PL SCI 221 - Final

seed coat (testa)

seed coat (testa)

protects embryo

food source

nourishes embryo

alteration of generations

alteration of multicellular diploid & haploid forms in the organisms life cycle, regardless of whether these forms are free-living

gametophyte

haploid gamete-producing phase in life cycle

sporophyte

diploid spore-producing phase in the life cycle

homospory

1 type of spore; basic condition

heterospory

2 types of spores

microgametophytes

developed from microspores. Pollen

serotinous cone

requires heat to release seeds

hilum

white scar on seed

micropyle

used for seed hydration & gas exchange. Tap root emerges from this point

plumule

first leaves after germination

hypocotyl

conjoined root

radicle

conjoined stem

cotyledon (scutellum)

absorbs food from endosperm

pericarp

seed coat

coleoptile, coleorhiza

protective structures that enclose plumule & radicle

epigeal

cotyledons emerge from the soil when seed germinates

hypogeal

cotyledons remain in the soil

orthodox seeds

seeds that survive drying and/or freezing. Can be stored for prolonged times

unorthodox seeds

sees that are not able to survive low temp or moisture - will lose viability. Cannot survive desiccation

root suckers

roots will produce new trees. Common in aspen

dormancy

period of growth inactivity in seeds or buds, even when environmental requirements for germination are met. Assures that seeds will germinate at the proper time

scarification

breaking of seed coat by mechanical action

stratification

seeds kept chilled and moist

Imbibition

the process of water movement by capillary action or by chemical interactions. Phase one

lag phase

activates enzymes to break down storage products/energy for embryo to begin to grow. Phase two

radicle emergence

radicle will begin to emerge. Once emerged, germination is complete. Phase three

gene

segment of DNA that directs the synthesis of a protein.

genome

sum of all DNA

Gregor Mendel

created field of genetics. Rejected ideas of blending inheritance & genetic material being a fluid that mixes

law of independent assortment

two traits (determined by two genes) are passed to offspring independently of each other

traditional breeding

accelerated evolution guided by humans rather than nature

transgenic plants

produced by inserting genes from almost any organism into plants. Primary used to introduce resistance to insects & herbicides

transgenes

genes inserted to creat transgenic plants

taxonomy

involves describing, naming, and classifying organisms (the oldest branch of plant study)

nomenclature

a system of naming objects

taxon

taxonomic group at any level in the hierarchical system

Carolus Linnaeus

Developed binomial Latin names for organisms

cultivars

cultivated varieties

International code of botanical nomenclature

rules for naming wild species

international code of nomenclature for cultivated plants

rules for naming cultivated plants

species

set of individuals closely related by descent from a common ancestor. most fundamental level of classification

genus

closest related species are grouped together

gemmae

small discs of tissue growing into new gametophytes

wheat, rice, corn

three major food crops worldwide

quantitative traits

continuous variation, determined by several genes, determined by environment

domains

archaea, bacteria, eukarya

cyanobacteria

Have chlorophyll a, produce oxygen, some fix nitrogen

monophyletic group

organisms descended from a common evolutionary ancestor or ancestral group

polyphyletic

derived from more than one common evolutionary ancestor or ancestral group and therefore not suitable for placing in the same taxon

paraphyletic

descended from a common evolutionary ancestor or ancestral group, but not including all the descendant groups

bryophyte types

moss, hornwort, liverwort

sphagnum (peat) moss

waterlogged environments, low temps, & acidity slow breakdown of OM. Anti-microbial properties, specialized cells for water storage

bryophytes

dominant gametophyte: no true xylem/phloem, no roots, small

calamites

extinct genus of tree like horsetails closely related to Equisetum

Psilophytes

lacks roots, anchored by rhizome. erect portion of stem bears enations

enations

outgrowths that look like leaves, do not have vascular tissue

Lycophytes

Club mosses. “ground pine” have true roots & stems. heterospory

Horsetails

whorled, scalelike leaves. stems photosynthesize. sporangia at tip of some stems. rhizome

Ferns

fronds often large & divided. Rhizome.

gymnosperm orders

conifers, ginkgophytes, gnetophytes

gymnosperms

vascular, seed plants

conifers

trees/shrubs. have simple needles or scales. wood of tracheas, parenchyma cells in rays & resin ducts. sieve cells in phloem. thick cuticle, sunken stomata

wax tubules

obstruct stomata to slow transpiration. “stomatal plugs”

Pine

largest family of conifers. dominant in boreal. mainly northern hemisphere

cypress

junipers, redwoods, cypress.

