Primary Plant Body Flashcards
What is the primary plant body?
Roots
Shoots-stems and leaves
Plants shoots are _____
Modular
-repetitive units
-photomere: internode, node, leaf, bud
Meristems
Clump of small, unspecialized cells
-dense cytoplasm
-large nuclei
-repeated cell divisions
Apical meristem
-near tips of stems and roots
-elongation of roots and shoots
-produce primary tissues to make plant body
-root apical meristem protected by a cap
-shoot apical meristem protected by leaf primordia or bent hypocotyl
Lateral meristems
Increase girth
Not present in all plants
Intercalary meristems
In stem internodes
Many monocots, horsetails
Primary growth
-result of cell division at the apical meristem
-elongation of organ (stem, root)
Secondary growth
-result of cell division at lateral meristem
-increase in girth
Lateral meristem types
Vascular cambium: secondary xylem and phloem
Cork cambium: cork cells of outer bark in woody species
Periderm is made up of
Cork=phellem
Cork cambium
Phelloderm
Part of the dermal tissue system
Phellogen is the same as
Cork cambium
Root functions
-anchorage
-absorption of water and minerals
Zones of roots
-zone of cell division
-Zone of elongation
-Zone of maturation
Root cap
-several layers of cells
-protects root apical meristem as root pushes through soil
-border cells: old cells sloughed off, replaced by new cells
-mucigel produced by outer layer
-new root cap produced when existing cap is removed
-gravitropism, hydrotropism
Zone of cell division
-cell divide every 12-36 hours
-apical meristem daughter cells divide into Protoderm, Procambium, and ground meristem tissues
Zone of Elongation
-roots lengthen because cells produced by primary meristems grow more on length than width
Zone of maturation
-cells differentiate into epidermal cells, some with a root hair
-cortex produced by parenchyma cells. Inner boundary differentiated into endodermis Surrounded by casparian strips composed of suberin
Endomyccorhizae and Ectomycorrhizae
Endo-thin mantle of hyphae that penetrate the root cortex
Ecto-thick mantle of hyphae that form a sheath outside the root
Quiescent Center
Dormant Center of meristem
How can plant elongate if it has a rigid cell wall?
Cell wall expands with use of enzymes to acidify walls of cellulose
Enzyme-expansins
Arbuscule
Invaginations to create more surface area with Plasmodesmata in mycorrhizae
What do fungi get from plants and what do plants get from fungi
P and N to plant root
Carbs to fungi
What do plants release to attract fungi
Hormones
Stele
All tissues interior to the endodermis
Pericycle
Cells immediately adjacent and interior to the endodermis
Monocot stele arrangement in roots
-primary xylem in discrete vascular bundles
-ring surrounds pith
-poem between bundles
Eudicots stele arrangement in roots
-Xylem x-shaped
-Phloem in discrete groups of cells between arms
Where do lateral roots originate
Pericycle
Casparian strip
Integral band-like portion of primary wall and middle lamella impregnated with suberin and lignin
Apoplasic, symplasitc and trans cellular roots
Between cell walls
Go through Plasmodesmata into cells and then transfer through cells following the outside portion of inner cell
Go through cells
Taproot be fibrous root
Single large root with smaller branch roots
Many small, thin roots
Modified roots
-aerial (prop, climbing, absorbing)
-pneumatophores
-contractile
-storage
-buttress
-parasitic
Rhizosphere
The volume of soil around living plant roots that is influenced by root activity
Monocot primary root
Short lived, and instead the main root system develops from roots that arise from the stem (adventitious roots). The lateral roots off this give rise to the fibrous root system
During growth of roots, they follow the path of ______
Least resistance
Often filling in areas made by dead roots
Root cap areas
Columnella-central column of cells. Site that perceives gravity (gravitropism) and water potential gradients (hydrotropism)
Lateral root cap-lateral portion
Lenticels
Spongy areas in the periderm with numerous intercellular spaces that permit the passage of air
Stems function
Support
Conduction
Shoot apical meristem purpose
-initiates stem tissues
-intermittently produces primordial or leaves, other shoots or flowers
-node:region of leaf attachment
-internode:stem between two nodes
Stele variation in monocot and eudicot stems
In eudicots, vascular cambium develops between primary xylem and phloem, and vascular bundles are in circle
I’m monocots, vascular bundles are completely arranged
Shoot apical meristems can divide in which ways
-anticlinal: horizontal -tunica
-periclinal: vertical -corpus
Area of slow and fast Division in shoot apical meristem
Slow:Central mother cell zone, and corpus
Fast: Peripheral or tunica
Vascular cambium cells divide ______, producing ______
Indefinitely
Secondary tissues
-wood in trees (secondary xylem)
-cork cambium: in outer cortex of woody eudicots and gymnosperms.
