Study On Relationship Rings And Tracheid Traits Of Japanese Larch To Ecological Factors

A study on Japanese larch was conducted in this paper, based on the review of the recent domestic and foreign literature. In this study, multivariate statistical methods were employed to analyze the effects of ecological factors,with different biological significance as the environmental variables,on the variation of ring width and tracheid traits. The study aimed to find out the dominant ecological factors affecting the changes, thus reveal the ecological response of Japanese larch to climate change. The major findings were as the followings:1.The curve of the mean of tracheid traits in the area of Gansu and Luoyang had small fluctuation, affected by the declined latitude. As displayed by the corresponding curves, the means of tracheid diameter, tracheid inside diameter and tracheid lumen diameter ratio declined, while the means of tracheid wall thickness, tracheid wall lumen ratio, tracheid length, and tracheid length width ratio increased.2. The regression analysis of ring growth and ecological factors revealed that:In the area of Ji’an, the higher annual effective temperature and the smaller evaporation in April of this year facilitated the radial growth of ring. In the area of Qingdao, the rising coldest monthly temperature of last year facilitated the radial growth of ring.3.The correlation analysis of tracheid traits and ecological factors showed that the influence of ecological factors on the tracheid traits was distinct. There was a significantly negative correlation between the tracheid diameter, tracheid inside diameter, tracheid lumen diameter ratio and tracheid wall thickness, tracheid wall lumen ratio, tracheid length, tracheid length width ratio. Latitude, coldness index, annual range of temperature and tracheid radial diameter growth were positively correlated, while other ecological factors and tracheid radial diameter growth were negatively correlated. The coldness index and tracheid wall thickness growth were negatively correlated. There was no significant correlation between latitude, the coldest monthly temperature of last year, annual mean temperature, annual range of temperature, temperateness, annual precipitation of last year, precipitation of the period from November of last year to January of this year, precipitation of April and May of this year, evaporation of the period from November of last year to January of this year, annual evaporation and tracheid wall thickness growth, while there was a positive correlation between other ecological factors and tracheid wall thickness growth. Latitude, coldness index, annual range of temperature and tracheid length growth were negatively correlated. There was no significant correlation between slope, warmth index, precipitation of the period from November of last year to January of this year, precipitation of April and May of this year and tracheid length growth. Other ecological factors and tracheid length growth were positively correlated.4.The regression analysis of tracheid traits and ecological factors showed that:The tracheid radial diameter growth was better when the annual mean temperature, annual evaporation, mean temperature of April and May of this year and annual effective temperature were smaller. The higher annual effective temperature was favorable for the growth of tracheid wall thickness. The higher net radiation energy from November of last year to January of this year, the higher monthly mean minimum temperature, the lower latitude and the higher coldest monthly temperature of last year were more conducive to the tracheid length growth.5.The regression analysis of tracheid traits and ecological factors in the area of Hubei showed that:The smaller evaporation of the period from November of last year to January of this year was more conducive to the tracheid radial diameter growth. The larger temperateness and the larger evaporation of the period from November of last year to January of this year were more conducive to the tracheid wall thickness growth. Tracheid diameter, tracheid length and tracheid length-width ratio on the response of the ecological factors did not reach the significant level.