Flashcards in Test 5 Deck (151):
The patterns of growth that contribute to plant body plan
Up and out
-Regions of cell division
-Also called initials
-Compare to stem cells
-One daughter cell differentiates while the other remains this type of cell
These refer to meristems being what?
Produces primary plant body (non woody structures)
Where are apical meristems found?
Produce secondary plant body (wood and bark)
Where are lateral meristems found?
Along the sides of the tree
What are the two types of meristem?
Apical and lateral
-Found at the tips of roots and stems and in buds
-Responsible for primary growth
-Elongation of shoots and roots
-Formation of roots, stems, and leaves
All refer to?
Primary growth in plants
What are the two types of apical meristems?
Shoot and root
-Supply the cells that extend stems and branches, allowing more leaves to form
Shoot apical meristems
-Supply the cells that extend roots, enabling the plant to "look for" more water and minerals
Root apical meristems
Apical meristems give rise to what?
Primary meristems (a generic name for stem cells)
-Enable the root to grow
-Have the root cap
-Is the zone of cell division
Root apical meristems
-Develops from initial cells
-Protects the root
The source of meristems
Zone of cell division
-Cells lengthen and push the root into the soil
Zone of cell elongation
The site where cells are differentiating
Zone of cell maturation
-Gives rise to the epidermis
--Is the outer layer of cells
--Gives root protection and absorbs minerals and water
-Produces the cortex
-Produces inner layer of cortex
-Produces the stele
--Is the vascular system (xylem and phloem)
Contains the pericycle, xylem, and phloem
-Where lateral roots form
-Can contribute to secondary growth
What do parenchyma cells do?
-In monocot roots only
-In stems of eudicots and monocots
Lays down the beginning of leaves and axillary buds
-Leaf and bud primordia
--Bulge on shoot apical meristems
The stem's primary meristems
_____ apical meristems form at the bases of leaf primordia.
Primary xylem and phloem are produced by what?
What is the vascular system arranged in?
Are vascular bundles arranged the same or different?
What do vascular bundles contain?
Xylem and phloem
Vascular bundles are scattered.
Vascular bundles are arranged in a cylinder and the pith is at the center.
Vascular cambium is found where?
These produce wood and bark
What are the two types of cambium?
Vascular and cork
Supplies cells that will become wood and bark
Wood and bark are what?
Secondary xylem and phloem
Produces waxy-walled cork cells and some of the cells that become bark
Secondary growth gives rise to what?
Wood and bark
What does vascular cambium produce?
Secondary xylem and phloem
What produces primary xylem and phloem?
Procambium of apical meristem
What thickens stems and roots?
How does vascular cambium thicken stems and roots?
Via initial cells that are undifferentiated
Trunks are also known as what?
What do tree trunks have?
Annual rings are seen where? And why?
Temperate zone forest trees. Seasonal changes.
What happens to trees in the winter?
They become dormant and stop growing rings
When molecules move from high to low concentration
The diffusion of H2O molecules from low solute to high solute
Requires energy and proteins. Drives molecules up the concentration gradient, low to high.
(Facilitated diffusion) high to low concentration
A measure of the effect of solutes on the osmotic behavior of a solution
Solute (osmotic) potential
Greater solute concentration equals what?
(lower) solute potential
-The overall tendency of a solution to take up water from pure water across a membrane
-Water moves toward a region of lower (more negative) water potential
The pressure going in the backwards direction
-The pressure outward - causes resistance to more H2O moving in
-Movement of a solution due to a difference in pressure potential
-Through xylem and phloem
These are in our kidneys to help concentrate our urine if dehydrated and to get rid of excess H2O
-In plants and animals
-Are channel proteins
Minerals have what?
-Can't diffuse across membranes
-Need transporter/carrier/channel proteins
-Increasingly more negative water potential from soil to stele
Where is this happening?
What are the two pathways by which water and ions get to the xylem from the soil?
Apoplast and symplast
What does apoplast mean?
Away from living material
What does symplast mean?
Together with living material
Water and ions also get to the xylem from the soil via what?
-Produced by ground meristem
-Has casparian strip
What color is the casparian strip?
-Part of the endodermal wall
-Made up of hydrophobic molecules
--Prevent water from moving between cells
-Forces water into cells
--Once in stele they enter into the apoplast
What isn't responsible for moving water through the xylem?
Pumping cells and roots
What is responsible for moving water through the xylem?
The pulling force of leaves
Water being pulled up a tree
-Concentration of water vapor in the atmosphere is lower than in a leaf
-Water vapor leaves plant through stomata
-Is between H2O molecules
-Forms H bonds
Evaporative loss of water from leaves indirectly generates a pulling force on the water in apoplast of leaves
The leaves are coated with a waxy cuticle which is what?
