青藏高原东缘10种禾本科植物种子萌发的基温和积温

The base temperature and the thermal time requirement for seed germination of 10 grass species on the eastern Qinghai-Tibet plateau

温度是影响种子萌发重要的环境因子之一。本研究利用积温模型分析了青藏高原东缘10种禾本科植物种子在5个恒温梯度下（5、10、15、20、25℃）萌发所需的积温和基温。结果表明,10种禾本科植物种子萌发的基温在0~4℃,积温在26.65~139.92℃.d,基温较低,积温较高,这与这些物种所生存的青藏高原东缘特殊的气候条件有关。海拔与萌发的基温之间存在显著的负相关性（P〈0.05）,说明种子萌发的基温与它们所处的温度环境相适应。一年生的两种雀麦较8种多年生植物种子萌发所需的积温较低,萌发较早,可优先占有空间资源,在群落竞争中获利。

Temperature is an important environmental factor influencing seed germination.In this study,we used the thermal time model to analyze the thermal time requirement and base temperature for germination of 10 grass species under five constant temperatures（5,10,15,20,25 ℃） on the eastern Qinghai-Tibet plateau.We found that the base temperatures ranged from 0 to 4 ℃,and thermal time ranged from 26.65 to 139.92 ℃·d.The base temperature was lower and the thermal time was higher for germination compared with other researchers＇ findings,which adapted to their special lived temperature environment of the Qinghai-Tibet plateau.There was a significant negative correlation between altitude and base temperature for germination（P0.05）,which reflected that the base temperatures of these seeds＇ germination were adapted to their specific temperature environment in this region.Two annual Bromus species had lower thermal time for seed germination than other 8 perennial species.Therefore,the annuals germinated earlier and occupied the priority of space resources and benefited from the community competition than the perennial species.