Biology
Transpiration is defined as:
- the rise of water up to the stem of a plant.
- the elimination of water with dissolved water products.
- the loss of water as water vapour from the aerial parts of a plant.
- the loss of water as water vapour from the roots as well as the leaves of the plant.
Answer
the loss of water as water vapour from the aerial parts of a plant.
Reason — Transpiration is the loss of water in the form of water vapour from the aerial parts of a plant.
The rise of water through the stem of a plant describes ascent of sap, not transpiration. Water moves upward through xylem due to transpiration pull, but that is a different process. The elimination of water with dissolved waste products refers to excretion, not transpiration. Plants do not eliminate dissolved wastes through transpiration. Roots do not lose water by transpiration. Water loss mainly occurs from aerial parts only.
Related Questions
Raisins swell when put in:
- Rain water
- Saline water
- Mustard oil
- Saturated sugar solution
The root hairs are suited for absorbing water from the soil because:
- They have a large surface area
- They have a semi-permeable membrane
- They contain a solution of higher concentration than the surrounding water.
- All the three.
Which one of the following favours the fastest transpiration rate?
- A cool, humid, windy day,
- A hot, humid, windy day,
- A hot, humid, still day,
- A hot, dry, windy day.
Vinay has kept a small herbaceous plant in a test tube containing water. The surface of the water is covered by a layer of oil. After three hours, he observed that the level of water in the test tube has decreased. This is due to:
- Absorption
- Transpiration
- Wilting
- Both (1) and (2)