Multicontamination Toxicity Evaluation in the Model Plant Lactuca sativa L

Area of Science:

• Environmental Science
• Plant Physiology
• Toxicology

Background:

• Soils often contain multiple toxic elements (TEs), affecting plant physiology differently than single contaminants.
• Understanding plant responses to combined TE contamination is crucial for environmental risk assessment.

Purpose of the Study:

• To investigate the impact of combined arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn) contamination on lettuce physiology and metabolism.
• To elucidate the mechanisms of toxicity and plant stress responses under multi-TE exposure.

Main Methods:

• Lettuce was exposed to combined As, Cd, Pb, and Zn for 45 days.
• Physiological parameters (biomass, water potential, gas exchange, photosynthetic pigments) and metabolic markers (malondialdehyde, 5-methylcytosine, free amino acids) were analyzed.

Main Results:

• Combined TE contamination significantly inhibited root and leaf biomass.
• TE accumulation induced oxidative stress, morpho-anatomical changes, and decreased water potential.
• Nitrogen (N) and carbon (C) metabolism were disturbed, increasing free amino acids.
• Photosynthetic efficiency and water use efficiency were reduced, indicating stress-induced senescence.

Conclusions:

• Combined TE contamination severely impacts lettuce, damaging the antioxidant system and impairing physiological functions.
• Lettuce exhibits high sensitivity to multi-TE contamination, affecting growth, metabolism, and photosynthetic capacity.