The Seed Dormancy Mechanisms And Germinating Conditions Of Taxus Chinensis Var. Mairei

This article takes the Taxus chinensis var.mairei seeds as the research object.The seeds have a long dormancy stage,so we studied the seed biological characteristics,inhibitors,methods to overcome the seed dormancy,shape and physiology-biochemistry characteristics during dormancy-breaking process to analyze the mechanisms of seed dormancy and germinating conditions.The results showed that the main reasons of seed dormancy of Taxus chinensis var.mairei seeds were the embryo's shape,physiology after-ripening and the existence of inhibitors in seeds,not the permeability of water.Each part of T.chinensis var.mairei seed contains some germination inhibitors which had the inhibitory effects on the percentage germination and root growth of Brassica campestris seedlings.The inhibiting effects of inhibitors in these parts were different,it showed as:embryo＞endopleura＞endosperm＞mesosperm＞exopleura.The main substances which can be inhibitors are organic acid,ester,amine,alcohol and ether.organic acid,ester and amine distributed in every part of the seeds,ether just distributed in embryo.acid substances(B phase) in every part had the strongest inhibition,the main substances which can be inhibitors in embryo were also mensurated by identification of B phase.Acid etching,hormone and heterotherm stratification can be used together as an effective method to overcome the seed dormancy.The regularities of content of nutrient substance and activity of some important metabolic enzyme were extremely concordance to the embryo's shape and physiology after-ripening during the process of breaking dormancy.