| For the sake of revealing the rule of variation of Quercus acutissima population, to put the theory way for collecting better Q. acutissima, based on the distribution of Q. acutissima in Shandong Province, six sites where Q. acutissima distributed, including Yaoshan, MountainTai, Wulian, Laoshan, Kunyu and Feixian forest farm were invested, and their growth, form and seed characters were studied. Also through five-tree-way, some plus-tree were collected and families were invested, to prepare better material for selecting fine varieties for ecological construction, Several puper clones were sslected,including TM2,TM4,TM15,TM17. Main results followed:1. Study on variation of Q. acutissima groupsVariation existed among Q. acutissima population. Great variation existed among natural Q. acutissima population. Variation coefficient of growth characters were big, and there schedule from high to low were: volume>height > crown > diameter. Coefficient of variation of form characters scheduled from high to low was form>branch>height under branch. Phenotypic variation among leaf characters was very significant, variation coefficient of leaf characters scheduled from high to low was leaf fresh weight >leaf area>leaf breadth>ratio of length to breadth>leaf length. Phenotypic variation among leaf characters was very significant.2. Study on selection of Q. acutissima familiesDifferences of growth characters among Q. acutissima families were great. Difference between variation coefficient of base diameter and that of height of Q. acutissima was significant. Variation coefficient of leaf characters scheduled from high to low was petiole length, leaf breadth, leaf length, ratio of length to breadth, differences of leaf length among families were significant.Variation coefficient of biomass among families were great, in which leaf dry biomass was greatest, then were branch dry biomass, dry root biomass and up/under biomass. Differences among families biomass were significant.Through membership function to value the Q. acutissima families, the result followed from high to low: 15, 28, 42 and 47 were super, They were greater more than average value 53.41% on height and 40% on base-diameter. Then they were5, 4, 20, 26, 19.3. Study on selection of Q. acutissima clones.(1) Study on growth charactersCorrelations among growth characters of Q. acutissima at 1-year-age were not significant, but existed very significant correlations at 2-year-old, when in 3-year-old, correlations decreased. Correlations among form characters were not significant during 1 to 3 years old. Different indexes had different correlation; normal positive correlation existed between form and height, base diameter, volume.Through path analysis, we got the multiple determined elements coefficient of system composition of height, base diameter, H/DBase, form and branch on volume was 0.9336.Selection age of form indexes may at 1-year-old, growth indexes may at 2-year-old.(2) Study on photosynthesis and physiological characters.Differences among net photosynthesis rate, transpiration rate, intercellular CO2 concentration, water use efficiency were significant, phenotype and genetic correlation between net photosynthesis rate and transpiration rate was great, also positive phenotype and genetic correlation between net photosynthesis rate and water use efficiency was great;(3) Study on water physiological charactersThe changes of soil and leaf water potential under drought stress were differently. Soil water potential decreased gradually as drought stress strengthened. As drought stress strengthened, the leaf water potential of different clones were different, showed decreased first then creased, creased gradually and creased first then decreased.The change of water indexes were different at different stress. With soil drought stress strengthened, relative leaf content of clones decreased gradually, water saturation deficit creased, but the range of change were different. The curves of leaf water loss were similar, under three different drought stresses, in the beginning of water loss, the decreased range was great, and speed was quick, but when at the end of water loss, the speed decreased.Content of enzyme and osmotic adjustment material varied greatly. SOD of clones 4, 11 and 13 creased firstly and then decreased, the others decreased. Soluble sugar showed different rules, Soluble sugar content of clones 1 and 17 creased , so we got conclusions that their resistance were strong, while that of clones 5 and 8 decreased, their resistance were weak.The change of photosynthesis characteristics was different. Photosynthetic rate decreased firstly and then creased, and there were great differences among the transpiration rate of clones.Correlation of different indexes of drought resistance varied with drought stress. At light drought stress, correlation between photosynthesis rate and transpiration rate, leaf water potential, soluble sugar content were very positive significant, also it was between leaf water potential and SOD besides its negative. Under moderate drought stress, correlation between soil water potential and transpiration rate was very negative significant. Under severe drought stress, correlation between photosynthesis rate and transpiration rate was negative significant too, and positive significant correlation existed between soil water potential and water saturation deficit.4. Through membership function to value the resistance against drought of Quercus acutissima clones, we got clones2, 4, 15, 17, 3 and10 were better, and named TM2,TM4,TM15,TM17. |
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