Plant Form Ch 36 Flashcards
What 2 systems does a vascular plant consist of
Root system
Shoot system
Vascular Plant:
Root system
- Anchors the plant and is used to absorb water and ions
- Roots are less competitive with other roots from the same plant than with roots from different plants
Vascular Plant:
Shoot system
- Consists of supporting stems, photosynthetic leaves, and reproductive flowers
- Repetitive units consist of internode, node, leaf, and axillary bud
How are plant cell types distinguished
- size of vacuoles
- Living or not at maturity
- Thickness of secretions found in their cellulose cell walls
Cell Wall: Primary v.s Reinforced
Describe relationship between cells.
- Some cells have a primary cell wall of cellulose, synthesized at protoplast or cell membrane
- some cells have a heavily reinforced cell wall with multiple layers of cellulose
Name and explain three basic tissue types
Dermal:
- the outer protective covering,
- forms the epidermis, one cell layer thick in most plants,
- covered with a fatty cutin layer constituting the cuticle, -
- contains special cells, including guard cells, trichomes, and root hairs
Ground:
- functions in storage, provide structural support, photosynthesis, and secretions
- Paired sausage-shaped cells
- Flank a stoma – epidermal opening (Passageway for oxygen, carbon dioxide, and water vapor)
- Stomatal patterning genes (reveal a coordinated network of cell–cell communication that informs cells of their positions relative to other cells and determines cell fate)
Vascular: Conducts fluids (water and nutrients) and dissolves substances
What does tissue consist of
One or more cell types
Dermal, ground, and vascular tissue extend through what system(s)
Root and Shoot
New growth occurs at
Meristems
What are meristems?
- Clumps of small particles with dense cytoplasm and large nuclei
Meristems act as
Stem cells do in animals
Meristems divide to produce
Differentiated cell, and meristematic cell
Apical meristems produce
Extensions of shoot and root systems
Lateral meristems produce
An increase in shoot and root diameter
Where are apical meristems located?
What do they give rise too?
What is the apical meristem composed of?
- Tips of stems and roots
- Primary tissues aka primary plant body
- Delicate cells that need protection, root cap, and leaf primordia
Apical meristem:
- Root Cap
- Leaf primordia
- Protects root apical meristem
2. Protect shoot apical meristem
Apical meristem gives rise to the three tissue systems by first initiating _________
Primary Meristems
Apical Meristem:
Name and describe the 3 primary meristems
Protoderm – forms epidermis
Procambrium – produces primary vascular tissue
Ground meristem – differentiates into ground tissue
Describe:
intercalary meristems
- Arise in stem internode
- to internode length
Lateral Meristems:
Where are they found?
What do they give rise too?
- In plants that exhibit seconndary growth
- secondary tissues which are collectively called the secondary plant body
Lateral meristems:
Name two types of woody plants, and tell what they produce
- Cork cambium produces outer bark
- Vascular cambium produces secondary vascular tissue
Secondary xylem is the main component of wood
Trichomes
- Cellular or multicellular hairlike outgrowths of the epidermis
- Keep leaf surfaces cool and reduce evaporation by covering stomatal openings
- Some are glandular, secreting substances that deter herbivory
Root Hairs
- Tubular extensions of individual epidermal cells
- Greatly increase the root’s surface area and efficiency of absorption
- Should not be confused with lateral roots
Ground Tissue:
Name and describe the cell types
Parenchyma:
- Most common type of plant cell
- Function in storage, photosynthesis, and secretion
Collenchyma:
- Provide support and protection for plant organs
- Allow bending without breaking
Sclerenchyma:
- tough, thick walls
- Provide support and protection (strength)
- 2º cell walls contain lignin
Sclerids -
Vascular Tissue:
Xylem
- Principal water-conducting tissue
- Transports water and minerals from roots to shoots
Vascular tissue:
Vessels
- Continuous tubes of dead cylindrical cells arranged end-to-end
- Vessel members tend to be shorter and wider than tracheids
Vascular tissue:
Tracheids
- Transport cell
- Dead cells that taper at the end and overlap one another
Vascular Tissue:
Transpiration
- diffusion of water vapor from plant
What tissue type includes fibers and parenchyma cells (ground tissue cells)?
Vascular tissue
Phloem
- Principal food-conducting tissue in vascular plants
- Contains two types of elongated cells (Sieve cells, Living cells)
Phloem:
- Describe Sieve Cells.
- Describe Living Cells.
