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119 Cards in this Set
- Front
- Back
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Transpiration
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pulls water vapor through stomata of leaves one molecule at a time
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Cohesion
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– water molecules stick to each other because of weak polar charges
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Adhesion
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water molecules stick to cellulose in cell wall due to polar nature of water molecules
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Osmosis
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movement of water from an area of high concentration to an area of low concentration
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Osmosis is Enhanced by aquaporin because of
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channels in plasma membrane called membrane water channels
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Soil mineral ions cant move accross membrane unless dissolved
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water
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Movement through xylem
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up only
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order of nutrient absorbtion in root
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• Water molecules through spaces between cell walls and plasma membranes, through plasomodesmata, through cell membranes to xylem in center of root
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Root pressure
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movement of water into plant and up xylem occurs even at night in the absence of transpiration
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High root pressure
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movement of water into plant and up xylem occurs even at night in the absence of transpiration
: may lead to guttation |
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Guttation
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collection of droplets of water or sap on the tips of leaves or blades of grass (not to be confused with dew)
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Transpiration
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– allows water to evaporate through stomata into surrounding air
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most plants use ____ to accumulate mineral ions inside root cells
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ATP
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Water and mineral ions must pass through _________ in order to reach xylem tissue in center of root
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endodermis
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Stomata open and close due to changes in
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turgor pressure of guard cells
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turgor pressure
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pressure created on inside of cell wall as water is taken up by cells
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Turgor results from
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active intake of potassium ions in guard cells
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Increase potassium concentration creates
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water potential
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water potential
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causes water to enter guard cell by osmosis (guard cells swell in size and spread apart to create stomata opening
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when high, stomata close to slow transpiration
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carbon dioxide
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Dormancy
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reduces need for water
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Deciduous leaves
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plants may lose leaves in drought or winter
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Thicker leaves lose less water due to
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thick cuticles
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Trichomes
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reduce water loss
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Translocation
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movement of carbohydrates in phloem to rest of plant from site of photosynthesis
*requires ATP |
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Pressure flow theory
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Carbohydrates flow from source and are released at sink
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Source
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storage site (root) or production site (leaf cell)
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Sink
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may be a place where sugars are used or stored
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Plants need_________ or __________ to build amino acids which are used to make protein molecules
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ammonia or nitrates
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Some plants have bacteria that live in nodes on rood or legumes for
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the utilization of nitrogen
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90% of all vascular plants form associations with
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fungi
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Fungi associated with plant root system enable plants to
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more readily absorb soil nutrients
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types of fungi associated with plants
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Arbuscular
Ectomycorrhizae |
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some plants can capture insects for__________, and live in ...
they are called _______ plants. |
nitrogen
acidic soils carnivorous plants |
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Parasitic plants
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Exploit photosynthetic activities of other plants to obtain nutrients
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Phytoremediation
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• Some plants have ability to take up heavy metals from soil
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Bioremediation
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process of using plants to clean environment
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TCE is a known carcinogen
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Studies indicate poplar trees can absorb TCE
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Daily Threats
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1. Virus
2. Bacteria 3. Animals 4. Invasive species |
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Dermal tissue
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first line of defense against invaders (fungi enter through stomata)
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cyanide
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• Stops electron transport and blocks cellular respiration
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Alkaloids - example and use by plant
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used to plant as insecticide
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tannins
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make unrippend fruit seem bitter
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Toxins do not harm plant because
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• Become active when metabolized by consumer
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Wound Response
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Triggers release of systamin
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systamin
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travels throughout plant to initiate production of proteinase inhibitors
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Allelopathy
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occurs when chemical signals secreted by 1 plant blocks growth of nearby seeds or plants
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Phytoestrogens
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compounds similar to estrogen fight symptoms of menopause
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Taxol
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effective in fighting cancer
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Quinine
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used to treat malaria
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convolution in plants
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some plants coevolved with bodyguards
ex acacia tree and ants |
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Photomorphogenesis
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changes in growth patterns due to light
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Etiolation
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tall spindly growth that occurs under low light conditions
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Phototropic responses
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bending to find sunlight
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Auxin
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plant hormone or growth regulator) causes phototropic responses
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Gravitropism
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responses of plant to earth’s gravitational pull
*present at germination - roots grow downward |
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what is responsible for gravitropism
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auxin
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stems respond __________ to gravity
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negatively
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Cytokinins
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• Found primarily in dividing tissues: seeds, fruits, leaves, root tips
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cytokinins and leaf senescence
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• Normally leaves turn yellow when removed from plant but this can be delayed by cytokinins
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Gibberellins – named after fungus, gibberella fujikuroi,
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• Synthesized in apical portions of roots and stems
• Has important implications on stem elongation |
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Effects of Gibberellins
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1. effects stem and leaf elongation by stimulating cell divisions and cell elongation
2. stimulates mutant plants to elongate and appear to be normal and tall 3. Used to break seed dormancy 4. Cause early flowering of biennial plants Bolting – cause flowering stock to form earlier 5. Commercially used to loosen clusters of grapes and make them be larger |
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Ethylene is produced when ..
