takes Clematis tangutica(Maxim.)Korsh,which distributes in high altitude,as the research object.By changing corolla direction from facing down to up,we observe the pollinator attracting,the pollen quantity,pollen germination rate,seed setting ratio and the seed characters of this species under the two different directions,aiming to find out the adaptive advantages of flowers drooping of C tangutica.The results showed that after flowers artificially erected,the pollen quantity and pollen germination rate significantly decreased when exposed in rain wash condition,and the pollen germination rate decreased sharply when presented in sunlight condition,indicating that the flower downward orientation might play an important role in protecting male function and increase male fitness by preventing flowers from rain wash and sunlight.After flowers artificially erected,the single flower seed yield and seed setting ratio of C tangutica reduced which indicated that flower upward orientation may decrease female fitness.The main pollinators of C tangutica were Bombus spp.and Apis cerana,and their visit frequencies and stay time/visit/flower did not differ significantly between flowers of these two orientations(facing up and down),suggesting that the flowers direction changing may not affect the reproductive contribution of the main pollinators.Our results suggested that the flower downward of C tangutica could not influence the pollinator variety and efficiency,but could significantly improve the male and female fitness,which might act as an effective adaptation strategy to ensure reproductive success of C tangutica.

关 键 词：甘青铁线莲 高海拔 花下垂 繁育系统 花朝向改变 

分 类 号：Q948.122.6[生物学—植物学]