Characteristics of ammonium and nitrate fluxes along the roots of Picea asperata

Abstract

Nitrogen (N), ammonium (NH₄⁺) and nitrate (NO₃⁻), is one of the key determinants for plant growth. The interaction of both ions displays a significant effect on their uptake in some species. In the current study, net fluxes of NH₄⁺ and NO₃⁻ along the roots of Picea asperata were determined using a Non-invasive Micro-test Technology (NMT). Besides, we examined the interaction of NH₄⁺ and NO₃⁻ on the fluxes of both ions, and the plasma membrane (PM) H⁺-ATPases and nitrate reductase (NR) were taken into account as well. The results demonstrated that the maximal net NH₄⁺ and NO₃⁻ influxes were detected at 13–15 mm and 8–10.5 mm from the root apex, respectively. Net NH₄⁺ influx was significantly stimulated with the presence of NO₃⁻, whereas NH₄⁺ exhibited a markedly negative effect on NO₃⁻ uptake in the roots of P. asperata. Also, our results indicated that PM H⁺-ATPases and NR play a key role in the control of N uptake.

Keywords:

• ions flux
• N uptake
• nitrate reductase
• plasma membrane H⁺-ATPases

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (No. 31370495 and 31070533).