Test #2 Flashcards
Monocots
- 1 cotyledon
- usually herbaceous
- parallel veins in leaves
- scattered vascular bundles
- fibrous root system
- hypogeal germination
Dicots
- 2 cotyledons
- herbaceous/woody
- netted veins in leaves
- vascular bundles in ring
- taproot system
- epigeal germination
epidermis
outer, protective cell layer on stems/leaves
waxy cuticle
helps retain water
stomata
allows co2 in and O2 out
vascular
conducting tissue
xylem
water and nutrients through the plant
phloem
sucrose - FOOD
ground tissue
composes bulk of the plant- pith and cortex
meristems
areas of actively dividing cells
apical
responsible for growth at tip of shoot or root
intercalary
in grasses, responsible for growth of stem internodes and leaves
axillary
responsible for development of buds for branches or flowers
roots
- anchor the shoot in soil
- support upright growth of stems
- absorb minerals and water
- provide storage of energy reserves
- taproot or fibrous
stems
- primary supporting structure
- conduit for movement of water, nutrients, and photosynthesis products
- also conduct photosynthesis and store energy
modified stems
rhizomes- underground
stolons- soil surface
leaves
- main site for photosynthesis and transpiration
- monocots - sheath, blade, and collar
- dicots - blade and petiole/simple or compound
flowers
- modified leaves
- stamen, pistil, petal, and sepal
- complete or incomplete
- perfect or imperfect
inflorescences
- arrangement of flowers
- spike- main stalk - wheat, barley, rye
- panicle- branched pattern (monocots) - sorghum, rice
- raceme- branched pattern (dicots) - soybean, alfalfa
- umbel- pedicels form single location - onion, parsley
- head- disk (develop seed) and ray (attract insects) flowers -sunflower, dandelion
fruit
ripened or mature ovary containing the seed or seeds
seeds
mature, fertilized ovules or eggs within the ovary
seed germination
dormancy must be broken
epigeal
cotyledons above surface
hypogeal
cotyledons remain below surface
photosynthesis
- process in which energy from sunlight is converted to chemical energy
- takes places in the chloroplast
chemical reaction of photosynthesis
6CO2 + 12H20 + sunlight —> C6H1206 + 6H20
light reactions
- 1st part of photosynthesis
- only ones actually requiring light
- photons strike and set off chain reactions
- produces ATP and NADPH
carbon fixation
- CO2 diffuses through stomata into chloroplast
- NADPH and ATP power reduction of CO2 to simple sugars
- want ribisco to catch carbon
CAM
- uses the C4 pathway at night and C3 pathway in the day
- adapted to hot temps
C4
- uses C4 and C3 pathways
- adapted to hot temps
C3
- no distinct bundle sheath
- rubisco
- photorespiration
- wheat, cotton, peanut, alfalfa, potato
C4
- bundle sheath cells
- PEP carboxylase + rubisco
- corn, sorghum, millet, switchgrass, big bluestem
- most effecient
Respiration
- conversion of sugars from photosynthesis to energy for use in metabolism
- occurs in both the cytoplasm and mitochondria
- C6H1206 + 6CO2 —> 6CO2 + 6H2O + Energy
Transpiration
- process of water loss from stomata
- cooling of the plant
- movement of nutrients within the plants
- nutrient uptake
evapotranspiration
-total water use by a plant
symbiotic nitrogen fixation
- process that makes atmospheric nitrogen available to plants
- common trait for legumes
- symbiotic relationship: legumes & bacteria
photoperiodism
- reaction of plants to changing lengths of the days
- involves the pigment phytochrome that sense changes in red and far red light
- changes everyday
flowering response
- short day plants: spring or fall-flowering (corn, soybean, rice, peanut)
- long day plants: spring or summer flowering (wheat, flax, canola, alfalfa, sugar beet)
- day neutral: based on age or amount of growth (petunia, cucumbers, tomatoes, tobacco)
vernalization
the cold period certain plants must go under to trigger flowering
growth
irreversible increase in weight or size due to increase join number and size of cells
development
when plants transition from germination, seedling, vegetative, flowering, and seed
annual
complete life cycle in one year or one growing season
biennial
complete life cycle in two growing seasons
perennial
persist for three or more years or growing seasons
pseudo-annual
perennial and biennial plants managed as annuals
ag biotechnology
scientific techniques used to create or transform plants
repro in plants
- via seeds
- sexually reproducing plants are either self or cross pollinated or mix
- mode of reproduction of crops determines breeding methods
basic genetics
- cell nucleus contains chromosomes that control inheritance
- chromosomes made up of DNA
- chromosomes occur in pairs
- alleles and genes
genotype
total genetic makeup
phenotype
- due to genotype, environment and their interaction
- physical appearance
heritability
proportion of phenotype controlled by genetic factors
qualitative traits
discrete, controlled by one or few genes
quantitative traits
more complex, controlled by several genes
yield complex quantitative trait
selection for disease and insect resistance, competitiveness, and drought tolerance
quality traits
starch fermentation characteristics or forage digestibility
harvestability
specific crop modifications to reduce loss
persistance
enhanced survivability over the long term
self-pollinated plants
- usually homozygous
- common methods of breeding include pedigree selection or mass selection
cross-pollinated plants
- heterozygous
- can use mass selection
- hybridization most commonly used
genetic engineering
- uses gene transformation to transfer genes of interest
- transfer occurs via bacterium or gene gun
- used for qualitative traits like herbicide and disease resistance
GMOs - GOOD
- biological pest resistance (bt corn)
- herbicide tolerance (roundup)
- adaptation to environmental stresses (salts)
- desirable functional characteristics (shelf life)
- desirable nutritional characteristics (golden rice)
GMOs - BAD
- overall safety unsure
- long term impact on human health unknown
- outcross with weedy relatives
- unintended effects on non-target organisms
- pests may develop resistance to technology
- economic and religious issues
traditional breeding
- years to release variety
- transfers many genes
- uses only genes of same or related species
- not prohibited
genetic engineering
- faster release of varieties
- transfers few genes of interest
- can use genes from any species
- prohibited in some countries
