Question

Introduction to Biochemistry M

Answer 1

Because cellulose is required for the stem growth as cellulose is the main constituent of the cell wall and also provides toughness to the stem.

When less sunlight is in those months the photosynthesis also lowers, resulting in the use of stored energy i.e starch. Hence the starch level decreases.

Explanation:

Cellulose is required for the growth and toughness of the stem. During spring the budding and growth is fastest in plants hence supply of cellulose increases.

The starch is the energy stored in plants. It is a polymer of glucose. When sunlight decreases in some months the  rate of photosynthesis lowers down and plant starts using the stored form of energy  ie. starch, required for various physiological activities and growth of the plants. This is the reason the starch level decreases in plants sometimes.