Cork tissues impregnated with _____ constitute outer bark
Suberin
Cork tissue also produces _____ cells (lenticels) which permit continuance of gas exchange
Unsuberized
Modified stem types
-storage: bulbs, corms, tubers
-growth/asexual reproduction: rhizomes, runner and stolons
-anchorage/climbing: tendrils
-photosynthesis/storage: Cladodes or cladophylls
What are leaves
-lateral appendages that share four defining features that have: vascularization, determinate growth, bilateral symmetry (abaxial/adaxial polarity), definite arrangement (Phyllotaxis)
Despite shared characteristics of leaves, leaves are not ______ across all vascular plants
Homologous
Leaf morphological groups
-microphylls: have one vein that does not leave a gap when it branches from the vascular cylinder of the stem. Characteristics of lycophytes
-megaphylls: have several veins that leave a gap when they branch from the vascular cylinder of the stem
Leaf development steps
- Leaf buttress: bulge on flank of SAM, Elongation of cells in leaf buttress
- Leaf primordium
- Petiole
- Blade
Simple vs compound leaves
Simple: undivided blades
Compound: blade divided into leaflets
-pinnately compound: leaflets arranged in pairs along common axis
-palmately compound: leaflets radiate out from common point
Leaf arrangement types
Alternate: one leaf per node
Opposite: two leaves per node
Whorl:circle of leaves at same level
Two functions of stems
Support
Conduction
Leaf primordia develop into ____
Bud primordia develop into
Leaves
Lateral shoots
Intercalart meristem
A localized meristem region in the elongating internode
Interfasicular regions
Vascular bundles separated by narrow parenchymous regions
Open vs closed vascular bundles
Open: bundles that do give rise to a cambium
Closed: bundles that do not become cambium. Surrounded by sclerenchyma
Leaf traces
The extensions from the vascular system in the stem towards the leaves
Leaf trace gaps
Wide Interfasicular regions, or gaps of ground tissue, in the vascular cylinder located above the level where leaf traces diverge toward the leaves
Stem bundle
Vascular bundle in stem
Sympodium
A stem bundle and it’s associated leaf traces
In which cells are there more chloroplasts: spongy or palisade
Palisade
Sun leaves vs shade leaves
Sun leaves:
-smaller
-thicker (more palisade)
-more extensive vascular system
-thicker epidermal walls
-more surface area of the mesophyll
Abscission
Normal separation of the leaf from the stem
Leaf scar
After leaf falls
Megaphylls have ____ but microphylls done
vascular gap
Blade is also known as a
Lamina
Areoles
Smallest irrigated unit in a leaf
Inflorescence
Flowering branch
Floating leaves have more stomata on what surface?
Non aquatic plants have more stomata on which side?
Adaxial
Abaxial
Palisade layer has more _______
Spongy layer deals more in the ______
Light reactions
Calvin cycle
Which surface of the leaf has more cuticle
Adaxial
Trichomes and boundary layer
Increase boundary layer to increase humidity and decrease the vast temp gradient
Spines can be modified ____ or ____
Stems or leaves
Epidermis functions
-cuticle
-gas exchange
-trichomes
-protection
Mesophyll differences in Eudicots and monocots
Eudicots have palisade and spongy
Monocots have spongy
