| Waterlogging is major natural disasters all over the world, about12%of farming soil contain excessive water in the world. In China, Huanghuai Plain and the middle and lower reaches of the Yangtze River is the most serious flooding area. Excessive water in soil will cause hypoxia or even worse effects in plant root rather than water itself. In low humidity, swamps, river, lake, flood happens after rainstorm, which will ruin agriculture and forestry.The study of submergence tolerance gene and agricultural cultivation measures, can not solve the problem of hypoxia caused by flooding or other unexpected natural conditions, so a fundamental solution to hypoxia of plant root will be the focus of the study.To release stress of plant hypoxia, I tried to optimize the development of new oxygen fertilizer membrane materials,further develop a new oxygen fertilizer, and do preliminary hydroponic research experiments of oxygen fertilizer, then to study the changes on physiological and biochemical index when fertilize the new oxygen fertilizer.Suspension of chitosan nanoparticles was prepared by the Ion gel method. Refer to the index of the average particle size of the particles, the dispersion of production; I did a single factor and orthogonal experiments to study the main factors to affect the preparation of chitosan nanoparticles. We can draw a conclusion that:the best combination is chitosan (CTS) concentration in1.0g/L, and sodium tripolyphosphate (TPP) in1.5%, in condition of stirring speed950r/min. The best average particle size range of CTS nanoparticles is300nm, which has a good reproducibility. The scanning electron microscopy analysis shows that the chitosan nanoparticles is in a sheet structure, its film-forming is in line with the application of the present study, finally the best conditions for preparation of chitosan suspension will apply in the preparation of the outer envelope of slow release fertilizer.The preparation method:in the mixer,add calcium oxide powder as a nuclear material, join the binder(sodium alginate) solution continuelly,and add nano-chitosan suspension as the outer coating materials, the entrie mixing granulation process controll the temperature at70-80℃, and then be dried.Lastly, paraffin wrapped in dried particles,that is it.The hydroponic preliminary verification experiment shows that the pH values in new oxygen fertilizer (NOF1&NOF2) in hydroponics always sustain a neutral range, NOF2are more lower and stable than NOF1,which will not change the soil micro-environment, then cause a even worse condition. In addition, new oxygen fertilizer (NOF1&NOF2) can release oxygen for around30days, which will be able to play a slow release of oxygen, and provide oxygen to the flooded plants. The experiment can draw a preliminary conclusion that new oxygen fertilizer (NOF1&NOF2) is environment-friendly,sustained&controlled release oxygen. The effect of the controlled release NOF2is better than NOF1and did not appear to release suddenly and largely and rapid decline.In artificial simulation of waterlogging stress, the "double sets of pots of soil cultivation experiment shows under the waterlogging stress, the physiological and biochemical of the leaves, Prunus zippenliana var.Puberi folia(Koehne)Yu et Li have varying degrees of change. However, imposed by the new oxygen fertilizer (NOF1&NOF2), those leaves maintained a partial normal level of chloroplast pigments, soluble sugar, proline, Ca2+, and the antioxidant enzyme system maintained normal level of SOD, the POD activity, as well as the maintenance of plants ROS, accumulation and clearance in dynamic equilibrium. To sum up, the new oxygen fertilizer can provide oxygen to plants, relieve the energy needs of the plants, reducing the process of anaerobic respiration metabolism, to induce the hypoxic plants to aerobic respiration, finally to promote the recovery of hypoxic plants growth. Comprehensive comparison of various indicators,especially in environment friendly&gentle controlled release aspect, NOF2are better than NOF1, and more conducive to resolving the problem of lack of oxygen by plant roots. |
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