Effect of nanomolybdenum on nitrate utilization in rice

This study primarily aimed to enhance rice’s utilization efficiency of nitrate nitrogen, which is a crucial nutrient for plant growth and development. By exploring the effects of molybdenum nanoparticles on key enzyme activities involved in nitrogen metabolism and nitrate nitrogen accumulation in rice, we aimed to provide a scientific basis for the development of new strategies to improve the nitrogen use efficiency of rice. This is particularly important for enhancing rice production and quality, as nitrogen is often a limiting factor in rice growth and yield.

To achieve this objective, a hydroponic experiment was conducted using rice plants. The experiment consisted of nine treatments to comprehensively evaluate the effects of molybdenum nanoparticles and sodium molybdate on rice nitrogen metabolism and growth. The treatments were as follows: 1) no molybdenum application as the control group (CK); 2) sodium molybdate at a concentration of 50 μg Mo/L (T1); 3) sodium molybdate at a concentration of 100 μg Mo/L (T2); 4) sodium molybdate at a concentration of 200 μg Mo/L (T3); 5) sodium molybdate at a concentration of 400 μg Mo/L (T4); 6) molybdenum nanoparticles at a concentration of 50 μg Mo/L (T5); 7) molybdenum nanoparticles at a concentration of 100 μg Mo/L (T6); 8) molybdenum nanoparticles at a concentration of 200 μg Mo/L (T7); and 9) molybdenum nanoparticles at a concentration of 400 μg Mo/L (T8). Rice plants were grown in a hydroponic system and subjected to these different treatments to investigate the effects of molybdenum nanoparticles and sodium molybdate on key enzyme activities involved in nitrogen metabolism, nitrate nitrogen accumulation, nitrogen content in rice stems and leaves, and rice dry matter accumulation. Specifically, we measured the activities of three key enzymes involved in nitrogen metabolism: nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT). We also assessed the nitrogen content in rice stems and leaves, as well as rice dry matter accumulation, to evaluate the overall effects of molybdenum nanoparticles and sodium molybdate on rice growth and development.

The results of the experiment showed that molybdenum nanoparticles had a significantly greater promoting effect on the activities of NR, GS, and GOGAT in rice leaves compared with sodium molybdate at the same concentration. This indicated that molybdenum nanoparticles were more effective in enhancing the nitrogen metabolism of rice than sodium molybdate. Furthermore, both sodium molybdate and molybdenum nanoparticles promoted nitrogen content in rice stems and leaves, as well as rice dry matter accumulation. However, molybdenum nanoparticles showed significantly better promotion effects on dry matter accumulation in both above-ground and underground parts of rice than sodium molybdate. These findings suggest that molybdenum nanoparticles can improve the nitrogen absorption and utilization of rice and promote rice growth and development. By providing a new solution for enhancing rice production and quality, this study has promising application prospects in agricultural production. The use of molybdenum nanoparticles as a fertilizer additive or as a standalone nutrient source can potentially increase rice yields and improve rice quality, leading to increased food security and improved livelihoods for rice farmers.