AP BIOLOGY

Detailed explanation-1: -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. The reason plants know which way to grow in response to gravity is due to amyloplasts in the plants.

Detailed explanation-2: -Roots grow downward, or towards the center of Earth, and away from light. These responses to external stimuli are called tropisms. Plants’ growth response to gravity is known as gravitropism; the growth response to light is phototropism. Both tropisms are controlled by plant growth hormones.

Detailed explanation-3: -The general response to gravity in plants is well known: roots respond positively, growing down, into the soil, and stems respond negatively, growing upward, to reach the sunlight.

Detailed explanation-4: -Have you heard of gravitropism? It’s the unique ability of plants to sense gravity, and respond accordingly. In other words, it’s how a plant knows to point its roots downward. Turn a tiny, brand-new clover seedling that has started to grow roots on its side, and it immediately changes the direction of its roots.

Detailed explanation-5: -Gravitropism. Plant parts tend to either grow in the same direction as gravity, or in the opposite direction. This type of tropism is called gravitropism. For example, the roots of most plants exhibit positive gravitropism when they grow downward.