Studies On Introducing, Acclimating And Shade-tolerance Of The Hosta Plants

Ground-cover plants is an important factor in landscaping Plant. They can improve the quality of afforest. The perennial root flowers was employed more and more extensively in urban landscape, bundant the landscape gardens, but restricted by climate in the region of the North, the variety employed shows deficient. The Hosta plants are perennial herbs of Liliaceae, which have highly decorative values of both leaves and flowers and thrive in the shade, they are excellent shade plants. It is clear that the research about shade-tolerance of Hosta plants benefit for optimizing of planting design and landscape ecology.For enriching Beijing's garden plant material, we traps-regional to go to foreign lead eighty-six variety into Beijing and carry on research to them, in the hope of to choose new variety that suitable to Beijing, popularize and apply. Theory guides were provided of Hosta plants of their cultivation and propagation in gardens.The Hosta plants can be divided into four groups according to their leaf-colors, respectively yellow, variegated, gray-green and green types. Chlorophyll, leaf epidemis and photosynthesis of eighty-six Hosta plants were determined under tree canopies. Yellow-leaf type Hostas have lowest chlorophyll contents and highest value of chla/chlb, secondly the variegated-leaf Hostas, gray-green-leaf and green-leaf Hostas have no significant differences in chlorophyll contents and value of chla/chlb. Gray-green-leaf Hostas are the most shade tolerable, and the yellow-leaf Hostas are the least.The effects of shade on the photosynthesis, chlorophyll contents and growth characters of four Hosta cultivars were determined under different light conditions (25, 50, 75% of full light) within pots. Light saturation points ranged from 400-800μmol m-2s-1 among four cultivars, of which Hosta'Elegans'and Hosta'Spilt Milk'had the lowest saturation point and compensation point. The maximal photosynthetic rate (Pmax) was significantly higher in shade than in full light in Hosta'Elegans'and Hosta'Spilt Milk', and was at maximum levels in seedlings grown in 25% of full light. While the best shade treatment for Hosta'Climax'and Hosta'Fried Bananas'was 50% of full light.Light compensation points, light saturation points, chlorophyll contents and value of chla/chlb can all be important index of shade-tolerance. According to their photosynthetic responses to shade treatments, the shade tolerant ability of four cultivars Edger' was in the order: Hosta'Elegans'> Hosta'Spilt Milk'> Hosta'Climax'> Hosta'Fried Bananas'.