花冠对紫茉莉繁殖适合度的影响

Effects of corolla on reproductive fitness of Mirabilis jalapa

关键词:  花冠  紫茉莉  花粉活力  柱头可授性  结实率  繁殖适合度

Key words:  corolla  Mirabilis jalapa  pollen viability  stigma receptivity  seed setting ratio  reproductive fitness

摘要:

以授粉后具花闭合特性的紫茉莉为研究材料,通过在不同天气状况下作去花冠和存留花冠处理,观察花冠对花粉活力、柱头可授性及结实率等繁殖特性的影响。结果表明:紫茉莉自然存留花冠比去花冠的花粉活力、柱头可授性、柱头上的花粉数及柱头上花粉萌发率各指标达最高值的时间重叠性更强,并以阴天存留花冠的最强。存留花冠通过这种时间的重叠性来保证花粉在柱头上的萌发,产生了有利的繁殖适合度。越晚去花冠结实率越高,结实率呈现花闭合自然存留花冠>花冠闭合期去花冠>散粉初期去花冠>花冠展开期去花冠的规律。因此,花冠对紫茉莉繁殖适合度具有利影响。紫茉莉花冠的存留提高了繁殖适合度,增强了对环境的适应能力。

Abstract:

Mirabilis jalapa has permanent floral closure phenomenon after pollination. The effects of corolla on the reproductive fitness of M. jalapa in different weather conditions were studied. The results showed that the time synchronization about the pollen viability,the stigma receptivity,the number of pollen grains and the pollen germination ration on stigma to the top between natural corolla existing and corolla removing were different. The synchronization time of natural corolla existing was more than that of corolla removing. The effects of corolla on seed setting ratio at different bloom stages of M. jalapa in different weather conditions had a certain rule. The seed setting rates of different treatments from high to low presented rule below,natural corolla existing>corolla removing while floral closure>corolla removing while initial dehiscence>corolla removing while initial dehiscence>corolla removing while earlier flowering. In general the retention of closed corolla after pollination improved the reproductive fitness and enhanced its adaptation to the environment.