Chapter 5 · Question 19
What are the methods used by plants to get rid of excretory products?
Q19
What are the methods used by plants to get rid of excretory products?
Answer Revealed
Direct Answer:
Plants excrete oxygen through stomata, CO2 through stomata, store waste in leaves and bark that are shed, and secrete gums and resins.
Simple Explanation
Plants get rid of waste in clever ways: they release oxygen during photosynthesis, drop old leaves that contain waste, store waste in bark, and produce gums and resins.
Exam-Ready Structure
Plants manage excretion through various methods because they do not have specialised excretory organs like animals. The methods include: 1. Gaseous wastes — Oxygen produced during photosynthesis and CO2 produced during respiration diffuse out through stomata in leaves and lenticels in stems. 2. Storage in old tissues — Many waste products are stored in older xylem (heartwood), which does not participate in transport. 3. Leaf fall — Deciduous plants shed leaves that accumulate waste products, effectively removing them from the plant body. 4. Secretion — Some plants secrete waste as gums, resins, latex, and tannins from specialised structures. 5. Crystals — Some plants deposit insoluble waste as calcium oxalate crystals (raphides) in vacuoles or cell walls, where they remain harmless. Since most plant wastes are not as toxic as animal nitrogenous wastes and can be reused or stored.
Key Points
- Gaseous wastes diffuse out through stomata
- Waste stored in old xylem and bark
- Shedding of leaves removes waste
- Gums, resins, and crystals store insoluble waste
Common Mistakes
- Listing only gaseous waste removal
- Saying plants have excretory organs like animals
Answer Sources
- Excretion strategies in plantstextbook section | Science | Life Processes | Excretion in plants | Pages 20