紫椴种子萌发特性及休眠解除方法研究

Study on Germination Characteristics and Dormancy Breaking Methods of Tilia amurensis Seeds

为探明紫椴种子休眠原因并找到休眠解除方法,以紫椴种子为材料,对其透性、萌发特性及休眠解除方法进行了研究。种子透性试验结果表明,紫椴种子经浓硫酸处理后透性增加,吸水率显著提高。种子萌发特性试验显示,紫椴完整种子萌发率为0,去掉种皮后,保留完整胚乳的种子萌发率为4.0%,切除部分胚乳(根尖未露出)的种子萌发率为23.3%,剥除胚乳帽露出根尖的种子萌发率为84.7%,离体胚萌发率为100%,此结果表明紫椴种子存在休眠,但其种胚并不存在休眠,其休眠是由胚外因素导致,胚乳(尤其是胚乳帽)是造成紫椴种子休眠的主要原因。种子休眠解除方法试验结果表明,浓H_(2)SO_(4)处理15 min+500 mg/L GA3溶液浸泡12 h+低温层积30天,可使紫椴种子发芽率达92.0%,可作为快速解除紫椴种子休眠的有效方法。综上,紫椴种子的种皮具有一定的透性障碍,但胚乳帽是造成其休眠的主要原因,使用浓H_(2)SO_(4)处理+GA_(3)浸泡+低温层积的综合处理方法可在30天内解除紫椴种子的休眠。

In order to find out the cause of Tilia amurensis seed dormancy and a method to quickly relieve the dormancy,the seed coat permeability,seed germination characteristics and dormancy release methods of Tilia amurensis pure seeds were studied.The permeability test results showed that:when treated with concentrated H_(2)SO_(4),the permeability and water absorption of Tilia amurensis seeds increased significantly.The experiment of seed germination characteristics showed that the complete seed germination rate of Tilia amurensis was 0.After removing the seed coat,the germination rate of seeds with intact endosperm,partially removed endosperm(root tip was not exposed),cap-stripped endosperm with exposed root tip,and in vitro embryos was 4.0%,23.3%,84.7%,and 100%,respectively.The results show that Tilia amurensis seeds have dormancy,but their seed embryos do not have dormancy.The dormancy is caused by extraembryonic factors,and endosperm(especially endosperm cap)is the main cause of seed dormancy of Tilia amurensis.The test results of seed dormancy breaking method show that the dormancy of Tilia amurensis seeds can be quickly relieved by being treated with concentrated H_(2)SO_(4) for 15 min+soaking in 500 mg/L GA_(3) solution for 12 h+at low temperature stratification for 30 d,reaching a germination rate of 92.0%.In conclusion,the seed coat of Tilia amurensis seeds has a certain permeability barrier,but the endosperm cap is the main reason for its dormancy.The comprehensive treatment method of concentrated H_(2)SO_(4) treatment+GA_(3) soaking+low temperature stratification can relieve the dormancy of Tilia amurensis seeds within 30 days.