Primary Study On Chemical Interaction Between White Birch And Larch

White birch and larch are main species in Daxing'anling forest region; they are also two kinds of fast-growing species of regeneration planting in Northeast of China. Many studies have showed there are distinct interspecific competition and community succession between them. Previous researches on interspecific competition mechanism and community succession have been done more from bioecological characteristics of individual or colony and resource competition (such as light, water, nutrient and so on), but the effect of chemical interaction on competition and succession are seldom mentioned. In this paper, mutual effects on seed germination and seedling growth of white birch and larch by volatiles from white birch and larch leaves and aqueous extracts from their bark and leaves at three levels of 0.2g/ml, 0.1g/ml and 0.01g/ml were studied and discussed from the point of view of chemical interaction. White birch and larch leaf volatiles, and their bark and leaf aqueous extracts had mutual effects in different degree on seed germination and seedling growth of two tree species. Radicel and embryo length of larch were inhibited significantly by 0.2 g/ml of bark aqueous extracts and white birch leaf volatiles. 0.01 g/mk 0.1 g/ml and 0.2 g/ml of white birch bark aqueous extracts all had inhibitory effects on radicel growth (p<0.05); however, only 0.2 g/ml of white birch leaf aqueous extracts had inhibition on radicel growth (p<0.05), and that germination percentage and index of larch seeds were inhibited significantly by 0.1 g/ml of white birch leaf extracts (p<0.05); not only 0.2 g/ml of white birch bark and leaf aqueous extracts but also white birch leaf volatiles had little inhibition on other larch growth indexes except on root growth, and net photosynthetic rate, chlorophyll a and leaf nitrogen concentration of larch seedling were promoted significantly by 0.01 g/ml and 0.1 g/ml of white birch leaf aqueous extracts (p<0.05).0.2 g/ml of larch leaf aqueous extracts had significant inhibition on radicle growth of white birch, but other concentrations of larch bark and leaf aqueous extracts and leaf volatiles had little inhibition effects on seed germination of white birch; inhibitory effects of larch leaf volatiles, and its bark and leaf aqueous extracts on white birch seedling growth were enhanced significantly. Net photosynthetic rate, chlorophyll a and root nitrogen concentration of white birch seedling were inhibited significantly by larch leaf volatiles and 0.2 g/ml of larch bark aqueous extracts (p<0.05), so were activity of root system and root fresh weight of white birch seedling done (p<0.01); and that 0.2 g/ml of larch leaf aqueous extracts significantly inhibited on activity of root system(p<0.05). Net photosynthetic rate and leaf nitrogen concentration of white birch seedling promotedsignificantly by 0.01 g/ml of larch leaf aqueous extracts. Our results proved that there were somechemical interactions between white birch and larch (p<0.05).