Transpiration And Translocation Flashcards
What is xylem?
“Pipelines” that move water and nutrients from roots to shoots
Thick lignified secondary cell walls
“Pulling” process for transpiration
What is phloem?
Moves products of photosynthesis from leaves to other parts of the plants?
“Pushing” process
What is transpiration?
Loss of water vapor through the stomata
CO2 moves in, it’s an exchange
(Water vapor more concentrated in the leaf than outside air)
Regulated by guard cells that open when the leaf is full of moisture, closes when moisture is low.
What is water cohesion?
Water sticks to itself - it’s how water droplets form.
Force of attraction between water molecules.
What is water adhesion?
Waters tendency to cling and stick to other surfaces.
Force of attraction between water molecules and other molecules.
What is the transpiration stream?
Root takes in water. The water forms a continuous chain up the xylem right to the tip of the leaf.
The cohesion helps draw the water molecules, and the adhesion helps keep it along the xylem.
This is a passive process that does not require an energy expenditure from the plant.
How does water enter roots?
Water enters root hairs via osmosis.
Can move between and in-between cells.
What are the 5 steps of transpiration?
1 water evaporates from the leaf and exits from the stomata
2 water enters the roots via osmosis
3 water molecules are cohesive, one exits and another enters
4 water molecules adhereto the sides of the xylem
5 tension is created by the constant upward pull of water evaporating
What are things that affect and impact transpiration?
Water limitations on site.
Stomatal control - for example desert plants only open at night
Healthy roots - mycorrhiza in the soil to help, for example
Weather conditions - Transpiration increases on hot days, decreases with humidity.
What is Translocation?
The process of moving the products of photosynthesis from where it happens to throughout the plants, where needed.
Active process, requires energy expenditure.
What are companion cells?
Phloem has companion cells that do the metabolic processes for the phloem. They provide the energy through their mitochondria to allow phloem to the pulling of photosynthetic products
What is the process of translocation?
1) photosynthesis creates sugars at the source of where it occcu4s
2) companion cells actively transport sugars into the sieve cells of the phloem
3) increased sugar in the phloem causes water to enter and turgor pressure to build
4) increased pressure drives the fluid down
5) sugar is actively removed where it’s needed, pressure drops and water returns back to xylem
What are the definitions for taxonomy and phylogeny?
Taxonomy = science of categorizing things
Phylogeny = evolutionary history and relations of organism groups
What makes a plant a plant?
Eukaryotic cells (with nuclear, multicelluar)
Rigid cell walls
Alternation of generations
Mechanisms for moving water and minerals up and down.
What defines non vascular plants?
Gametophyte dominant generation
Absorbs moisture through surface
Typically small, lacks structural support
Requires water to reproduce
What defines a seedless vascular plant?
Sporophyte dominant phase
Flagellated sperm
Spores not seeds
What’s the difference between gymnosperm and angiosperm?
Gymnosperm = usually cones bearing plants, gametophye greatly reduced, pollinated by wind.
Angiosperm = flowering plants, double fertilization occurs producing food for embryo, pollinated by other animals/insects
What is needed and produced by photosynthesis?
Needed = co2, h2o, light energy
Produced = glucose, oxygen, heat
What are the two stages of photosynthesis?
Stage 1 = light dependent, happens in the thykaloids of the chloroplast, requires water, sunlight, pigments
Stage 2 = light independent, Calvin cycle, happens in the stroma
What is the light dependent stage of photosynthesis?
Light and water react with pigments
Water is split, o2 is the byproduct
ATP and NADPH is created for the Calvin cycle to power it
What is the light independent stage or Calvin cycle?
ATP and NADPH is used to split co2
Carbon is fixed and and glucose produced
Many cycles occur
What are the end products of photosynthesis?
Energy as storage atp
Heat
Carbohydrates
Cellulose
What does cellular respiration do?
Converts energy stored in the form of glucose into usable chemical energy
What is meiosis and mitosis?
Meiosis = mother cell divides twice. Produces 4 daughter nuclei
Mitosis = mother cell produces 2 daughter nuclei, maintains ploidy. Growth or repair of cells
What is Alternation of generations?
Two different mutlicelluar forms/phases/generations
Plants reproduce both sexually and asexually, both types required to complete cycle
What happens in the sporophyte/haploid generation?
Sporophyte makes the spores, meiosis
What happens in the diploid/gametophyte generation
Mitosis, gametophyte makes the gametes
What are the five key steps in Alternation of generations?
Sporophyte makes spores (meiosis)
Spores grow into gametophyte (mitosis)
Gametophyte makes gametes
Gametes fuse
Zygote grows into sporophyte (mitosis)
What defines Alternation of generations for byrophytes?
Gametophyte is dominant generation
Sporophyte is directly supported and dependent on gametophyte
Water required for fertilization
Plants must be in close proximity
What defines Alternation of generations for ferns and their allies?
Sporophyte is dominant generation
Ferns are only plants that have independent mutlicelluar stages
Flagellated sperm
What defines Alternation of generations for conifers?
Sporophyte is dominant stage
Reproduction occurs entirely within cones
Wind pollination
Seed occurs from single fertilization event
Within male pollen cones the sporophyte forms a microspore that develops into a male gametophyte as a pollen grain
What defines Alternation of generations for flowering plants?
Ovary produces megaspores that develops into female gametophyte
Sporophyte generation makes up almost their whole life cycle
Double fertilization occurs where each sperm plays a role
What planta is the gametophyte generation dominant? What plants is sporophyte generation dominant?