Impermeable to water and CO2
How does a leaf balance water loss and CO2 gain?
-Pores in the epidermis
-Consist of guard cells
When are stomata open and closed?
Open = day
Close = night
When do stomata close during the day?
When the plant is losing too much water
What are the cues for opening and closing of stomata?
Light, low CO2 levels, and water potential
Stomata closing during the night explains what?
Why they stay open during the day
Low levels of this in the intercellular spaces of a leaf cause stomata to open.
-The tendency of a solution to take up water from pure water across a membrane
-If water is too low, then stomata will close
Describes water potential
Where does photosynthesis occur?
The movement of carbohydrates and other solutes through the plant in phloem
Sucrose, amino acids, minerals, etc
The carbohydrates moved through the phloem
Where do carbohydrates move (from, to)?
From sources to sinks
Photosynthesis and storage
Where carbohydrates are moved from (Sources)
Immature leaves, roots, flowers, and developing fruit
Where carbohydrates are moved to (Sinks)
The pulling force in a plant
The two places where metabolic energy is required during translocation
Loading and unloading stations
-From sources into phloem
-Removal of solutes from phloem into sinks
How can phloem move sap?
Bidirectional (up and down)
How does water move up xylem?
Removing a ring of bark (the layer that contains phloem)
What happens when solutes accumulate above the girdle?
What happens to the bark beneath a girdle? Why?
It dies because it no longer receives nutrients
The food substances that have "ingredients" of macromolecules
Inorganic molecules that can also be mineral nutrients
Organisms that make organic compounds from simple inorganic compounds
Plants, some protists, some bacteria
-Fungi and animals that must ingest organic compounds
-Depend directly or indirectly on autotrophs
Organisms that are different from hetertrophs
Most autotrophs are photosynthesizers, meaning?
They use light to produce organic compounds
Some autotrophs are chemolithotrophs (bacteria), meaning?
They get energy from reduced inorganic substances
An inorganic compound that chemolithotrophs get energy from
-Required to complete a life cycle
-Can't be replaced by another element
Macronutrients and micronutrients
The two categories that essential elements fall into
This is made of living and non living components
What does soil provide for plants? (5 things)
1) Mechanical support
4) Bacteria and other organisms
5) Harmful substances
The structure of soil depth refers to?
What are the layers of soil called?
-They can be significantly different and leaching may occur
When minerals dissolve in H2O and are carried to deeper horizons (unavailable to roots)
-The association of fungi with roots
-Fungus that expands root surface
Why are mycorrhizae important?
Roots can't get enough nutrients from the soil
Phosphorus (in the form of phosphate) is what?
Another way plants get nutrients
Plants and bacteria participate in what?
Global nitrogen cycle
Nitrogen fixers release ammonium and ammonia
Nitrifiers oxidize ammonium and ammonia
-Reduce nitrate back to NH4
-Occurs in plants
-Bacteria in soil
-Return N2 to atmosphere
Why do plants need nitrogen?
For proteins and nucleic acids
Where can we find N2?
Why can't plants use N2 directly?
It's extremely stable because of the triple bond
Where do plants get N2 from?
Nitrogen fixing bacteria
What do nitrogen fixing bacteria do?
Fix nitrogen by converting N2 to ammonia (NH4), which makes all other life possible
What type of bacteria live in oceans and freshwater? Give an example.
Photosynthetic bacteria; cyanobacteria
What type of bacteria live on land?
Free living soil bacteria
When do free living soil bacteria release nitrogen?
When they die
What happens with the bacteria that live in association with plant roots?
They release up to 90% of the nitrogen they fix to the plants and release amino acids into the soil
What are rhizobium?
A nitrogen fixing bacteria
These live in a mutualistic relationship with legumes
-Peas, soybeans, clover, and alfalfa
-Infect plant roots and develop nodules
-Have an enzyme called nitrogenase
Rhizobium : Nitrogen fixing bacteria
Catalyzes reaction that reduces nitrogen gas
What do legumes attract? How?
Rhizobium; They release flavonoids
What do flavonoids do?
Trigger transcription of bacterial nod genes (encode nodulation - nod - factors)
What happens after the infection of plant cells?
Bacteria secrete nod factors
What happens when nod factors are secreted?
Cells in the root cortex divide, producing primary nodule meristem and nodule tissue
Where is primary nodule meristem found?
Only in legumes
What does the outer layer of nodule exclude? Why?
O2 because it inhibits nitrogenase
What is leghemoglobin and what does it do?
A plant protein that binds O2
-Has iron and binds O2 like human hemoglobin
-Binds most of the O2 so only a few free O2 can't significantly inhibit nitrogenase
Why are there carnivorous plants?
The soil, sun, and air don't meet all their needs
Where are carnivorous plants found?
Nutrient deficient soil