濒危植物毛柄小勾儿茶种子休眠与萌发生理的初步研究

毛柄小勾儿茶（Berchemiella wilsonii （Schneid．）Nakai var．pubipetiolata H．Qian）为中国特有种，国家三级保护植物。TTC染色法测得毛柄小勾儿茶种子的生活力较低，仅为32％，空粒和无生活力的种子分别为28％和40％，说明毛柄小勾儿茶发育完全的种子较少。种子吸水速度试验证明毛柄小勾儿茶种皮透水性较差，不利于种子萌发时对水分的吸收，发芽抑制物的生物鉴定结果表明，毛柄小勾儿茶种子的不同部位都存在发芽抑制物，且种胚中的含量最高，不利于种子的萌发，使毛柄小勾儿茶种子处于休眠状态之中。几种不同浓度GA。溶液浸种24h的预处理可以不同程度地提高毛柄小勾儿茶种子的发芽率和发芽指数，其中300mg／L GA3的效果最显著，并且300mg／L GA3的预处理可以在萌发初期（萌发前3天）显著地提高毛柄小勾儿茶种子中过氧化物酶、过氧化氢酶和脱氢酶的活性。毛柄小勾儿茶种子生活力低，且处于休眠状态，再加上与种子发芽力有关的几种酶的活性较低，致使毛柄小勾儿茶种子的发芽率较低，同时这些也是从种子萌发生理方面导致毛柄小勾儿茶濒危的重要原因。

A Preliminary Study on Dormancy and Germination Physiology of Endangered Species Berchemiella wilsonii (Schneid.) Nakai var.pubipetiolata H.Qian Seeds

Berchemiella wilsonii (Schneid.) Nakai var.pubipetiolata H.Qian,an endangered plant,is endemic to China and the national third-class protected plant.Seed vigor,tested by TTC,is very low(32%),however,empty seeds and seeds without vigor amount to 28% and 40%,respectively,demonstrating that there is a limitation in seed development of B.wilsonii (Schneid.) Nakai var.pubipetiolata H.Qian.The poor water permeability of seed coat,testified by water absorption experiment,hinders water absorption during seed germination.In every part of the seed exists germination inhibitors,the most in seed embryo,which restrain seed germination and induce seed dormancy of B.wilsonii var.pubipetiolata.Seed germination rate and germination index are improved after soaked by different GA_3 concentrations for 24 hours before germination.The effect of 300 mg/L GA_3 is the most significant and it can also markedly increase the activity of catalsae,peroxidase and dehydrogenase during the early 3 days after germination.Sees germination rate of B.wilsonii var.pubipetiolat is rather low because of the presence of seed dormancy and low seed vigor,as well as poor activity of the several enzymes concerned with germination capacity,and these are also considered as the main factors to cause B.wilsonii var.pubipetiolat endangerment in the aspect of germination physiology.