模拟增温对蓝翠雀花繁殖的生态学效应

Ecological effects of simulated warming on the reproduction of Delphinium caeruleum

关键词:  模拟增温, 高山植物, 蓝翠雀花, 繁殖特征, 资源分配

Key words:  simulated warming, alpine plant, Delphinium caeruleum, reproductive characteristics, resource allocation

摘要:

气候变暖通过改变植物的开花物候、繁殖分配和花部特征,进而影响植物与传粉者之间的相互作用,最终导致植物的繁殖成功发生变化。高山地带是全球变暖最为敏感的地区,为探究温度升高对该地区植物繁殖过程的生态学效应,该研究以青藏高原高寒草甸典型高山植物蓝翠雀花(Delphinium caeruleum)为对象,通过开顶式生长室(OTC)进行增温处理,探究了增温对蓝翠雀花开花物候、生物量分配模式、典型花部特征和繁殖成功的影响,以及对传粉者访花行为和传粉效率的改变。结果表明:(1)增温使蓝翠雀花的开花物候提前,并显著缩短了单株花期和单花寿命。(2)增温后,蓝翠雀花增加了营养生长的资源投入,表现为植株高度增加,而减少了繁殖分配,表现为花直径减小,蜜距长度缩短,花粉活力和花蜜分泌量均显著降低。(3)增温后花部特征的变化导致蓝翠雀花唯一有效传粉者苏氏熊蜂(Bombus sushikini)的单次访花时间缩短且单次落置的花粉数量减少,传粉效率降低,最终对繁殖成功产生负面影响。该研究结果揭示了全球气候变暖背景下,蓝翠雀花繁殖特征的演化及与传粉者相互作用关系的改变,为明确气候变化对植物繁殖过程的生态学效应提供了参考。

Abstract:

Climate warming affects the plant-pollinator interactions by altering flowering phenology, reproductive allocation, and floral traits of plants, which ultimately leads to changes in reproductive success of plants. Alpine regions are the most sensitive areas to global warming. To explore the ecological effects of temperature increase on the plant reproductive process in these regions, this study focused on Delphinium caeruleum, a typical alpine plant species in the alpine meadows of the Qinghai-Tibet Plateau. By using an open top chamber(OTC)for warming treatment, the effects of warming on the flowering phenology, biomass allocation patterns, typical floral characteristics, and reproductive success of D. caeruleum were investigated, as well as changes in pollinator visiting behavior and pollination efficiency. The results were as follows:(1)Warming advanced the flowering phenology of D. caeruleum and significantly reduced individual flowering duration and floral longevity.(2)After warming, the resource investment to vegetative growth increased, resulting in taller plant height. However, the reproductive allocation reduced, leading to decrease in flower diameter, nectar spur length, pollen vitality and nectar volume.(3)Bombus sushikini was the only effective pollinator of Delphinium caeruleum, and it exhibited shortened per-flower visit duration and reduced pollen deposition per visit due to post-warming floral trait alterations. These changes consequently decreased pollination efficiency and ultimately exerted negative impacts on reproductive success. This study reveals the evolution of reproductive characteristics of D. caeruleum and its altered interactions with pollinators under global climate warming. These results provides a reference for clarifying the ecological effects of climate change on plant reproductive progresses.