Question

name the various plant hormones .also give their physicological effects on plant growth and development ? it is class 10 question from chapter control and coordination please give it in short​

Answer 1

Answer:

Explanation:

Plant hormones fall in 2 categories:

1. Growth Promoter
2. Growth Inhibitor

Growth Promoter:

             The hormones which have positive effect

             on plant growth is called as growth promoter

             hormone.

Growth promoter include:

• Auxins
• Gibberellins
• Cytokinins

Auxins:

• In stem,promotes cell arrangement in region behind apex
• .Promotes cell division in cambium.
• In root,promotes growth at very low concentrations.
• Promotes bud initiation in shoots.
• Promotes apical dominance and fruit growth.
• Causes delay in leaf senescence
• Inhibits abscission

Gibberellins:

• Promotes cell enlargement in the presence of auxins.
• Promotes bolting in some rosette plants.

• Promotes bud initiation in shoots of chrysanthemum callus
• In apical dominance,enhances action of auxins
• Substitute for red light.Therefore,promotes flowering in long day plants.

Cytokinins:

• Inhibits primary root growth
• Inhibits lateral growth root
• Promotes stomatal opening
• Causes delay in leaf senescence
• Promotes bud initiation and leaf growth

Growth inhibitor:

            The hormones which have negative effect

             on plant growth is called growth inhibitor.

Growth inhibitor include:

• Abscisic acid
• Ethene

Abscisic acid:

• Inhibits stem and root growth notably during physiological stress e.g.,drought and water logging.
• Promotes bud and seed dormancy
• Promotes flowering in short day plants
• Sometimes promotes leaf senescence
• Promotes abscission
• Promotes closing of stomata under conditions of water logging

Ethene:

• Inhibits stem growth during drought etc
• Inhibits root growth
• Break dormancy of bud
• Promotes flowering in pineapple
• Promotes fruit ripening
• Stimulates ripening of tomatoes and citrus fruit.

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