Midterm #1 Flashcards
Mangoliophyhta
Flowering plants
Spermatophyta
Seed plants
Tracheobionta
Vascular plants
Ploidy levels
Number of genes
Species
Group of individuals who produce viable and fertilitie offspring when they interbreed
Cultivar
Recognized species cultivated by us
Intergenic hybrids
Cant be fertile without human assistance
X between two genera indicates the cross
Angiosperms
Flowering vascular plants with covered seeds, double fertilization and fruit
Gymnosperms
Naked seeds- cones
Carpel (can be one or more)
Stigma, style and ovary (female)
Stigma
Sticky to attract pollen
Style
Leads from stigma to ovary
Petal
Attractive for reproduction. Contains spores, stamens and carpels
Stamens
Anther and filament
Anther
Where pollen is produced
Filament
Stalk
Sepal
encloses flower before it opens
4 major flower organs
Sepal, stamens, carpel, petal
Inflorescence angiosperm flowers
Clusters
Complete angiosperm flowers
Contain all four flower organs
Incomplete angiosperm flowers
Lack one or more organs
Flowers
Made by angiosperms to produce seed and fruit (all make fruits even though we don’t know it)
Fruit
As seeds develop from ovules, the ovary wall thickens and matures into a fruit
Some dry fruits open at maturity to release seeds
The ones that do not rely on wind, water or animals to eat and digest
Although most are fleshy, they do not have to be
Subspecies
Would be capable of producing viable and fertile offspring but can not in nature because of geographical and other barriers
Corn
Tassel- stamenait flower
Ear- Each silk is a stigma
Canola (brassica spp.)
Most valuable crop in Canada, oil is used extracted from seeds. Complete flower. We use brassica rapa L
Alternate generations: Sporophyte generation (2n)
Plant parts you are most familiar with
Produce haploid (n) spores by meiosis
Grow into gametophytes
Dependant on this generation for survival
(Zygote and germination)
Alternate generations: Gametophyte generation (n)
Some plants grow in this state
Produce haploid gametes by meiosis
Fusion of gametes produces diploid sporophyte
(Pollen grain and embryo sac forming)
Zygote
Union of sperm and egg cell
Predominant Generation
Higher plants- 2n is more predominant
Ferns- even
Mosses- n is more predominant
Pollen grain
Absorbs and germinates water (contains tube nucleus and generative nucleus )
Tube cell
Produces pollen tube which grows down style and penetrates micropyle (pore)
Generative cell
Goes down pollen tube and discharges sperm into the embryo sac
One sperm fertilizes the egg and forms a diploid zygote (becomes the embryo)
The other fuses with the two nuclei and produces a triploid cell that will develop into the endosperm
After double fertilization….
Ovule= seed
Zygote= sporophyte
Triploid cell= endosperm
Male gametes
Microspores (in pollen grains)
Female gametes
Megaspores eg. (embryo sac)
Charles Darwin
Looked at angiosperms as a totally mystery
Endosperm development
Typically develops before the embryo does
Triploid nucleus of the ovule divides, super cell us formed after double fertilization (endosperm)
Becomes multicellular when membranes from around nuclei
Starts as a liquid, becomes a solid
Will not produce without sufficient O2
Endosperm
Monocots and some dicots= endosperm is food for seeds
Other dicots= Food reserves are exported to and stored in the cotyledons
Rarely: Food reserves are stored in maternal tissues
Embryo development
1st meiotic cell division of the zygote splits the fertilized egg into a terminal egg (turns into embryo) on basal cell
Basal cell
Continues to divide, produces a thread of cells called the suspensor which anchors the embryo to the parent plant
Pushes embryo into nutritious tissues
Epicotyl
First miniature pair of leaves
Scutellum
Cotyledon of a monocot (grass)
Coleoptile
Covers young shoot
Coleorhiza
Covers young root
Pistil
A carpel or 2 or more fused carpels (ovary will have more chambers)
Monocots
One cotyledon
Flowers: multiples of 3
Leaves: Parallel veins
Roots: Primary roots replaced by adventitious roots (grows from stem)
Pollen: One pore (furrow)
Dicots
Two cotyledons
Multiples of four and five
Network of veins
Primary root can persist (tap root)
3 or more furrows
Sexual reproduction
Various strategies to move gametes around to dispense seeds
Pollen (Species specific)
Ranges from 6-100 micro meters
Outercoating (exine)- made up of very tough polymers of pollen
- Different patterns
- Composed of sporopollen
- Surface is made up of proteins which is how it is recognized by stigma
Sporopollenin
Very unknown because so difficult to break down that it gets broken down too far
Palynology
Study particulates in sediments and fossils
Pollen can be used to….
