Abstract: Microstructure and ultrastructure of Panax ginseng leaves grown under four light transmission rate (LTR) shades were investigated. The results showed that, specific leaf weight, leaf thickness, number of mesophyll cells per unit leaf area and surface area of mesophyll cell and cell layers were increased as the increase of light intensity in the leaves grown under 5%. 20% and 35% LTR shades. The leaves grown under 50% LTR shade were decreased. Under 5% and 20% LTR shade, mesophyll cells were loose arranged in horizontal. Under 35 % LTR shade mesophyll cells were compact and palisade-like cells appeared adjacent to up epidermis in the leaves. Under 50% LTR shade, bigger round-like mesophyll cells formed and arranged irregularly. The leaves under 5 0% LTR shade, had larger chloroplasts with the most development of grana lamella. As the increase of light intensity, granum and strom lamella were relatively decreased and increased respectively, and more and bigger plastoglobulis and starch grains also formed in chloroplasts. By the analyses of microstructure and ultrastructure of the cell in the ginseng leaves grown under four LTR shades. The authors that 35 % LTR shade was optimal light condition for ginseng growth.

Key words: Panax ginseng, Light intensity, Microstructure and Ultrastructure, Surface area of mesophyll cell