1. Effects of foliar spraying of nano-potassium molybdate on photosynthetic characteristics and nitrogen metabolism of rapeseed seedlings.
- Author
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XIAO Xiao-lu, DUAN Bo, JIANG Zhan, YANG Xue, and MA Ni
- Subjects
RAPESEED ,NITRITE reductase ,MOLYBDATES ,PHOTOSYNTHETIC pigments ,NITRATE reductase ,ENZYME metabolism - Abstract
To improve yield, effects of nano-potassium molybdate was investigated on photosynthetic characteristics and nitrogen metabolism of rapeseed. Different concentrations (0
-1 100 mg·L-1 ) of nano-potassium molybdate were sprayed on rapeseed seedling under hydroponic conditions. Changes of gas exchange parameters, key enzyme activities of carbon and N assimilation and N contents of leaves were measured. Results showed that spray of nano-potassium molybdate increased photosynthetic pigment and net photosynthetic rate of leaves, while decreased gas exchange parameters (including transpiration rate, stomatal conductance and intercellular CO2 concentration). The activities of Rubisco and PEPC enzyme increased gradually with the nano-molybdate concentration, in which Rubisco enzyme activity was significantly enhanced at 550 mg·L-1 and 1100 mg·L-1 compared to control, and PEPC enzyme activities increased significantly at 1100 mg·L-1 . The activities of nitrate reductase, nitrite reductase and glutamate synthase were significantly increased at 550 mg·L-1 compared with control. No significant change was observed at higher concentrations. Nitrate-N contents were significantly reduced after the spray of nano-potassium molybdate, while ammonia-N contents and N concentrations were not significantly changed compared with control. In addition, protein content increased significantly at 550 mg·L-1 . In summary, 550 mg·L-1 nano-potassium molybdate spray enhanced carbon assimilation efficiency of rapeseed, while N assimilation efficiency was also significantly increased. The promotion of photosynthesis in rapeseed by nano-potassium molybdate was mainly related to nonstomatal factors: increased photosynthetic pigment contents and enhanced activities of key enzymes for photosynthesis. It could promote the conversion of inorganic to organic N in rape leaves by enhancing the activities of key enzymes of N metabolism. [ABSTRACT FROM AUTHOR]- Published
- 2023
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