The Effect Of Cold Stress On Ultrastructure And Physiological Metabolism In Eriobotrya Japonica Lindl

Under controlled temperature condition, the ultrastmctural and physiological effects of cold stress on seedling leaves and young fruits of Eriobotrya japonica Lindl. were studied. The results showed as follows:1 The effect of cold stress on ultrastructure in E.japonica Lindl.Under 7℃, 2℃cold stress , most organelles of E.japonica Lindl. leaves were basically not injured, they were arranged orderly; under -2℃cold stress, the structure of chloroplast membrane were destroyed, thylakoid was not packed to normal grana, the membrane structure of mitochondrion could be found, but the number of cristae were little, these results showed E.japonica Lindl. Leaves would be injured gently; under -7℃cold stress , plasma membrane was already broken, protoplasts was concentrated greatly into a mass, chloroplasts was decomposed wholly, grana lamellace twisted and disordered and even fused; membrane system of mitochondrion was totally destroyed, cristae could not be found. These results showed E.japonica Lindl. would be injured badly under -7℃cold stress.Under 6℃, 3℃cold stress, plasma membrane of young fruits of Jiefangzhong, Zaozhong 6 was clear, the changes of chloroplasts structure was distinguished, the changes of mitochondrion structure was not distinguished; under 0℃cold stress, plasma membrane and tonoplast structure of Jiefangzhong young fruits was not injured, the structure of mitochondrion was clear under electromicroscope, but chloroplasts structure of Zaozhong 6 young fruits was injured badly, the number of cristae decreased clearly, these results showed cold resistance of Jiefangzhong was stronger than Zaozhong 6; under -3℃cold stress, plasma and tonoplast of Jiefangzhong and Zaozhong 6 young fruit were broken, protoplasts were concentrated greatly into a mass. These results showed Jiefangzhong and Zaozhong 6 young fruits would be injured under -3℃cold stress.2 The effect of cold stress on physiological metabolism in E.japonica Lindl.Under 7℃, 2℃cold stress, PMP, MDA content of E.japonica Lindl. leaves raised at primary stage of cold stress and declined at late stage of cold stress, the activity of SOD, POD, CAT, APX raised first and declined then too, their activity degree maintained high, soluble sugar, protein content was also increased first and then decreased, their concentration maintained high, Chl, Car content was also increased first and then decreased, these changes indicated that E.japonica Lindl. adapted to 7℃, 2℃cold stress; under -2℃cold stress, PMP, MDA content kept increased tendency, the activity of protective enzymes was inhibited, soluble sugar and protein content maintained increase; under -7℃cold stress, PMP, MDA content raised greatly, the activity of protective enzymes was inhibited greatly, these showed that E.japonica Lindl. was injured badly.Under 6℃, 3℃cold stress, PMP, MDA content in Jiefangzhong and Zaozhong 6 young fruits raised at primary stage of cold stress and declined at late stage of cold stress, the activity of SOD, POD, CAT, APX raised first and declined then too, their activity maintained high; soluble sugar, protein content was also increased first and then decreased, their concentrations maintained high, these changes indicated Jiefangzhong and Zaozhong 6 adapted to 6℃, 3℃cold stress; under 0℃cold stress, changes of PMP, MDA content in Jiefangzhong young fruits were familiar with 6℃cold stress, PMP, MDA content in Zaozhong 6 raised all the time, and protective enzymes activity was inhibited too,these indicated young fruits of Zaozhong 6 were already hurt; under -3℃cold stress, PMP, MDA content in Jiefangzhong and Zaozhong 6 young fruits raised to maximum; the activity of protective enzymes was inhibited wholly, soluble sugar, protein content raised to maximum and then declined, these changes presented that Jiefangzhong and Zaozhong 6 young fruits would be injured under -3℃cold stress.The results of this thesis provided theoratical reference for climatic factors of cultivation and cultivated area, and had important theoratical and practical significance in fruit production.