| Due to massive emissions of sewage, and in recent years a large number of agricultural fertilizers unreasonable application, a lot of nutrients, particularly nitrogen are transferred to soil and water,it caused eutrophication. Wetland is a new process of governance of the 1990s the rise of the river, lakes and other water pollution, by plant absorption, adsorption and microbial transformation matrix degradation process and a series of pollutants in sewage. As one of the large number of essential plant nutrients, nitrates are higher plants mainly inorganic nitrogen, high in plant tissue accumulation. High concentrations of nitrate to the plant itself will cause some damage, but the specific mechanism of stress rarely reported. In this experiment, We ues Canna(Cana generalis Bailey) as materials, the hydroponic method of different processing cycles, the administration 0,10,50,100,150 mmolL-1 absorption of nitrate nitrate Canna, seedling growth, photosynthetic parameters and the antioxidant enzyme activity and other physiological and biochemical indexes. At the same time, we screened at Canna nitrate nitrate absorption of several single factor has a significant impact on the response surface optimization method, a combination of these factors alone, screened at the best combination of Canna nitrate uptake. Through tests, we get the following results:1. Canna seedlings in response to different concentrations of nitrate in their physical performance difference between the larger, canna seedling absorption of nitrate in 0-100mmol rising, nitrate accumulation in leaves also increases with increasing external nitrate concentrations. When you stop for nitrogen, nitrate content in leaves decreased, and the most obvious decrease 50mmol,150mmol nitrate accumulation process has been at a high level. Compared to the control (N-absent stress) and 150mmol (high concentration of nitrogen stress), the concentration of nitrate under 50mmol of canna grow most good, most exuberant metabolism of nitrate. After five weeks for cultivation of nitrogen, nitrogen deficiency then cultured five weeks.100 and 150mmol nitrate Canna intimidated more serious process of growth eased. With the increasing in processing time, its growth and activity of enzymes related to metabolism of nitrate also increase, which indicated that nitrate stored in the leaves can be used again in the case of nitrogen deficiency in the outside world for normal growth of plants.2.Whether it is a low concentration of nitrate or nitrate absorption enhancer of absorption and plasma membrane H+-ATPase 14-3-3 and relevant. Respectively O,50,150mmol/L nitrates irrigated Canna 1d and 4d, and then transferred to a nitrogen deficiency in the nutrient solution processing continues 1d and 4d, analyzing nitrate uptake and plasma membrane H+-ATPase, the hydrogen pump activity and quality membrane H+-ATPase and 14-3-3 protein interaction level, the results show, with no nitrates (CK) comparison, two concentrations of nitrate-treated plasma membrane H+-ATPase and the phosphorylation level of the plasma membrane H+-ATPase the amount of 14-3-3 protein interactions significantly increased. At the same time, the low concentration of nitrate treatment, plasma membrane H+-ATPase and the 14-3-3 protein were increased the level of gene expression, it shows that low concentration (50 mmol) nitrate treatment can improve the root plasma membrane HT-ATPase phosphorylation level and with the plasma membrane H+-ATPase and the 14-3-3 protein interactions, plasma membrane H+-ATPase and the 14-3-3 protein gene transcription level increases the expression of membrane proteins that activate the canna the apex, enhanced root H pump activity,so as to promote the absorption of Canna nitrate.Different concentrations bring adout different distribution for metabolite every nitrates Canna organs. By canna root and stem of the 13C-NMR analysis revealed that Canna carbon metabolism major product-soluble carbohydrate synthesis mainly in the stem and leavesat 0 and 50mmol nitrates, roots have less content. The Canna after 150mmol nitrates at the root of synthetic carbohydrate are to more than stems and leaves; at the same time, a high concentration of nitrate nitrogen stress canna roots produce more nitrogen metabolism of amino acids such as aspartic acid and glutamic acid, but the content of these materials will vary with time of treatment is reduced。3. Response surface methodology analysis found that nitrate concentration and treatment time on nitrate absorption Canna had significant influence. At the same time, the processing time and the amount of EM bacteria and nitrate concentration and treatment time have significant interaction. By optimizing our software, established Canna uptake of nitrate optimum conditions were:nitrate concentration 33.7mmol/L, EM bacteria added 6.18mL,3.29 days at a time, nitrate uptake predictive value 93.3968mg/L/day. Canna root NO3-N is the actual absorption of 94.13 mg/L/ day, and is very close to the predicted value. The test results can improve the wetland plants to provide new ideas and methods on nitrogen uptake. |
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