Question

NaCl is harmful to most crop plants. A scientist at the University of Toronto genetically modified a plant so that it could be grown in dry parts of the world where the available water has a high level of NaCl. This genetically modified plant copes with the high levels of NaCl by transporting salt into its vacuoles where it accumulates to abnormally high levels. Which feature would be observed in the genetically modified plant when compared to a non-modified plant?

• A. The leaves in the modified plant are more yellow in colour.
• B. The modified plant has salt crystals on the surface of its leaves.
• C. The Cytosol (the material between the plasma membrane and the vacuole membrane, excluding the organelles) in the modified plant has a lower osmotic pressure.
• D. The cytosol in the modified plant has a higher osmotic pressure.

Answer 1

The correct option is D The cytosol in the modified plant has a higher osmotic pressure.

Osmotic pressure is the pressure required to stop the flow of pure water or solvent into a solution across a partially permeable membrane. Water moves from a region of low osmotic pressure to a region of high osmotic pressure. As high leaves of NaCl is accumulated in the cells, of modified plant the osmotic pressure of cytosol is increased. Accumulation of salts in vacuoles causes compartmentalization of salts away from the cytosol and protects cytosol from the harmful effects of the high salt concentration.

So, the correct answer is 'The cytosol in the modified plant has a higher osmotic pressure.'.