Abstract:

The Pinus elliottii seedlings were cultured in nursery land in Fenyi County,Jiangxi Province(27°30′N,114°30′E).The seedlings were treated with 4 different methods, named treatment 1(steady-state nutrition+Pt), treatment 2 (nonfertilization + Pt), treatment 3(steady-state nutrition+soil from pine forest),treatment 4 (normal fertilization+soil from pine forest) respectively. For the seedlings of steady-state nutrition, the relative nutrient addition rate was 7.5%, the amount of nutrient added during the cultural period was calculated according to the theory of steady-state mineral nutrition.The amount of N element for per seedling in steady-state nutrition treatment was 39.22 mg ,and was 55.20 mg for per seedling in normal fertilization without PK and any micronutrients treatment.At the end of growing season, the growth and the percentage of ectomycorrhizal infection of seedlings in different treatments were determined. The result showed that the ability to form ectomycorrhiza of Pinus elliottii seedlings was stronger, inoculated with both Pt and natural ectomycorrhiza. However, the highest percentage of ectomycorrhizal infection was in treatment 1(steady-state nutrition + Pt), which amounted to 94.8%. The growth of seedlings indicated that treatment 1 > treatment 3 > treatment 2 > treatment 4. For example,compared with the seedlings in treatment 2(nonfertilization+Pt),the height and the basal diameter of seedlings in treatment 1 were 20.5% and 14.0% higher,the number and the total length of the lateral roots 25.6%,40.9% higher,the fresh weights of leaf, stem, root,and the whole plant 34.6%, 43.7%, 38.8% ,and 37.0% higher,and the dry weights of those parts above mentioned 25.7%, 38.6%, 42.4% ,and 32.7% higher, respectively. There was a larger difference between treatment 1 and treatment 4.The results demonstrated the comprehensive effect of steady-state mineral nutrition and Pt. And the effect of Pt on growth of seedlings would be realized better by scientific fertilization. The growth of seedlings in treatment 4 was worst. Finally, the results of this study were discussed from the aspects of the interaction mechanism between the steady-state mineral nutrition and Pt mycorrhization,as well its practical application.

Key words: Pinus elliottii, Steady-state mineral nutrition, Pt ectomycorrhiza, Seedling culture