Delayed NH₃ and N₂ O uptake by maize leaves

Area of Science:

• Plant Physiology
• Environmental Science
• Biogeochemistry

Background:

• Ammonia (NH3) and nitrous oxide (N2O) are key atmospheric nitrogen compounds with significant environmental implications.
• Understanding plant gas exchange is crucial for nutrient cycling and atmospheric chemistry.
• Maize (Zea mays) is a globally important crop, making its nitrogen uptake mechanisms of significant interest.

Purpose of the Study:

• To investigate the absorption mechanisms of ammonia (NH3) and nitrous oxide (N2O) by maize leaves.
• To elucidate the short-term uptake kinetics and metabolic fate of NH3 in maize.

Main Methods:

• Utilized stable isotope labeling with Nitrogen-15 (15N) to trace NH3 and N2O absorption.
• Employed a short-term exposure method (90 minutes) with a high NH3 concentration (40 μl l⁻¹).

Main Results:

• Provided evidence for NH3 and N2O absorption in maize leaves.
• Identified two potential NH3 entry pathways: immediate metabolism and storage followed by metabolism.
• Observed that a storage compartment can delay NH3 absorption post-exposure.

Conclusions:

• Maize leaves exhibit complex NH3 uptake mechanisms involving rapid assimilation and storage.
• Similar uptake and metabolic strategies may apply to N2O absorption by maize.
• These findings contribute to understanding plant-atmosphere nitrogen exchange.