A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours and then placed in bright sunlight for a few hours. Observe the diagram and answer the questions: A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours and then placed in bright sunlight for a few hours. Observe the diagram and answer the questions:
What will be the result of the starch test performed on leaf ‘A’ shown in the diagram? Give an example of a plant with variegated leaves.
Topic: Result of the starch test
Answer
The GREEN part of leaf A turns BLUE-BLACK, showing that starch is present — it had chlorophyll and photosynthesised. The PALE YELLOW part remains BROWN (yellowish brown), showing that no starch is present — it had no chlorophyll and could not photosynthesise.
Example of a variegated plant: CROTON (also Coleus, money plant, Tradescantia).
Describe BOTH parts and then name the plant — the question asks for both, and the example is worth a mark of its own.
Build each half in three steps: presence or absence of chlorophyll → photosynthesis occurred or not → starch present or absent → colour with iodine.
IODINE TEST: blue-black means starch is PRESENT; brown (unchanged) means it is ABSENT.
STATE THE CONCLUSION explicitly if you have room — that CHLOROPHYLL IS NECESSARY for photosynthesis. An answer giving the two colours correctly but never saying what they prove has stopped one step short.