Enhancing Wheat Tolerance to Cadmium Stress through Moringa Leaf Extract Foliar Application

Area of Science:

• Environmental Science
• Plant Science
• Agricultural Science

Background:

• Cadmium (Cd) is a hazardous heavy metal found in soil and plants, posing significant human health risks due to its accumulation in staple crops like wheat.
• Wheat absorbs and translocates Cd from roots to shoots and grains, increasing dietary exposure and health concerns for approximately 60% of the global population.
• Moringa leaf extract (MLE) shows potential in alleviating heavy metal stress in plants.

Purpose of the Study:

• To evaluate the Cd stress tolerance of two wheat varieties (Akbar-19 and Dilkash-2020) under exogenous application of MLE.
• To investigate the efficacy of MLE foliar spray in mitigating the negative impacts of Cd toxicity on wheat growth, physiology, and biochemical parameters.

Main Methods:

• Wheat plants were subjected to different treatments: control (0% MLE, 0 µM Cd), MLE only (3% MLE, 0 µM Cd), Cd stress only (0% MLE, 400 µM Cd), and combined treatment (3% MLE, 400 µM Cd).
• Morphological parameters (shoot/root weight, length, leaf area/number), photosynthetic attributes, oxidative stress markers (H2O2, MDA), antioxidant enzyme activities (CAT, SOD, POD, AsA), organic osmolytes (phenolics, proteins, sugars), and ionic content (Na+, Ca2+, K+, Cd) were measured.

Main Results:

• Cadmium stress significantly reduced morphological attributes by up to 30.5% and photosynthetic efficiency by 69.8%.
• Cd toxicity induced oxidative stress, increasing H2O2 and MDA by 75%, while MLE application boosted antioxidant enzyme activities (CAT, SOD, POD, AsA) by up to 81.5% and improved organic osmolytes by 77%.
• MLE treatment enhanced the uptake of essential mineral ions (Ca2+, K+) by 35% and reduced Na+ and Cd accumulation in roots by 22% and 44%, respectively, under Cd stress.

Conclusions:

• Cadmium toxicity severely impairs wheat growth, photosynthesis, and biochemical status.
• Foliar application of 3% MLE is effective in alleviating Cd toxicity by enhancing growth and physiological parameters.
• MLE mitigates Cd-induced oxidative stress and reduces the uptake of toxic elements like sodium and cadmium in wheat.