Question

Heavy metals are detoxified in plants by
(A) ABA
(B) Allelopathins
(C) Phytochelatins
(D) Phytoalexins

Answer 1

Hint: Metallic substances with a comparatively high density in comparison to water are referred to as heavy metals. Metals damage chloroplasts and interfere with photosynthesis in plants, which is how they primarily exhibit their harmful effects. Phytochelatins are the enzymes which help in the detoxification of heavy metals in plants.

Step by step solution:

Assuming that weight and toxicity are connected, heavy metals also include metalloids like arsenic, which can cause toxicity at low exposure levels. The heavy metals lead, mercury, arsenic, and cadmium are most frequently linked to human toxicity.
Heavy metals, both necessary and non-essential, typically have harmful effects on plants that include low biomass accumulation, chlorosis, suppression of growth and photosynthesis, altered water balance and nutrient assimilation, and senescence. These effects eventually result in plant death.
Heavy metal toxins like Cd, Cu, Zn, Ni, Co, Cr, Pb, and As are mild to highly contaminated agricultural soils in many parts of the world. Metals damage chloroplasts and interfere with photosynthesis in plants, which is how they primarily exhibit their harmful effects. Interference of metal ions with photosynthetic enzymes and chloroplast membranes results in the inhibition of photosynthesis.
A family of peptides known as phytochelatins (PCs) is crucial for the detoxification of heavy metals like cadmium in plants and some microorganisms. PCs are made by an enzyme from glutathione.
Hence, option (C) is correct.
Note: Through metal chelation, phytochelatins are essential for heavy metal control and decontamination, and their notable impact is on Cd tolerance. Phytochelatins produced in the cytosol bind Cd, and an ATP-binding transporter transports the Cd-PC complex via the tonoplast.