- a.The red and purple pigments directly absorb heat from the Sunlight, thus replacing the need for photosynthesis.
- b.The leaf contains green chlorophyll but it remains hidden under other pigments.
- c.Coloured leaves steal glucose from neighbouring green plants through air using microscopic spores.
- d.None of the above
Answer: (B) The leaf contains green chlorophyll but it remains hidden under other pigments.
Leaves that look red, purple or yellow still contain chlorophyll; its green colour is simply masked by larger amounts of other pigments such as anthocyanins (red and purple, dissolved in the cell sap) and carotenoids (yellow and orange). Photosynthesis therefore goes on normally, as in Coleus, croton, red amaranth and red cabbage. Option A is wrong because heat cannot replace the light reactions of photosynthesis, and option C is fiction. Carotenoids act as accessory pigments that pass absorbed light energy on to chlorophyll a. Plants that truly lack chlorophyll, such as the parasite Cuscuta (dodder), cannot make food and draw it from a host through haustoria.