| As the excellent resource which owns cold resistance in Genus Camellia plants in nature,Camellia chekiangoleosa is popular with wide-ranging scientific researchers. Wild plant resources usually possess the superior gene that can't be found by artificial means. Genus Camellia plants are accustomed to the warm and wet climate where they are naturally distributed in South China, they couldn't perform well under high and low temperature condition that has become the main limited factor of introduction. In order to test heat and cold resistance of wild provenances of C. chekiangoleosa in seeding stage,this thesis systematically dealt with the heat and cold tolerance for wild different provenances under summer and winter temperature stress conditions,including both indoor and field treatments. The thesis evaluated the heat and cold resistance of different provenances,with the methodology such as physiology and biochemistry, semi-lethal temperature and morphology,combining with analysis of variance,correlation and membership functions between indexes.The main achievements of the dissertation are as follows:1.Under the same indoor high temperature treatment,physiological and biochemical index which showed the similar trend among different provenances including REC,the content of MDA,soluble protein,chlorophyll,the activity of SOD and POD could be chosen to be the heat resistance indicator of C. chekiangoleosa respectively.Significant differences were found in REC,the content of MDA,soluble protein,chlorophyll among provenances.The index of chla/chlb couldn't used to evaluate heat resistance of C. chekiangoleosa.2.Under the same low temperature treatment,trend of variances of REC,the content of MDA and soluble protein were similar with the extension of time among different provenances. REC ,the content of MDA showed significant difference in treatment time,while the content of soluble protein in provenances.3.Physiological and biochemical indexes under field heat stress experiment which were approximate to that under indoor stress were remarkably different from CK.At the same time, physiological and biochemical indexes among provenances reached level of significant difference after adequate cold pretreatment in the process of natural falling of temperature in winter. 4.REC of tested plant was measured by electrical conductivity method with a serie of high or low temperature treatment,the semi-lethal temperature was the point of inflexion on the curve which accorded with Logistic equation. high semi-lethal temperature ranged from 58.20℃to 62.37℃under lower temperature treatment,D and F was higher than contract. As the temperature of treatment rose, high semi-lethal temperature fell to 56.91℃to 60.00℃,D was higher than CK. The range of Low semi-lethal temperature of provenances was -19.01℃to 13.91℃,all of the provenances except G was far lower than CK.5.Physiological and biochemical indexes which had certain correlation with semi-lethal temperature were well correlated with each other. In the process of analysis subordinate function,provenance D stood out during high temperature stress,while provenance A performed poor. In terms of value of the comprehensive evaluation,the descending order of cold tolerance of provenances was C,I,F,D,A,B,E,G.Both the heat and cold resistance were related to results of morphology at certain extent. |
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