Family Selection With High Nitrogen Efficiency And Investigation On The Effect Of Cultivating Seedling Of Liriodendron Chinense With Mycorrhizal Fungi

Pot experiment with twenty-three open-pollinated Liriodendron chinense families from Liping of Guizhou at two nitrogen levels was conducted to study family differences of growth response to nitrogen supply.The result showed there existed significant differences between families for seedling growth,dry matter accumulation, leaf shape as well as root parameters at high and low nitrogen levels.Marked reduction in seedling height,dry matter accumulation,leaf and root parameters were observed under low nitrogen stress,whereas larger proportion of photosynthesis production were allocated into roots to promote nitrogen absorption.Family variation in seeding growth, leaf and root parameters were increased under low nitrogen stress in comparison with high nitrogen level,which would be benefit to discriminating superior L.chinense families with high nitrogen efficiency.Nitrogen efficiency of different L.chinense families varies between 17.5%～98.8%.Eight families exhibited high N efficiency and showed high productivity at low N level,whereas another twelve families with large N sensitivity and high productivity at high N level were identified.The results also demonstrated that seedling height,dry matter accumulation,leaf shape as well as root parameters were under moderate to strong family genetic control,which would be valuable in the evaluation on families performance for N efficiency.Pot experiment with twenty-three open-pollinated Liriodendron chinense families from Liping of Guizhou at two nitrogen levels was conducted to study family variation and inheritance of nitrogen absorption and utilization efficiency related to nitrogen supply.The growth response of different families to nitrogen supply was found to be marked.Nitrogen efficiency of families tested ranged from 17.5%to 98.8%.The families were classified into two types according to the nitrogen efficiency,namely a stable type with high nitrogen efficiency and a sensitive type with low nitrogen efficiency.There existed significant family variation for nitrogen absorption and utilization efficiency of various organs and total plant at different nitrogen levels, besides leaf nitrogen utilization efficiency at low nitrogen level,which were under moderate or strong genetic control with family heritabilities ranged from 0.5115 to 0.9630.Stable type of families with high nitrogen efficiency exhibited greater biomass accumulation,broader and larger amount of leaves,more developed lateral and fibrous roots under low nitrogen level,because of high nitrogen and phosphorus absorption efficiency.However,the families with high nitrogen efficiency did not show high leaf nitrogen utilization efficiency.It was investigated that Liriodendron chinense belongs to a tree species with classical endotrophic arbuscular mycorrhizal fungi.Three types of dominant mycorrhizal fungi were isolated and identified,including Glomus versiforme,G. caledonium and G.musseae.Liriodendron chinense seedlings from Wuyishan of Fujian was used to examine the effect of mycorrhizal inoculation,and G.musseae was found to exhibit the best stimulative effect.Furthermore,mycorrhizal inoculation with G. musseae was found to markedly promote nitrogen and phosphorus acquisition of seedling and obviously enhance seedling growth,root development and dry matter accumulation.Height,root collar diameter,root length,lateral root number and dry matter accumulation of growing seedling with mycorrhizae increased on the average by 42.41%,38.30%,12.90%,21.13%and 137.78%respectively in comparison with non-mycorrhizal seedlings.Further,mycorrhizal inoculation with G.musseae could significantly improve growing medium quality,therefore the available nitrogen and phosphorus content increased by 158.48%and 48.09%than original medium respectively.