Effects of polyethylene microplastics, arsenic, and their combined contamination on maize seed germination

Area of Science:

• Environmental Science
• Plant Science
• Toxicology

Background:

• Microplastic (mPE) and arsenic (As) contamination are growing concerns in agricultural ecosystems.
• Understanding their combined effects on crop plants like maize (Zea mays L.) is crucial for food security and environmental health.

Purpose of the Study:

• To investigate the individual and combined impacts of mPE and As on maize seed germination and antioxidant enzyme activities.
• To determine the concentration-dependent effects and interactions between mPE and As.

Main Methods:

• Maize seeds were exposed to varying concentrations of mPE (0.1-2%) and As (1-10 mg/L).
• Germination indices (rate, vigor, energy, length, weight) and antioxidant enzyme activities (POD, SOD, CAT) were assessed.
• Synergistic and antagonistic interactions between mPE and As were analyzed.

Main Results:

• Low mPE or As concentrations slightly promoted germination and growth, while high concentrations significantly inhibited them.
• Combined exposure showed synergistic effects on vigor and shoot length at low mPE concentrations and antagonistic effects at high mPE concentrations.
• Low mPE/As enhanced antioxidant enzyme activities, whereas high As reduced POD and SOD activities.

Conclusions:

• The interaction between mPE and As on maize germination is concentration-dependent.
• High arsenic levels may impair the plant's antioxidant defense system.
• Results inform risk assessment for combined microplastic and arsenic contamination in agriculture.