Supported by the National Key Technology R&D Program of China (No. 2011BAD11B05), the Science & Technology Planning Project of Guangdong Province (No. 2015B020215012) and the Science & Technology Planning Project of Guangzhou City (No. 201508030039)
碳是植物必需的首要营养元素，但在植物营养、平衡施肥等理论和技术层面上长期被忽略，碳营养已成为影响作物高产优质的短板。本研究分别在三个氮水平下，研究了外源喷施两种不含氮的有机碳对蕹菜鲜重、干重、分枝数、碳氮代谢及营养品质指标的影响。结果表明，在不同氮水平下喷施有机碳有促进蕹菜生长的作用，效果因不同的氮水平及有机碳源而异。中氮（100 mg kg-1）水平下，以丙三醇的效果最好，其鲜重、干重、全碳含量及全氮含量与CK相比均有显著提高，增幅分别为12.88%、15.48%、7.05%和8.33%，且铁（Fe）含量与CK相比也显著提高，增幅高达16.2%，亚硝酸盐及钾（K）含量显著降低。高氮（120 mg kg-1）水平下，以α-酮戊二酸的效果最好，其鲜重、干重、全碳及全氮与CK相比均差异显著，增幅分别为17.97%、20.91%、7.97%和9.56%，蕹菜中的锌（Zn）与CK相比也显著提高，增幅高达16.18%，亚硝酸盐及K含量显著降低。在试验的三种氮水平下，有机碳处理可使蕹菜叶片中水溶性碳占全碳的百分比（WC/TC）及水溶性氮占全氮的百分比（WN/TN）下降，表明外源有机碳可促进蕹菜碳氮的合成代谢，从而促进生长，改善品质。研究结果提供了一条通过施肥补碳调控碳氮平衡实现蔬菜高产优质的新途径。
Carbon is the number one of the 17 essential nutrient elements, but over the past 100 years, little has been reported about carbon fertilizer products produced by the chemical fertilizer industry. It is usually believed that the carbon nutrient plants absorb comes from the air in the form of carbon dioxide, which as a matter of fact meets only 1/5 of the demand of a plant. Therefore, plants are always in the state of “hunger for carbon”. Organic carbon used as fertilizer can eliminate plants’ hunger for carbon that is caused by depending mainly on carbon dioxide in the air as carbon source. Water Spinach was cultivated in solutions different in nitrogen level in a batch system in this research. Effects of two kinds of nitrogen-free organic C (α-ketoglutarate and Glycerol) on fresh weight, dry weight, number of branches, carbon and nitrogen metabolism (expressed as water soluble N/ total N or water soluble C/ total C ) and nutrition quality indices (Zinc, Iron and Nitrites) of the water spinaches were analyzed. Results show that foliar spray of organic carbon promoted growth of the Water Spinach regardless of nitrogen level in the solution. However, the effect varied with nitrogen level and source of organic carbon. The effect of foliar spray of Glycerol was the best on the water spinaches growing in the solution moderate in nitrogen level (100 mg kg-1), raising the fresh weight, dry weight, total carbon and total nitrogen of the plants 12.88%, 15.48%, 7.05% and 8.33% higher than that in CK, respectively. Besides it also increased Fe content in the plant by 16.20% while decreasing Nitrite significantly, which indicates that nutrition quality of the plants was greatly improved. K content in the plant was found decreased significantly, which implies that the spray may help reduce luxury absorption of K in the soil. The effects of foliar spray of α-ketoglutarate was the best on the water spinach growing in the solution high in nitrogen level (120 mg kg-1), increasing the fresh weight, dry weight, total carbon and total nitrogen by 17.97%, 20.91%,7.97% and 9.56% and the content of Zn, a nutritional quality indicator, by 16.18%, too, while decreasing Nitrite content significantly, which indicates that the plants were greatly improved in nutrition quality. K content was also found decreased in the plants, implying that the spray may help reduce luxury K absorption from the soil. In the experiment, the spray of organic carbon fertilizer, either Glycerol or α-ketoglutarate, lowered WC/TC and WM/TN in leaves of the water spinach, regardless of N content in the solution, which indicates that extraneous organic carbon can promote synthesis and metabolism of carbon and nitrogen in the plants, thus stimulating growth and improving nutritional quality of the Water Spinach. The findings in this study demonstrate that it is organic C, rather than organic N, that raises crop yield and improves quality of the crop. Meanwhile crop yield is found to be related by a certain degree to SN/TN and SC/TC in the plant, which show that these parameters can be used as important physiological indicators for high-yield-oriented fertilization. Currently high yield of a crop is restricted by the crop’s dependence mainly on the air for carbon supply, or hunger for carbon. It is, therefore, quite obvious that how to solve the problem of “Hunger for carbon” is the key to high yield agriculture. This study has found that organic carbon fertilizers may help satisfy crops’ hunger for carbon. So it is feasible to use organic C to balance fertilization, rather than just using NPK in balanced fertilization. Further research in this aspect is of important significance to balanced fertilization and has some profound academic meaning for further developing theories of modern plant nutrition.
桂 丕,陈 娴,廖宗文,汪立梅,钟秀娟,毛小云.不同氮水平下有机碳对蕹菜碳氮代谢及生长的影响[J].土壤学报,2016,53(3):746-756. DOI:10.11766/trxb201509060378 GUI Pi, CHEN Xian, LIAO Zongwen, WANG Limei, ZHONG Xiujuan, MAO Xiaoyun. Effect of Organic Carbon on Carbon and Nitrogen Metabolism and the Growth of Water Spanich as Affected by Soil Nitrogen Levels[J]. Acta Pedologica Sinica,2016,53(3):746-756.复制