The correct Answer is A-2, B-1, C-4, D-3
Explanation
This question pertains to the fundamental processes and tissues involved in water and nutrient transport in plants, specifically focusing on vascular tissues (xylem and phloem) and related physiological mechanisms like root pressure and transpiration.
Statement-wise Analysis
- A. Xylem - 2. Transport of water and minerals
- Correct: Xylem is the primary vascular tissue responsible for the upward transport of water and dissolved minerals from the roots to various parts of the plant, including stems and leaves.
- B. Phloem - 1. Translocation of products of photosynthesis
- Correct: Phloem is the vascular tissue responsible for the translocation (transport) of organic nutrients, primarily sugars produced during photosynthesis, from the leaves (source) to other parts of the plant where they are needed for growth or storage (sink).
- C. Root pressure - 4. Push effect on water column at night
- Correct: Root pressure is a positive pressure that develops in the xylem sap of roots, primarily at night when transpiration is low. It is caused by the active absorption of mineral ions by root cells, which lowers the water potential inside the root, leading to water moving into the root xylem by osmosis. This creates a hydrostatic pressure that can push water up the xylem, though its role in long-distance transport is limited compared to transpiration pull.
- D. Transpiration - 3. Loss of water in the form of vapour
- Correct: Transpiration is the process by which water vapor is released from the aerial parts of plants, primarily through stomata in the leaves. This evaporative loss of water creates a negative pressure (tension) in the xylem, which is the main driving force for the ascent of sap in tall plants.
Key Takeaway
Xylem transports water and minerals, phloem translocates photosynthetic products, transpiration is the evaporative loss of water creating pull, and root pressure is a positive pressure pushing water, mainly at night.