Primary Study On Cold Tolerance Feature Of Trachycarpus Fortunei

Considering the great cold hardiness and unique character of the windmill Palm (Tr achy carpus for tune i), it could be an excellent evergreen landscape plant resource in northern gardens. The objects of this research include the cold-resistant windmill Palms (introduced from Xi'an in 1980) and their offsprings. At the very beginning of the study, four parts which could reflect the cold tolerance were researched to form the frame. First, the potential possibility of cold tolerance was observed with the help of Kira Index from an ecological view. Then the membrane permeability of leaves and leafstalks were tested by Electrolyte Leakage methods. After that the ability of recovery from chilling injury was evaluated by Tissue Culture. Research on anatomical structure of leaves was followed to find out the connection. After the initial study listed above, more researches focused on physiological indicators were taken to establish a system to determine the cold hardiness of the windmill palm.(1) From the ecological view, three conclusions could be drawn:The first, Beijing fully meet the palm's heat demand during the growing season. Then the shortage of precipitation in Beijing may have some bad influence on the windmill palms'growing, luckily, the effect will be no harder than the natural distribution limit area; The third one is the windmill palm may face severe cold stress in Beijing.(2) Electrolyte Leakage methods combined with logistic curve analysis is suitable for testing cold resistance of the windmill palm, and observation on ability of restoration from freeze injury on the natural state and the tissue culture has consistent results with Electrolyte Leakage method. While at the same time, it is hard to find the connection between anatomical structure of palm leaves and the cold hardiness for no key indexes could be found.(3) Parents and 25 offsprings of them were marked by AFLP Analysis (Amplication Fragment Length Polymorphism Analysis). By polymorphic bands and cluster analysis, these samples are divided into four groups according to genetic relationship.The conductivity trend of palm in natural cooling process and cold hardness has some relevance. Almost all the offsprings with parents are both cold palms have better cold hardiness than those were offsprings of Non-cold palms. (4)Take the Semi Lethal Temperature and Freezing Injury Classification as standard to test the result of other 5 experiment.10 indexes with high similarity are found by Correlation Analysis, they are Semi-lethal Temperature, Freezing Injury Classification, decrease on Fo, Fv/Fm, MDA and Content of Starch,as well as increase on Content of Soluble Sugar and Proline, The peak of MDA and Proline Accumulation.(5) With the help of Principal Component Analysis, key factors of palm's cold hardiness are discovered. New mathematical model is established with the methods of Stepwise Regression Analysis:Y=-2.296E-16+0.549 X Sugar11.3-0.458 X Freezing Injury Classification+0.192 X Fv/Fm伤害.In the end, the hypothesis that the offspring of cold hardiness palm have better cold tolerance is verified by Cluster Analysis.