CONTROL AND COORDINATION IN PLANTS

 

CONTROL AND COORDINATION

Systematic working of the various organs of an organism(plants or animals) producing a proper response to the stimulus is called coordination.

Coordination in Touch me not

Coordination in Plants

• Not so elaborate controlled by phytohormones and external stimulus.

Phytohormones

• Control and coordination in plants is done by Phytohormones
• They are naturally occuring chemical substances which control one or other aspect of growth
• Auxin- Cell enlargement and differentiation
• Gibberellins- In presence of auxin promotes cell enlargement and differentiation
• Cytokinins- Promotes cell division, opening of stomata
• Abscisic acid- Closing of stomata, wilting and falling of leaves

NASTIC MOVEMENTS

• Non directional movement of a plant part in response to an external stimulus.
• May or may not be a growth movement.
• All parts of the organ of a plant are affected equally irrespective of the direction of the stimulus
• Thigmonasty: Nastic movement in response to touch of an object 
• Photonasty: Nastic movement in response to light