- (seedless vascular plants and gymnosperms) and sieve tube members (angiosperms), Sieve-tube members are more specialized (more efficient), Associated with companion cells
- Living cells that contain clusters of pores called sieve areas or sieve plates
Roots
Simpler pattern of organization and development than stems
What are the 4 regions of roots
- Root cap
- Zone of cell division
- Zone of elongation
- Zone of maturation
Root Cap
- Contains two types of cells that are formed continuously by the root apical meristem
1. Columella cells – inner
2. Root cap cells – outer and lateral - Functions mainly in protection of the delicate tissues behind it
Zone of Cell Division
- Derived from rapid divisions of the root apical meristem
- Contains mostly cuboidal cells, with small vacuoles and large central nuclei
- Apical meristem daughter cells soon subdivide into the three primary tissues:
Protoderm, procambium, and ground meristem
Zone of Cell Division:
- WEREWOLF (WER) gene
- SCARECROW (SCR) gene
- Suppresses root hair development
2. Necessary for differentiation of endodermal and ground cells
Zone of Elongation
- Roots lengthen because cells become several times longer than wide
- Width also increases slightly
- No further increase occurs above this zone
- Mature parts of the root, except for increasing in girth, remain stationary for the life of the plant
Zone of Maturation
- Elongated cells become differentiated into specific cell types
- Root surface cells become epidermal cells
Have very thin cuticle
Include root hair and nonhair cells - Parenchyma cells produced by cortex (ground meristem)
Inner boundary becomes endodermis - Casparian strips
Stele – tissues interior to endodermis
Pericycle
Modified Roots:
- Taproot system
- Fibrous root system
- Adventitious roots
- specific functions
- single large root with small branch roots
- many small roots of similar diameter
- arise from any place other than the plant’s root
- produce modified roots
Prop roots
Keep the plant upright
Aerial roots
Obtain water from the air
Pneumatophores
Facilitate oxygen uptake
Contractile roots
Pull plant deeper into soil
Parasitic roots
Penetrate host plants
Food storage roots
Store carbohydrates
Water storage roots
Weigh 50 kg or more
Buttress roots
Provide considerable stability
Stems
- undergo growth from cell division in apical and lateral stems
- Shoot apical meristem initiates stem tissue and intermittently produces primordia
Stems:
- Node
- Internode
- Blade
- Petiole
- Axillary bud
- Terminal bud
- point of attachment of leaf to stem
- area of stem between two nodes
- flattened part of leaf
- stalk of leaf
- develops into branches with leaves or may form flowers
- extends the shoot system during the growing season
Monocot (one cotyledon) vs. Dicot (two cotyledon) Stems:
Cotyledon
embryonic leaf in seed-bearing plants, one or more of which are the 1st leaves to appear from a germinating seed
Monocot (one cotyledon) vs. Dicot (two cotyledon) Stems:
- Major distinguishing feature between monocot and eudicot stems is
- Monocot vascular bundles are usually scattered throughout ____________
- Eudicot vascular tissue is arranged in a ring with
- the organization of the vascular tissue system
- ground tissue system
- internal ground tissue (pith) and external ground tissue (cortex) - Rose family and legumes
Vascular tissue arrangement is directly related to
the stem’s ability for secondary growth
Vascular Tissue Arrangement:
- eudicots
- monocots
- vascular cambium develops between the primary xylem and phloem
- there is no vascular cambium – no secondary growth
Connects the ring of primary vascular bundles
vascular cambium
Tree Stump Rings
- reveal annual patterns of vascular cambium growth
- Cell size depends on growth conditions
Tree Stump Rings:
In woody eudicots and gymnosperms, the ________ arises in the outer cortex
cork cambium - Produces boxlike cork cells on outside
Tree Stump Rings:
Periderm
- cork cambium, cork, and phelloderm
- Forms outer bark
Lenticels
Cork cambium produces unsuberized cells that permit gas exchange to continue
Bulbs
swollen underground stems, consisting of fleshy leaves
Corms
superficially resemble bulbs, but have no fleshy leaves
Rhizomes
horizontal underground stems, with adventitious roots
Runners and stolons
horizontal stems with long internodes that grow along the surface of the ground
Tubers
swollen tips of rhizomes that contain carbohydrates
Tendrils
twine around supports and aid in climbing
Cladophylls
flattened photosynthetic stems resembling leaves
Leaves
- Principal site of photosynthesis
- Expand by cell enlargement and cell division
- Determinate in structure – growth stops at maturity
Name and describe 2 different morphological groups of leaves
- Microphyll
- Leaf with one vein branching from the stem and not extending the full length of the leaf
- Phylum Lycophyta - Megaphylls
- Several to many veins
- Most plants
Eudicot Leaves
- flattened petiole
- Slender stalk called petiole
- Leaf flattening increases photosynthetic surface
- Flattening of the leaf blade reflects a shift from radial symmetry to dorsal–ventral (top–bottom) symmetry
stipules
- Outgrowths at base of petiole
- May be leaf-forming or modified as spines
Veins
- Vascular bundles in leaves
- Main veins are parallel in most monocot leaves
- Veins of eudicots form an often intricate network
Simple leaves
- contain undivided blades
- May have teeth, indentations, or lobes
Compound leaves
have blades that are divided into leaflets
The leaf’s surface is covered by transparent
epidermal cells
Leaf Epidermis
- Most have no chloroplasts
- Epidermis has a waxy cuticle
- Different types of glands and trichomes may be present
- Lower epidermis contains numerous stomata flanked by guard cells
Mesophyll in Eudicots :
- Palisade mesophyll
- Spongy mesophyll
- usually two rows of tightly packed chlorenchyma cells
- loosely arranged cells with many air spaces in between.
Function in gas exchange and water vapor exit
Mesophyll in Monocots
- mesophyll is usually not differentiated into palisade/spongy layers
Modified Leaves:
- Floral leaves (bracts)
- Spines
- Reproductive leaves
- Window leaves
- surround true flowers and behave as showy petals
- reduce water loss and may deter predators
- plantlets capable of growing independently into full-sized plant
- succulent, cone-shaped leaves that allow photosynthesis underground
Shade leaves
larger in surface area but with less mesophyll than sun-lit leaves
Insectivorous leaves
- trap insects
- Pitcher plants have cone-shaped leaves that accumulate rainwater
- Sundews have glands that secrete sticky mucilage
- Venus flytrap have hinged leaves that snap shut
