Cytokinin

Definition

Cytokinins are a class of plant hormones that play a critical role in cell division, growth, and differentiation. They are essential for various plant processes, including the regulation of shoot and root development, and the promotion of cell proliferation. Cytokinins are involved in plant responses to environmental stimuli, helping plants adapt to changing conditions by influencing growth patterns and physiological responses.

5 Must Know Facts For Your Next Test

1. Cytokinins are primarily synthesized in the roots of plants and transported to other parts, particularly the shoots, where they promote growth.
2. They work in conjunction with auxins to regulate various aspects of plant development, including apical dominance, where the main central stem grows more strongly than others.
3. Cytokinins can delay senescence (aging) in leaves by promoting cell division and protein synthesis, thereby enhancing leaf longevity.
4. These hormones also play a role in nutrient mobilization within the plant, facilitating the distribution of nutrients from older tissues to younger ones.
5. Cytokinins have been found to influence the formation of root nodules in legumes, which is essential for nitrogen fixation.

Review Questions

• How do cytokinins interact with auxins in regulating plant growth?
  • Cytokinins and auxins work together to regulate plant growth and development. Auxins promote cell elongation and root development, while cytokinins stimulate cell division and shoot growth. This interplay is crucial for maintaining the balance between root and shoot development, ensuring that plants can grow optimally in their environment.
• Discuss the role of cytokinins in delaying leaf senescence and its significance for plant health.
  • Cytokinins play a vital role in delaying leaf senescence by promoting cell division and protein synthesis. This function is significant because it helps maintain photosynthetic efficiency and prolongs the life of leaves, allowing plants to continue capturing sunlight and producing energy. By delaying aging, cytokinins ensure that plants can better respond to environmental stresses and optimize resource use during critical growth periods.
• Evaluate the impact of cytokinins on nutrient mobilization in plants and how this process contributes to overall plant health.
  • Cytokinins significantly impact nutrient mobilization by facilitating the transfer of nutrients from older tissues to growing parts of the plant. This process is crucial for maintaining overall plant health as it ensures that developing shoots receive adequate nutrients necessary for growth. Additionally, effective nutrient mobilization helps plants adapt to environmental changes and supports their ability to flourish even under stress conditions, highlighting the essential role cytokinins play in promoting resilience in plants.

Related terms

Auxin: A plant hormone that promotes cell elongation and is crucial for coordinating growth and response to environmental stimuli.

Gibberellin: A group of plant hormones that stimulate stem elongation, seed germination, and flowering.

Abscisic Acid: A plant hormone that plays a key role in stress responses, regulating processes such as seed dormancy and stomatal closure during drought.