Leaves, Stems, and Modified Structures (Page 1 Notes)

Flashcards covering stomata, guard cells, stipules, modified leaves and stems, underground storage structures, and rosette growth form based on Page 1 notes.

What is the stomatal complex and what does it regulate?

The stomatal complex consists of the stoma and the surrounding guard cells, and it regulates the flow of gases and water vapor into and out of the leaf.

Where are stomata primarily located on leaves?

Stomata are found primarily on the undersides of leaves.

What are guard cells and what is their function?

Guard cells flank the stomatal pore and open and close the stoma in response to environmental conditions.

What are stipules and where are they located?

Stipules are small, leaflike appendages at the base of a petiole.

Which plant is noted for having particularly large stipules, and what is unique about them?

Sycamore (Platanus sp.); the stipule appears to surround the stem and is very leaflike.

What roles have stipules historically had and what are their possible modern roles?

Historically, they protected the leaf bud or emerging leaf; they may now have a minor photosynthetic role or be modified into spines or tendrils.

What are modified leaves and give examples mentioned?

Leaves evolved to perform functions other than photosynthesis; examples include bracts (petals of poinsettia) and structures like twining tendrils and spines.

What are bracts and which plant is given as an example?

Bracts are modified leaves; poinsettia petals are actually bracts.

What is the function of stems and what do they provide?

Stems enable growth in height or width, transport water and other substances, and serve as the attachment site for leaves and flowers; some stems are photosynthetic.

What are underground bulbs and how are they related to stems?

Underground bulbs contain short stems with attached scales (modified leaves), as seen in structures like onion layers.

What is a tuber and give an example?

A tuber is an underground stem thickened for storage; the common potato is a tuber.

What is the rosette plant form and how does it arise?

Rosette form arises from shortened stems in the aboveground parts, causing leaves to radiate from a central point like rose petals; examples include African violets, cabbages, strawberries, and daylilies.