Question

Bring out the Physiological effects of Auxin.

Answer 1

There are various physiological effects of auxin:

• Auxins promote elongation of stem and coleoptile. It promotes the growth by the elongation of cells in the apical meristem.
• Growth in the lateral bud is inhibited when the apical bud of a tall plant remains intact. However, the lateral bud grows rapidly on the removal of apical bud. Suppression of growth in the lateral bud by apical bud due to auxin produced by apical bud is termed as apical dominance.

• Auxin is responsible for initiation and promotion of cell division in the cambium, which is responsible for the secondary growth. This property of induction of cell divisions has been exploited for tissue culture techniques.
  
• Auxin promotes the growth of root only at extremely low concentrations. At higher concentrations, it always inhibits the growth of the root.
• When leaves and fruits mature, they shed from the stem. This is called abscission. Auxin prevents abscission.

• Seedless fruits are produced in tomato and apple, by external application of auxin on flowers. Such seedless fruits are called parthenocarpic fruits.
  
• A synthetic form of auxin is used to eradicate weeds in the field.