Question

Where is the auxin hormone made in a plant stem?

Answer 1

Hint: Auxin is a plant hormone that helps in the growth of the plant. Most of the growth in plants takes place from its apical portions through auxin functioning. The apical parts of stems, roots, and leaves grow in length with the help of the auxin hormone.

Complete step by step answer: The plants have developed the process of photosynthesis for meeting their nutritional demands. But for growth and maintenance, the plants need more than food. Plant hormones are chemical substances that help in plant growth and support other metabolic processes. One of the growth hormones in plants is auxin.
-Auxin is a family of plant hormones that assist longitudinal growth at the apical meristems of plant parts like stems, roots, and leaves. Thus, it is present and produced at the tips of actively growing tissues of the plant. It causes cell elongation and increases the cell division rates where it is present.
-It also aids in positive phototropism. This means that the plant bends towards the light source. But it should be known that plants do not bend towards the light, it is the non-uniform distribution of auxin in plants that causes differential growths in the parts where it is present.
-The shady parts of the plant have more auxin concentrations and thus grow faster making the plant bent toward the light. This phenomenon is called positive phototropism.
-Auxin has different roles to play in stem and roots. In stems, it promotes the growth in the regions it is present in more concentration. But in roots, it decreases the growth rate and shows negative phototropism roots as roots bents away from the light source.
-The regions having less concentration in roots that are non-shady grow faster than root parts in the shade having more auxin. But it should be known that the auxin is majorly made in tips of the stems, roots, and leaves that cause them to attain certain lengths. Promoting growth is the main function of auxin.

Note: The most common type of auxin is IAA or Indole acetic acid. It is used in many plant tissue culture techniques for promoting plant growth in vitro conditions. Other major plant hormones are gibberellins, cytokinin, ethylene, and abscisic acid.