| Z.schneideriana Hand.-Mazz. is one member of the family Ulmaceae, it's the national level Ⅱ protected wild plant and a rare native plants endemic to China. In addition to the high-quality timber species, Z.schneideriana Hand.-Mazz is important landscape trees. Because of its profound cultural connotation, beautiful tree and rich of autumn leaf color, it's very popular for people. But most of them are seedlings on the landscape which resulting in uneven in growth and unsatisfied in landscape effect at present. It is a serious impact for its application in the landscape. There is an urgent need for new varieties of the Z.schneideriana Hand.-Mazz which are high ornamental valuable.We have tried to probe into the growth characters of different strains of Z.schneideriana Hand.-Mazz and the reproduction methods of yellow-leaved Z.schneideriana Hand.-Mazz, with an end to first rationalizing and scientizing planting design when Z.schneideriana Hand.-Mazz of different colored leaves are used in ornamental plant landscaping, which can in turn improve the scientific and artistic value of different stains of Z.schneideriana Hand.-Mazz in landscaping, and second to getting a large number of its nursery stocks to extend its application in a short time, which can serve the market's demand for the nursery stocks of new stains. In the end, we have attained following results and conclusions.1.Its growth characters(1)Its leaves'color variation and variation typeZ.schneideriana Hand.-Mazz leaves take on varied colors which are generally classified into the red, the yellow, and the green. In the sample trees, the red accounts for57.5%, the yellow22.5%, and the green20%. We take British royal horticulture association colorimetric card to conduct color measurement and color scheme classification. Three groups are made:green group,red group and yellow group.(2)Phenological changes in different strains of Z.schneideriana Hand.-Mazz.In general, phenological changes of red strain in the spring come earlier than the other two strains, and apart from axillary expansion of yellow strains in the beginning period comes five days earlier than yellow ones. Other phenological changes of the two strains in spring are basically the same.Yellow stains'phenological changes in autumn comes first; next is red ones; the last is green ones; Green strains are the last one in entering color-changing period in autumn, yet the earliest in entering the last period of defoliation; Looking at the yearly phenological change, we have found that leaves of the green strains keep green for the longest time.(3)Growth rule of different strains of Z.schneideriana Hand.-MazzFrom the perspective of trees'month-on-month increase in height, three strains of Z.schneideriana Hand.-Mazz all have two growth peaks throughout the year. They are respectively in April and August, with the highest growth peak appearing in April. Of the three strains of Z.schneideriana Hand.-Mazz, green strain enjoys the fastest growth. Before November, the yellow and the red yellow stain's growth rate differs very little, seemingly racing against each other.In November, the yellow strain almost stops growing, but the red strain does not stop growing until December. And ultimately accumulated growth of red strains is bigger than that of yellow strains.Three strains'yearly basal diameter growth trend varies little. They start to grow in March, and after October they stop growing. Concerning month-on-month growth of basal diameter, red and yellow strains come across two growth peaks throughout the year. They are respectively in May and August, with the highest growth peak appearing in August. However, the green strain only has one growth peak in the whole year which occurs in May.2.Tissue culture and rapd propagation systemTakeing a section of bud stem born as explants in the current year. Through research, we obtained the tissue culture and rapd propagation system of Z.schneideriana Hand.-Mazz. (1)Expland disinfection:30S70%alcohol and0.1%mercury for3minutes is the best disinfection method.(2)Primary culture:MS+6-BA0.5-1.Omg/L is the best primary medim for rapid propagation of Z.schneideriana Hand.-Mazz.(3)Do screening to get the best way of conducting subculture is MS+6-BA0.5mg/L, with the bud's proliferation index at5.10.(4)Do screening to get the best way of cultivating strong saplings is MS+6-BA0.5mg/L+GA30.5mg/L.(5)Do screening to get the best way of rooting culture is1/2MS+NAA0.5mg/L, with the rooting rate at77.78%。... |
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