| In order to enrich the species of drought resistance landscape plants in Huhhot region, we conducted broadly research on introduction and evaluation for landscape plants. We screened the plants and then investigated their seed production and seedling drought resistance features. The research involved three parts and the following was the main results:1 We evaluated the tested plants form six aspects including ecological adaptability, effect of beautification and ornamentation, overwintering ability and so on. In Huhhot region, the 47 tested landscape plants (including cultivated plants) belonged to 21 families,37 genuses. Based on comprehensive scores, then we conducted sorting and classification, according to the levels of synthesized index, all evaluated materials were categorized into four groups that included level 1:score≧0.9,level 2:0.8-0.9, level 3: 0.7-0.8,level 4:<0.7. The results showed:①There were 12 ecological plants species in the level 1 group that they had the highest integrative index. They were basically the native plants and a few of introduced plants which had adapted climatic conditions of Huhhot region for a long period. These plants should be planted widely in Huhhot.②There were 15 ecological plants species in the level 2 group which had fairly high integrative index and could be used as common ornamental species in Huhhot.③There were 15 species in the group 3 with lower integrative index. According to the actual situation, these plants could be used as supplementary ornamental species for special conditions and purposes.④There were 5 species in the level 4 group. Most of them were exotic plants, usually had lower resistancies for cold, drought and infertile soil. This group had the lowest integrative index, so they were not suitable for using as ornamental plants in Huhhot.2. Seed production features of 5 selected ornamental ecological plants were investigated, focusing on the problems of long flowering period, inconsistency of maturation, seed abortion, and seed shattering for low seed yield.① Studies on seed yield components showed that seed production performances of the 5 ecological plants were different. Based on the values of seed yield componenis, the potential seed yield of Allium mongolicum was the highest, reaching 79964.93kg/hm2.The potential seed yield of Allium tenuissimum was the lowest, being only 4018.56kg/hm2. The harestable seed yield of Allium mongolicum could reach 25280.81kg/hm2 and it was also the highest. Compared with other Allium, the harestable seed yield of Allium tenuissimum was 1500.01kg/hm2 and it was also the lowest. Among the five plants tested, the seed production performance of Allium mongolicum was the highest, while the Allium tenuissimum was the lowest, the rest species were moderate.② Seed shattering is a main obstacle for ecological plants seed production during the whole process of seed development. Seeds began to shatter at 15-20d after flowering stage. Seed shattering had two ways, namely fruit shattering from the stalk and seed shattering from dehiscent fruit. Seed shattering from dehiscent fruits was the primary cause for seed loss. Seed shattering were occurred in the early ripening stage to the fully ripening stage.3 Research on the characteristics of drought resistance of seedlings for the selected plants of Asparagus gobicus, Iris tenuifolin, Viola verecumda, Haplophyllum dauricum, Linum perenne, Allium mongolicum, and Allium anisopodium, was conducted. Seedling survival and behaviours under different stress conditions were observed. The results showed:① Under the drought conditions, Viola verecumda had the highest survival rate, followed by Asparagus gobicus. They had higher cultivated survival rate than Allium mongolicum, Allium anisopodium, Linum perenne, Iris tenuifoli, Haplophyllum dauricum. Under extensive management conditions, the survival rate of the 7 cultivated plants form high to low was Viola verecumda, Asparagus gobicus, Allium mongolicum, Allium anisopodium, Linum perenne, Iris tenuifolin, Haplophyllum dauricum.② With increasing in days of the drought treatment, the water consumption by transpiration increased lineally. The correlation coefficients were above 0.9. With increasing in days of the drought treatment, the water consumption by transpiration increased from slow to high, The order of water-holding capacity of the tested plants was as follow:Linum perenn, Allium anisopodium, Allium mongolicum, Viola verecumda, Haplophyllum dauricum, Asparagus gobicus, Iris tenuifolin.③ By comparing seedling characteristics of 7 ecological plants under different stress conditions, the order of drought resistances of the tested plants, were Iris tenuifolin, Allium anisopodium,Asparagus gobicus, Viola verecumda, Haplophyllum dauricum, Linum perenne... |
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