Transport in Plants Test - 16

• Transpiration is the process in which plants release the water inside it in the form of moisture or water vapor to the external atmosphere.
  
• Water is transient (lasting only for a short time) in plants. Less than 1 %of the water reaching the leaves is used in photosynthesis and plant growth. Most of it is lost through the stomata in the leaves. This water loss is known as transpiration.
• Hence the excess water is lost by stomata by the process of  Transpiration.
• So, the correct answer is 'Transpiration'.

Osmosis is the movement of a solvent across a semipermeable membrane toward a higher concentration of solute (lower concentration of solvent). In biological systems, the solvent is typically water, but osmosis can occur in other liquids, supercritical liquids, and even gases. When a cell is submerged in water, the water molecules pass through the cell membrane from an area of low solute concentration to high solute concentration. For example, if the cell is submerged in saltwater, water molecules move out of the cell. If a cell is submerged in freshwater, water molecules move into the cell. So, the correct option is "D" (All of the above).

Osmosis is the process of net movement of water across a permeable membrane driven by a difference in solute concentration on two sides of the membrane.

• Water transport is a physical process and not a physiological process. It does not require living cells and protoplasm. 
• The driving force is the transpiration pull generated by the loss of water through leaves. This is the reason why xylem tracheids and vessels are dead on maturity. 
• Food transport is a physiological process and requires living cells similarly stomatal movement also is a physiological process and requires living cells.

Sieve elements are made of sieve cells. They are the components of phloem tissue and transport food material in plants. Sieve element in angiosperms are sieve tubes and companion cells. While in gymnosperms and pteridophytes they sieve cells.

• The movement of water into the cell depends on the Diffusion Pressure Deficit (DPD) or the suction pressure of the cell. 
• A cell that is having more solutes than solvent will have less diffusion pressure and more suction pressure. So, water will move from the adjacent cell having less DPD.

• Diffusion is the movement of a substance (gases or liquid) from an area of high concentration to an area of low concentration. In diffusion, there is no involvement of semipermeable membrane.
  
• The flow of water from a region of higher water potential to a region of lower potential, when the two solutions are separated by a semi or differentially permeable membrane is known as osmosis. 
• Osmosis term is used specifically for the transport of solvent, not solute.
• Plasmolysis is the process of shrinkage or contraction of the protoplasm of a plant cell as a result of the loss of water from the cell. 
  
• The absorption of water by the solid particles of an adsorbent without forming a solution is called Imbibition. Example - absorption of water by dry seeds.
  

Correct Option: A

Correct option: B.
Explanation:

• Root pressure is the positive pressure that develops in the roots of the plants by the active absorption of nutrients from the soil.
• The active absorption depends on the active accumulation of solute in xylem sap.
• Root pressure is maximum when transpiration is very low and absorption is high because transpiration is the output of water from a plant, and absorption is the input of water into a plant.
• If the output is low and the input is high, the pressure will be at its greatest. 
  So, the correct answer is 'Transpiration is very low and absorption is high'.

Osmosis is defined as the movement of solvent particles from a region of high concentration to a region of low concentration across a semipermeable membrane. In this case, the water is the solvent, and it moves into the cells because there is a lower solvent concentration (but high solute concentration) within the cells this will take place until the concentration of water is the same inside the cell as outside. So, the correct answer is 'Concentration of water is the same inside the cell as outside'.