| Urban landscape construction plays a key role in the construction of ecological civilization.At present,on the application of garden plant in China,there are fewer types of plants which are growing and the large number of fast-growing trees were planted especially in some northeast cities started from the middle of last century which lead to the lack of the excellent garden plant. The Salix has a history of 2000 years in china,there are many kinds of Salix in southwest mountain area and the northeast area.Although it is the most common landscape plant,the types of application are singleness.In order to be rich in the appliciation of Salix and increase the variety of Salix,it is required to screen the execllent wild Salix resources and introduce from the cold area(north or mount area) to the warm area(south or plain areas).So the extreme of heat becomes the limiting factor during the introduction and the heat resistance of wild Salix resources is the key to the success of intorduction.Therefore,by studying the physiological and biochemical indexes in high temperature of typical salix which are from north china, establishing a comprehensive evaluation index system of heat resistance of Salix and evaluating the resistance of wild resources of the Salix is a very significant element job.This job can provide the reliable basis during the process of intorduction and appliciation of wild Salix,it can also provide reference for the selection of good breedings, the basis for improvement of other breeds as well as the basic data to more areas especially the southern area.In this study,I choice Salix viminalis as the basic material, treated with high temperature in selected time and temperature, mensurated relevant physiological and biochemical indexes.By analysing the condition of the changes of physiological and biochemical indexes,discuss the response of Salix which treated with high temperature and provide the basis for heat resistance evaluation system of wild Salix.Here are the main conclusion:1.Salix under 40℃and 45℃: chlorophyll fluorescence parameters of Fo was higher than the control value, the value of Fm decrease,Fv/Fm value decreased with the increasing temperature; cell membrane permeability and MDA content increased; in addition to 40℃ peroxidase did not change significantly, the activity of antioxidant enzymes in general the upward trend; osmoregulation substance, soluble protein, soluble sugar increased, the content of free proline.2.Under the stress of high temperature, Fv/Fm decreased, the change of heat resistance of the weakest of the ’HR29’ was the biggest, the changing rate of Fv/Fm can reflect the strength of the wild plant resources of Salix.3.In the wild Salix planting resources, the best heat resistant was ’SS06’, the worst resistance was ’HR29’. Under high temperature stress, the cells’ SS06 ’relative permeability rate is lower than the ’HR29’, which was negatively related to heat resistance of plants and membrane damage degree, damage degree of membrane is small, the higher resistance of the.In summary, the comprehensive evaluation shows that ’SS06 ’ heat resistance score was the highest, so’ SS06’is suitable for the application in the north and South regions, compared to other wild Salix germplasm resources are better at heat resistance, provide the basis for other works. During the introduction and application,it should be combined with the wild germplasm resources of Salix acquisition, temperature, longitude and altitude etc. |
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