Tag: coordination in plants

Phototropic curvature is the result of uneven distribution of auxin. Darwin and Darwin observed that the coleoptiles of canary grass responded w unilateral illumination by growing towards the light source (phototropism). After a series of experiments, It was concluded that the tip of coleoptile contains auxin that caused the bending of the entire coleoptile in relation to the direction of light.

Auxins induce phototropism in plants, that growth of a plant part towards light (shoot) or away from light (root). 

The pollen tube paves its way through the solid part of the stigma and style by secreting pectinases and hydrolytic enzymes. Pollen tube travels inter-cellularly and chemotropically along the concentration gradient of calcium-boron-Inositol sugar complex.

Positive geotropism is the movement towards earth. In the case of roots, they grow towards the earth and are thus, called as positively geotropic. Whereas shoots are negatively geotropic.

Irritability, reactivity and sensitivity are excitatory response shown by plants to respond to changes in their environment. The most common response shown by plants is movement in response to environment change. For example, closing of leaves of Mimosa pudica on touching or closing of traps on a Venus fly trap.

The area of the plant which receives a stimulus is called as perceptive region. Tip or apex of the shoot is the perceptive region for the light. It is the site which receives the phototropic stimulus and shows corresponding response. 

The movement of plant part in response to contact with a solid touch is called as thigmotropism. The movement of plant part in response to light is called as phototropism. The movement of plant part in response to force of gravity is called as geotropism. The movement of plant part in response to external chemical stimulus is called as chemotropism.

The movement of plant part in response to force of gravity is called as geotropism. The movement of plant part towards the gravity is called as positive geotropism. Roots show positive geotropic movement. The movement of plant part away from the gravity is called as negative geotropism. Stems show negative geotropic movement. 

Wilting of leaves is the loss of rigidity and caused when turgor pressure is lignified and reach zero it happens in the inadequate water supply and is caused by the hormone abscisic acid to prevent water loss.