Two students, Renu and Rohit, were having a discussion on the plastids. Renu emphasised that all parts of the plants, even roots, contain plastids. However, Rohit did not agree with the statement and told her that plastids are absent in plant roots since the roots are underground and do not need to perform photosynthesis. Who is correct? Justify your answer.

Renu is correct. Plastids are present in all parts of a plant, including the roots. Rohit's mistake is assuming that all plastids are meant for photosynthesis. In fact, there are different types of plastids:

• Chloroplasts contain chlorophyll and carry out photosynthesis; these are mainly found in the green parts of the plant that are exposed to sunlight.
• Leucoplasts are colourless plastids that store food materials such as starch, oils and proteins. These are found in non-green parts of the plant, including roots.

Since roots are underground and do not perform photosynthesis, they do not contain chloroplasts but they do contain leucoplasts for storage. Therefore, plastids are indeed present in roots, and Renu is correct.