Concept checks                                     

 

 

 

These concept checks have been included to encourage you to think about some of the processes involved in the formation of new shapes, forms, or structures that have evolved in order to make the plant in question more likely to survive a hostile environment. What is required of you? Simply, you need to research the question or topic, and make notes which contain as much useful and relevant information as you can find for each of the questions. Make sure that the information you gather provides you with a defined and clear answer in each case.

Leaves and environment
  • Distinguish between simple and compound leaves.

  • Where and how are leaves produced?

  • How is leaf shape and size controlled?

  • Describe the structural differences between sun and shade leaves

  • What is meant by the terms hydromorphy, mesomorphy and xeromorphy

Leaf structure and function

  • List the three main functions of the leaf

  • How do the upper and lower epidermis differ in a typical leaf?

  • Does gas exchange occur more rapidly during daylight or at night? Explain your answer.

  • Distinguish between palisade cells and spongy mesophyll. What are their primary functions?

  • What is the function of a bundle sheath?

  • What is a leaf sheath and what are its functions?

  • Define the term succulence as it applies to leaf, root and stem. What is the adaptational significance of succulence?

Functional leaf adaptations

  • Why are leaves with a large volume and small surface area are found in arid regions rather than in the wet tropics?

  • How do leaf spines and tendrils differ in function and structure, compared to stem thorns and tendrils?

  • What is a cladode? How does it differ from a typical leaf? Find some examples of cladodes. (give references as well)

  • Give examples of at least three insectivorous plants and explain how each of these is adapted for insect capture. How do the traps function?

  • Explain what is meant by leaf budding. What are the short-term and long-term advantages to this type of reproduction?

Anchorage, uptake and support structures

  • Why is a rhizome stem-like, rather than root-like?

  • Compare the structure of bulbs and corms.

  • Describe the structure and function of a pneumatophore.

  • Describe the functional role of a prop root.

  • What is a liana? Where do they occur?

  • What is the difference between a stolon and a runner?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Adaptations -   partial glossary           

Bulb. Defined as a specialized underground organ produced by a monocotyledon. It consists of a short, fleshy and usually vertical stem axis, which has a growing point located at its apex. Alternatively, a flower-producing apical bud or primordium enclosed by thick fleshy scales occurs.

 

Corm. The swollen base of a stem, which is encapsulated and enclosed in dry scale-like leaves.


Eye. An axillary bud found on underground plant parts, such as a tuber. The term 'eye' is also used to describe axillary buds that occur in several species where the stem joins the tuberous root.


Leptomorph. A slender rhizome with long internodes.

 

Leaf spine: a spine is a modified leaf or leaf primordium; functions in providing additional support to plants that do not necessarily produce tendrils. Leaflet spines are found in species with compound leaves.

 

Offset: A lateral shoot or branch which develops from the base of the main stem in certain plants. Many bulbs produce offsets from their bases.

 

Offshoot: An alternative term generally equivalent to offset. Applies to lateral branches on stems of monocots. Date palm, pineapple, banana, and orchids produce offshoots.

 

Pachymorph: A thick, fleshy rhizome that is short in relation to its diameter.

 

Runner: A specialized stem which develops from the axil of a leaf that grows horizontally along the ground, and forms a new plant at one of the nodes. Common in grasses.

 

 

Back to Adaptations