Plants Flashcards
Bryophytes
- Primitive plants
- NO vascular tissue
- Must live in MOIST environments
- NO roots or xylem
- Absorb water by diffusion
Tracheophytes
- HAVE xylem and phloem
- Include ancient seedless plants(ferns) that reproduce by spores
- seed plants - gymnosperms; angiosperms
Gymnosperms
- Conifers
- Dry conditions
- Needle leaves
- Thick and waxy cuticle
- Stomates located in stomatal crypts to reduce water loss
Angiosperm
- Flowering plants
- AKA anthophyta
- Most diverse and plentiful plants
- monocotyledons(monocots); dicotyledons (dicots)
Monocot
- ONE cotyledon
- SCATTERED vascular bundles in stem
- PARALLEL leaf veins
- Floral parts in 3s
- FIBROUS roots
- ex/ grasses
Dicots
- TWO cotyledons
- vascular bundles in stme IN A RING
- NETLIKE leaf veins
- Floral pats in 4s or 5s
- TAProots
- ex/ trees, flowering plants
Cutin
Waxy coating on leaves to reduce water loss
Gametangia
Protective jack of cells that protect gametes and zygotes from drying out
Sporopollenin
A tough polymer that is resistant to environmental damage
Walls of spores and pollen
Desiccation
Dehydration
Meristem tissue
- Continually divides, generating new cells
Primary growth
- Vertical
- Elongation of the plant down to soil and up to air
- New cells from apical meristem
Apical meristem
Constantly dividing growth layer located at the buds of shoots and tips of the roots
Root growth
- Concentrated near the root tip
- From top to deeper into soil:
- Zone of differentiation(epidermis, ground tissue, xylem, phloem)
- Zone of elongation
- Zone of cell division(apical meristem)
- root cap
Root cap
Secretes substances that helps digest the earth as the root tip grows
Secondary Growth
- Lateral growth
- News cells produced by the lateral meristem
- For woody plants
- Responsible for the enlargement of the trunk
Epidermis
- Covers root
- modified for absorption
Cortex
- Storage
- Consists of parenchyma cells that contain many plastids for storage of starch
Plastids
Organelles found only in plants
Parenchyma cells
In the cortex; contain many plastsids for storage of starch
Stele
- AKA vascular cylinder
- Transport
- xylem and phloem
Pericycle
In Monocots, Layerso of tissues where lateral roots arise
Endoderm
- Layer of cells that surrounds the stele
- Each endoderm cell is wrapped with the Casparian strip
- To select what minerals enter the stele and body of the plant
Casparian strip
A continuous band of waxy material that is impervious to water and dissolved minerals
Lateral movement
- Movement of water and solutes across a plant
- Accomplished by the symplast and apoplast
Symplast
A continuous system of cytoplasm of cells interconnected by plasmodesmata
Apoplast
The network of cell walls and intercellular spaces within a plant body that permits extensive extracellular movement of water within a plant
Mychorrhizae
- Where older regions of roots lack root hairs
- Supply the plant with water and minerals
- Symbiotic structures consisting of the plant’s roots with the hyphae(filaments) of a fungus
Rhizobium
- Symbiotic bacterium
- Lives in the nodules on rootes of legumes
- Fixes nitrogen gas from the air
Taproot
- A single, large root that gives rise to lateral branch roots
- Dicots
Adventitious roots
Roots that arise above ground
Aerial roots; Prop roots
Aerial roots
- For trees that grow in swamps or salt marshes
- stick up out of the water and serve to aerate the root cells
Prop roots
Grow aboveground to help support the plant
Vascular bundles
- Vascular tissue that run the length of the stem in strands
- Xylem on the inside; phloem on the outside; meristem tissue in middle
Pith
Parenchymal tissues modified for storage
Leaf
- Epidermis - Upper and Lower
- Waxy cuticle
- Guard cells
- Palisade Mesophyll
- Spongy Mesophyll
- Veins
Epidermis
Protection
Don’t contain chloroplasts and don’t photsynthesize
Waxy cuticle
- Made of cutin
- Minimizes water loss
Guard cells
- Modified epidermal cells
- Contain chloroplasts
- Control the opening of the stomates in response to changes in water pressure
- Become turgid(swollen) when absorb water by osmosis and let stomata open
- Become flaccid when loset water and close stomates
Palisade mesophyll
- Tightly packed
- Photosynthesis
Spongy mesophyll
- Loosely packed
- Photosynthesis
- Diffuse and exchange of gases into and out of these cells
Veins
- Located in the mesophyll
- carry water and nutrients from soil to leaves
- Carry sugar from leaves to rest of plant
Transpiration
Loss of water from leaf
Trichomes
Spikelike projections that also protect the leaf
What is ground tissue made of?
