Study On The Growth And Eco-physiological Characteristics Of Fatshedera Lizei Under Different Lighting Conditions

Agroforestry is a manmade complicated and open eco-economy system with vary component elements, multi levels, different species composition and various functions, is a system that combines agriculture with forestry reasonably based on the principles of sustainable development, ecological system and social economy. It is apparent that in order to raise land use ratio and enhance economical benefits, agroforestry becomes an important issue of agriculture and forestryThis research project was carried out in 2007 in Chongming island of Shanghai, a 8-year old camphor (Cinnamomum camphora) stand was selected to build an agroforestry system with bush ivy (Fatshedera lizei). 3 different converge for the stand were formed through thinning, then 1-year seedlings of bush ivy was planted under these various microsites under canopy. A comparison study on growth characteristics of bush ivy in different microsites under canopy with different coverage was done in the paper. This research provides rational basis for multiple management of camphor-bush ivy and appropriate culture model.The research results are as follows:1 the growth index of bush ivy planted under different canopies of camphor standUnder different light conditions the growth properties of bush ivy are different. The vigorous growth of bush ivy started in July and whole growth season end in November. Its growth curve could be described using logistical model and followed S shape. The highest height growth of seedlings was in August, growth peak of diameter at ground level was recorded in July. When stop growth in December, the height of bush ivy seedlings under low canopy coverage reached to 28.14cm, and diameter of ground level achieved to 6.79mm.Its increment amount was higher significantly than that of the seedlings planted under other treatmentsThe most increment of leaf number was in July, but the highest increment of leaf area occurred in August. At the end of the growing season, 13 leave per individual seedling were accounted for the seedling under low canopy coverage condition, and its average leaf area reached to 359.11 cm2 per leaf, which were significantly higher than that of other treatments. The dynamic analysis of biomass increment showed that for the seedlings growing under low canopy coverage condition the average biomass of both aboveground and underground per individual seedling were 9.39g and 1.39g respectively at the end of the growing season. Their values were the highest compare with other treatments; but the seedlings under the middle canopy coverage condition had the highest value of root-shoot ratio (0.27) compared with that of other treatments.2 Photosynthetic physiological indicators of bush ivy under different light conditionsUnder different light conditions the growth and the physiological indicators of bush ivy are different. Photosynthetic rate under low canopy coverage was significantly different with other treatments, and its peak values were 6.06μmol ? m-2?s-1 and 4.71μmol ?m-2?s-1 showed at 10am and 3pm.Stomatal conductance and Transpiration rate under low canopy were significantly different with other treatments too.Photosynthetic pigment in leaves changes with the light intensity, both of the maximum value of the total chlorophyll (2.19mg/g) and the minimum value of chlorophyll a / b (1.36) were recorded in the seedlings of bush ivy growing in the microsite under middle canopy coverage.Under low canopy coverage condition, the content of carotenoid was 2.14mg / g, significantly higher than the level of other treatment; Under middle camphor canopy, soluble protein and soluble sugar contents were 114.16mg / g and 62.07mg / g respectively which are significantly higher than the level of other treatment.3 Growth difference of bush ivy under different fertilization levelFour different fertilizing treatments were designed for bush ivy seedlings growing under different canopy coverage conditions, a compared study on growth difference for these treated seedlings was done in the paper. The results showed that at same light condition under low canopy coverage, the growth index of bush ivy seedlings treated with fertilizer of 15g per individual, are higher than that of other fertilizer treatment levels. The growth index includes height, leaf number and area of higher increment of seedlings;the highest value of diameter appeared under low canopy coverage with fertilizer of 10g per individual.