| As the important crop influencing food security of developing countries, the demand of potato in china was stable and strong. There was a large room for improvement in yield and quality of potato, which created the conditions for application of plant growth regulators on potato. Whlie few research about the appplication of DA-6in potato had been reported both at home and abroad, especially its impact on potato biomass, photosynthesis, tuber quality, and yield-related activity was unclear. Taking high-yielding potato variety "Holland no.15" as experimental material, the above of aspects were studied detailedly in this paper. With the method of greenhouse cultivation and field plot experiment, tests were conducted to study effects of DA-6, taking uniconazole and a mixture of the two plant growth regulators as control groups. DA-6, at the dosage of10,20,30mg·L-1and uniconazole, at the dosage of20,30,50mg-L-1and the mixture of the two plant growth regulators at different dosages were sprayed to leaf during the early stage of anthesis so as to explore their effect on potato growth and yeild as well as the mechanism, aiming to provide theory evidence for the application of DA-6to potato. The main results were as follows:1. Different concentrations of DA-6had dramatically enhanced leaf area index and net photosynthetic rate. At the same time, they had delayed the activity depressing of RuBPCase and improved the function of photosynthetic physiology, which created conditons to obtain high yield finally. Between ten and twelve in the morning,13days after spraying, photosynthetic rate of DA-6at the dosage of10,20,30mg-L-1were increased by13.85%,15.33%and14.67%than control group. By contrast, the different concentrations of uniconazole generated less influence on potato photosynthetic function.2. Dfferent concentrations of DA-6also had increased the SOD activity of leaves and reduced the content of MDA in potato, which enabled potato to have strong ability of eliminatinging active oxygen radicals and enhance anti-reversibility of plants as well as slow down aging. All the features mentioned above are benefit for the yield of crop. On the other hand, the different concentrations of uniconazole were less effective in improving the SOD activity and reducing MDA content. However they were much more effective in the control of potato plant height, preventing excessive growth, and mading stem wider and leaf blade thicker, and enhancing anti-reversibility of plants. Those were in favor of the transfering of photosynthates to underground tubers.3. Dfferent concentrations of DA-6and uniconazole could raise the content of starch in potato tubers significantly and increase vitamin C content in some degree. In terms of enhancing the protein content and reducing sugarcontent, DA-6worked better than uniconazole. The effect was proportional to concentration positively in the definite dose range. Both of them could improve the quality of potato tubers, and then meet the demand of food processing industry and market, providing support to create more economic benefits for potato planting.4. The use of different concentrations of DA-6and uniconazole had improved the yield of potato tested in different degree and the effect of increasing yield went up with an increase in the amount of concentration. The yield of DA-6at the dosage of10,20,30mg-L-1were increased by3.17%,5.56%and5.87%than control group. Meanwhile ratio of big tuber in the potato harvest went forward too. The effects were much more significant when the two growth regulators were mixed together.5. It could reach better adjusting effect for potato when the ratio of DA-6and uniconazole was1:1～1:2. Under this ratio, the two growth regulators showed additive effect on the regulation of plant growth, improvement of tuber quality and increase in production. |
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