Proline Spray Relieves the Adverse Effects of Drought on Wheat Flag Leaf Function

Area of Science:

• Agricultural Science
• Plant Physiology
• Crop Science

Background:

• Drought stress is a major constraint on global crop production.
• Exogenous proline has shown benefits for crops like maize and rice under drought.
• Its effects on wheat, particularly leaf water-holding capacity, are less understood.

Purpose of the Study:

• To investigate the impact of exogenous proline on wheat flag leaves under varying drought conditions.
• To assess proline's role in improving water-holding capacity, antioxidant status, and yield.
• To understand the physiological and anatomical responses of wheat to drought and proline treatment.

Main Methods:

• Wheat plants were subjected to two drought levels (mild: 60% FC, severe: 45% FC) and three proline concentrations (0, 25, 50 mM).
• Measurements included leaf anatomical features, water-holding capacity, antioxidant enzyme activity, proline content, chlorophyll content, and grain yield.
• A control group with no stress and no proline was included.

Main Results:

• Drought stress reduced chlorophyll, deformed leaf veins, and decreased grain yield, while increasing catalase and peroxidase activity and proline content.
• Exogenous proline improved chlorophyll content, water-holding capacity, antioxidant enzyme activity, and leaf tissue structure.
• Proline application (25 and 50 mM) increased wheat yield by 2.88–10.81% (mild drought) and 33.90–52.88% (severe drought).

Conclusions:

• Exogenous proline effectively mitigates drought stress in wheat.
• Proline enhances physiological and anatomical traits, leading to improved grain yield under drought.
• Water-holding capacity and antioxidant defense are key mechanisms through which proline benefits drought-stressed wheat.