| In view of the fertilizer accommodator in the process of cultivating plug seedlings, this experiment used sweet pepper as material to study the index of N,P dosage. Based on the obtainment of seedling index in the prearrangement experiment, the saturated D-optimal design method was adopted to study the effects of different combinations of N,P on the seedling index, imbibing of nutrition elements, configuration and physiology index and flower differentiation as well as mechanism in order to improve the quality of seedlings and provide further theoretical bases and technological guide for popularization of the plug seedlings. The main results were as follows:1.By the analysis of the relationship about quantitative characters and the ratio between characters and seedling quality, a few of typical indexes were found to be suited as seeding index :(stem diameter/shoot height + root weight/crown weight)×total weight. Meanwhile path analysis and gray relational grade analysis technique were used to study the relationship between seedling index and seedling characters. The results indicated that except for stem diameter, all characters appear positively related with each other, while stem height has negative direct effect. Sweet pepper seedling should have such feature as high dry matter content, large root system and proper shoot height .2. On the basis of parameters from field test, the saturated D-optimal design method was adopted to set up the functional model of seedling index and N and P phosphorus norm,the effects of N and P on the seedling index were obvious. The trend of the seedling index lowered after increasing as N and P density faster increasing. Within the range of experimental supreme density, the improvement of the density of P and N could improve N and P impact on seedling index, but if exceeding supreme fertilizer density, the effect drop instead, which obeyed the law that the remuneration decreased progressively too. At the same time, on the low N and P level, the maximum seedling index obviously lowered than middle N and P level, which displayed on the lowest function of restraining the factor rate. P and N efficiency could be fully played on the low N and P level.3. Seedling index effective equation of yards indicated the contribution of unit N and P dosage to seedling quality was N> P. In different seedling age, the best density (mmol/l) of N and P were: two leaves (6.69, 1.07),four leaves( 6.93, 1.14), six leaves (7.11, 1.17), eight leaves (7.23, 1.23).The theoretical N and P dosage(g / plant ) separately were: two leaves (0.0071, 0.0045), four leaves (0.0162, 0.0108), six leaves (0.0244, 0.0173), eight leaves(0.0323, 0.0241). N and P ratio dropped gradually by 1.6:1-1.3:1. The seedling index of six leaves was 0.077, and eight leaves was 0.149.4. By measuring indexes correlated with the quality of the seedling, we could know high N and middle P was propitious to the improvement of shoot height and stem diameter. Middle N and P could promote dry material to accumulate, meanwhile P played a decisive role to dry material assign and low P favored the distribution to root as well as middle P and high P favored the distribution to crown. Middle N and P could promote seedling index with negative effect between them. At the aspect of photosynthesis capability, high N and middle P could increase the content of pigment and net photosynthetic rate. Middle N and P could raise photosynthetic leaf area, which was unanimous to the trend of material accumulation. At the aspect of root absorbing capability, root absorbing area and root volume in middle N and P was the highest of all treatments, which had high root absorbing ability. 5. In course of seedling development, the absorption law of nutrition was obvious. The density of N, P, K and Fe, Cu, Mn, Zn all represented the trend high - low – high- high during the stage of two leaves, four leaves, six leaves and eight leaves. The higher density of N was favorable to the absorption of the N, Cu and Mn, whereas the higher density of P was favora...
|
PDF Full Text Request