Question

The chemicals produced in one part of a plant that affect the growth and respponse of other parts are called


a.Enzymes
b. Hormones
c. Target cells
d. Tropisms​

Answer 1

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• Plant hormones are also called phytohormones. Auxin, the first plant hormone identified, generates a growth response at a distance to its synthesis site and, therefore, fits the definition of a chemical messenger transported.

Answer 2

The chemicals produced in one part of a plant that affect the growth and response of other parts are called (b) Hormones.

Plant Hormones- The organic chemical compounds responsible for plant growth, flowering, protection against various stress, etc.

Types of Plant Hormones:

• Growth promoting e.g. Auxin, Gibberellic acid, etc
• Growth inhibiting e.g. ethylene, abscisic acid  

More about Hormones:

• Auxin: This hormone is mainly responsible for activities like root promotion, flowering, etc.
• Gibberellin: This hormone is mainly responsible for activities like elongation of internode, increase in length of axis, etc.
• Cytokinin: This hormone is mainly responsible for activities like cytoplasm growth, overcoming apical dominance, etc.
• Ethylene: This hormone is mainly responsible for activities like hasting fruit ripening, breaking seed dormancy, etc.
• Abscisic acid: This hormone inhibits metabolic activities of seed, promotes seed dormancy at unfavourable times.

Other than Plant hormones, factors like moisture, temperature, etc play important roles in the development of plants.