Gibberellin

Definition

Gibberellin is a group of plant hormones that play a crucial role in regulating growth and development, particularly in seed germination, stem elongation, and flowering. These hormones stimulate various processes by promoting cell division and elongation, allowing plants to adapt to environmental conditions and optimize their growth. Gibberellins are essential for breaking seed dormancy and initiating the transition from vegetative to reproductive phases in plants.

5 Must Know Facts For Your Next Test

1. Gibberellins were first discovered in the 1930s when researchers found that a fungus (Gibberella fujikuroi) was causing rapid growth in rice seedlings.
2. These hormones can promote not only stem elongation but also fruit development and seedless fruit formation in certain plant species.
3. Gibberellins are synthesized mainly in young tissues such as seeds, leaves, and stems, influencing growth patterns during critical developmental stages.
4. The application of gibberellins can lead to increased yields in crops by enhancing growth rates and delaying senescence.
5. Different types of gibberellins exist, with gibberellic acid (GA3) being one of the most commonly studied and used in agricultural practices.

Review Questions

• How do gibberellins influence seed germination and what specific processes do they initiate?
  • Gibberellins play a vital role in breaking seed dormancy and triggering germination. They promote the production of enzymes like alpha-amylase that break down stored starches into sugars, providing energy for the growing embryo. Additionally, gibberellins stimulate cell elongation in the embryo, allowing it to push through the seed coat and establish itself as a new plant.
• Discuss the interaction between gibberellins and other plant hormones in regulating growth and development.
  • Gibberellins interact with other plant hormones such as auxins and cytokinins to coordinate various growth processes. For instance, while gibberellins promote stem elongation, auxins help maintain apical dominance by directing growth towards light. Cytokinins can counterbalance gibberellin effects by stimulating cell division, leading to a complex interplay that allows plants to adapt their growth based on environmental conditions.
• Evaluate the practical applications of gibberellins in agriculture and horticulture, particularly regarding crop yield improvements.
  • Gibberellins are widely used in agriculture to enhance crop yields and improve fruit quality. Their application can lead to increased size and weight of fruits, earlier flowering, and uniformity in ripening. By manipulating gibberellin levels, farmers can effectively manage growth patterns to maximize production. This has significant implications for food supply and agricultural efficiency as global demand for crops continues to rise.

Related terms

Auxin:

A class of plant hormones that primarily regulate cell elongation, apical dominance, and root formation.

Cytokinins:

Plant hormones that promote cell division and are involved in various processes such as shoot and root development.

Abscisic Acid: A plant hormone that plays a key role in regulating stress responses, particularly during drought conditions, by promoting stomatal closure.