| Being an ancient exclusive species to China, Eucommia ulmoides was not only used as a valuable Chinese medicinal material and the industrial raw material for abstracting natural rubber, but as the good timber species and the ones for water-soil conservation and greening as well. The study on drought resistance of Eucommia ulmoides owns of immense significance ecologically and provides the solid theoretical basis for the complete expression of its ecological value. The present work concerns 9 introduced clones of Eucommia ulmoides, integrating measurement of the drought resistance index with analysis of phenotypic characters and ornamental value, from which the comprehensive evaluation as well as the preliminary selection of superior clones could be achieved. In addition, the polyploid induction of Eucommia ulmoides were conducted with the seeds as experimental materials . The objective of the study was to develop a scientific basis for the selection and breeding of the new species characterized by high production, top quality and strong resistibility, thus highlighting the development and utilization of Eucommia ulmoides. The research results were listed as following.1. The cell of upper epidermis of the leaf is larger than the one on the lower epidermis in which the stoma is located 4 of the most representative drought resistance indexes among 15 items of foliar anatomical structures were: thickness of midrib, thickness of palisade tissue, ratio of palisade tissue thickness to sponge tissue thickness, CTR. Each one of the clones is significant different in leaf thickness, palisade tissue thickness, stoma size, density of the stoma, dehydration rate and critical water saturation deficiency etc. The comprehensive assessment about 22 drought resistance indexes was conducted using Fuzzy Mathematics subordinate function values analysis and the following conclusions were drawn: clone 8,clone 7,clone 3 were superior in drought resistance, clone 5,clone 6,clone 4 were moderate whereas.Clone 1,clone 2,clone 9 inferior, respectively. 9 clones of Eucommia ulmoides were arranged in order of the drought resistance from superiority to inferiority: clone 8,clone 7, clone 3,clone 5,clone 4,clone 6,clone 1,clone 2,clone 9.2. From the investigation and analysis concerning 9 growth trait items of annual grafting seedlings of clones, the conclusion that variations of characters among clones were relatively big could be drawn, with the average coefficient of variation 19.02%. The most biggest variation turned out to be the leaf area with the CV 30.96% whereas the smallest variation was branch diameter with the CV of 9.95%. According to ANOVA, except the branch diameter all the other traits showed differences or significant differences among the 9 clones. Standardization of each phenotypic character of nine clones of Eucommia ulmoides separately had been conducted, organized in order of the sum from the high to the low:clone 7,clone 8,clone 5,clone 4,clone 6,clone 2,clone 1,clone 3,clone 9. Hereinto, clone 7 and clone 8 showed the superiority related to the living quality and leaf characters, and owned advantages of drought resistance. Furthermore, all the tested cloned species expressed high ornamental value.3. The optimum combination of the colchicine concentration and the duration of seeds soaking were selected through the induction of polyploidy plants using seeds as materials under the cultured condition: soaking seeds for 48h in 0.3% colchicine solution. Consequently, the methology to induct the doubled plants of Eucommia ulmoides through seeds was described after: the mature seeds of Eucommia ulmoides, which should be soaked in 500ppm GA3 for 24h primarily, were transferred to 0.3% colchicine solution for 48h and then be cultured in the hormone-free MS salts. From above the relatively high induction rates could be promised without influencing the planting percent. 424 introduced polyploid plants were obtained from the presented research. |
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