羊草种子休眠机制及破除方法研究

羊草种子休眠程度深、发芽率低是限制栽培利用的重要因子.采用不同破除羊草种子休眠的方法,测定各处理对种子萌发的影响,以探索破除羊草种子休眠的有效途径.结果显示:(1)刺破种皮的裸种子较完整种子的萌发率、吸水速率、生活力分别由对照的6%、63%、0%显著增加到60%、86%、94%.(2)完整羊草种子分别用清水浸种1 d、30% NaOH浸种80 min、清水浸种1 d后用30% NaOH浸种60min其萌发率由6%分别显著提高到36%、60%、84%,而各浓度赤霉素处理完整种子其萌发率较对照均无显著变化. (3)采用清水浸种1 d后用30% NaOH处理60 min,再施加200 μg/g GA3综合处理,可使羊草完整种子的发芽率由6%提高到91%,接近其种子生活力94%.研究表明,羊草种子的稃与种皮不影响种子水分的吸收,但影响种子对GA3的吸收、不同程度地阻碍大分子物质的渗入、限制羊草种子内部萌发抑制物的渗出,从而引起种子休眠;分析认为稃和种皮以及种子内部萌发抑制物质是引起羊草种子休眠的主要原因.

Study on Seed Dormancy Mechanism and Breaking Technique of Leymus chinensis

Seed dormancy of Leymus chinensis is one of the most important factors limiting its culture and utilization.Present study investigated the seed dormancy mechanism and dormancy breaking technique of L.chinensis and the results showed that:(1) Piercing naked seed compared with intact seed the germination rate,water absorption rate,viability by contrast,6%,63%,0% significantly increased to 60%,86%,94%;(2)Water soaking one day,30% NaOH soaking 80 min,soaking in 30% NaOH for 60 min after soaking with water for one day could complete germination rate of L.chinensis intact seeds significantly from 6% to 36%,60%,84%,while the different concentration of gibberellin treatment to intact seeds had no significant changes compared with the control;(3) Seeds soaked with 30% NaOH by 60 min after soaked with water one day,and then imposed 200 μg/g GA3,could germinate to 91%,close to the seed viability 94%.This study showed that glume and seed coat did not affect the seed imbibition rate,but affected absorption of GA3 and water absorption had been hampered to varying degrees by macromolecular substances,which led to seed dormancy.These results implied that palea,seed coat,and germination inhibitors contained in the seeds may play an important role in controlling seed dormancy of L.chinensis.