Exam 2 Flashcards
green algal sister clade to land plants
stoneworts
how are stoneworts different from other green algae
- prominent, multicellular gametangia
- calcium carbonate crusts
- dominated by multicellular haploid individuals
- 5-15cm in length
- food for fish/geese
angiosperms include
monocots and eudicots
problems had to be overcome living on land
- desiccation
- structural support
- move h20 and nutrients
- disseminate gametes
land plants are distinguished from gleen plants by:
- terrestrial
- cuticle w/ pores ( most have stomata)
- alt. of generations
- retention of embryos
- thick-walled spores
- complex gametangia
Desiccation land vs water
- water-larger leaves=more photosynthesis
- land-larger leaves=more evaporation
cuticle w/ pores/stomata does:
regulates water and gas exchange in terrestrial environments
Evolutionary changes in the water conducting cells of the vascular tissue enabled plants to:
- grow larger
- be farther from water
sporopollenin
water tight material covering pollen/spores
problems w/ land plat reproduction
- getting gametes together
- protecting and disseminating
- Protecting embryo
what land plants have swimming sperm
mosses and ferns
gametangia
protected structures that produce gametes
gametangia for sperm
antheridium
gametangia for eggs
archegonium
what do gametangia do
protect gametes from desiccation and damage
2 critical innovations for land plant reproduction
- offspring retention
- gametangia
gametophyte dominant
- (n)
- bryophytes (moss)
sporophyte dominant
- 2n
- pteridophytes (ferns)
- Gymnosperms (conifers)
- Anthophyta (flowering plts)
body plan
describes an organism’s architecture
Meristem
- role in growth
- divide rapidly by mitosis
- undifferentiated
Parenchyma
- versatile and abundant
- living when mature
- totipotent
- sites of
- photosynthesis (leaves)
- carbohydrate storage (roots)
- nutrient transport (phloem)
- important for wound repair and some growth
callus
undifferentiated cells
collenchyma & sclerenchyma ____________
provide support
Collenchyma
- living when mature
- thickened cell walls–bend and stretch
- support young stems and leaves
sclerenchyma
- support after growth ceases
- dead when mature (no cytoplasm)
- hollow cells
- in mature plants–2º cell walls w/ lignin
- xylem: tracheids & vessel elements
Tissue
group of simillar cells functioning together as a unit
4 plant tissues
- meristem
- epidermis
- ground tissue (mesophyll)
- vascular tissue
meristem
Initially meristematic, differentiates into parenchyma, collenchyma and sclerenchyma
epidermis
- covers entire plant
- protects
- control flow in/ out of plant
- composed of parenchyma
- stomates: guard cells
- secretes cuticle
- trichomes
trichomes
- defense
- temperature regulation
mesophyll
- plant ‘bulk’
- parenchyma
- collenchyma
- sclerenchyma
- functions:
- photosynthesis
- carbohydrate storage
- support
- make/release
- hormones
- pigments
- defensive toxins
vascular tissue: _________
xylem and phloem
vascular tissue
- localized conducting tissue
- transport water& nutrients (root to shoot)
- support structure:
- vessel elements
- tracheids
- dead at maturity” no membranes & conduct fluid
tracheids
- pits-holes in 2°cell wall
- h2O moves vertically and laterally through pits
vessel elements
- perforations- lack 1° and 2° cell wall
- less resistance: width and perforation
phloem structure
- sieve-tube members and companion cells
- parenchyma, some sclerenchyma for support
- sieve tube: few organelles
- companion cells-many organelles
phloem structure
transport sugar, hormones, amino acids, toxins
the root system _________
stabilizes plants and aquires nutrients
root structure
- modular
- high surface area:volume ratio
- long
- rhizods _______ vascular tissue
- true roots_______ vascular tissue
- no
- have
- cacti have _________roots
- pines have ________ roots
- shallow, wide-spreading
- deep
storage root function
carbs: carrot- fuels reproduction
prop roots function
anchorage: corn-adventitious- stem origin
aerial roots function
gas exchange: mangrove
phenotypic plasticity
change phenotype depending on environment
indeterminate growth
grow throughout life
dynamic growth
growth to areas of high nutrients (roots)
Root
- Eudicot
- oak, maple, roses
Root
- Monocot
- Grass, wheat
shoot system provides ______ & ________
support and circulation
rhizome
- continuously growing horizontal underground stem
- pterophyta
node
point where plant branches
internode
segment between two nodes
axillary bud
bud that grows from axil of a leaf ( where branches out)
types of modified stems
- water-storage structure
- stolons
- rhizomes
- tubers
- thorns
stolons
stems growing horizontally along soil surface, creating new plants at each node
tuber
underground, swollen rhizomes that store carbs
thorns
protect plants from large herbivores
stem
eudicot
stem
monocot
monkey face
lateral bud
- forms leaves
- off branch
petiole
stalk that connects to blade of a leaf
function of compound leaves
(doubly compound) large but rarely damaged by wind/rain
needle function
adapted to v hot/cold climates
parallel veins
monocot
branching veins
eudicot
growth direction and shape via
direction of cell vision and direction of cell enlargement
Apical meristems
- root and shoot tips
- lengthens plant
- herbaceous growth
lateral meristems
- rings along roots and shoots
- widens plant
- woody growth
primary growth
increased length
primary root growth
ensures access to water and nutrients
root cap
- protects root meristem
- contionously sloughed off
- secretes mucigel
- senses gravity
mucigel
- slimy polysaccharide that covers the root cap
- protects, prevents desiccation
modular architecture of stems
- terminal bud
- bud scale
- bud scale scars
- nodes
- internodes
min plant age determined by
counting bud scale scars
xylem ray
lateral transport (parenchyma)
cork
bark (protection)
cork cambium
adds cells to outside
vascular cambium
adds some cells to ouside and many to inside
secondary growth
increases plant width
vascular cambium and cork cambium produce _______ and _______
wood and bark
lateral meristems
- cork cambium
- bark
- vascular cambium
- wood
heartwood
old secondary xylem
sapwood
secondary xylem transporting water