Stipules

Definition

Stipules are small leaf-like structures found at the base of a leaf stalk (petiole) in some plants. They can play various roles, such as protecting young leaves and buds or functioning in photosynthesis. Stipules are often paired and can vary in size, shape, and presence depending on the species.

5 Must Know Facts For Your Next Test

1. Stipules can be found in various forms, including leaf-like, scale-like, or spiny, depending on the species of plant.
2. In some plants, stipules may fall off as the plant matures, while in others they remain for their entire life cycle.
3. Stipules can sometimes be mistaken for small leaves or modified stems due to their appearance.
4. Certain stipules are known to produce glandular structures that secrete nectar, attracting pollinators.
5. The presence or absence of stipules can be an important characteristic in identifying and classifying different plant species.

Review Questions

• How do stipules contribute to the overall health and development of a plant?
  • Stipules play a significant role in protecting young leaves and buds from environmental stressors such as herbivory or harsh weather. By providing this protection, stipules help ensure that new growth can develop safely. Additionally, if stipules have photosynthetic capabilities, they can contribute to the plant's overall energy production during critical growth stages.
• Discuss how stipules vary across different plant species and their implications for plant classification.
  • Stipules can vary significantly in form and function among different plant species. Some plants may have prominent stipules that resemble leaves, while others may have reduced or absent stipules. This variation is crucial for botanists as it aids in identifying and classifying plants within specific families or genera. For example, stipule characteristics are used to differentiate between certain species within the legume family.
• Evaluate the ecological significance of stipules in plants and their interactions with other organisms.
  • Stipules serve various ecological functions that impact plant interactions with other organisms. They can provide protection for developing buds and leaves from herbivores, reducing predation pressure. Additionally, stipules that produce nectar attract pollinators, enhancing reproductive success. The diversity of stipule forms across species illustrates their adaptive significance in different environments, affecting not only plant fitness but also the broader ecosystem dynamics.

Related terms

Petiole: The stalk that attaches the leaf blade to the stem of a plant, supporting the leaf and facilitating the transport of nutrients.

Leaf Blade: The broad, flat part of the leaf that is primarily responsible for photosynthesis and transpiration.

Axillary Bud: A bud that forms in the axil, or angle, between a leaf and a stem, which can develop into a branch or flower.