| Camellia oleifera is one of four woody edible oil trees in the world. This study selected six typical camellia forests to research Camellia associative-nitrogen-fixing bacterium. The systematic study included distribution of nitrogen fixation bacteria, selection and identification of nitrogen fixing bacteria with high nitrogen efficiency, morphological and physiological characteristics, environmental factors and inoculation effects. The results indicate that:(1)There are significant differences between the nitrogen fixing bacteria quantity in different camellia forests and different parts of roots.Wild>planted forest, mountainous forest>flat (nursery), adult forest>young forest.The number of different root sites shown:root surface>root>rhizosphere. The results proved most strains can be separated from the surface root of wild camellia forests, and it was the foundation to develop and apply bacterial fertilizer.(2)There were significant differences between the nitrogen efficiency in different camellia forests and different root sites. The most and the highest nitrogen efficiency strain was obtained in the roots of wild forests, the maximum 31.3546mg/g.(3) Environmental factors contain temperature, pH, acid or alkali producing, carbon sources and osmotic pressure, which were studied by comparison of the growth rate of high nitrogen efficiency strains N5-18, N7-3 and B7-7. The results show that:for strain N5-18, the optimal temperature is 20℃, optimal pH is 6, and it made good use of malice acid, sucrose and glucose, and had a strong endurance to osmotic pressure. For strain B7-7, the optimal temperature is 20℃, optimal pH is 6, optimal carbon sources citric acid, and osmotic pressure did not affect growth. Strain N7-3 optimal temperature 30℃, optimal pH 6, optimal carbon sources citric acid, and high osmotic pressure inhibited growth.(4)To combine the results of morphological and physiological identification and the result of BIOLOG system, strain N7-3 was recognized as Strain N5-18 and B7-7 need to be further confirmed.(5)Inoculation effect:inoculated the three kinds of high nitrogen efficiency strains could obviously promote camellia growth, and plant height, stem, developed leaves, biomass, chlorophyll content, total nitrogen content and nitrate reductases activity were significantly improved. Plant height, stem, biomass, chlorophyll content of camellia inoculated with N7-3 were higher than N5-18 and B7-7, nitrate reductases activity increased most was camellia inoculated with B7-7, total nitrogen and crude protein content on leaves increased most was camellia inoculated with N5-18. |
