study on Mycorrhization of Pine in Nursery and Field by Cutting Primary Root Apex of Young Seedlings

Based on the principle that the exudation from root can stimulate the germination and growth of the mycorrhizal fungus,the method of growing pine seedlings by cutting their apexes off and inoculating with mycorrhizal fungus is proposed.The results show that the pine seedlings developed in this way can promote the development and growth of root system and ectomycorrhizae formation,increase the biomass of seedling and improve the quality and yield of plantable seedlings. The number and total length of lateral root,percent of seedlings with ectomycorrhizae,percent of feeding roots with ectomycorrhizae,height,root collar diarneter,fresh and dry weight increased,on the average,by 20.0%～960.O%,56.2%～389.5%,0.0%～400.0%, 56.2%～1792.0%,22.3%～179.3%,31.2%～253.3%,33.3%～918.2% and 21.8%～740.0% respectively,and with the survival rate of seedlings and percent of the first grade seedlings increased by 9.0%～22.1%and 49.3%～ 150.0% respectively and percent of the second, third grade, and cull seedlings decreased by 40.6%～77.3%,61.6%～88.5% and 82.5%～100.0% respectively. The survival rate,height,root collar diameter and volume index of the seedling increased,on the average,by 5.5%～46.0%,13.0%～56.4%,25.5%～61.7% and 87.8%～450.0% respectively. The benefit analysis confirms that the use of this method has significant economic and social bene-fits,with a countable value of ￥44 662 5 yuan/hm2 in nursery alone.