Retention Capability of PM2.5 and It’s Explanation by Leaf Surface Micro-structure of Common Broad-leaved Plant Species in Beijing Leaf Anatomical Structures of Different Regional Amygdalus pedunculata Pall.and Their Drought Resistance Analysis Mechanism on Leaf Color Transformation of Loropetalum chinense Olive var. rubrum Studies on Drought Resistance of Different Regional Amygdalus pedunculata Pall. Mechanism on Leaf Color Transformation of Loropetalum chinense Olive var. rubrum Leaf Comparation on Anatomical Structure and Epidermal Characteristics of Pteroceltis tatarinowii Maxim. in Different Areas Comparative study on structure of leaf epidermis form and ecology adaptation of climbing honeysuckle plants in the northern China Effects of Canopy Position on Leaf Structures in Golden-Leaf Privet(Ligustrum×vicaryi)