Efficacy of γ-Aminobutyric Acid (GABA) on Physio-biochemical Attributes of Lettuce (Lactuca sativa L.) Under Cadmium Toxicity

Cadmium can cause harmful effects in plants, even at low concentrations as it’s easily enters the plant from the soil solution through root uptake. Current research was conducted to explore the potential of Gamma amino butyric acid in mitigation of Cadmium (Cd) toxicity in Lactuca sativa. Two varieties of Lactuca sativa (the iceberg and lettuce) were exposed to Cd concentrations i.e., (250 µM) and GABA (100 µM) to examined different morphological, physiological, biochemical parameter, antioxidant activity and mineral content of lettuce. Both varieties of Lettuce (Lactuca sativa L.) when treated with 250 µM Cd, it showed reduction in growth and physio-chemical parameters. Cd accumulates by roots and causes a noticeable reduction in length of root and it transfer to aerial parts and declines the photosynthesis process which ultimately, result in reduction of plant growth and yield. Cadmium exposed L. sativa seedlings showed elevation in malondialdehyde (MDA) and hydrogen peroxide (H2O2) content. On other hand, GABA supplementation increased growth of L. sativa plants beside incrementation in the activity of antioxidant enzymes (POD, CAT and POX), protein accumulation and proline content. GABA treatment induced tolerance in L. sativa plants treated with cadmium stress is credited to enhanced activity of antioxidant enzymes and reduced levels of oxidative stress markers (MDA, H2O2). Exposure to GABA also showed increased level of proline and total soluble proteins in L. sativa plants grown in normal and Cd-contaminated conditions.