Question

What are plant hormones? Describe its types. And give its function also. ​

Answer 1

$\huge \bf{ \mid{ \overline{ \underline \red{Answer - }}} \mid}$

$\underline \bold \pink{PLANT \: HORMONES - }$A chemical substance which control and coordinate in a plant is called plant hormones.

✴️ It is also known as phytohormones.

$\underline{ \underline \bold \red{Types \: of \: Plant \: Hormones - }}$

There are four types of plant hormones :-

1. Auxins

2. Gibberellin

3. Cytokinin

4. Abscisic acid (ABA)

$\underline{ \bold \blue{1. \: auxins - }}$Auxins are the hormones which promote cell differentiation and cell enlargement. It also promotes fruit growth.

$\underline{ \bold \orange{2. \: gibberellins - }}$Gibberellins are the hormones which help in breaking the dormancy in seeds and buds. It also help in cell differentiation and cell enlargement in the presence of auxins.

$\underline{ \bold \pink{3. \: cytokinins - }}$These plant hormones help in cell division, fruit growth and opening of stomata.

$\underline{ \bold \red{4. \: abscisic \: acid - }}$These hormones help in the dormancy in seeds and buds and also promote in the closing of stomata.

$\underline{ \underline \bold \green{FUNCTIONS \: of \: PHYTOHORMONES - }}$

The various functions in plants which are regulated by plant hormones are :-

1. It regulates germination of seeds.

2. It regulates the growth of root, stem and leaves and also regulate the flowering of plants.

3. It regulates the movement of stomata in leaves and also regulates the ripening of fruits.

Answer 2

Answer:-

The control and coordination in plants is done by plant hormones or phytohormones . The plant hormones co-ordinate the activities of the plant by controlling one or the other aspect of the growth of the plant . So , the plant hormones are also known as plant growth substances.

There are four major types of plant hormones which are involved in the control and coordination in plants . These are as follows :-

1.Auxins -

▶Auxins are the plant hormones which promotes cell enlargement and cell differentiation in plants .

▶Auxins also promote fruit growth .

▶Auxin hormone controls a plant's response to light and gravity . In other words , auxin hormone is responsible for the phototropic and geotropic responses of plants .

▶Auxin is made by cells at the tip of stems and roots . Auxin moves away from light and towards gravity .

▶Auxin has a positive effect on the growth of stem and roots . Auxin speeds up growth in stem but it slows down growth in roots .

▶Synthetic auxins are applied in agriculture and horticulture.

2.Gibberellins:-

▶Gibberellins are plant hormones which promotes cell enlargement and cell differentiation in the presence of auxins.

▶Gibberellins help in breaking the dormancy in seeds and buds.

▶They also promote growth in fruits.

▶Gibberellin hormone is involved mainly in shoot extensions .

▶Gibberellin stimulates elongation of shoots of various plants .

3.Cytokinins:-

▶Cytokinins are the plant hormones which promotes cell division in plants.

▶Cytokinins also help in breaking the dormancy of seeds and buds .

▶They delay the ageing in leaves.

▶Cytokinins promote the opening of stomata .

▶They also promote fruit growth .

4.Abscisic Acid :-

▶Abscisic acid is a plant hormone which functions mainly as a growth inhibitor.

▶Abscisic acid promotes the dormancy in seeds and buds .

▶It also promotes the closing of stomata.

▶Abscisic acid promotes the wilting and falling of leaves .

▶It also causes the detachment of flowers and fruits from the plants .