Biology
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)
Answer
Both (1) and (2)
Reason — The decrease in water level is due to both absorption by the plant and transpiration from the leaves.
Absorption is the uptake of water by roots, but here it is not the cause of water level decrease in the test tube alone—it is part of the process linked with transpiration. Wilting is a result of water loss, not the cause of water level decrease.
Related Questions
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.
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.
Root hairs are the epidermal outgrowths of the outermost layer of roots. They are well-suited for absorption of water from soil due to which of the following features ?
P. Large surface area.
Q. Lower concentration of cell sap.
R. Semi permeable nature of the cell membrane.- Only P
- Only Q
- Only P and Q
- Only P and R
Xylem tissue forms a tubular passage to transport water and mineral salts from the roots to the aerial parts of a plant. It consists of different types of cells.
P. Sieve tubes and companion cells
Q. Wood parenchyma and wood fibres
R. Tracheids and vesselsWhich of the following are xylem components?
- Only P
- Only P and R
- Only Q and R
- All P, Q and R