Ascorbic acid is essential for inducing chromium (VI) toxicity tolerance in tomato roots

Area of Science:

• Environmental Science
• Plant Biology
• Toxicology

Background:

• Chromium (Cr) pollution poses a significant threat to global crop productivity.
• Minimizing Cr toxicity in crops is crucial for food security.
• Ascorbic acid (ASC) has shown potential in mitigating heavy metal stress in plants.

Purpose of the Study:

• To investigate the role of ascorbic acid (ASC) in alleviating hexavalent chromium [Cr(VI)] toxicity in tomato roots.
• To understand the mechanisms by which ASC protects tomato plants from Cr(VI) induced damage.

Main Methods:

• Tomato roots were exposed to Cr(VI) with and without exogenous ASC application.
• Biochemical assays were performed to measure Cr accumulation, oxidative stress markers, and ASC levels.
• The effect of lycorine, an ASC biosynthesis inhibitor, on Cr(VI) toxicity was also evaluated.

Main Results:

• Cr(VI) exposure significantly reduced root length, dry weight, and tissue density, while increasing Cr accumulation and cell death.
• Cr(VI) decreased the endogenous ASC pool and its regenerating enzyme activity, leading to oxidative stress and cellular damage.
• Exogenous ASC application effectively reversed Cr(VI)-induced toxicity.
• Inhibition of ASC biosynthesis by lycorine exacerbated Cr(VI) toxicity, which was alleviated by exogenous ASC.

Conclusions:

• Ascorbic acid plays a vital role in protecting tomato roots against hexavalent chromium toxicity.
• Endogenous ASC is essential for mitigating Cr(VI)-induced oxidative stress and cellular damage.
• ASC application represents a promising strategy for managing chromium contamination in agricultural systems.