藏东南5种菊科植物种子萌发对温度和光照的响应

Responses of Seed Germination of Five Asteraceae Species to Temperature and Light in Southeastern Tibet

种子萌发是植物生活史的关键阶段,对植物种群的维持和群落动态起着决定作用。研究种子萌发对温度和光照的响应,对明确物种对环境的适应策略有重要意义。选择藏东南5种菊科植物作为研究对象,通过设置5个变温(5/1℃、15/2℃、20/5℃、25/10℃、30/15℃)、1个恒温(1℃)和两种光照条件(12 h光照/12 h黑暗、持续黑暗)的萌发试验研究了温度、光照对其种子萌发的影响。结果表明:温度显著影响5种菊科植物种子的萌发(P<0.001)。中低温条件下5种植物的种子萌发率均随温度升高而升高,最大萌发率及其出现的温度存在种间差异。牛蒡(Arctium lappa)在1至30/15℃温度梯度下萌发率无明显变化趋势,其余4种植物萌发率均随温度升高呈“钟形”曲线。在不同温度条件下,光照对5种菊科植物种子的萌发率和萌发速率整体上表现出促进作用,低温条件下更为显著(P<0.05)。本研究结果揭示了5种菊科植物种子萌发在高寒地区应对变化环境的响应特征,反映了菊科植物对高寒环境的适应策略。

Seed germination plays a decisive role in plant establishment and community dynamics, and forms a critical stage in a plant’s life cycle. Research on seed germination response to temperature and light has great significance in determining the adaptation strategies of species to their environment. Five Asteraceae species in southeastern Tibet were selected as the research objects. The effects of temperature and light on seed germination were studied by setting five variable temperatures(5/1℃, 15/2℃, 20/5℃, 25/10℃, 30/15℃), one constant temperature(1℃) and two light conditions(12 h light/12 h dark, continuous dark). The results demonstrated that the seed germination of five Asteraceae species growing in southeastern Tibet was significantly affected by temperature(P<0.001). The seed germination percentage of all five species increased with temperature under medium and low temperature conditions, and there were interspecific differences in the maximum germination percentage and the temperature, at which it occurred. The germination percentage of Arctium lappa showed no significant trend under the temperature gradient from 1 to 30/15℃, while the germination percentage of the other four species showed a "bell-shaped" curve with increasing temperature. Under different temperature conditions, as a whole, light promoted the germination percentage and germination rate of these five Asteraceae species, especially under the low temperature condition(P<0.05).This work revealed the seed germination characteristics of five Asteraceae species in response to changing environments in alpine regions, reflecting the adaptation strategies of Asteraceae to alpine environments.