Please enable JavaScript.
Coggle requires JavaScript to display documents.
Leaves (Morphology and Anatomy of Other Leaf Types (Sclerophyllous Foliage…
Leaves
Morphology and Anatomy of Other Leaf Types
Succulent Leaves
Numerous adaptations to survive in desert
Thick and fleshy
Shape reduces surface to volume ratio
Favors water conservation
Mesophyll is transparent
Allows light to penetrate deeper than foliage leaves
Photosynthesis occurs deeply
Mesophyll contains few air spaces
Reduces internal evaporative surface area
Sclerophyllous Foliage Leaves
Have to produce more sugars by photosynthesis
Plant would lose energy making leaves if not
Feasible
Schlerenchyma present just below epidermis
Thick cuticle with abundant waxes
Resistant to animals, fungi temperature and up light
Bud Scales
Small and rarely compound
Wind damage is not a risk
Common modification of leaves
Tougher and waxier than normal leaves
Spines
Axillary buds
Protects plant from animals
Hard and resistant to decay
Tendrils
#
Grow indefinitely
Contain cells that sense contact
Modified leaf
Curl up after touch
Peas, cucumbers, squash
Leaves with Kranz Anatomy
C4 leaves
Lack palisade parenchyma and spongy mesophyll
Have prominent bundle sheaths
Insect Traps
Gain nitrogen by digesting insects
Classified as
Active
Move during capture
Passive
Incapable of movement
Numerous stomata, vascular bundles and mesophyll
Have many trichomes
#
Leaves of Conifers
Schlerophylls
Epidermis and hypodermis have thick cell walls
Always simple, never compound
Mostly perennial
Internal Structure of Foliage Leaves
Epidermis
Contains
Epidermal cells
Coating of cutin on outer walls
Retain water
Makes leaf slippery
Prevents spores from sticking
Makes fungal digestion harder
Guard cells
Guard stomatal openings
Trichomes
Provide shade on leaf
Make walking or chewing difficult for animals
Secrete powerful stinging compounds
Stomata
Openings in the leaf
Allow water out
Most are on lower epidermis
Few fungi can penetrate the leaf
Mesophyll
Interior to the leaf epidermis
Lower portion is spongy mesophyll
Open, loose aerenchyma
Permits carbon dioxide diffusion
Upper portion Palisade Mesophyll
Normally one layer thick
Sometimes three or four layers
Under penetrating sunlight
Sometimes on upper and lower portion
Vascular Tissues
Between the palisade and parenchyma
Eudicot
Large midrib (midvein)
Lateral veins emerge
Branch into minor veins
Minor veins
Release water from xylem
Load sugar into phloem
Petiole
Considered part of leaf
Transition between stem and lamina
Like cortex
Somewhat compact
Two small flaps of tissue at base
Stipules
Various functions
Initiation and Development of Leaves
Basal Angiosperms and Eudicots
Produced through activity of shoot meristem
Little to no mitosis or cell division occur
Only maturation
Monocots
Initiated by expansion of shoot apical meristems
Constant basal expansion
Protoxylem and protophloem are constantly stretched
Concepts
Shoot System
Stems
Leaves
Support
Tendrils
Protection
Bud scales
Spines
Storage
Leaves of fleshy bulbs
Nitrogen procurement
Trapping and digesting insects
Photosynthesis
Protect plant
Modified leaves
