Explain the different kinds of troism
Answers
Answer:
Tropism refers to a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus.
Types of Tropism:
Phototropism: It is the movement of plant in response to light.
Ex:In plants shoots respond to light by bending towards light.
Chemotropism:It is the movement of plant in response to chemical.
Ex:The growth of pollen tubes towards ovules.
Geotropism: It is the movement of plant in response to the gravity.
Ex:The roots of the plants always grows downwards whereas the shoots of the plant always grows upwards.
Hydrotropism: It is the movement of plant in response to the water.
Ex:The roots of the plants grow in the direction of the place where water is available.
Phototropism:plant response to due to light as an external stimuli
Eg like stem is positively phototropic n roots r negatively phototropic
Geotropism:plant response due to gravity
Eg roots grow in downward direction I.e. towards gravity hence positively geotropic and stem is negatively geotropic
Hydrotropism:plant mov in response to water as a stimulus
Eg:as roots absorb water they r positively hydrotopic
Note:roots r more hydrotropic than geotropic
Thigmotropism:due to touch as a stimuli
Eg :tendrils of a plant tend to move towards a support say as a stick nearby to envelop n gain support
Chemotropism:due to chemicals
Like the neck cells secrete chemicals in pollen tube
Heliotropism:exhibited in sunflower n bcoz of this it moves from west to east