Plant Structure Flashcards
Three main organs of plants
roots, leaves, and stems
What do roots do
supply water and minerals to the plant
What do leaves do
supply sugars to the plant
What do stems do
supply support and structure and transport systems
Function of roots
Anchoring the plant
Absorbing minerals and water
storing organic nutrients
here does absorption of water and minerals occur in most plants
root hairs
Types of Roots
Taproot systems
Adventitious roots
Fibrous roots
Taproot system
one main vertical root
lateral roots, or branch roots
Adventitious roots
can arise from stems or leaves
Fibrous roots
seedless vascular plants and monocots
thin lateral roots with no main root
Modified roots
prop roots strangling roots Pneumatophores Buttress roots Storage root Haustorial roots Climbing root
Prop roots
Aerial roots
Add structural support
Strangling roots
Grow around objects supporting the plant
Strangler figs
- epiphytes
Pneumatophores
Roots that rise up in the air
Pores allow gas exchange
Mangroves
Buttress roots
support large trees
Storage root
tap root
lateral root
Haustorial roots
Parasitic plants (mistletoe, dodder, snow plants) Absorb water and nutrients from other plants
Climbing root
Adventitious root
Supports climbing plants
Negatively phototrophic
(Ivies)
What does a stem consist of
an alternating system of nodes, and internodes
Nodes
the points at which leaves are attached
Internodes
the stem segments between nodes
Axillary bud
can form a lateral shoot, or branch
Apical bud or terminal bud
located near the shoot tip and causes elongation of a young shoot
Apical dominance
dormancy in most non-apical buds
Modifies stems
corm Rhizome Cladophylls Stolon Bulbs
Corm
Short, underground storage stem
Taro, Gladiolus, Saffron
Rhizome
Horizontal stem
Usually underground
Sends out roots, shoots
(Ginger, poison oak, bermuda grass)
Cladophylls
Flattened photosynthetic stems resembling leaves
Stolon
Horizontal stem At the ground surface or just underground Adventitious roots Produces clone at the end of the stem (strawberry, many grasses)
Bulbs
Underground stems
Modified leaves - storage when dormant
(garlic, onion)
What do leaves consist of
flattened blade and a stalk called the petiole, which joins the leaf to a node of the stem
Modified leaves
Bracts
Tendrils
Storage leaves
Bracts
Associated with the reproductive structure
Often brightly colored
(Bougainvillea, Poinsettia)
Tendrils
Used for attaching for climbing Can photosynthesize Can be thigmotropic (pea plant) In other plants, tendrils derive from stems
Storage leaves
can store water
nutrients
toxins
succulents (ice plants, agave)
Defense mechanisms
spines, thorns, prickles
spines
Modified leaves
used for defense
common in xerophytes
thorns
modified stems
prickles
modified epidermis
Roses are an example
Types of plant tissues
dermal
ground
vascular
Dermal tissue system
epidermis
cuticle
periderm
Trichomes
Epidermis
In non-woody plants
one cell layer thick
Cuticle
waxy coating
help prevent water loss from the epidermis
Periderm
in woody plants
protective tissues
replaces the epidermis in older regions of stems and roots
Trichomes
are outgrowths of the shoot epidermis and can help with insect defense
Vascular tissue system
carries out long-distance transport of material between roots and shoots
Two vascular tissues
Xylem and Phloem
Xylem
conveys water and dissolved minerals upward from roots into the shoots
Phloem
transports organic nutrients from where they are made to where they are needed
Stele
the vascular tissue of a stem or root
What is the stele of the root in angiosperms
a solid central vascular cylinder
vascular bundles
strands of xylem and phloem. The stele of stems and leaves is divided into vascular bundles
Ground Tissue system
tissues that are neither dermal nor vascular.
Includes cells specialized for storage, photosynthesis, and support
Pith
Ground tissue internal to the vascular system
Cortex
ground tissue external to the vascular tissue.
