| Chinese fir, recommended as the most important timber tree species in southern China, spread through seventeen provinces. At present, the national Chinese fir culture area covers 11,000 thousand hektare and volume up to 3.5 hundred millions. But the long-term forestry production practice indicated that Chinese fir continuous plantation obstacle and low economic efficiency of Chinese fir plantation ecosystem caused by long term pure plantation cultivation, and Auto-toxicity was one of the most improtant factors accounting for continuous planting problems. Professor Lin Sizu, Ma Xiangqing and Cao Guangqiu discoveryed that high concentration of aqueous extracts of Chinese fir fresh and rhizosphere siol showed significantly inhibitory effects on the seed germination of Chinese fir. However the former allelopathy research neglected allelopathy of Chinese fir litter and allelochemicals identification in the decomposition process.Therefore, the allelopathy of Chinese fir litter has been mensurated unceasingly by bioassy in the decomposition process and identification allelochemicals at every stage, in expectation of the provision of theoreic basis for the resolution fo continuous planting problems.The results of the experiments were following:1. In the experiments of Chinese fir litter decomposition, the residual rate of litter always decreased during one year, from three months to nine months the residual rate were remarkable, but from nine months to tweleve months the residual rate were lessened.2. Allelochemicals extracted form residual litter had different effect on the different Chinese fir seeds germination index, sometime Allelochemicals extracted form residual litter had inhibitory effects but sometime had stimulating effects. The results were different with the former researches which aqueous extracts of Chinese fir fresh and Rhizosphere siol had inhibitory effects on Chinese fir seed germination and seedlings growth.3. Allelochemicals extracted from residual litter decrease unceasingly because its had been drained during different decomposition process.4. The polar and litter-polar allelochemicals extracted from residual litter had different effect... |
