青藏高原野生百脉根种子休眠及萌发特性的研究

Study on Seed Dormancy and Germination Characteristics of Birdsfoot Trefoil from Qinghai-Tibetan Plateau

百脉根(Lotus corniculatus L.)是一种富含营养物质的豆科牧草,适应酸性、干旱及贫瘠的土壤,在我国分布广泛,然而种子的休眠特性限制了它的利用。为此,以青藏高原亚高山草甸的野生百脉根种子为试验材料,通过擦破种皮、化学腐蚀、低温冷冻等方法研究打破种子休眠的办法。研究结果表明,野生百脉根种子的硬实率高达92.3%,种皮厚度为(65.63±2.26)μm,比对照高出60.4%(p<0.01),可见野生百脉根种子以种皮厚、透水性差为特点。试验还发现,擦破种皮后,种子的发芽率由8.7%提高到85%;浓度为98%的浓硫酸浸泡5,15,25min均能有效地降低种子的硬实率,提高发芽率,其中以15,25min处理效果最好,相比而言,浓度为40%的NaOH处理效果不明显。GA_3、低温湿沉积+GA_3及-4℃,-20℃及液氮超低温冷冻能显著提高发芽率。

Birdsfoot trefoil（Lotus corniculatus L.）is a nutritional legume species.It adapts to slightly acidic,droughty,infertile or wet soils and widely distributes in China.However,seed dormancy results in poor subsequent stand establishment.Seeds were collected from sub-alpine meadow of QinghaiTibetan plateau.The objective of this study was to break dormancy by treating seeds with scarification,chemical soaking and gibberellic acid（GA_3）immersion as well as freezing.Results indicated average hard seed rate of Birdsfoot trefoil was up to 92.3% and coat thickness of dormant seeds was（65.63±2.26）μm,which was 60.4percent larger than control.Mechanical scarification significantly removed seed dormancy,and the final germination percentage（FGP）was increased from 8.7 %to 85%.Chemical scarification treated by concentrated sulphuric acid（98% H_2SO_4）of 5,15,25 min was also effective in reducing hard seed and improving seed germination.Moreover,15 and 25min-soaking were better compared with control.However,no significant effects were observed between 40% NaOH treatment and control.In addition,the higher germination rate was achieved by use of gibberellic acid or combination of cold-wet storage and GA_3,-4℃,-20℃and Ultra-low temperature freezing.