There are five common stimuli in the environment : light, gravity, chemicals, water and touch (or contact). These five stimuli give us five types of tropisms : phototropism, geotropism, chemotropism, hydrotropism and thigmotropism. In phototropism, the stimulus is light ; in geotropism the stimulus is gravity, in chemotropism the stimulus is a chemical, in hydrotropism the stimulus is water, and in thigmotropism the stimulus is touch (of a solid surface). It is obvious that the tropisms are named according to the stimulus.
1. The movement of a plant part in response to light is called ________.
(i) Phototropism
(ii) Geotropism
(iii) Chemotropism
(iv) Hydrotropism
2. The movement of a plant part in response to gravity is called _________.
(i) Phototropism
(ii) Geotropism
(iii) Chemotropism
(iv) Hydrotropism
3. The movement of a plant part in response to a chemical stimulus is called _________.
(i) Phototropism
(ii) Geotropism
(iii) Chemotropism
(iv) Hydrotropism
4. The movement of a plant part in response to water is called __________.
(i) Phototropism
(ii) Geotropism
(iii) Chemotropism
(iv) Hydrotropism
5. The directional growth movement of a plant part in response to the touch of an object is called _______.
(i) Phototropism
(ii) Geotropism
(iii) Chemotropism
(iv) Hydrotropism
