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以无覆盖为对照,研究了一层膜遮荫(遮光率约30%)、二层膜遮荫(遮光率约55%)、三层膜遮荫(遮光率约80%)对一年生木荷、苦槠、湿地松、香樟、枫香、杨梅、无患子和青冈栎等容器幼苗生长和生理生化反应。试验表明一层遮荫后8种树种植株都生长健壮,主要表现为根颈较粗、须根数量增加。容器幼苗叶片中叶绿素a/b值香樟和杨梅以一层和二层遮荫较高,其余6种树种以一层遮荫覆盖最高。除了胞间CO2浓度外,8种树种不同处理间容器幼苗叶片的蒸腾速率、气孔导度和水分利用率的变化基本与净光合速率的变化呈正相关,其中净光合速率、蒸腾速率、气孔导度和水分利用率香樟和杨梅以一层和二层遮荫较高,其余6种植物以一层遮荫最高,但不同处理胞间CO2浓度的变化较为复杂,故影响不同处理的光合作用可能有气孔和非气孔的因子。容器幼苗叶片中丙二醛含量香樟和杨梅以一层遮荫和二层遮荫较低,其余6种树种以一层遮荫最低;8种树种不同处理间超氧化物歧化酶、过氧化氢酶和过氧化物酶活性以及还原型谷胱甘肽含量的变化基本与丙二醛含量的变化呈负相关。因此,夏季适度遮荫能促进容器苗的生长。
Taking the non-coverage as control, the effects of one layer of film shading (shading rate about 30%), two layer shading (shading rate about 55%), three layer shading (shading rate about 80% , Bitter gizzards, Pinus elliottii, Camphora, Liquidambar formosana, Myrica rubra, Phragmites australis, and Cyclobalanopsis glauca seedlings growth and physiological and biochemical reactions. Experiments show that after a layer of shading eight kinds of tree species grow robust, mainly for the root neck coarse, fibrous increase. The leaf chlorophyll a / b value of camphora and bayberry in the seedling leaves was higher than that in the first and second layers, and the shade of the other six species was the highest. In addition to the intercellular CO2 concentration, the changes of transpiration rate, stomatal conductance and water use efficiency were all positively correlated with the changes of net photosynthetic rate. The net photosynthetic rate, transpiration rate, stomatal conductance And water use efficiency. Cinnamomum camphora and arbutus had the highest shade in the first and second layers, while the other six plants had the highest shade in one layer. However, the changes of CO2 concentration in the intercellular CO2 were more complicated, which may affect the photosynthesis of different treatments Stomata and non-stomatal factors. The contents of malondialdehyde (MDA) in the seedling leaves of container were shaded by one layer and shade by two layers, while the shade of the other six species was the lowest by one layer. The activities of superoxide dismutase, The change of the activity of hydrogenase and peroxidase and the content of reduced glutathione were basically negatively correlated with the content of malondialdehyde. Therefore, moderate summer shade can promote the growth of container seedlings.