FITOHORMON 2

Summary

This script explores the concepts of growth and development in living organisms, focusing on plants. It delves into the mechanisms of growth, including cell division and expansion, and introduces key plant hormones such as auxins, gibberellins, cytokinins, and ethylene. The discussion covers their roles in processes like cell elongation, flowering, fruit ripening, and dormancy. Additionally, the impact of environmental factors like temperature and light on plant growth is examined, alongside the application of growth regulators in modern agriculture to improve crop yield and quality.

Takeaways

• 😀 Growth in living organisms refers to an irreversible increase in size due to cell multiplication and enlargement.
• 😀 Development is the process of an organism maturing and involves changes in organ structure and function.
• 😀 Growth and development occur simultaneously in organisms, with growth affecting body size and development affecting organ function.
• 😀 Internal factors such as genetics and hormones, and external factors like light, temperature, and nutrients, influence plant growth and development.
• 😀 Plant growth involves two types: primary (lengthening of cells) and secondary (increasing girth of stems and roots).
• 😀 Auxin is a plant hormone that stimulates root formation, cell elongation, and flower/fruit development.
• 😀 Gibberellins stimulate seed germination, stem elongation, and flowering, and are synthesized in seeds, fruits, and young leaves.
• 😀 Cytokinins promote cell division and growth, and are involved in the regulation of plant organ formation and delay in leaf aging.
• 😀 Ethylene is a gaseous hormone that regulates fruit ripening, leaf abscission, and stress responses in plants.
• 😀 Abscisic acid (ABA) is a growth inhibitor that induces dormancy, prevents seed germination, and controls leaf and fruit abscission.
• 😀 Other plant growth hormones include Kalins, which promote growth in specific plant organs such as roots, stems, and flowers, and Florigen, which stimulates flowering.

Q & A

What is growth in living organisms?

Growth refers to the irreversible changes in the size of an organism, including the increase in cell number or cell size. It is measurable through weight, length, and cell number.

How does development differ from growth?

Development is the process by which organisms mature and undergo changes in structure and function, such as organ maturation, while growth focuses solely on an increase in size.

What are the factors that influence the growth and development of organisms?

The growth and development of organisms are influenced by internal factors like genetic makeup and physiological processes, as well as external factors such as temperature, light, water, oxygen, and nutrients.

How do hormones impact plant growth?

Plant hormones regulate various aspects of growth, such as stem elongation, root development, flowering, and fruit ripening. They play a crucial role in the plant's response to its environment.

What is the role of auxin in plant growth?

Auxin is a plant hormone that promotes stem elongation, influences root growth, and regulates the development of plant organs.

What does gibberellin do in plants?

Gibberellin is a hormone that promotes stem elongation, encourages seed germination, and plays a role in flowering processes.

How does cytokinin affect plant growth?

Cytokinin stimulates cell division, encourages the growth of lateral buds, and inhibits the formation of roots.

What is the function of ethylene in plants?

Ethylene is a hormone that controls fruit ripening, leaf abscission (falling), and other aspects of plant maturation.

How does abscisic acid contribute to plant growth?

Abscisic acid is a growth inhibitor that promotes dormancy in plants, helping them survive adverse conditions by regulating responses to stress.

What is the role of florigen in plant growth?

Florigen is a hormone that stimulates the formation of flowers in plants, marking an important transition in the plant's life cycle from vegetative to reproductive stages.