Question

Chlorosis occurs when plants are grown in
A. Shade
B. Strong sunlight
C. Fe- free medium
D. Dark

Answer 1

Hint:
A plant needs various certain conditions to grow. Like humans, deficiency of any major nutrient can make them suffer from a disease, which will retard their absolute growth. The micro and macronutrients being an important diet supplements play a vital role in growth.

Complete answer:
Plants like humans have requirements. Their basic requirements are water, optimum temperature. The nutrients required for their growth play a major role. They can either get them from soil or in some cases from the fertilizers or external sources.
Chlorosis is a disease in plants particularly leaves in which they start to develop yellow pigmentation. This happens due to the lack of a particular nutrient.
Option A: Shade: There are many plants which grow in the shady regions. Some plants do not require sunlight to grow.
Option B: Strong sunlight: The sunlight is important for a plant to grow. But strong or excessive sunlight will produce more than required energy in plants which will produce reactive oxygen. This can be fatal for the plants.
Option C: Fe-free medium: Iron and magnesium are the important requirements of the plant's nutrition diet. Their absence will cause the yellowing of the leaves which is known as chlorosis. This means there is a loss of chlorophyll in the leaves.
Option D: Dark: There are plants which grow in the dark. Major plants need sunlight but some can grow in dark also.

So the answer is option C: Fe-free medium.

Note: Chlorosis reduces the photosynthesis rate as the chlorophyll content has decreased. This will cause the plant to die soon if not provided with the iron and magnesium-rich nutrients. The primary symptom of this disease is the development of yellow pigment on plants. In severe cases, the outer edges become brown and scorchy.