Plos One:中科院版纳植物园李庆军研究组发现次级花粉展示新机制

摘要 : 近日，国际学术期刊《Plos ONE》上在线发表中国科学院西双版纳热带植物园植物进化生态学研究组李庆军研究组的一篇研究论文

近日，国际学术期刊《PLoS ONE》上在线发表中国科学院西双版纳热带植物园植物进化生态学研究组李庆军研究组的一篇研究论文，题为“A New Secondary Pollen Presentation Mechanism from a Wild Ginger (Zingiber densissimum) and Its Functional Roles in Pollination Process”，博士生范永立为论文第一作者，李庆军研究员为论文通讯作者。

植物在开花和花粉囊开裂之后，通常将花粉展示在花药上以等待传粉者将其带到另一朵花的柱头上。但是，自然界中有一些植物在开花之后并非只将所有花粉展示在花药上，而是还会将部分(或全部)花粉展示在其它器官(如花柱、柱头、花丝和苞片)上，从而形成次级花粉展示(secondary pollen presentation)现象。次级花粉展示现象最早由传粉生态学之父Sprengel于1793年在桔梗科风铃草属(Campanula L.)中发现，至今，人们已在16个科中共发现9类次级花粉展示模式。尽管次级花粉展示现象被认为是植物在传粉过程中的一种适应机制，但是，目前为止很少有实验证据证明次级花粉展示机制是如何促进传粉的。

博士研究生范永立在其导师李庆军的指导下，于2011至2012年对分布于云南临沧的野生姜科植物多毛姜 (Zingiber densissimum S.Q.Tong & Y.M.Xia)的传粉生态学进行了研究，发现了自然界中一种新的次级花粉展示模式。研究发现，多毛姜在开花之后，花药上的花粉通过表面的粘附作用形成特殊的花粉链结构，该结构使花药上的一部分花粉粘到唇瓣(传粉者访花通道)上，从而使唇瓣成为花粉的第二展示器官。通过进一步对传粉效率的研究发现，传粉者(两种蜂类)在访花时，无论何种访花姿势的传粉者都能够同时从花药和唇瓣上带走花粉。与无次级花粉展示的情况相比，该次级花粉展示机制显著提高了传粉者的花粉移出率。传粉者从唇瓣上移出的花粉则在传粉者下次访花时通过头部和前足传递到另一朵花的柱头上。该研究证明了这种新的次级花粉展示模式通过增加花粉展示面积来提高花粉散发效率，从而促进传粉。该次级花粉展示模式是自然界中的首次报道，同时也是次级花粉展示机制在姜科植物中的首次记录。


多毛姜花、花粉和传粉者

原文链接：

A New Secondary Pollen Presentation Mechanism from a Wild Ginger (Zingiber densissimum) and Its functional Roles in Pollination Process

原文摘要：

Background and Aims

Secondary pollen presentation (SPP), a floral mechanism of reproductive adaptation, has been described for more than 200 years, with nine types SPP recorded. However, few studies have been done experimentally to link the floral mechanism of SPP to its functional roles in pollination process. This study aims to describe a new SPP mechanism from a wild ginger (Zingiber densissimum, ZingiberAceae) and explore how the pollen arrangement of SPP affects pollen removal during the interaction with different pollinators.

Methodology/Principal Findings

Field observations and experiments revealed that flowers lasted for less than one day. The breeding system was partially self-incompatible. Two bee species, Macropis hedini (which carried pollen dorsally) and Amegilla zonata (which carried pollen ventrally) were the primary pollinators. About a third of pollen grains were relocated from the anther to the labellum staminode of flowers through the adherence of aggregated pollen chains, while other grains were presented on the anther. In a single visit, each bee species removed pollen grains from both the labellum staminode and the anther. Macropis hedini was more effective than Amegilla zonata.

Conclusions/Significance

Our study describes a new SPP mechanism in angiosperms. The new SPP mode enables pollen grains presented on the anther and the labellum staminode simultaneously via the adherence of aggregated pollen chains, thus promoting pollen to be taken away by different pollinators. This SPP mechanism plays a key role during pollen removal and may have evolved under the pressure to improve male fitness.

DOI: 10.1371/journal.pone.0143812

作者：李庆军

;