Gibberellin

Definition

Gibberellin is a plant hormone that plays a crucial role in regulating growth and development processes, such as seed germination, stem elongation, and flowering. It functions by promoting cell division and elongation, thereby influencing various physiological processes throughout the plant's lifecycle.

5 Must Know Facts For Your Next Test

1. Gibberellins are produced in various parts of the plant, including young leaves, stems, and developing seeds.
2. One of the most well-known effects of gibberellin is its ability to break seed dormancy and stimulate germination by triggering the production of enzymes that digest stored food in seeds.
3. Gibberellins also promote stem elongation by causing cells to expand and divide, which is why they are sometimes used in agriculture to increase crop yields.
4. In addition to their role in growth, gibberellins can influence flowering by inducing the transition from vegetative to reproductive growth in some plants.
5. Gibberellins are commercially used in various applications, including grape production to increase size and prevent premature seed development.

Review Questions

• How do gibberellins influence seed germination and what mechanisms are involved in this process?
  • Gibberellins influence seed germination by breaking seed dormancy and stimulating the production of enzymes necessary for the digestion of stored nutrients within the seed. When gibberellins are present, they trigger the synthesis of enzymes like alpha-amylase, which helps convert starches into sugars that provide energy for the growing embryo. This hormonal action allows seeds to absorb water more effectively, leading to rapid growth as the seed begins to germinate.
• Discuss the relationship between gibberellins and other plant hormones, particularly auxins and cytokinins, in regulating plant growth.
  • Gibberellins work alongside other plant hormones like auxins and cytokinins to coordinate various aspects of plant growth and development. While gibberellins primarily promote stem elongation and seed germination, auxins facilitate cell elongation in specific regions like roots and shoots. Cytokinins encourage cell division and can counteract the effects of gibberellins when it comes to certain growth processes. The interplay between these hormones ensures that plants can adapt their growth responses according to environmental conditions.
• Evaluate the impact of gibberellin application on agricultural practices and crop yields, considering both benefits and potential drawbacks.
  • The application of gibberellin in agriculture has significantly impacted crop yields by promoting desirable traits such as larger fruit size and enhanced germination rates. Farmers use gibberellins to improve the uniformity and quality of crops like grapes and barley. However, there are potential drawbacks, such as the risk of over-application leading to excessive growth or altered flowering times that can disrupt normal growing cycles. Additionally, reliance on synthetic gibberellins raises concerns about long-term sustainability and possible environmental effects.

Related terms

Auxin: A class of plant hormones that promote cell elongation, root formation, and growth responses to light and gravity.

Cytokinin: A type of plant hormone that stimulates cell division and promotes shoot development, often working in opposition to auxins.

Abscisic Acid: A plant hormone that plays a key role in stress responses, particularly during drought conditions, by promoting seed dormancy and inhibiting growth.