Molybdenum-Induced Effects on Nitrogen Metabolism Enzymes and Elemental Profile of Winter Wheat (<i>Triticum aestivum</i> L.) Under Different Nitrogen Sources

oleh: Muhammad Imran, Xuecheng Sun, Saddam Hussain, Usman Ali, Muhammad Shoaib Rana, Fahd Rasul, Muhammad Hamzah Saleem, Mohamed G. Moussa, Parashuram Bhantana, Javaria Afzal, Ali Mohamed Elyamine, Cheng Xiao Hu

Format: Article
Diterbitkan: MDPI AG 2019-06-01

Deskripsi

Different nitrogen (N) sources have been reported to significantly affect the activities and expressions of N metabolism enzymes and mineral elements concentrations in crop plants. However, molybdenum-induced effects in winter wheat cultivars have still not been investigated under different N sources. Here, a hydroponic study was carried out to investigate these effects on two winter wheat cultivars (&#8216;97003&#8217; and &#8216;97014&#8217;) as Mo-efficient and Mo-inefficient, respectively, under different N sources (NO<sub>3</sub><sup>&#8722;</sup>, NH<sub>4</sub>NO<sub>3</sub>, and NH<sub>4</sub><sup>+</sup>). The results revealed that the activities of nitrate reductase (NR) and nitrite reductase (NiR) followed the order of NH<sub>4</sub>NO<sub>3</sub> &gt; NO<sub>3</sub><sup>&#8722;</sup> &gt; NH<sub>4</sub><sup>+</sup> sources, while glutamine synthetase (GS) and glutamate synthase (GOGAT) followed the order of NH<sub>4</sub><sup>+</sup> &gt; NH<sub>4</sub>NO<sub>3</sub> &gt; NO<sub>3</sub><sup>&#8722;</sup> in both the wheat cultivars. However, Mo-induced effects in the activities and expressions of N metabolism enzymes under different N sources followed the order of NH<sub>4</sub>NO<sub>3</sub> &gt; NO<sub>3</sub><sup>&#8722;</sup> &gt; NH<sub>4</sub><sup>+</sup> sources, indicating that Mo has more complementary effects towards nitrate nutrition than the sole ammonium source in winter wheat. Interestingly, under &#8722;Mo-deprived conditions, cultivar &#8216;97003&#8217; recorded more pronounced alterations in Mo-dependent parameters than &#8216;97014&#8217; cultivar. Moreover, Mo application increased the proteins, amino acids, ammonium, and nitrite contents while concomitantly decreasing the nitrate contents in the same order of NH<sub>4</sub>NO<sub>3</sub> &gt; NO<sub>3</sub><sup>&#8722;</sup> &gt; NH<sub>4</sub><sup>+</sup> sources that coincides with the Mo-induced N enzymes activities and expressions. The findings of the present study indicated that Mo plays a key role in regulating the N metabolism enzymes and assimilatory products under all the three N sources; however, the extent of complementation exists in the order of NH<sub>4</sub>NO<sub>3</sub> &gt; NO<sub>3</sub><sup>&#8722;</sup> &gt; NH<sub>4</sub><sup>+</sup> sources in winter wheat. In addition, it was revealed that mineral elements profiles were mainly affected by different N sources, while Mo application generally had no significant effects on the mineral elements contents in the winter wheat leaves under different N sources.