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auxin is transported down from apical meristem
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ethylene
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• Major roll in fruit development
• Production of ethylene increases when plant is exposed to toxic chemicals, temp extremes, drought, pathogens, and other stresses |
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Abscisic acid
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produced in mature leaves and fruits
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ABA
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suppresses bud growth and leaf senescence (death
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Embryo development in seed
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• First cell division – asymmetric
• At first, all cells of embryo undergoes cell divisions • Later cell divisions at tip of shoots and root (apical meristem) |
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Upper cell
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becomes embryo in seed
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Lower cell
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becomes stalk like suspensor
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Cotyledons
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seed leaves
* undergo seed development at same time |
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• First sperm fertilizes
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egg to form zygote
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• Second sperm fertilizes
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both polar nuclei which then form endosperm or stored food
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• One or 2 cotyledons have also developed
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attached at embryo, often first leaves
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• Food reserves stored in mature seed
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supply energy needed at time of germination
*May be stored in cotyledons or endosperm |
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Adaptive advantage of seed
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• Contain food that supplies energy until young plant can photosynthesize
• Aids in dispersal of plants into new habitats and away from parent plant • Allows seed to remain dormant until environmental conditions are favorable for germination and fertilization • Some seeds don’t germinate until under extreme heat or fire • Some seeds must have germination inhibitors leached from seed coat • When seeds are digested (enzymes erode the seed coat) • Others germinate when light is available |
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Fruits
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• Define as “mature ovary”
• Function in seed dispersal • Fruits develop at same time as seed development is occurring |
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Method of fruit(seed) dispersal
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• Wind
• Animals • Man • Water |
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• Germination occurs when
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embryo emerges from seed and develops into mature plant
*Water and oxygen must be available |
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– vernalization (cold treatment)
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prevents seed from growing too early in growing season
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Vegitative (nonreproductive) growth
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occurs until plant is mature enough to produce reproductive structures (flowers)
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Stages of germination
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1. Embryonic root (radical) emerges first and establishes rood system
2. Embryonic shoot then elongates to that first leaves and tip of stem emerge from soil |
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Phase change
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change from nonreproductive to reproductive mode
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- Short day plants
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flower when day light is less than 12 hrs per day
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- Long day plants
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flower when day light is more than 12 hrs per day
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- Day neutral plants
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flower independently of external daylight
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flowering times may be altered under
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greenhouse conditions
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- Vernalization
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period of cold treatment needed before flowering occurs
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Pollen matures in
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anthers
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Pollen then is transferred to
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stigma of flower
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A complete flower has four whorls
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sepals(Calyx), petals, stamen, carpel(Gynoecium)
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1. Calyx
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composed of sepals (green and leaf-like; protect flower in bud stage) first structure to open during flowering
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2. Petals
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collectively make of corolla
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4. Gynoecium
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collectively made up of female parts of the flower (referred to as carpel)
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stigma
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sticky to receive pollen
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style
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neck-like structure
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Ovary
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contains ovules which mature into seed after fertilization
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microgametophytes
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- Male gametophytes called pollen grains
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macrogametophytes
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- Female gametophytes called embryo sac
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Pollen Formation
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Each pollen sac contains four specialized chambers enclosing microspore mother cells (2n)
These undergo meiosis (reduction division) to form four haploid microspores (N) - A single mitotic division results in pollen grain with 2 nuclei - Then released from anther |
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Embryo sac formation
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Megaspore mothercell (2N) occurs in ovules or embryo sac
- Undergoes meiosis to produce 4 megaspres - Usually only 1 megaspore survives to form embryo sac *other three disintegrate - Remaining megaspore undergoes 3 mitotic divisions to produce 8 nuclei (N) |
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Double Fertilization
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- Occurs in all angiosperms or flowering plants
- Results in fertilization of egg - Fertilization of both polar nuclei which will develop into endosperm (stored food) - This fertilization results in primary endosperm (2) |
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Birds are attracted to what color light
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Red and orange
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2 basic reasons for self pollination
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1. Ecologically aventageous – flowers don’t have to rely on pollinators and don’t waste energy producing pollen/nectar
2. Producers more uniform progeny |
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Dioecious plants
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have no choice. Have to exchange pollen with another plant
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Monoecious plants
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have both sexes on 1 plant but male and female flowers are separate (insures some cross pollination)
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Dichogamous plants
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– functional stamens and carpels on same plant but reach maturity at same time
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Self incompatibility
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when plant knows it has both sexes and does not inhibit pollen tube growth
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Vegitiative reproduction (Asexual)
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new plants are clones of adult plant parts (no flower)
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Runners
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new plants form at tip of runners (called stolons)
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Rhizomes
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underground stems that grow horizontally under surface and send up leaf material above ground
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Suckers
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roots which give rise to new plants
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Adventitious plantlets
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made from stem and leaf cutting
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Apomixes
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embryos in seed are produced asexually from parent plant. New plant identical to parent plant
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Bulbs and corms
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form small bulbs or corms to side of larger structure
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Woody plants
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have longer life due to secondary meristem
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Annual plants
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grow flower and form fruits and seeds within 1 growth season
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Biennial plants
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plants that have life cycles that take 2 years to complete
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Biennial plants years
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- First year they produce nutrients and store them in underground storage organs. Have rosette growth first year
- Second year – produce flowers and seeds |
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Perennial plants
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grow year after year and flower repeatedly
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