Cold Resistance Characteristics Of Zanthoxylum Bungeanum

Zanthoxylum bungeanum is one of tree species with superior economic worth in China, and possess abundant nutritive value,medical and health care value. But its distributing is yet limited because of many causes such as climate. Low temperature is an important factor that restrain the plant distributing and growing on the earth. Zanthoxylum bungeanum is a main fruit tree in gansu. Developing the delicious production has becoming a kind of new Agriculture industry, and the areas of cultivating have increased year by year. But because of the worse cold resistance and weaker disease resistance, the development is limited to some extent. There are so many freezing injuries in the production and lots of new Zanthoxylum bungeanum being introduced that it is necessary to study the cold sistance and the ability of three Zanthoxylum cultivars over winter.Cold resistance is the hereditary characteristic of the fruit tree. It is significant to determine the hardiness of Zanthoxylum bungeanum, witch is useful for rational planting, cold resistance breeding, appraising and popularizing the cold resistance Zanthoxylum bungeanum. In this paper, were used to determine three main Zanthoxylum bungeanum planting in QianAn county of GanSu province, having different hardiness in their branches after treated with different low temperatures, by main Component analysis, regression analysis,path analysis and grey connection analysis.The cold resistance characteristics of Zanthoxylum bungeanum was first systematically investigated from the levels of morphology,physiology,biochemistry and molecular biology, based on cold resistance system, aims to study the cold resistance characteristics and mechanism. The cold resistance characteristics of Zanthoxylum bungeanum has genetic variation of a larger company at one-year-old branches,the cold resistance characteristics is best in three cultivars of tests,in turn: QianAnYiHao﹥YouJiao﹥DaHongPao. Analysis of electrolytic leakage of Zanthoxylum bungeanum possesses a "low –fast-low"change in response to stable decrease of low temperature. This process issimulated by Logistic equation and "　S　"　type　curve,It indicates that effect between temperature and electrolytic leakage is increase negatively.LT50 is diffent with low temperature (-16.48～-20.20 ℃) ,and actual harmoniously. Analysis of protective enzyme indicates SOD activity under low temperature treatment demonstrate in various degree reducing , afford to deal with time at the same time. SOD activity of -15,-20 ℃and cold resistance is positive correlation ,and SOD activity of -5℃is negative correlation; It turned out in path analysis that its lethal temperature between different cultivars is range from-20 to -25℃. The change of soluble sugar contents under low temperature treatment is 　"　S　"　type　curve,and the cold resistance closely related(R2=0.9994); Grey connection analysis indicates the best associated temperature of cold resistance are -25℃(degree of association =0.77), -20℃(0.74)and -15℃(0.74);The best associated hour is 72 hours , the degree of association is between 0.75 and 0.76. MDA content under low temperature treatment increases with dealing with the decline of temperature, and then reduce gradually.Association analysis and collate indicates that the best associated temperature of MDA content and the cold resistance are -25℃(degree of association=0.85) and -20 ℃(0.83);and most heavy degree of association is QinanYiHao (0.86), Secondly it is YouJiao (0.83) and DaHongPao(0.81). The contents of Chla under low temperature treatment is decline with temperature descend, and positive correlation; The contents of Chlb is ascend with temperature descend and changed little;The ratio of Chla/b had positive linear. Longitudinal and transverse section was observed and measured in electron microscope, It proves relationship between cold resistance and branches anatomical structure of different cultivars: The relationship bewteen xylem,diameter of the trunk,diameter of the xylem,epidermis/peridermof the trunk and relative REL chang is positive correlation, phloem,Peridem/diameterof the trunk and relative REL chang is negative correlation; Relationship between cold resistance and branches anatomical structure of the secondary xylem, the developed degree whose microscopic structure of anatomical structure of the secondary xylem and cold resistance is negative correlation.Integrated analysis of cold resistance indexes,which are proved effective by primary analysis, indicates that through main component analysis and regression analysis, data can be greatly simplified without significant effect on information content. Evaluation medal based on these data proved to have high evaluation accuracy(98.23%).