Araucaria

southern hemisphere. Wollemi pine

Ginkgophytes

ginkgo biloba last living species. broad leaves, unique venation. deciduous

angiosperms

monophyletic. Only plant group w/ flowers. Seeds in ovary which develops into fruit. Gametophyte generation reduced. dominant plant group

double fertilization

angiosperms. creates 3n endosperm. One sperm nucleus fuses to egg, one unites w/ 2 polar nuclei to form triploid endosperm

Lily family

monocot, herbaceous. large flowers, parts in 3s. parallel veined. most grow from bulbs

electromagnetic radiation

shorter wavelength = higher energy (vice versa)

carotenoids

accessory pigments in photosynthesis. Absorbs wavelengths that aren’t absorbed by chlorophyll. prevents damage by light to chlorophyll. conjugated double bonds

chlorophyll

essential pigment of photosynthesis. conjugated double bonds

photosystems

units that contain chlorophyll & carotenoids. Embedded in the thylakoids

light reaction

the reaction which occurs as the first phase of photosynthesis, in which energy in the form of light is absorbed and converted to chemical energy in the form of ATP.

Photosystem 1 (PSI)

an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane

Photosystem 2 (PSII)

captures photons and uses the energy to extract electrons from water molecules.

antenna complex

transfers excitation energy to the reaction center.

reaction center

membrane-bound pigment–protein complexes that use light to catalyze a transmembrane electron transfer against a steep thermodynamic gradient

surface tension

water molecules have fewer hydrogen bonds on the surface, minimizing surface area. creates this…

metastable

not being in a stable equilibrium state. examples include: supercooled water, stretched water, glassy water

diffusion

follows concentration gradient. effective over short distances

osmosis

occurs when there is semipermeable membrane. flow depends on concentration difference. drives movement in & out of cells

turgor pressure

Provides structural support to herbaceous plants. Generated by osmosis.

bulk flow

movement of water & any solutes together. driven by pressure differences (+ or -)

aquaporins

channel proteins that facilitate transport of water across membranes. Water can flow any direction, channel can open/close. facilitate rapid plant movements

buliform cells

control folding of leaves

motor cells

control rapid movements of Mimosa leaves. Possible because of rapid moment of ions, followed by water exiting the cells via aquaporins

sieve elements

Elongated cells, connected via sieve plates to form continuous tube system that’s spreads throughout plant. make up sieve tubes. Missing most cellular components

companion cells

derive from same mother cell & maintain close connection w/ sieve elements. contain all organelles typical for plant cell

sieve plates

end walls containing large pores to connect b/w adjacent sieve elements

pressure flow hypothesis

phloem sap is moved by a pressure gradient maintained by loading at source & unloading at sink. Sap moves via bulk flow from high to low pressure in sieve tubes (requires energy)

apoplasmic loading

active transport of sugars from apoplast (cell wall) into companion cell. sugars cannot leak back to bundle sheath. Most herbs

symplasmic loading

sugar follows downhill concentration gradient from bundle sheath into phloem. Cell walls connected via plasmodesmata. much of water comes from xylem. Most trees

Cohesion-tension theory

water pulled into leaves against gravity due to cohesion & adhesion. Atmosphere pulls harder than soil on the water column, so water moves up. Passive transport (transpiration)

population

group of individuals of same species in same area

community

all or some organisms in a common environment

ecosystem

all the organisms in an area & the physical environment w/ which they interact