大赖草种子的休眠和寿命

大赖草(Leymus racemosus (Lam.) Tzvel)主要生长于额尔齐斯河低阶地的固定、半固定沙丘上,是小麦育种中的重要种质资源及保护植物.种子萌发意味着植物从一个耐干旱和极端温度阶段(种子)过渡到一个脆弱的阶段(幼苗),是植物生活周期中的一个重要阶段,但目前,有关大赖草种子萌发的生活史特性的研究很少,研究了大赖草种子萌发的生活史特征得出:大赖草种子低温的条件下贮藏6、8、12、18和24个月时,萌发率的变化不显著(P>0.05),刚采收的大赖草种子的休眠类型为非深度生理休眠和条件休眠,层积处理可以促进大赖草的萌发(提高萌发率、萌发指数和缩短初始萌发时间),并能降低大赖草种子萌发所需的温度.大赖草的种子初始萌发时间长、萌发速率低及生态环境的恶劣是导致大赖草在自然生境中种群更新低的主要原因.

Seed Dormancy and Longevity in Leymus racemosus(Lam.)Tzvel

In the present paper,the history traits related to seed germination of Leymus racemosus(Lam.) Tzvel,an endangered but economically important perennial grass mainly occurring in the stabilized and semi-stabilized dunes in the northwest of the Junggar Basin of Xinjiang Uigur Autonomous Region,China were studied.The seed longevity and the type of seed dormancy were analyzed,as well as the seed bank of L.racemosus was investigated.The preliminary analysis results showed that two years cold temperature storage did not affect seed germination characteristics in L.racemosus and freshly harvested L.racemosus'seed had no-deep physiological dormancy and condtional dormancy.The seeds of Leymus racemosus needed long time to be germinated in the initial period.The low germination of the seeds and adverse ecological circumstances were the main reasons why the community of Leymus racemosus in natural living environment renewed slowly.