Question

There are ………………… geotropism seen in plants.
A. Positive
B. Negative
C. Neutral
D. Both A and B

Answer 1

Hint: Functions of plant parts decides the type of geotropism or gravitropism. According to the functions, geotropism can differ in different parts. It is of two types- positive and negative geotropism.

Complete answer: Geotropism is also known as gravitropism. It is a coordinated process that is observed in plants and fungus for the differential growth of roots and stems towards the gravity pulling it. This guides the plant roots to move downward or horizontally in the shallow soil. They can occasionally branch and send some roots vertically downwards. It provides structural anchorage and integrity of the plant. The roots grow with gravity and show positive geotropism and the stem grows upward and shows negative geotropism. Different plant parts grow in different directions because they have different functions. The roots grow along with the gravity because they need to absorb water and nutrients whereas the stem grows upwards. After all, they need to photosynthesize and produce chemical energy and carbohydrates. Charles Darwin discovered geotropism for the first time and he reported both positive and negative geotropism.
Hence, the correct option is D-Both A and B.

Note: Geotropic behavior of roots and stems are controlled by a variety of hormones and inorganic regulators. It is a complicated process that induces curvature formation because it indicates complex secondary events to form ultimate curvature in roots and shoots. It is a direction oriented growth of plants.