Gametophyte dominant = bryophytes
Sporophyte dominant = vascular plants
What defines a cell wall?
Semi permeable mesh/membrane
Primary cell walls of cellulose
Secondary cell walls exists
What defines a cell membrane?
Transports/secretes substances in and out of cell walls
Separates inside of cell from cell wall
What is the cytoplasm?
Goo inside cell holding it all together
Contains organelles
What is the nucleas?
Control center of cell
Rna and dna
What is the Vancoule in the cell?
Storage, takes up large volume of cell
Regulates concentration of water in relation to environment
What is the chloroplast?
Links physical world to biological world
Converts energy to sugar - photosynthesis
What is the mitochondria?
Powerhouse of the cell
Site of cellular respiration
Converts glucose to ATP powering cell functions
How does meristematic and permanent tissue work?
Meristematic tissue divides to create permanent tissue.
What is the difference between primary growth and secondary growth?
Primary growth is up/down, Longitudinal (cell division, elongation, cell specialization/differentiation)
Secondary growth is lateral, produces secondary growth (secondary phloem and xylum) only occurs in gymnosperms and dicots, perennial only
What are plant communities?
Plants thatgrow together due to having a shared ecological niche
What is climate from an ecological perspective?
Climate is the most fundamental ecosystem driver.
What is succession? What is seral? (ecosystems)
Succession = change in the composition and structure of biotic communities over time
Seral = the stage of succession of a biotic community that is transitional. If undisturbed, the seral stage will give way to another community that represents a further stage of succession.
What are BEC zones? What are subzones? What are variants?
Zones = Most general category in the BECsystem, named after the tree species, most commonly grown on intermediate sites in the zone ex ICH
Subzones = same general patterns of plant communities on similar sites. Named for precipitation and temperature. Always a two letter code, ex ICH xw
Variants = slight vegetation differences but very similar on zonal sites. Represented by a number at the end of the code.
What is a zonal site?
Nutrient inputs meet outputs.
Sites that best reflect the regional climate
What is a site series?
The finest scale of classification
Represented by a number
Site level classification named for the mature vegetation community
What is disturbance?
A change in environmental conditions that cause a pronounced change in an ecosystem
Shapes structure and succession
What are different types of disturbances
Natural disturbances = biotic, abiotic. Fire, wind, browsing, pathology.
Anthropogenic = clear cutting, mining, development.
What are key descriptors of disturbances?
Extent, space effected
Frequency , how often
Intensity, energy output
Severity, change, or loss of material
What’s the difference between stand initiating and stand maintaing disturbances?
Stand initiating = starts a new forest, tends to happen infrequently, returns to primary or secondary succession
Stand maintaining = happen more frequently, keeps successional stages stable.
What is a small to medium scale disturbances?
Generally under 2ha
Produces small-scale changes in ecosystem structure and composition
Leads to increased ecological diversity by creating patchiness within ecosystems.
What are large scale disturbances?
These are usually patches greater than 2 ha in size
Shade intolerant species often establish after.
What is succession?
A temporal stage that is a pathway of plant community development that is characteristic of a particular environment
Defined as a change in the composition and structure of biotic communities over time
What is primary vs primary and secondary succession?
Primary = may take 100s of years, starts with simple plants (mosses/lichens), key components is the soil developing. Ie glaciers receding. Starting from nothing.
Secondary = still have developed soil, has a seed bank, shorter time period to recover.
What is the climax theory?
Disturbances of some kind
Colonization by shade intolerant and/or pioneer plants
Competition and interaction for light and nutrients
Plants modify the environment, creating shade or providing nutrients
Shade tolerant or climax vegetation occupies site, ecological convergence
What are the 4 stages of structural and successional development after a disturbance?
1 Establishment and stand initiation
2 Thinning and stem exclusion - some trees don’t make it
3 Transition/understory initiation - light availability changes, different things grow
4 Shifting mosaic - old seral/growth. We see the most similarities in a plant community in a given environment at this stage.
How does shade tolerance or intolerance relate to succession?
Shade intolerant plants often need mineral soil, cannot establish under forest canopy
Intermediate -
Shade intolerant = better adapted to low light conditions, can establish under canopies,often require a stronger lfh soil
What is structure?
Describes the appearance of a stand or a community.
Certain structures are only possible in certain successional stages
What is biodiversity?
The natural variety of life in living systems
3 levels
Genetic diversity = adaptability and diversity within a population for resilience.
Species diversity = number and relative abundance of species in an area. Variety adds complexity which offers more habitat and niches
Ecosystem diversity = variety of distinguishable habitats found in an area.
Biodiversity includes structural diversity
What is the role of disturbances such as fire in landscapes and biodiversity
Destroy, create and alter habitats.
To manage ecosystems we have to have to understand natural disturbances in order to emulate them
What are different fire types?
Surface = stand maintaining
Crown = stand replacing, changes age of forest
Ground
What’s the relationship between fire return intervals and severity
The longer the return interval, the higher the severity, therefore more likely to be stand replacing fires
If there’s frequent fire in an ecosystem, there’s less fuel build up
What is a landscape and landscape ecology?
A landscape can be defined by a watershed
Landscape ecology is understood by the relationships among ecological processes on a larger scale, taking into account spatial and temporal patterns
How can stand management maintain biodiversity?
Stand structure = horizontal and vertical
Old growth retention
Wildlife trees
Coarse woody debris
Forest floor
Habitat availability and specialization
