Spring low temperature stress reduces wheat yield by accelerating post-anthesis flag leaf senescence via ROS...

Area of Science:

• Agricultural Science
• Plant Physiology
• Climate Change Adaptation

Background:

• Spring low-temperature stress (SLTS) is a growing threat to wheat (Triticum aestivum L.) production due to global warming.
• The long-term physiological consequences of SLTS on wheat post-anthesis development are not well understood.

Purpose of the Study:

• To investigate the physiological legacy effects of SLTS on wheat flag leaf senescence and grain yield.
• To identify key physiological indicators associated with yield reduction under SLTS.

Main Methods:

• Wheat cultivars with differing SLTS resistance (Yannong19 and Xinmai26) were subjected to control (10°C), mild (2°C), and severe (-2°C) low-temperature stress at anther differentiation.
• Evaluated flag leaf senescence, SPAD values, antioxidant metabolism (SOD, POD, CAT activities), reactive oxygen species (H₂O₂, MDA), and grain yield.
• Utilized Random Forest analysis to determine yield-influencing physiological factors.

Main Results:

• SLTS accelerated flag leaf senescence, reduced SPAD values, and decreased grain yield (9-42%), with greater impact on the susceptible cultivar Xinmai26.
• SLTS lowered soluble sugar, soluble protein, and glutathione (GSH) content, along with SOD, POD, and CAT activities.
• Accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) was observed, particularly under severe stress and in the susceptible cultivar.
• Random Forest analysis identified early-stage POD activity and SPAD values, followed by late-stage H₂O₂ and GSH, as primary drivers of yield variation.

Conclusions:

• SLTS disrupts antioxidant homeostasis, leading to accelerated post-anthesis flag leaf senescence and significant wheat yield loss.
• Physiological markers like POD activity, SPAD values, H₂O₂, and GSH content are critical indicators of SLTS impact on wheat yield.
• Findings provide valuable insights for developing strategies to enhance wheat resilience against climate change-induced low-temperature stress.