温度对17种高寒草地植物种子大小与萌发特征关系的影响

Effects of temperature on the relationships between seed size and germination characteristics of seventeen alpine grassland plant species

种子大小是种子的重要属性之一,而温度是影响种子萌发的重要因素。本研究以在青藏高原东缘收获的17种植物种子为研究对象,通过设置不同温度条件(10、15、20、25℃)室内萌发试验,研究了温度对种子大小与种子萌发特征(发芽率、发芽势、发芽指数、平均发芽时间、死亡率及真菌侵染率)关系的影响。结果表明:1)整体上,种子大小与种子发芽率、真菌侵染率呈显著正相关关系(P<0.05),而与发芽势、发芽指数、平均发芽时间及死亡率均无显著相关关系(P>0.05)。2)在10℃条件下,种子大小与种子发芽率无显著相关关系(P>0.05),但在15、20和25℃条件下,种子大小与发芽率之间均呈显著正相关关系且随着温度升高相关性增强(P<0.05)。3)在各温度条件下,种子大小与真菌侵染率均呈显著正相关关系(P<0.05),且在25℃条件下两者相关性最强。因此,温度的增加不仅可以提高大粒种子的发芽率,同时也增加了其遭受病原真菌侵染的风险。本研究为气候变化背景下青藏高原植物种子的萌发与存活提供了理论依据。

Seed size is an important component in plant growth,and temperature is an important factor affecting seed germination.In this study,17 plant species seeds harvested on the eastern edge of the Qinghai-Tibet Plateau were used as the study materials;through setting different temperature conditions(10,15,20,25℃)laboratory germination experiments,we explored the effect of temperature on the relationships between seed size and seed germination characteristics(germination percentage,germination potential,germination index,mean germination time,and mortality and fungal infection rates).Our results showed that:1)overall,seed size had a significant positive relationship with seed germination percentage and fungal infection(P<0.05),whereas there were no significant relationships between seed size and germination potential,germination index,mean germination time and mortality(P>0.05).2)At 10℃,there was no significant relationship between seed size with seed germination percentage(P>0.05),whereas there was a significant positive relationship between seed size and germination percentage at 15,20 and 25℃(P<0.05);the relationship between seed size and germination was positively correlated with temperature.3)Seed size showed a significant positive relationship with fungal infection rates at each temperature(P<0.05),and the relationship was strongest at 25℃.Our study provides evidence that an increase in temperature will increase both the germination rates of large seeds as well as the risk of infection by pathogenic fungi.This study provides a theoretical basis for seed germination and survival in the Qinghai-Tibet Plateau under climate change.