Research On Shade-tolerance Of Ground Covers And Its Application In Landscape

Ground cover is an important factor in landscaping plant. They can improve the quality of afforest. It is clear that the research about shade-tolerance of ground cover benefit for optimizing of planting design and landscape ecology. Based on the investigations of its landscape use in Hangzhou, the paper discussed the resources utilization and ecological planting of ground cover. Four species were chosen as the materials for the researches of plant growth, leaf structure, chlorophyll and proline content, and photosynthesis charateristic under different shading levels, such as Lysimachia christinae 'Aurea', Ajuga multiflora , Ardisia japonic a and Belamcanda chinense. The criterion for judging the capability of shade-tolerance of ground cover has been tried to illustrate. The result were summarized as follows:1.The investigation of landscape use of ground cover in Hangzhou showed that, the applicated area of traditional species represented large percentage as 60% in total area of 54052 m2. And the area of new species of ground cover was 17%. The new species, which have colorful flower or variegated leaves, have good potential use in landscape. 2.The resource utilization, mass propogation and study of stress resistance of ground cover have been noticed already. Eventhough various species of ground cover have been suggested for using, we have long way to go for widely landscape use because of lacking mass production of seedlings. 3.Four species showed different responses under series shading levels. Lysimachia christinae 'Aurea' had the highest value on plant fresh weight, root fresh weight and length of branch under 27% shading, and the largest leaf area appears under shading of 73%. Under the full sun, the fresh weight of Ajuga multiflora and Belamcanda chinense were the heaviest. Compared with full sun, the ratio of leaf thichness of palisade mesophyll and epidermal mesophyll of plant was lower under 80% shading. The cell arragement was dense in Ardisia japonica, and was loose in Belamcanda chinense. The cell interspace increased when the shading degree increasing.Among the four species of ground cover, the light saturation point and light compensated point of Ardisia japonica was the highest, and the value was 645 and 202 u mol/m2s, respectively, while the light compensated poin of Belamcanda chinense was the lowest. The chlorophyll content of Lysimachia christinae 'Aurea'increased with the increasing of shading degree, the ratio of a/b decreased. The absolute value of proline content in Ardisia japonica was the highest. The following was Belamcanda chinense, Lysimachia christinae 'Aurea' and Ajuga multiflora. As the increasing of shading degree, the poline content of Ajuga multiflora and Belamcanda chinense decreased, while that of Lysimachia christinae 'Aurea' increased.Among the indexes of anatomatical, structure, and physiology characteristic, the leaf structure and proline content is rel tively relevant to the plant growth. They are the significant indictor for judging the capability of shade-tolerance.4.The biological characteristics must be considered when ground covers were used in landscape. On the other hand, the landscape senery in vertical view also should not be ignored.