| Water and fertilizer are the most important factors that influence the grape yield and quality. At present, there have many research of coupling effects of Water and fertilization in field crops, while the reports were less in fruit trees. Especially, the reports of the influence on the grape yield, quality, physiological metabolism and nitrogen distribution of Coupling effects of Water and fertilization were less. Using 2 years Centennial Seedless as experimental material, taking 15N isotope tracer technique, through studying on the influence of the ratio of water and fertilizer to grape growth, nitrogen metabolism related enzyme activity, nitrogen utilization efficiency and its distribution, the basic rule of nitrogen metabolism and the demand for water and fertilizer in different growth period of grape were preliminary proved. at the same time, in order to provide theoretical basis for precise irrigation fertilization in grape production, the model of Coupling effects of Water and fertilization was set up by four factors, five levels of general rotation design.The main results were as follows:1. The net photosynthetic rate (Pn) of Centennial Seedless was unimodal curve under different water conditions, the peak value in around 11:00. The peak size and irrigation was positively correlated. The fluorescence parameters of Centennial Seedless were positively related to irrigation amount at shoot growth period, fruit set period and veraison period.The diurnal variation of fluorescence parameters were positively related to field capacity.2. In the shoot growth stage and fruit-set period, the treatment of 55%～60% of field capacity, fertilizer ratio of N:P:K=2:5:3 could increasing of leaf area,effectively improved photosynthetic rate; Photosynthetic rate was increased by normal water content and properly increasing potassium fertilizer at late growth stage. With the aggravation of water stress degree, pro and MDA content increased by gradient, SOD activity increased at first and then decreased. Under moderate stress level, pro and MDA content were increased by increasing phosphate and potassium fertilizer, in order to improve the ability that plant resist to water stress.3. The NR activity was effectively improved by the treatment of 55%～60% of field capacity, fertilizer ratio of N:P:K=2:5:3, the absorption and utilization of nitrogen fertilizer were promoted. The GS activity increased at first then decreased and the GPT activity increased by water stress. Under mild stress level, increasing potassium fertilizer could lead to the increase of GPT and GS activity, in order to improve the transformation and availability of nitrogen fertilizer. There was a certain correlation between total protein, total nitrogen and NR,GS,GPT. The impact of fertilizer ratio on the correlation was not big. Under mild stress level, increasing potassium fertilizer could lead to the increase of the Key Enzymes of Nitrogen Metabolism activity, in order to improve the protien content and the transformation and availability of nitrogen fertilizer. So as to improve the resistance of plants to water stress.4. The Ndff value of various tree organs were not changed under different water and fertilization ratio treatments, the Ndff value of leaves and shoots were higher,while stem and root were lower. Show that the 15N requisition ability of new vegetative organs (shoot, leaf) is stronger and that storage organs (stem, root) was weaker.At the same fertilization ratio, the capacity of grape plants to absorb nitrogen was enhanced by Mild-to-moderate water stress, and organ Ndff value was improved.The N distribution rates and use efficiencies of various tree organs in different treatments were the same.The 15N distribution rates of roots were significantly higher than other organs, new shoot and stem were second, and leaf was minimal.From the perspective of the 15N utilization rate of the whole plant, the nitrogen utilization efficiency between 15.3% and 25.7% in different water and fertilization ratio.At the same fertilization ratio, the N requisition ability of grape saplings at the mild stress level was best. Under the same water stress level, increasing phosphorus and potassium fertilizer could lead to the increase of nitrogen fertilizer use efficiencies.5. The regression model showed that:soil relative water content(W) had the biggest impact on the growth of Centennial Seedless. The W treatments had obvious positive effects on shoot grown, leaf area, next was Nitrogen application(N)and phosphorus application(P), There were significantly positive interaction effects of WXN on shoot grown, leaf area of Centennial Seedless. The decision model of shoot grown was established to obtain the optimized combination. We concluded that the recommended combination of W, N, P and K for growers was W=80%FC, N=40 g.plant-1, P2O5=4.06 g.plant-1, K2O=4.67 g.plant-1, At this point the new shoots up to 73.23 cm. From the decision model of leaf area, the recommended combination of W, N, P and K for growers was W=72%FC, N=23.8 g.plant-1, P2O5=10 g.plant-1, K2O=30 g.plant-1, At this point the leaf area up to 259.15 cm2.6. The W, N, K treatments had obvious positive effects on the yield of grape with the size sequence of W>N>K>P. There were significantly positive interaction effects of W×N, W×K on the yield of Centennial Seedless. And water and nitrogen excess would have diminishing returns effect on the yield. From the decision model of grape yield, the recommended combination of W, N, P and K for growers was W=71.28%FC, N=20 g.plant-1, P2O5=8.45 g.plant-1, K2O=30 g.plant-1, At this point the yield up to 5.41kg.plant-1.7. The P, K treatments had obvious positive effects on the soluble solids and W, N had negative effects with the size sequence of K>P>N>W. There were significantly positive interaction effects of WxN, WxP on the soluble solids of grape fruit. From the decision model of the soluble solids, the recommended combination of W, N, P and K for growers was W=60%FC, N=17.38 g.plant-1, P2O5=12.73 g.plant-1, K2O=56 g.plant-1, At this point the soluble solids up to 17.33%.8. The W, P treatments had obvious positive effects on the fruit acidity and K, N had negative effects with the size sequence of K>W>N>P. There was significantly positive interaction effects of WxK on the fruit acidity. So, appropriate to add N, K were beneficial to reduce the fruit acidity of grape berries, and fruit acid content was increased in high soil moisture content.9. The N, P, K,W treatments had obvious positive effects on the Vc content with the size sequence of P>K>N>W. There were significantly positive interaction effects of W×K,N×K on the Vc content of grape fruit. From the decision model of the Vc content, the recommended combination of W, N, P and K for growers was W=64.07%FC, N=21.51 g.plant-1, P2O5=20 g.plant-1, K2O=32.71 g·plant-1, At this point the Vc content up to 6.424mg.100g-1. |
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