不同光照及赤霉素处理对菟丝子寄生关系建立的影响

The Effects of Different Lights and Gibberellin on Establishment of Parasitism between Dodder and Its Hosts

摘要:

菟丝子属 (Cuscuta spp.) 隶属于旋花科 (Convolvulaceae)，为寄生草本植物。成熟菟丝子的根、叶已退化，只能通过缠绕寄主及形成吸器从寄主体内获取养分。菟丝子种子中储存的营养物质通常只能维持幼苗不超过3周的时间，因而，尽早发现寄主并与之建立寄生关系对其生存至关重要。菟丝子有着广泛的寄主范围，必然有与之相适应的浸染机制，但对首次使用LED作为光源，研究不同光照条件及GA3对菟丝子(Cuscuta spp.)弯钩打开、缠绕发生与吸器形成的影响。结果表明，光照信号作为一个必要条件参与了菟丝子对寄主的识别及缠绕发生的调控，而化学信号可能起到一定的促进作用；GA3参与了对菟丝子缠绕发生的调控，但对弯钩打开没有明显的作用。除了典型的光敏色素作用外，还有另一类光反应(HER)参与了上述过程，这类光反应可由879 nm远红光引发，证明菟丝子存在HER，还有Pfr向Pr的暗转化过程，在缠绕发生过程中光敏色素和隐花色素发生相互作用。

Abstract:

The effects of different light treatments and GA3 on hook opening, twining and parasitism of Cuscuta australis were studied using LED as light sources for the first time. The results showed that light was a necessary factor for dodders to parasitize the hosts successfully and chemical signals might facilitate host recognition and twining. GA3 involved in controlling twining response，but no distinct effect on hook opening. Furthermore, besides typical phytochrome reaction, another photoreaction called HER was involved in these processes, which could be caused by 879 nm far red light. So it demonstrated directly that there was not only HER in dodders, but also dark conversion from Pfr to Pr, and there were mutual interaction of phytochromes and cryptochromes in twining.