The Screening Of High-nitrogen Utilization Efficiency Chinese-fir Family And Effects On Different Family Seedling With Nitregen Forms

Nitrogen is one of the necessary nutrient elements for tree growth, and the effectiveness of it affects not only tree growth but also the productivity of ecosystems.In this present dissertation, we systematic invest the nutrient utilization and adaptive mechanism of Chinese fir seedlings under the condition of different nitrogen nutrition levels and forms. In this present dissertation,we try to explore the potential physiological and ecological functions of plant and provide a theoretical basis for low nitrogen nutrition fir breeding, screening and further explore relevant Chinese fir cloning of low nitrogen tolerance through these studies. It is very important to cultivate the species in order to improve their productivity and to resolve the current crisis of short supply of wood in China. And the results suggested:(1)Nitrogen deficiency fir seedling height growth rate for the inhibition of the overall nitrogen concentration was reduced with the inhibitory effect of the more obvious trends, and the impact of the different families have differences.49families in the normal nitrogen and nitrogen stress height while maintaining the highest growth rate, while moderate and severe stress showed no growth advantage, this family is most sensitive to nitrogen stress and less patience.46families in low nitrogen levels relative to other various lines height highest growth rate in the moderate and severe stress obvious growth performance advantages, the height indicator46pedigrees optimal results with low nitrogen tolerance.(2) Nitrogen supply affects the nitrogen nutrient content and the distribution of biomass of Chinese fir seedlings both under and on the ground,However, the effect of difference families of the Chinese fir didn’t reach the significant level. The leaf system affected by Nitrogen’s supply is larger than the root and stem system and the change rule present a downward trend except little Individual family. And orther side,the root-shoot ratio are reduced with the decrease of Nitrogen level on the biomass allocation.(3) The chlorophyll content of Chinese fir seedlings was a positive correlation with nitrogen nutrition level. The chlorophyll a and total chlorophyll content are changing with time is greater than chlorophyll b content. N supply level obviously influence on chlorophyll fluorescence characteristics of the Chinese fir seedling. Chlorophyll fluorescence Fv, Fm are affected obviously by the difference levels of Nitrogen,the main performance is the Fv and Fm are significantly reduced. The opposite is the F0, Fv/FO and Fv/Fm is not such obvious change with the different deal of Nitrogen levels,and at the beginning of the test, the effect is so weak,until the45th days. The difference is gradually revealed contracted with the Chinese fir seedings without N deal with.(4) NR activity of chinese fir seedlings is affected by nitrogen supply level, but more greatly affected by seasonal factors. NR activity in the same processing cycle reduced with the decrease of nitrogen supply level, in the time, the value is up to maximum in the summer and decreased obviously in the autumn.(5) Using principal component analysis, correlation analysis based on different nitrogen concentrations Chinese fir seedlings physiological indices of effect index as a variable principal component analysis of six different pedigrees low nitrogen tolerance Chinese fir seedlings under different sort nitrogen supply levels. In severe nitrogen deficiency levels,46> No.45>57>32>49>10; at moderate levels of nitrogen deficiency,32>57>46>45,>49>10. Under mild nitrogen deficiency levels,32>49>57>45,>46>10.(6) Chinese fir seedlings at the same nitrogen content of different nitrogen forms, height, chlorophyll, leaf nitrogen content, nitrate reductase activity in NO3-N nutrient treatment showed a clear advantage, followed by mixing nitrogen treatment, NH4+-N treatment promoted the weakest. Mixed nitrogen nutrient on chlorophyll fluorescence Fm role in promoting the strongest, followed by, NO3-N treatment, NHU+-N treatment weakest. Fv largest increase in NH4+-N treatment under the influence of Fv NO3-N and mixed nitrogen source is not obvious rule. Shoot ratio and Fv/Fm under different nitrogen treatment, no significant differences. Fir seedlings on nitrogen form tendentious preference, NO3-N is more conducive Uptake Chinese fir seedlings, when Dorsch nitrate fertilizer, ammonium fewer facilities.