Notes Flashcards
botany
scientific study of plants
what does botany include
anatomy, physiology, taxonomy, ecology,
can include photosynthetic protists, fungi, bacteria, and cynobacteria
what do we get from plant
food, O2, cotton, paper, wood, medicine (photoalexing), aspirin, opiates, salve (aloe), coffee, tea, chocolate, tobacco, water, alcohol, perfumes, shade, prevent erosion, soap, dyes, fossil fuels
when did botany become specialized
past 3 centuries
subdivisions of botany
physiology, ecology, anatomy, morphology, taxonomy, systematics, evolution, genetics, paleontology, pharmacology, molecular biology, cells biology, histology, conservation, geobiology, pathology, biotechnology, genomics, horticulture, forestry, range management,
what does botany not include
mycology, phycology,
cell theory
1- all organisms are made of 1 or more cells
2- cells are the fundamental units of structure, function & organization, cells are the smallest unit of life, nothing smaller than cell can be alive
3- new cells come from preexisting cells
what makes up plant cell
1- protoplast
2- cell wall
cell wall and plasma membrane and its contents
what is in protoplast
1- plasma membrane
2- nucleus
3- vacuole
4- cytoplasm
plasma membrane
forms boundary at outer edges of protoplast, regulates entry & exit of material, coordinates synthesis of cell wall, interprets signals from outside of cell
nuclues
controls cell activity by directing protein synthesis, contains DNA
vacuole
central, greater than 90% of cell volume, full of water, pigments, salts, organic solutes, toxins
cytoplasm
region of cell exterior of nucleus, vacuole & interior to plasma membrane
what does cytoplasm include
numerous organelles that are suspended in fluid cytosol
what are some organelles in the cytoplasm
golgi apparatus, mitochondrion, ribosomes, ER, chloroplasts, microbodies
cell wall
cellulose and additional polysaccharides like hemicellulose and pectins
what is a major component of plant cells
cellulose
do cells always have a primary cell wall
yes
what is between 2 cells
middle lamella
what is middle lamella
area between 2 cells and composed of pectin substances
hole
plasmodesmata
cytoplasmic
connection between cells
secondary cell walls
not always present
interior to primary cell wall, after cell quits growing & very rigid, has lignin
what does lignin provide
structure, adds strength to cells, especially xylem
pit
area
opening that lacks secondary cell wall but primary cell wall present
what are the 2 types of cell division
mitosis
meiosis
mitosis
eukaryotes, results in exact copies
meiosis
eukaryotes, daughter cells 1/2 ploidy level, & genetically unique
can involve cells of any ploidy level
what does meiosis lead to in animals
gamates
what does meiosis lead to in plants
spores
general cell types of plants
parenchyma
callenchyma
sclerenchyma
paranchyma
make paranchyma tissue, occur in plants as continuous masses, mast abundant and versatile cells in plants
paranchyma characteristics
unthickened primary cell wall, living at maturity capable of cell division involved in photosynthesis
what are parenchyma cells involved in
involved in photosynthesis, storage and secretion
collenchyma
collencyma tissue, give structure, support, usually occur under epidermis in stems and in leaf petioles
characteristics of collenchyma
unevenly thickened primary cell wall, living at maturity, walls can stretch, support young growing structures of flower and leaves
sclerenchyma
usually lack protoplasts at maturity (most type non living)
not flexible, no more growth is possible
fibers and sclerids
characteristics of sclerenchyma
thick, often lignified secondary wall
what is sclerenchyma important in
strengthening element in plant parts that have reached mature size
fibers
long, skinny slender occur in strands or bundles
sclerids
short, stout, variable in shape
meristems
activate cell division in plants
primary growth
growth that results from cell division
in primary meristem where does growth occur
apical meristem of root and shoots, results in lengthening or roots and shoots
apical meristem
primary meristem- tissue system- tissues
protoderm- dermal- epidermis
ground meristem- ground- parenchyma, sclernchyma, cotex, callenchyma, mesophyll, pith
procambian- vascular- primary xyleum, primary phloem
what do meristems contain
cells that able to divide repeatedly
what does plant growth include
both cell division and cell enlargement
primary
occurs first
secondary
occurs second
primary growth
growth from cell division in primary meristem
lengthening of plant part
secondary growth
growth from cell division in a secondary meristem
thickening of plant part
primary cell wall