- Parenchyma cells
- Collenchyma cells
- Sclerenchyma cells
Parenchyma cells
- Thin and flexible primary cell wall
- NO secondary cell wall
- Traditional plant cells
Collenchyma cells
- UNEVENLY thickened primary cell walls
- NO secondary cell walls
Sclerenchyma Cells
- Thick primary and secondary cell walls that are fortified with lignin
- Support
The 2 types of elongated cells that make up the xylem
Tracheids and vessel elements
Tracheids
- Its secondary cell walls are hardened with lignin
- Support and transport
Xylem
- Carries water and nutrients from soil UP agaisnt gravity with no energy
- Transpirational pull
- Cohesion tension
Transpirational pull
- For each molecule of water that evaporates from a leaft by transpiration, another water molecule is drawn in at the root to replace it
What affects the rate of transpiration?
- Humidity (high-slows down; low-speeds up)
- Wind(reduce humidity-speed up)
- Light intensity
- Closing stomates stops
Phloem
- Made of sieve tube elements and companion cells
- Carry sugar from leaves to rest of plant by translocation; requires energy
Endosperm
Cotyledon
Double fertilization
- Sperm + Ovum = Embryo (2n)
- Sperm + 2 polar bodies = Cotyledon(3n)
What does the embryo of the seed contain?
Hypocotyl
Epicotyl
Radicle
hypocotyl
Becomes the lower part of the stem and the roots
Epicotyl
Becomes upper part of the stem
Radicle
Embryonic Root; First organ to emerge from the germinating seed
Gametophyte
- n
- Produces gametes by mitosisthat fuse during fertilization to yield 2n zygotes
- Each zygote develops into a sporophyte(2n) that produces haploid spores(n) by meisis
Gametophyte generation dominates the life cycle in….?
- Mosses, bryophytes(primitive plants)
- Haploid(n)
- Sporophyte is dependent on gametophyte and obtains its nutrients from it
Fern
- Seedless vascular plant
- intermediate between brophytes and vascular plants
- Sporophyte generation is larger and independent from gametophyte
- Both photosynthesize
Gametophyte is dependent on teh sporophyte in….?
- seed plants (flowering and conifers)
- Gametophyte generation exists inside the sporophyte generation
Antheridium
Structure that produces sperm,
develops on the gametophyte
Archegonium
Structure that produces eggs
Develops on gametophyte
Megaspores
Produced by large FEMALE cones and will develop into female gametophytes
Microspores
Produced by small MALE cones and develop into male gametophytes OR pollen grains
Protonem
Branching filaments produced by germinating moss spores, becomes the gametophyte in moss
Sporangia
Located on the tip of the mature sporophyte, wehre meiosis occurs, producing haploid spores
Sori
Raised spots located on the underside of sporophyte ferns, clusters of sporangia
Auxins
- Unequal distribution causes phototropism
- enhance apical dominance
- Stimulate stem elongation and growth by softening cell wall
- Used as rooting powder to develop roots quickly
Cytokinins
- Stimulate cytokinesis and cell division
- Delay senescence (aging) by inhibiting protein breakdown
Gibberellins
- Promote stem and leaf elongation
- induce bolting(rapid growth of a floral stalk) to ensure pollination and seed dispersal
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Abscisic Acid
- Inhibits growth
- Promotes seed dormancy
- Enables plants to withstand drought
- Closes stomates during water loss
Ethylene gas
- Promotes ripening, which triggers more gas
Tropism
- Growth of a plant toward or away from a stimulus
- thigmotropisms(touch), geotropisms, gravitropisms(gravity, photostropisms(light)