1) Reconstruct past environments
2) Follow changes in the plant ecosystem over time
3) Links populations to climate change
Huge flaw: Wind pollen is way over represented
Animal pollination (will be more effected by climate change)
80% of plants, more efficient
15% by bees
100 000 animals involved, 250 000 species of plants
Methods of attraction
colour, nectar, deception, “cheaper” than producing so much pollen
Insects
See green, blue and UV light (so can see colours that we can not)
Flowers have landing guides (some even mimic female insects to attract males)
Birds
See red, green and blue (likes red cuz no insects)
Darwin’s predictions
Orchid in madagascar
Nectar was 11.5 inches into the plant
Said there must be an insect to reach it
41 years later, the insect was found
Amorphophallus titanium
Corps flower
1) Releases heat and odour
2) Attracts and traps beetles
3) They transfer pollen
4) relaxes and beetles leave
Reffelesia arnoldii
Worlds largest flower, diameter is about 1m
Imperfect flower
Smells like rotting meat
Fertilization
Fusion of gametes
Pollination
Happens with microsporangium breaks open
Monocot seed structure
Bran, endosperm, germ
Bran
Outermost layer, contains most of the fibre and is a good source of the B vitamins
Endosperm
Made up of mainly starch (carbo hydrates). Contains most of the proteins, vitamins and minerals
Germ
The embryo or sprouting section of the seed. Source of vegetable oils and a rich source of vitamin E and complex B vitamins
Orthodox seeds (tolerant seeds)
Embryo and endosperm are protected by a hard seed coat
When seed enters a state of dormancy, moisture levels drop
remains viable for extended periods as long as it doesn’t dry, or get too cold
Svalbard global seed vault- seed trust
Safeguards as much as the world seeds as possible
Can’t store unorthodox seeds
860 000 samples (-19C)
Sexual reproduction advantages
High survival rates in fluctuating climates
Sexual reproduction disadvantages
At risk for extinction
Asexual reproduction advantages
No need for pollinator
Passes on all genes instead of just half (clone)
Grows faster because fed from photosynthesis from the growing plant
Disadvantages of asexual reproduction
Vulnerable to locan extinction
Fragile seed
Methods of asexual reproduction (apomixis)
Parthenogenesis, diplospory, adventitious embryony
Parthenogenesis
Genotype is identical to the parent
Endosperm can happen with or without fertilization
diplospory
Megaspore mother cell does not innate or finish meiosis (remains 2n)
Requires pollination: endosperm gets fertilized but the egg does not
adventitious embryony (eg. citrus)
Normal meiosis, fertilization and embryo development
Cells in the nucleus form embryos in the micropyle region
Grow into embryo sac of sexual embryo
One of the seedlings will be from the sexual cross, one will be clones of the original plant
Stolons
Above ground stem, develops roots and shoots at nodes
Rhizomes
Below ground stem, develops roots and shoots at the notes (ginger)
Bulbs
Storage organs with compressed stem and thick, fleshy leaves (lily, onions)
Corms
Compressed stem
Upper nodes develop shoots
Bottom nodes develop roots
New corms form around the original
Tubers
Storage organs that can reproduce
Formed on stolons or rhizomes
Garlic
Bulb is made up of cloves
Each clove grows into a new plant
Species has done this for so long it almost can not produce seed
Grafting
Twigor bud grafted onto a plant. Bud wood
Stock plant: produces the root system
Sicon: Variety grafted onto
In vitro propagation (tissue propagation)
Plants are totipotent
Single cells can be used to generate any kind of cell tissue, including the whole plant
Domestication syndrom
Large fruit/ seed
Loss of seed dormancy
Loss of seed shattering
Uniform maturation
Reduction of bitterer flavours
Loss of seeds
Teosinte
Small grain hard shell cover turned into corn
Development of male gametophytes in stamen
Microsporocytes (in microsporangia) divide by meiosis (there are four haploid microspores, each one develops into a pollen grain)
Development of the female gametophyte (embryo sac)
Megasporangium - large and diploid
Divide by meiosis and from 4 haploid but only one will survive
Divide to form the embryo sac
Seed development
Each ovule develops into a seed, the ovary develops into a fruit
Huge energy drain. As the embryo reproducers they store resources
when the seed germinates, the embryo turns into s new sporophyte (which produces its own flowers and fruits)
In SOME species, they move from the endosperm to the cotyledon
Epicotyl
Extends the stem above the surface
Castor beans
Thick cotyledons and greater endosperm
The debate… (unknown risks)
Transfers of allergens to food (no good evidence)
Could kill insects like caterpillars
Worries about genes escaping into weeds
Genes escaping into weeds
Male sterility
GME transgenic crops (endosperm and embryo would form without fertilization)
Denigreer transgene into chloroplast DNA of the crop (this can not be transferred by pollen)
GME flowers not to open
Dioecious
Distinct male and female parts
Monoecious
Has male and female flowers
Plant biotechnology and genetic engineering
Gene transfers can be down quickly and specifically without the need of an intermediate species
Transgenic organisms: Have been engineered to express a gene from another species
Reducing world hunger
Biotechnology can make crop yields much large, without needing extra land
Reducing fossil fuel dependancy
Fast growing plants (switch grass/ poplar) can help satisfy NRG needs
Polymers in cell walls would be broken into sugars in enzymatic reactions, fermented into alcohol and distilled to yield biofuels
Heterosis (hybrid vigour)
The tendency of a crossbreed individual to show qualities better than both parents
F1 hybrids
Crossing two inbread lines, maximizes heterosis
Plants are uniform
Corn: easy to hybridize, detassle corn you don’t want pollen from
Pericap
Wall of ovary
Zygote after double fertilization
Develops into a sporophyte embryo with a rudimentary root and one or two seed leaves called cotyledons
Stages of germination
1) Imbibition
2) Enzyme synthesis: Emzymes begin to digest the storage materials of the endosperm and nutrients are transferred to growing regions
3) Radicle emerges first: Hook forms above the ground
Simple fruit
Developed from one or more carpels
Aggregate fruit
Developed from one or more carpels
Parthenocarpy
Fruit develops in the absence of fertilization
Epigenetic
Genome does not change
