Leaf Development and Anatomy Flashcards
What are the leaf basics?
2 parts: Petiole and lamina (some stipules in some species)
What does the petiole do?
Holds lamina up and away from the stem
Why does the lamina have vascular tissue?
For conduction and transport and structural support
What is the first order vein called?
Mid-vein
What are lateral veins?
Veins with 2 degrees
What are small veins
Veins with 3 degrees
What type of veins do monocots usually have?
Parallel veins with transverse veins between
What are the features of evergreen leaves?
Thick tissue, thick wavy cuticle, often small and compact
Leathery from hardened tissues inside
Low N content
What are deciduous leaves?
Leaves that shed seasonally and have a higher N content
How do leaves develop?
- Leaf primordium elongates and a strand of procambium develops into it
- Tissues mature basipetally (petiole develops last)
- Procambium produces vascular tissues
- Ground meristem produces mesophyll = main tissue
Where are all stems connected to?
The vascular system
Attachment of leaves and branches results in gaps in the node
What does adaxial mean?
Upper surface on epidermis
What does abaxial mean
Lower surface on epidermis
What are the features of the epidermis?
usually 1 cell thick
Has a cuticle
Has stomata: for gas exchange consist of stomatal pores and a pair of guard cells
Can be on both surfaces but usually more below
May have trichomes e.g hairs, glands, etc.
What is the stomata?
specialized groups of cells within the epidermis (most are usually found on the lower leaf surface) Guard cells have chloroplasts in them
