Abstract

In recent years, in order to improve nutrient use efficiency, especially nitrogen use efficiency, fertilizer value-added technology has been developed rapidly. However, the mechanism of the effect of synergistic fertilizer on plant nitrogen utilization is not clear. A study was, therefore, conducted to explore the activities and gene expression of key enzymes for nitrogen assimilation and the gene expression of nitrogen transporters in wheat after the application of synergistic fertilizer. Soil column experiment was set up in Qingdao Agricultural University experimental base from October 2018 to June 2019. Maleic acid and itaconic acid were copolymerized with acrylic acid as cross-linking monomer to make a fluid gel, which was sprayed on the fertilizer surface to make nitrogen and phosphorus synergistic fertilizer. A total of 6 treatments was set according to different nitrogen and phosphorus fertilizer ratios:

(1) 100% common nitrogen fertilizer+100% common phosphate fertilizer

(2) 70% nitrogen synergistic fertilizer+100% phosphorus synergistic fertilizer;

(3) 100% nitrogen synergistic fertilizer+70% phosphorus synergistic fertilizer;

(4) 100% nitrogen synergistic fertilizer+100% phosphorus synergistic fertilizer;

(5) 70% nitrogen synergistic fertilizer+70% phosphorus synergistic fertilizer;

(6) 100% commercial nitrogen synergistic fertilizer+100% commercial phosphorus synergistic fertilizer.

The results are as follows:

Ethylene Diamine Tetraacetate Acid Tetrasodium Salt (EDTA-4Na)

(1) the enzyme activities of wheat plants under synergistic fertilizer condition were higher than those under ordinary fertilizer, except under the treatment that nitrogen and phosphorus synergistic fertilizer were both reduced;

(2) the expression level of the genes under the treatment “100% nitrogen synergistic fertilizer+100% phosphorus synergistic fertilizer” was significantly higher than those in other treatments. Combined with the higher performance of nitrogen concentration in various parts of the plant under the condition of applying synergistic fertilizer, this study indicated that the application of synergistic fertilizer can improve the nitrogen metabolism of the plant by increasing the nitrogen level in the rhizosphere soil, inducing the expression of nitrogen transporter genes and key assimilation enzymes genes.