ZINC (Syllabus: GS Paper 3 – Sci and Tech/Environment)

Context: Researchers have discovered that zinc plays a crucial role in the health of legume crops.

Zinc

• About: It is a component of mixed ores alongside lead, is primarily found in veins associated with minerals like galena, chalcopyrites, iron pyrites, and sulfides.
• Global Importance: Ranked as the fourth most widely used metal globally, after steel, aluminium, and copper.
• India maintains self-sufficiency in zinc production, with significant reserves in Rajasthan, Andhra Pradesh, Madhya Pradesh, and Bihar.
• Global Reserves: Australia holds the largest share of global zinc reserves at 27%, followed by China (18%), and Russia, Mexico, Peru, Kazakhstan, and the USA.
• Uses of Zinc:

oThe largest consumer of zinc is the galvanising industry, utilizing its corrosion-resistant properties to protect steel.

oZinc is extensively used in producing die-castings crucial for automobiles, electrical components, and hardware.

oZinc oxide finds widespread use in manufacturing products like paints and rubber due to its properties.

Biological Role of Zinc:

• Trace Mineral Importance: Zinc is a trace mineral essential for nearly 100 enzymes, vital for DNA creation, cell growth, protein building, tissue repair, and immune system function.
• Role in Nitrogen Fixation: Zinc aids in nitrogen fixation in plants, crucial for converting atmospheric nitrogen into ammonia, benefiting legume crops through a symbiotic relationship with rhizobia.

Key Findings

• Legume nodules involved in nitrogen fixation are sensitive to environmental factors such as temperature, drought, flooding, soil salinity, and nitrogen levels.
• Zinc regulates nitrogen fixation efficiency in legumes through a transcriptional regulator called Fixation Under Nitrate (FUN), which controls nodule breakdown under high soil nitrogen levels.
• Zinc modulates FUN activity by forming large filament structures that can be dismantled to release active FUN based on zinc availability in the soil.