野慈姑和矮慈姑种间花粉传递与生殖干扰不对称性  

Interspecific pollen transfer and asymmetry in reproductive interference between Sagittaria trifolia L. and Sagittaria pygmaea L.

作　　者：唐莎莎 费采虹 杨聪 尚书禾 熊浩镧 王欣怡 汪小凡[1] Tang Sha-Sha;Fei Cai-Hong;Yang Cong;Shang Shu-He;Xiong Hao-Lan;Wang Xin-Yi;Wang Xiao-Fan(College of Life Sciences,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学生命科学学院,武汉430072

出　　处：《植物科学学报》2022年第6期762-770,共9页Plant Science Journal

基　　金：国家自然科学基金(31970250)。

摘　　要：本研究观测了两种慈姑属(Sagittaria)植物野慈姑(S.trifolia L.)和矮慈姑(S.pygmaea L.)共享传粉者的种间访花活动,利用染色示踪方法检测了种间花粉传递是否存在及其强度,通过统计二者在单生/混生样地中的结实情况判断物种间生殖干扰存在与否,以及对植株有性生殖成功率的影响。结果显示:(1)主要共享传粉者存在种间访花行为,但访花者种间运动频率显著低于种内运动,且对野慈姑雄花存在访花偏好。(2)在混生样地中野慈姑和矮慈姑的雌蕊群上均能检测到共享传粉者带来的种间花粉传递,约1.4%的柱头上落置了染色标记的异种花粉;野慈姑花粉散布于矮慈姑花上的距离较远,数量较多,而矮慈姑花粉主要表现为近距离传递。(3)两物种在自然生境中共存时,矮慈姑种子不完整胚比例显著增加,而野慈姑完整胚比例维持在80%以上,表现为种间生殖干扰的不对称性。此外,本研究还对减轻生殖干扰的生态机制进行了探讨。Closely-related sympatric species are often at risk of interspecific reproductive interference due to similar reproductive biological characteristics. Fruits can be formed in hand-pollination hybridization experiments of Sagittaria trifolia L. and S.pygmaea L., but the arrival of interspecific pollen tubes to the ovule is delayed due to different growth routes. Here, we investigated sympatrically growing S. trifolia and S. pygmaea populations with overlapping flowering periods and observed the interspecific movement patterns of shared pollinators, using pollen tracers to detect the existence and intensity of interspecific pollen transfer. The existence of reproductive interference and its effect on sexual reproductive fitness were measured using seed set in single-/mixed-plots of the two species. Results showed that:(1) The main shared pollinators visited flowers of both species, but the frequency of interspecific movements was significantly lower than that of intraspecific movements, and pollinators showed a preference for male flowers of S. trifolia.(2) Interspecific pollen transfer by shared pollinators was detected in both species under natural conditions, and the proportion of stigma with alien pollen was only about 1.4%. The pollen of S. trifolia was carried further and in greater quantity to S. pygmaea flowers, while the pollen of S. pygmaea was mainly transferred in short distances.(3) When the two species coexisted in natural habitats, the proportion of undeveloped S. pygmaea seeds increased significantly, while the proportion of developed S. trifolia seeds remained above 80%, indicating asymmetry in interspecific reproductive interference. In this study, we explored the ecological mechanisms that mitigate reproductive interference, providing a new perspective for understanding the coexistence and reproductive strategies of related plant species in the wild.

关 键 词：共享传粉者 种间花粉传递 生殖干扰 种子折损 慈姑属 

分 类 号：Q944.43[生物学—植物学]