Tropism

1. Identify the stimulus. 2. Check whether the movement is growth based. 3. Note the direction of growth. 4. Decide positive or negative tropism. 5. Name the correct type such as photo or geo tropism.

A directional growth arrow diagram works well, especially for shoot toward light and root toward gravity.

A common wrong answer is to describe any bending as tropism even when growth direction is not involved. Tropism must be directional growth.

Tropism is the directional growth movement of a plant part in response to a stimulus.

Tropism is the directional growth movement of a plant part in response to a stimulus. Rule: tropism is directional growth, and it may be positive or negative depending on movement towards or away from the stimulus. A shoot growing towards light shows positive phototropism, and roots growing downward show positive geotropism.

Tropism happens when a plant grows towards or away from a stimulus. The movement is directional, so the direction of the stimulus matters. Plant parts can show positive tropism when they grow towards the stimulus, or negative tropism when they grow away from it. This is different from fast movement in animals because it is mainly a growth response in plants. Rule: tropism is directional growth, and it may be positive or negative depending on movement towards or away from the stimulus. A plant kept near a window bends toward the light source. The shoot shows positive phototropism because it grows in the direction of the stimulus. Questions may ask for the meaning of tropism, the type of tropism in a given situation, or positive versus negative movement. A common wrong answer is to describe any bending as tropism even when growth direction is not involved. Tropism must be directional growth.