青钱柳种子休眠机制

Seed Dormancy Mechanism of Cyclocarya paliurus

青钱柳种子具有深休眠特性。对青钱柳离体胚及不同处理种子的萌发试验、种壳透水性和透气性测定以及种子各部分内源抑制物质的提取、生物测定和鉴定等的研究表明:1)青钱柳种胚基本不存在休眠,果皮和种皮存在一定的机械束缚和透水、透气性障碍,果皮中存在活性较强的内源抑制物质是引起青钱柳种子休眠的主要原因。2)种子各部分甲醇浸提液的生物测定结果说明,青钱柳种子各部分均含有内源抑制物质,抑制活性为果皮>种皮>完整种子>种胚。3)对抑制活性最强的果皮甲醇提取液采用系统溶剂法进行初步分离,生物测定结果表明各分离相中乙醚相的抑制活性最强,GC-MS鉴定结果显示乙醚相中相对含量为35.09%的组分是具有较强抑制作用的香草酸。研究结果首次较系统地阐明青钱柳种子的休眠机制。

Grown for both its fine timber and medicinal use,Cyclocarya paliurus is a monotypic genus of Juglandaceae,and is an endemic plant to China.However,the seeds remain deeply dormant in natural condition.In order to assess the dormancy mechanism of the seeds,a germination test of both isolated embryos and seeds were conducted with different treatments,and water and gas permeability of the husk,as well as the bioassay and identification of extracts from different seed fractions were measured.The results showed that C.paliurus seed scarcely had embryo dormancy,and the dormancy of the seed was mainly attributed to its pericarp and seed coat.The mechanical and permeability barrier of pericarp and seed coat had a negative effect on germination to a certain extent,but seed dormancy of C.paliurus was mainly due to the inhibitory substances in the pericarp.The bioassay results indicated that the inhibitors were distributed in all the fractions of the seeds,and the inhibition activity was found as the following： pericarp seed coat intact seeds embryo.Methanol extract of the pericarp was further separated by the method of systemic solvents,and a bioassay of the separated fractions showed that the ether phase had the strongest inhibitory effect.Analysis of GC-MS revealed that the maximal component in ether phase of the pericarp was vanillic acid,accounted for 35.09% .The results from this study systematically illustrated the dormancy mechanism of C.paliurus seeds for the first time,and would provide some theoretical bases for breaking the seed dormancy in practice.