钩藤幼苗生长的适宜遮阴度探索

Exploring on suitable shading for seedling growth of Uncaria rhynchophylla

为了探索适宜于钩藤幼苗生长的遮阴条件,从而为钩藤人工种植技术的构建提供理论依据,以苗龄为1 a的钩藤为材料,分别设置了轻度遮阴(透光率55%~75%)、中度遮阴(透光率25%~35%)、重度遮阴(透光率5%~15%)等处理,以全光照作为对照(CK),就不同遮阴处理对钩藤幼苗生长的影响情况进行了试验研究,并于定植90 d后测定其形态指标(株高、茎粗、叶面积、叶片数量、分枝数、比叶重)和生理生化指标(叶片光合参数、光合色素含量、含水量、可溶性总糖、可溶性蛋白和丙二醛含量)。结果表明:轻度遮阴处理的钩藤幼苗其株高、茎粗和分枝数均极显著高于全光照、中度遮阴和重度遮阴各处理的;净光合速率、可溶性蛋白质和可溶性糖含量大小均表现为全光照>轻度遮阴>中度遮阴>重度遮阴;叶片含水量、叶绿素总含量均随着遮阴程度的增加而增加;气孔导度表现为轻度遮阴>全光照>中度遮阴>重度遮阴;丙二醛含量表现为轻度遮阴<中度遮阴<全光照<重度遮阴。综合分析钩藤幼苗各项形态指标和生理生化指标的测定结果后认为,透光率为55%~75%的遮阴处理更适于钩藤幼苗的生长。

This study investigated the effects of different shade density （light transmittance is 55%-75%, 25%-35% and 5%-15%, respectively） for seedling growth of Uncaria rhynchophylla. One-year-old U. rhynchophylla seedlings were used to the test, and the seedlings were used to determine morphological indexes （including plant height, stem diameter, leaf area, leaf number, branch number and specific leaf weight） and physiology and biochemistry indexes （including photosynthetic parameters, photosynthetic pigment content, leaf water content, soluble protein content, soluble sugar content and MDA content） after 90 d planting. The results showed that the light shading were conducive to the organs growth of U. rhynchophylla seedlings, and various morphological indexes （e.g. plant height, stem diameter and branch number） have been more significantly improved relative to full illumination, the moderate shading and the severe shading. The net photosynthetic rate, soluble protein content and soluble sugar content under four light conditions showed full sun light 〉 light shade 〉 medium shade 〉 severe shade. The leaf water content and the total content of chlorophyll increased with the increase of shade density. The stomatal conductance of leaf showed light shade 〉 full sun light 〉 medium shade 〉 severe shade. MDA content of leaf showed light shade 〈 medium shade 〈 full sun light 〈severe shade. Analyzing synthetically morphological index, physiological and biochemical indexes of U. rhynchophylla seedlings under four light conditions, we thought that shading treatments of 55%-75% were more conducive to the seedlings growth of U. rhynchophylla.