Suaeda salsa strategically utilizes nitrate and ammonium nitrogen for salt tolerance

Area of Science:

• Plant Physiology
• Environmental Science
• Biochemistry

Background:

• Soil salinization is a significant environmental stressor limiting plant growth.
• Halophytes, like Suaeda salsa, tolerate saline soils, but their nitrogen utilization strategies under these conditions are not well understood.

Purpose of the Study:

• To investigate the effects of different salinity levels and nitrogen forms (nitrate-N, ammonium-N) on Suaeda salsa growth, physiology, and metabolism.
• To elucidate the distinct nitrogen-use strategies employed by Suaeda salsa under salt stress.

Main Methods:

• Controlled experiments exposing Suaeda salsa to varying salinity and nitrogen treatments.
• Analysis of growth parameters, physiological traits, nitrogen metabolism, osmotic adjustment, oxidative stress markers, and metabolomic profiles.

Main Results:

• Nitrate nutrition promoted biomass accumulation, shoot height, and root elongation, with nitrate contributing significantly to osmotic adjustment under high salinity.
• Ammonium nutrition favored tissue hydration, canopy width, and root thickening, with efficient assimilation and detoxification of ammonium.
• Distinct metabolic profiles emerged, with nitrate-N associated with antioxidant capacity and jasmonate signaling, while ammonium-N promoted nitrogen-rich osmotic metabolites.

Conclusions:

• Suaeda salsa exhibits dual nitrogen-use strategies, adapting its physiological and metabolic responses to nitrate and ammonium availability under salt stress.
• This plasticity in nitrogen utilization is crucial for the plant's ecological success in saline environments.