光照强度对青钱柳叶形态结构、光合特性和生长的影响1）

采用人工遮阴的方式设置了3个光照强度，模拟药用青钱柳在矮化及不同栽植密度下的光环境，研究其光合和荧光特性、叶片形态和解剖结构、光合器官的成分和结构以及生长和生物量积累对不同光照强度的响应。结果表明：随着光照强度的减弱，青钱柳苗的净光合速率、非光化学猝灭系数、气孔密度、叶片厚度、栅栏组织宽度、地径、生物量及比叶质量均显著下降，在叶绿体中积累的淀粉粒数量也明显减少。但随着遮阴的加强，遮阴植株具有更高的PSII量子产率、光化学猝灭系数、叶绿素总量。此外，在弱光条件下，叶绿体中含有大量发育完好的基粒内囊体、叶绿素质量分数和叶绿素b的比例更高。适度遮阴（一层遮阴）条件下，青钱柳苗的树高生长、叶面积、叶总生物量比最大，而根总生物量比和根冠生物量比最小。

Influence of Light Intensity on Leaf Morphological Structure,Photosynthe is s Characteristci s and Growth of Cy-clocarya paliurus

A light controlled trial with three light gradients (100%, 50%and 15%of natural sunlight) was conducted to simu-late the light conditions under different planting density and coppice management.We studied the responses of Cyclocarya paliurus seedlings in photosynthesis, fluorescence characteristics, leaf morphology and anatomy, chloroplast ultrastructural and compositions, growth, and biomass accumulation to three light intensity levels in shading shelter.The net photosyn-thetic rate, non-photochemical quenching ( NPQ) , stomata density on unit leaf area, leaf thickness, palisade parenchyma length, basal diameter growth, biomass accumulation, specific leaf weight and starch grains in chloroplast were significant-ly decreased with the decline of light intensity.However, with the increasing of shading level, shading plants possessed higher values of quantum yield of PSII, photochemical quenching and total chlorophyll content.We detected a large num-ber of well-developed grana stacks and higher proportion of chlorophyll b in shade-type chloroplast grown under shading conditions, and the highest tree height, leaf area and leaf-total biomass ratio under the medium shading ( one shading net) , while the root-total biomass ratio and root-top biomass ratio were the lowest.The adaptive changes of C.paliurus un-der low light intensity allowed shading plants more efficiently capturing and transferring the limited photon flux, and hence, the plants could obtain optimum ecological adaptability in low light environment.However, the growth and biomass accu-mulation of C.paliurus under heavy shading were severely inhibited, while the leaf biomass accumulation under medium shading was not significantly influenced.