Study On Cold Resistance Of Chimonanthus Praecox Varieties

Wintersweet(Chimonanthus praecox (L.)Link)is one of the important traditional flowers of China.Its medicinal, landscaping purposes,economic using is very wide. In northern region wintersweets often suffer from cold temperature,and the study of cold-resistant capability and physiological indicators had not been reported yet.So it is significant to determine the hardiness of wintersweet which is important in appraising, popularizing and utilizing the cold resistance wintersweet.In this paper, three varieties were studied by main component analysis, variance analysis and subordinate function values analysis. The cold resistance characteristics of wintersweet was systematically investigated from the levels of morphology, physiology and biochemistry, based on cold resistance system, aims to study the cold resistance characteristics and mechanism.The major results were summarized as follows:1.The changes of physiological and biochemical indicators on three varieties were basically same during the overwintering.The organizational water content of'Yuwan Canghong'was more stably than two others,its electrolyte leakage,MDA content were the lowest,and its the activity of protecting enzymes,soluble protein content,soluble sugar content,chlorophyll content was the highest.On the contrary, the change range of organizational water content of'Hupo'were the bigest, its electrolyte leakage,MDA content was the highest,and other physiological and biochemical indicators were the lowest.The physiological and biochemical indicators of'Chushui Furong'were middle level.2.Transverse sections were observed and measured by electron microscope.It proved that the relationship between the area of xylem and the cold resistance was positive negative correlation, the area of phloem and the cold resistance was negative correlation.3.The changes of physiological and biochemical indicators on three varieties were basically same under freezing resistances. According to the Logistic equation,the half lethal temperature of three varieties was -21.2℃,-24.2℃and-22.5℃,which was the same with the recover test result.There was a negative correlation between the electrolyte leakage,the half lethal temperature,MDA content and the cold resistance of wintersweet,while there was a positive correlation between the activity of protecting enzymes,soluble protein content,soluble sugar content,chlorophyll content and the cold resistance of wintersweet.4.The relationship between rotecting enzymes,soluble sugar,cell membrane permeability, lipid peroxidation,shooting rate and the cold-resistance ability of wintersweet was closer by component analysis.5.The cold-resistance ability of three varieties, from higher to lower,was'Yuwan Canghong'>'Chushui Furong'>'Hupo',by subordinate function values analysis.