Ethephon increases photosynthetic-nitrogen use efficiency, proline and antioxidant metabolism to alleviate decrease...

Area of Science:

• Plant Physiology
• Agricultural Science
• Biochemistry

Background:

• Salinity poses a significant global threat to crop productivity, impacting plant growth and development.
• Ethylene, a key plant hormone, plays a crucial role in plant responses to both normal and abiotic stress conditions.
• Understanding ethylene's role is vital for developing strategies to mitigate salinity stress in agriculture.

Purpose of the Study:

• To investigate the role of ethylene in alleviating salinity stress effects on photosynthesis in mustard plants.
• To examine the interplay between nitrogen levels, ethylene, and salinity stress on plant physiology.
• To assess the impact of ethylene modulation on proline accumulation, antioxidant metabolism, and photosynthetic efficiency.

Main Methods:

• Mustard plants were subjected to salinity stress (100 mM NaCl) under varying nitrogen (5 and 10 mM) and ethephon (ethylene-releasing compound) treatments.
• Ethylene evolution, proline content, reduced glutathione (GSH), and antioxidant enzyme activity were measured.
• Photosynthetic nitrogen use efficiency (NUE) and overall photosynthesis were assessed, with ethylene action inhibition using norbornadiene (NBD).

Main Results:

• Salinity stress increased proline and GSH content and antioxidant enzyme activity, while reducing photosynthesis.
• Both 10 mM nitrogen and ethephon treatments were effective in mitigating salinity stress, with combined application yielding the greatest photosynthetic increase.
• Ethylene application, particularly at optimal nitrogen levels, reduced oxidative stress and enhanced photosynthetic-NUE, while ethylene inhibition negated these benefits.

Conclusions:

• Ethylene plays a significant role in regulating proline and antioxidant metabolism under salinity stress, thereby improving photosynthetic functions in mustard plants.
• Modulating ethylene levels, especially in conjunction with optimal nitrogen supply, offers a promising approach for enhancing crop photosynthesis and resilience in saline conditions.
• This study highlights the potential of ethylene-based agricultural strategies to combat salinity-induced yield losses.