Comparative Study On Leaf Anatomical Structure Of Japanese Larch In Different Areas

Japanese Larch (Larix kaempferi(Lamb.)Carr.) has the characteristics of strong adaptability, fast growth in the early stage, faster forest establishment, fewer pests and diseases and excellent material, becoming China’s northeast, northwest, north and south of subalpine area important wood pulp and construction timber species, and the main afforestation tree species of conversion of cropland to forest and shelter forest projects. This paper is the first in a wide range of (26°20′～48°13′N,101°28′～130°50′E) to Japanese larch in comparative anatomy studies, get the anatomical characters of Japanese larch leaf in different areas, preliminary analysis of the leading ecological factors of affecting its change, provide basic datas to further reveal the ecological countermeasures for different regional distribution Japanese larch in response to climate change.Taking Japanese larch as research object, nine sampling points (380sample) was set in the nationwide by latitude gradient, at the same time five altitudinal gradients sampling points (100sample) was set in Hubei area, the comparative anatomical structure of needles in the long and short shoot was studied respectively in this paper. Anatomic structure index selected as follows:width of the needles, thickness of the needles, cuticle thickness, the upper epidermis thickness, the lower epidermis thickness, mesophyll thickness near the upper epidermis, mesophyll thickness near the lower epidermis, thickness of stele, endodermis thickness, transfusion tissue thickness, vascular bundle thickness, the maximum tracheid diameter, and the ratios of each anatomic index and the blade thickness. Correlation analysis between the anatomic, anatomic and coniferous morphological index and ecological factors associated was studied in the end. The results were as follows:1) Obtained the statistics datas about leaf anatomical structures of Japanese Larch in the main cultivation areas nationwide.2) The Japanese larch needles anatomical structures indexes showed some variations in different cultivation areas,12of the anatomical structure coefficient of variation between0.175-0.336. Width of the needles, thickness of the needles, the upper and the lower epidermis thickness, thickness of stele’s variation is relatively small; the variation of the mesophyll thickness is relatively large.3) The curve’s change of the upper and the lower epidermis thickness and cuticle thickness with latitude increasing is not clear; the other nine anatomical traits with increasing latitude curve showed "W" type, which in Hunan and Linkou area Japanese Larch anatomical characters value is large, Ji’an and Luoyang area index value is small. Compared the Japanese Larch’s long and short shoot on nine areas, we get that, anatomical traits of the long and short shoot changes with latitude are consistent, and anatomical traits index of the long shoot are generally longer than the short shoot’s.4) There is no significant difference with increasing altitude in width of the needles, cuticle thickness, the upper and lower epidermis thickness, transfusion tissue thickness and vascular bundle thickness; with elevation’s increasing the curve showed the inverted" N" type of the thickness of the needles, thickness of stele, endodermis thickness, the maximum tracheid diameter, mesophyll thickness near the upper and the lower epidermis, at an altitude of1470m appeared minimum value and at1790m was the maximum value.5) The correlation analysis of anatomical structure indexes indicated that, the measured indexes are basic correlation, which the correlation between thickness of the needles, thickness of stele, endodermis thickness, transfusion tissue thickness, vascular bundle thickness are relatively large; in addition to the epidermal thickness and stomata length, there were basic significant correlation between anatomical and morphological indexes.6) The correlation analysis between Japanese larch anatomical structure indexes and the ecological factors showed:the correlation between the latitude and longitude, annual average temperature, annual evaporation, annual net radiation, C and N in the soil of the content, etc. and Japanese Larch anatomical structure indexes are significant, that is, the ecological factors have obvious effect on leaf anatomical structure of Japanese Larch.