Plant Science Midterm 1 Study Guide Flashcards
Early Atmosphere made up of…
CH4, NH4, SO2, CO2, H2S, H2
Today’s Atomsphere is made up of
N2(78.08 percent) O2(20.95 percent) Ar (0.93 percent) CO2 (0.035 percent)
Total:99.995 percent
Evolution solved practical problems.
Plants moved onto the land
Evolutions that were being made for plants
- Roots = Water 2. Protect from UV radiation: epidermal pigments, ozone layer from O2 3. Minimize water loss: impermeable waxy cuticle. 4. Get CO2, and O2 through impermeable cuticle- guard cells and stomata.
- Transport water (and nutrients) to distant tissues-vascular system
- Structural support: Lignin wood
- Eliminate the need for a water layer for movement of motile sperm: Pollen.
- Means of moving male gamete: Pollen tube
- Feed and protect zygote-seed with 3N endosperm
Evolution early fern tree forests
390-350 X 10^6 years ago
Domination of cone-bearing plants
230-145 x 10^6 years ago
Pteridophytes
Ancient spore fern plants
Appearance of Flowers
transformed the world in an explosion of color, nectar, scent pollen, and diversity.
Age of the Dinosaur and 3/4 plant and animal species lost.
250 to 66 million years ago 65mya
Origin of Photosynthesis
Switched from removing electrons from H2S and like compounds (Iron compounds) to obtaining e- from water (photo + lysis) a new PS-PSII
Photolysis of water produced very toxic (to the methanogens): Oxygen.
Prokaryotes become organelles through endosymbiosis- still in the oceans (1.5 BYA)
Young Dicot Stem
Ring of vascular bundles
Young Monocot Stem
Scattered vascular bundles.
Vascular cambium
A cylinder of meristematic cells one layer thick
Vascular Cambium continued
adds secondary: xylem (=wood) to the inside and secondary phloem on the outside
Heart wood
secondary xylem
Apical meristems
Occur at the tips of stems (and in buds) and roots.
Barley Stem Leaf node
- Sheath (around the stem) 2. Stem (runs from the bottom to the middle part of the barley 3. Auricles (are Leafs that are surround the barley with a thin look) 4. Blade: the hair of the barley 5. Ligule
Dicot leaf
- Dorsel fin 2. Adaxial or Dorsel surface 3. Abaxial or bottom surface
Apomixis
embryo formed without meiosis or fertilization.
1. bypass of meiosis during embryo sac formation
2. development of embryo with no fertilization
3. formation of viable endosperm
Reasons for grafting
Propagation, Disease resistance, dwarfing, superior roots, repair wounds, change cultivar, aesthetics.
Three pieces to grafting
Scion, Graft Union, Root Stock
What makes a successful graft union?
Formation of a continuous vascular connection between the stock and scion is essential.
Function of leaf sheath
Intercalary meristem (helps the plant grow vertically: Supports elongation of plant
Monoecious
both male and female flowers on one plant
Dioecious
Male and Female flowers on different plants
Grasses =
spike (sessile flower on one main stem)
or panicle (subbranches
Tillers
Branches that develop from axillary buds at the lower nodes of a grass
Apical dominance
Main/central stem of a plant is stronger and other subbranches are still produced. This happens with corn.
Linnaeus
Responsible for developing for Binomial nomenclature, a unique combination of genus and specie (the specific epithet)
System of Plant Classification
Kingdom, Divisions, Classes, Orders, Families, Genera, Species
What happened 10,000 years ago?
Man domesticated and cultivated cereals and herbaceous. These transitions occurred 10,00–3500 years ago
Dicots that make up our food
Dicots make up 21.5 percent of crops:
-Potatoes: 8.5 percent - Cassava 4.4 percent - Sweet potatoes 3.6 percent - Soy beans 3.0 percent - Tomatoes 2.0 percent
Three types of Ovary placement in relation to the flower
Epigynous: above the ovary
Perigynous: Around the ovary
Hypogynous: Below the ovary
Pollen tubes contain.
a tube nucleus and two generative nuclei
How does fertilization occur in Angiosperm?
one generative nuclei fuse with the egg and the second with the two polar nuclei
1. Forms the zygote 2. Forms the nutritive tissue the endosperm.
Endosperm in seeds: Dicot
Nourish developing embryo, but is not present in mature dicot seeds.
Endosperms: Monocot
Endosperm is present even in the mature seeds of monocot grasses..
4 types of fleshy fruit
Simple, Aggregate, multiple fruit, accessory fruit
Multiple fruit
Is formed from many individual flowers in an inflorescence.
Reason for asexual reproduction
To maintain a chimaera (e.g. variegation-one organism with two cells of two genotypes.
- More seeds are produced
- Too much variation
-Grifting to produce unique combination
-Shortens generation time in plant breeding
Line
Genotype similar (identical in selected genes so in breeding program) Phenotype similar (depends on environment)
Steps in seed germination
- Imbibe water and swells (rupture seed coat) Metabolism increases (Enzymes become active, protein synthesis)
- Radicle emerges first to absorb water (why does it need water?)
Hypogeal: cotyledon remains below ground (pea; monocots)
Epigeal: cotyledons emerge above ground
Temperature
Some temps are used to initiate flower development (i.e., vernalization)
Chilling requirement
Some plants also need cold temperatures to induce bud break in Spring the breaking of dormancy.
What is good about variability in reproduction
It is essential for evolution (survival of fittest)
Mitosis
- Centromeres are duplicated 2. Lining up individual Centromeres 3. One cell divides into two cells
Meiosis
Same, but lining up of paired centromer. 2. Migrate to opposite poles. 3. Line up individual centromeres. 4. Two cell divisions and four cells are produced.
Reason why diploid is dominant phase in angiosperms.
Because it holds more back up information in polyploids
Short Day Plants
Plants that flower when the day length is less than a critical length. If they are exposed to day lengths in excess of this critical length
Long Day Plants
Plants that flower when the day length is greater than a certain critical length.
Day neutral plants
Plants flower in all possible photoperiods ranging from a few hours to 24 hours of light.
Material is transported through a cell by …
diffusion, protoplasmic streaming, and by mass flow
Fick’s first law of diffusion (1855)
The movement of energy or material across a barrier is proportional to the Concentration gradient, and the Area for Diffusion, and inversely proportional to the Resistance to the diffusion caused by the thickness of the barrier and it’s inherited resistance to the diffusing substance.