laid down around all plant cells
secondary cell wall
thick cell wall laid to interior of primary cell wall
tissues
groups of cells that perform a common function
what can a tissue do that cells cannont
perform functions
tissue systems
ground tissue, vascular, dermal
ground tissue system
bulk of plant body
pith of stem, cortex of stem and root, mesophyll of leaf
vascular tissue system
used for transport
xylem
phloem
xylem
transports water up
principle water conducting tissue in plants, also involved in mineral conduction and support
secondary cell wall, strong, plants first get big
what are the principal conduction cells of xylem
vessel elements
tracheids
vessel elements
perforation,
opening, no cell wall
tracheids
no perforation, has pits, tapered ends
long and narrow
phloem
transports food thru plant
principal food conducting tissue in vascular plants
transports products of photosynthesis (sugars) disolved in water
what are the principal cell types of phloem
sieve tube elements
companion cells
sieve tube elements
living, tube like
companion cells
gives metabolic functions to sieve tube elements
cells of epidermis
unspecialized tabloid cells guard cells, subsidiary cells trichomes (epidermal hairs) may be several layers thick multiple epidermis is thought to serve as water storage tissue
guard cells
regulate opening and closing of stomata
stomated
often associated with epidermal cells called subsidiary cells
are subsidiary cells always present with guard cells
no
function of trichomes (leaf hairs)
reduce water loss, increase reflection of solar radiation, may provide defense against insects
dermal tissue system
primary- epidermis
secondary- periderm
epidermis
outermost layer of cells of the primary plant body, covers plant
function of dermal tissue system
protection against herbivores, absorption of water and minerals (roots, secretion of cuticle, prevent water loss (shoots), control gas exchange
secondary growth
results in thickening of stems and roots
produced by secondary meristems
what makes up the secondary plant body
vascular cambian, cork cambian
what does a seed consist of
seed coat, embryo, stored food (biggest variable)
mature embryo and see
embryo consists of stem-like axis with cotyledons
what are cotyledons
seed leaves of young plant
monocot
one cotyledon
dicot
two cotyleons
embryonic structures
epicotyl
plumule
hypocotyl
radicle
epicotyl
embryonic stem above cotyledons
plumule
embryonic shoot
hypoctyl
embryonic stem below cotyldons
radicle
embryonic root
what are cotyledon of dicot embryos usually
fleshy
do dicot cotyledons occupy most of see
yes
what is the function of monocot cotyldon
food storage
photosynthetic organ
absorbing structure
what has the most highly developed embryo of monocots
gasses
what do grasses possess
massive cotyledon called scutellum
scutellum functions
absorption of food stored in endosperm
seed coat
all seeds are enclosed
varies from papery to extremely tough
purpose of seed coat
protect enclosed embryo and stored food
micropyle
opening through which pollen tube entered ovule of flower, visible in seed coat as a small pore commonly associated with scar called hilum
embryo formation
begins with division of zygote
at lower end, a stalk-like suspensor develops
anchors embryo and absorbs nutrients
globular stage of embryo development
embryo develops into a nearly spherical structure
undifferentiated cells at first, primary meristem later forms
cotyledon development
“heart shaped stage”
in dicots globular stage begins to develop into 2 lobed form
“torpedo stage”
development continues, cotyledon and embryo elongate, embryo becomes curved
during embryo development does nutrients move from parent to tissue ovule
yes
what happens after the stop of the movement of nutrients to seed
placenta (point of attachment) separates from ovary
what happens after placenta separates from ovary
seed becomes desiccated and goes into dormancy
see coat hardens
requirements for germination
resumption of embryonic growth called germination
what does germination depend on
water, oxygen, temperature, light
what seeds require exposure to light to germinate
small seeds like lettuce
dormant seeds
fail to germinate even when conditions are favorable
what is dormancy great for
great value to survival value to plant
ensures favorable conditions for germination
what is the first structure to emerge from the seed
radicle or embryonic root
what does the radicle allow
for seedling to become anchored in soil and begin absorbing water
what is the first root called
primary root
epigeous germination
cotyledon is above ground
what is considered plumule
anything above ground
castor beans
epigeous, dicot, food stored in endosperm
