青藏高原高寒草甸六种杂类草植物种子萌发期抗旱性研究

为了明晰种子萌发期干旱耐受性与种子相关性状的关系，本研究采用聚乙二醇(Polyethylene glycol，PEG)模拟干旱胁迫的方法对六种高寒草甸杂类草植物种子在不同程度干旱胁迫下的萌发率变化，以及种子大小、萌发率和系统发育距离与萌发干旱耐受性的关系进行了研究。结果表明，随着PEG浓度的增加，种子萌发率呈降低趋势；较低浓度PEG对半抱茎葶苈(Draba subamplexicaulis)、尼泊尔蝇子草(Silene nepalensis)、蓬子菜(Galium verum)种子萌发具有显著的抑制作用；较高浓度PEG对六种杂类草种子萌发均有显著的抑制作用。种子大小与萌发干旱耐受性正相关，即随着种子大小的增加，种子萌发阶段的抗旱性增加；而萌发率和系统发育距离与萌发干旱耐受性无相关性。综上，可以优先考虑大种子物种作为退化草地恢复中抗旱物种。

The Study on Drought Tolerance of Six Forbs during Seed Germination in an Alpine Meadow of Qinghai-Tibet Plateau

To clarify the relationship between seed related traits and drought tolerance during seed germination,responses of seed germination proportion of six forbs from alpine meadow to different degrees of drought stress,and relationships of seed size,germination proportion,and phylogenetic distance with drought tolerance during seed germination were studied. Polyethylene glycol (PEG) was used to simulate drought stress. Our results showed that different treatments of PEG concentration had different effects on seed germination of six forbs. With the increase of PEG concentration,seed germination proportion decreased;The lower PEG treatment had significant inhibitory effects on the seed germination for Draba subamplexicaulis,Silene nepalensis, and Galium verum,respectively;The higher PEG had significant inhibitory effects on the seed germination for each of six weeds. There was a positive correlation between seed size and drought tolerance during seed germination. With the increase of seed size,the drought resistance of seed germination increased. There was no correlation between germination proportion and phylogenetic distance with drought resistance of seed germination. Priority can be given to large-seeded species in the selection of drought-resistant species for the restoration of degraded grassland.