AP BIOLOGY

Detailed explanation-1: -Plant roots have positive gravitropism, growing towards the center of Earth. But leaves and stems do the opposite–negative gravitropism. Botanists don’t yet fully understand how plants can perceive gravity and respond to it. One of the most well-accepted theories involves the hormone known as auxin.

Detailed explanation-2: -Stems, on the other hand, exhibit negative gravitropism since they grow upwards and against the force of gravity (see Figure 1). If you place a plant on its side or even upside down, the stem will curve its way up and the roots will curve their way down.

Detailed explanation-3: -The roots grown downward in the direction of gravity, which is positive gravitropism, and the shoot grows upward away from gravity, which is negative gravitropism.

Detailed explanation-4: -When the stem grows against the force of gravity (upwards), this is known as a negative gravitropism. When a root grows in the direction of the force of gravity (downwards), this is known as a positive gravitropism.

Detailed explanation-5: -For instance, the roots of the plants grow towards the gravitational field whereas the stem grows away from the gravitational field. The downward growth of roots is an example of a positive gravitropism whereas the upward growth of roots is an example of negative gravitropism.