Which of the following is not a primary function of a green leaf?
Manufacture of food
Interchange of gases
Evaporation of water
Conduction of food and water
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-2 – 2018
A) Manufacture of food (Photosynthesis): Green leaves contain chlorophyll and are the main sites for converting light energy, CO₂, and water into glucose (food). This is a primary function.
B) Interchange of gases: Leaves have stomata, pores that regulate the exchange of gases (CO₂ intake and O₂ release) with the atmosphere. This is a primary function essential for photosynthesis and respiration.
C) Evaporation of water (Transpiration): Water is lost from the plant mainly through stomata on the leaves in the form of water vapor. This process helps in the ascent of sap and cooling. This is considered a primary function related to water balance and transport.
D) Conduction of food and water: While vascular tissues (xylem for water, phloem for food/sugars) are present in the leaf veins and transport substances within the leaf and to/from the rest of the plant, the *conduction* itself is a transport process performed by these tissues, not a primary metabolic or exchange *function* of the leaf tissue as a whole. The primary functions are the synthesis (photosynthesis) and exchange processes.
Therefore, conduction of food and water is not considered a primary function of the leaf organ itself, unlike photosynthesis, gas exchange, and transpiration.
– Conduction is a transport process occurring within the vascular tissues (xylem and phloem) found within the leaf veins.
– The question asks for a primary *function* of the leaf, distinguishing between synthesis/exchange processes and transport.