Study On Some Processes Of The Growth And Physiology Of Different Acacia Melanoxylon Clones

This thesis first made some research and analysis on the growth situation of 16 Acacia melanoxylon clones—whose provenance are from Austrilia—introduced to Zhangzhou, Fujian province, and then analyzed the physiological characteristics of the clones and the relations with the growth situation through physiological indices research. The goal of this thesis is to explore the adaptable environment of the Acacia melanoxylon clones and to evaluate its germ plasm resources, in order to choose the fine Acacia melanoxylon clones suitable for local condition, and provide theoretical basis for the planting of large areas of Acacia melanoxylon in the local, or even in other areas. The main research results are as follows:1. The growth phenotype of different Acacia melanoxylon clones that are introduced varies from one another. The average DBH of 4.5-year old Acacia melanoxylon clones is 9.13cm, tree height is 6.85m, and the timber volume of a tree is 0.0289 m3, with characteristics of fast and well growth. The average DBH of HM14——whose growth phenotype is the best——is 11.95cm, tree height is 9m, and the timber volume of a tree is 0.0526 m3, while HM16, with worst growth phenotype, has average DBH of 7.58cm, tree height is 6.3m, and the timber volume of a tree is 0.0168 m3.2. The physiological characteristics of different Acacia melanoxylon clones that are introduced varies from one another. Chlorophyll a's content is from 1.318mg/g to 2.366mg/g, chlorophyll b's content is from 0.738mg/g to 1.338mg/g and chlorophyll(a+b)'s content is from 2.056mg/g to 3.703mg/g, they are positively correlated with one another, and have no significant correlation with chlorophyll(a/b), whose avarage value is around 1.7. The value of chlorophyll fluorescence parameters is from 26.88 to 35.56, and Fm is from 189.13 to 240.62 and Fv/Fm is from 0.832 to 0.866. Chlorophyll a, chlorophyll b and chlorophyll(a+b) of the Acacia melanoxylon clones have strikingly negative correlation with initial fluorescence Fo, they have no significant correlation with other chlorophyll fluorescence parameters, namely, the higher of Chlorophyll content, the lower of Fo. Through tests on the ratio betweent the rate of water loss and free water/bond water, the result shows that clones with better drought resistance are: HM3,HM4,HM7,HM9,HM16. Through tests on electrical conductivity under low temperature stress and by the aiding of Logistic equation come to the result that the cold-resistant range of the Acacia melanoxylon clones are from -2.46℃to 1.08℃in spring, and most of them are below 0℃. And through tests on chlorophyll fluorescence parameters, with the increase of low temperature stress, the chlorophyll fluorescence parameters Fv/Fm will reduce and Fo will increase.3. Through the analysis of the correlation between the growth phenotype of Acacia melanoxylon clones and the climatic factors in the provenance, come to the conclusion that the climatic factors which hamper the growth of Acacia melanoxylon clones in the local is deficiency in light and high relative humility. Meanwhile, the effect of cold damage and drought should also be minded.4. There is no specific relation betweew growth phenotype and physiological characteristic of the Acacia melanoxylon clones. Chlorophyll(a/b) was positively correlated with DBH, crown and volume, namely that the higher of the chlorophyll(a/b) value, the bigger of DBH, crown and volume and the better for the growth.There are no significant correlativity among chlorophyll (a+b) content, chlorophyll fluorescence parameters, drought resistance, cold resistance and the growth phenotype.5. Through comprehensive analyse of all the growth and physiological indexes of the Acacia melanoxylon clones, four superior Acacia melanoxylon clones are selected, they are: HM14,HM12,HM15,HM8. This can be references to the area or areas with similar climate when introducing the Acacia melanoxylon clones. To summerize, among 16 clones the most suitable ones for Zhangzhou, Fujian province are: HM14, HM12, HM15, and HM8. Single physiological indices has no great importance on the growth of Acacia melanoxylon. We must take the difference of climate between provenance and locality into consideration during instruction of the Acacia melanoxylon and give guidance from all aspects to the planting.