Which one of the following would be a suitable plant to test that chlo

Which one of the following would be a suitable plant to test that chlorophyll is necessary for photosynthesis?

Lady Plymouth
Cactus
Cuscuta
Oleander
This question was previously asked in
UPSC Geoscientist – 2023
To test if chlorophyll is necessary for photosynthesis, you need a plant that has some parts with chlorophyll and some parts without chlorophyll. Variegated leaves, which have green (chlorophyll present) and non-green (chlorophyll absent) patches, are ideal for this experiment. After exposing the plant to light and testing for starch (a product of photosynthesis) using iodine solution, the green parts will test positive (turn blue-black), while the non-green parts will test negative (remain brownish), demonstrating that chlorophyll is required for starch production during photosynthesis. Lady Plymouth (Pelargonium zonale) is a common plant species with variegated leaves often used for this demonstration.
– Experiment requires comparison between parts of a plant with and without chlorophyll.
– Variegated leaves are suitable for this purpose.
– Green parts contain chlorophyll, non-green parts do not.
– Testing for starch after photosynthesis reveals which parts photosynthesized.
Cactus leaves are modified into spines (though the stem is photosynthetic); Cuscuta is a parasitic plant that lacks chlorophyll and obtains nutrients from a host; Oleander has uniformly green leaves. None of these are typically used for a simple experiment demonstrating the necessity of chlorophyll using variegation.