seed coat poisonus
hypogeous
cotyledon stays below ground
pea
hypogeous, dicot,
shoot emergence in monocots
onion, epigious, singular tubular cotyledon forms the hook, cotyledon is also photosynthetic
corn
hypogeous, radicle is covered by coleorhiza breaks through, coleoptile reaches soil, 1st leaves of plumule emerge
root
hidden half
underground portion of plants
root functions
anchorage and absorption of water and minerals
nutrient storage, produce hormones
some modified for support, aeration, propagation, and parasitism
2 types of root systems
taproot
fibrous
what is the first root of a plant called
primary root
what does primary root become in gymnosperms and dicots
taproot
what does primary root become in monocots
short lived, has fibrous root system
adventitious root
develop at the base of stem, gives rise to fibrous root system,
fibrous root system
forms extensive mass of similarly sized roots
adventitious root
roots that grow from somewhere other than another root (from stem or leaves)
origin and growth of primary root tissues
tip of root is covered by root cap
root cap
sleeve like mass of cells that protects the growing tip has mucigel and senses gravity
mucigel
lubricates root as it passes through soil, protects root from desiccation
root parts
procambium- middle
ground meristem (cortex)- around middle
apical meristem- tip of root
protoderm- outer layer of root
growth regions of root
at tip- apical meristem- region of cell division
beyond (rod) is region of elongation, beyond (roe) is region of maturation
apical meristem in root
gives rise to new root cells,
primary regions of roots
internally relatively simple due to absence of leaves (no nodes or internodule)
epidermis
in young roots, absorbs water and minerals
aided by root hairs
root hairs
tubular extensions of epidermal cells that increase absorptive surface area
where is root hairs confined to
region of maturation
cortex
occupies greatest part of root
cells store starch and other substances
numerous intercellular spaces in cortex
what is the inner layer of the cortex called
endodermis
endodermis
universal arrangement of cells, compact arrangement of cells (inner wall thickened
what do some cells have in the root
exodermis
exodermis
outer layers of cortex, compact arrangement of cells
vascular cylinder (stele)
consists of vascular tissue and pericycle
pericycle
origin of lateral roots
contributes to vascular cambium in roots with secondary growth
vascular cylinder in dicots
solid core of primary xylem, ridge like projections of xylem extend toward pericycle
between xylem ridges are strands of primary phloem
vascular cylinder in monocots
center of vascular cylinder occupied by pith, xylem not in ridges as in dicots, phloem alternates with xylem
secondary growth
secondary growth in roots & (stems) consists of the formation of secondary xylem and secondary phloem
where does secondary phloem and secondary xylem come from
vascular cambium
where does periderm come from
cork cambium
secondary growth in roots
vascular cambium between primary xylem and primary phloem produces secondary xylem inside and secondary phloem outside
primary xylem and primary phloem separated by secondary growth
periderm
cork (produced to outside)
cork cambium (secondary meristem)
phelloderm ( produced to inside)
what does periderm do
replaces epidermis as protective covering
lenticels
portions of periderm that allow gas exchange between roots and surrounding soil
origin of lateral roots
arises in pericycle
develops root cap and apical meristem prior to emerging from parent root
aerial roots
adventitious root produced from above ground structures
what does roots require for respiration
oxygen
how do plants deal with the need for oxygen in wetlands
form aerenchyma to ventilate submerged tissues
some develop roots that grow up out of water
pneumatophores
roots that grows up out of water to provide aeration
special root adaptations
contractile roots
epiphytes
parasitism
buttress roots
contractile roots
shorten to pull bulb into ground
epiphytes
grow on other plants, but are not parasitic on them
parasitism
haustoria
buttress roots
help provide support for large trees
adaptations for food storage
most roots are storage organ for nutrients
some storage roots are fleshy because of an abundance of storage parenchyma
mutualism
species interaction where both species benefit
what is a type of mutualism
mycorrhiza (fungus root)
mycorrhiza
roots must form a mutualistic relationship with fungi because it aids plant in water and mineral absorption
two types of mycorrhiz
endo-inside plant cells
exo- outside plant cells
what is a root nodules
bacteria reduce nitrogen so plant can use it
