Question

which hormone is present in the tip of stem?​

Answer 1

Answer:

Auxin is present in the tip of stem cell

Answer 2

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Control and Coordination in Plants

Plants also show movement by growth of their various parts. It is the plant hormones that promote its growth. The movement of plant parts is due to various stimuli like gravity, water, light, chemical, touch, etc. So, the function of control and coordination in plants is performed by the chemical substances called plant hormones or phytohormones.

SHIKHA GOYAL MAR 11, 2016 13:18 IST

Despite not having sense organs plants can also sense things and respond to them. Plants respond to things like light, gravity, touch, water etc. These are environmental stimuli for a plant. Plants coordinate their behaviour by using their hormones and respond to the environmental changes. This they do by affecting the growth of a plant.

Jagranjosh

Therefore, pants use only hormones to coordinate their behaviour. They respond to the stimuli very slowly because they have no nervous system. Plant hormones are called phytohormones.

Dormancy: The inactive condition of a part of a plant in which metabolism almost stops is called dormancy. For example, seed, bud etc.

Plant Hormones

The control and coordination system in plants is done by plant hormones. They affect the growth of a plant in one or the other aspect. The growth of a plant is divided in three stages:

i) Cell division

ii) Cell enlargement

iii) Cell differentiation

So, a plant hormone not only controls these stages of plant growth but also promotion of breaking of dormancy, falling of leaves, fruit growth, ripening of fruits, ageing of plants etc.

The four types of plant hormones responsible for control and coordination in plants are:

1) Auxins

2) Gibberellins

3) Cytokinins

4) Abscisic acid (ABA)

While auxins, gibberellins and cytokinins promote the growth of a plant, abscisic acid prevents or hampers the growth of a plant.

Auxins

Auxins hormone controls a plant response to light and gravity. It is made by the cells present at the tip of a stem and roots. This hormone moves the plant away from light and towards gravity. It speeds up the growth of stem and slows down the growth of roots.