Studies On Evaluation And Regeneration Features Of Ornamental Plants In Huhhot

With the rapid development of gardening, the demand for greening and beautifying to city becomes highly important.The present greening plants have not yet met the high standard demand, and the four seasons'landscape has become the necessary tendency for development. It is necessary and urgent to introduce and multiply the excellent ornamental plants.In order to enrich the species of ornamental plants in Huhhot region, this dissertation studied broadly on introduction and evaluation. The selected ornamental plants with multiplication difficulties were researched in-depth study in multiplication biology. The experimental research of this project was divided into four parts, and the results are as fowllows:1. 260 ornamental plants (species and varieties) belonging to 43 families and 84 genus were evaluated in Huhhot region based on a comprehensive evaluation system in which 6 aspects (including ecological adaptability, outlook appearance and plant resistance and etc) were considered. All evaluated materials were categorized into four groups based on their integrative indices, i.e., group 1 including materials with grades≧0 .9; group 2 = 0.8～0.9; group 3 = 0.7～0.8; group 4﹤0.7. The results showed:①There were 108 woody species in the first group with the highest integrative index. They were basically local native plants and a few were well domesticated species for a long period in Huhhot region. Plants in this group were preferred species and should be planted widely in Huhhot.②There were 70 woody species in the second group which had fairly high integrative index and could be used as common ornamental species in Huhhot.③There were 48 species in the third group with lower integrative index. These plants could be used as supplementary ornamental species for special conditions and purposes.④There were 34 species in the forth group. Most of them were foreign woody species with lower tolerances to cold, drought or infertile soil. They showed the lowest integrative index and therefore not suitable for using as ornamental plants in Huhhot.2. Ten species of Lonicera cv. Fanguo, Prunus davidiana(Carr.) Franch., Lonicera ferdinendi, Lonicera edulis Turcz., Viburnum brejaeticum, Viburnum Lantana L., Euonymus phellomanes Loes, Ribes odoratum Wendl., Fraxinus pennsylvanica Marsh.var.Lanccolata Sary.and Catalpa bignonioides Wald.with multiplication difficulties were studied on their seedling growth. Plant growth rate in terms of seedling height and above-ground diameter were measured in one-year old seedlings. It lays a foundation for carrying out management measure scientifically and reasonably, making the nutrition growth better and flowering early. The results showed:Seedling growth of the ten plants generally showed a slow–fast–slow pattern with highest annual growth rate of 52.78 cm in Catalpa bignonioides Wald and lowest growth rate of 10.07cm in Lonicera ferdinendi. Fast growth from mid July to mid September took about 70%-80% of the annual growth.Annual increases of above-ground diameter ranged from 2.27 cm to 10.45 cm in different plants. Fastest above-ground diameter increase occurred in early August to the late Septembe which may take about 70% of the annual increase in Lonicera cv. Fanguo, Prunus davidiana(Carr.) Franch., Lonicera ferdinendi, Lonicera edulis Turcz., Euonymus phellomanes Loes, Ribes odoratum Wendl., Fraxinus pennsylvanica Marsh.var.Lanccolata Sary.and Catalpa bignonioides Wald. Fastest above-ground diameter increase occurred in late July to mid Septembe which may take about 60% of the annual increase in Viburnum brejaeticum and Viburnum Lantana L.3. Seed biology features of the selected ten plants with multiplication difficulties were studied on their seed dormancy and germination behaviours. Alternatative temperatures, GA3 and KNO3 treatments were used in order to break dormancy and improve germination. The results showed: storage in different temperatures and suitable hormone concentration were main factors for breaking seed dormancy. Seed germination rates of Lonicera ferdinendi, Lonicera edulis Turcz., Lonicera cv. Fanguo, Prunus davidiana(Carr.) Franch., Ribes odoratum Wendl., Viburnum brejaeticum, Fraxinus pennsylvanica Marsh.var.Lanccolata Sary.and Catalpa bignonioides Wald. could reach 97.25%, 70.75%, 84.00%, 70.00%, 61.50%, 90.00%, 99.25% and 95.25% respectively with suitable treatments. The problems on seed dormancy relieving and improving germination rate had been settled. But the seed 0f Viburnum Lantana L.and Euonymus phellomanes Loes. had deep dormancies. Their dormancies can not be broken by above treatments.4. Clonal techniques were used in order to explore methods for fast multiplication through asexual means for the ten plants with multiplication difficulties. The results showed: the cutting time, choice of hormones and hormone dosages were key factors affecting rooting performances. Rooting rates of Prunus davidiana (Carr.) Franch, Lonicera edulis Turcz, Lonicera ferdinend, Viburnum brejaeticum, Viburnum Lantana L., Ribes odoratum Wendl.and Euonymus phellomanes Loes.were 97.22%, 94.45%, 83.33%, 72.22%, 72.22%, 63.89%and 75.00% respectively, with suitable treatments of plants'green cuttings in summer.The research had both enriched species of ornamental plants in Huhhot and provided a theory basis for seed multiplication, cloning techniques, planting adaptable range and application of new and well ornamental plants. It also provided a basic data and scientific direction for planting and selecting new and well species in northern region.