Question
Why is transpiration called ‘a necessary evil’?
✓
Answer
- The loss of water in the form of water vapour is called transpiration.
- About 90 – 93% of transpiration occurs through stomata, small apertures located in the epidermis of leaves.
- For this process stomata must remain open and then only gaseous exchange by diffusion takes places.
- Gaseous exchange is necessary for respiration and photosynthesis. If stomata remain closed then it will affect productivity of plant.
- The process is necessary evil because water which is important for plant is lost in the process.
- At the same time it helps in absorption of water and its translocation. Hence it cannot be avoided.
So Curtis has rightly called it as necessary evil.
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