Test 1 For Plant Physiology

Front 1

Determinate growth

Back 1

(In animal cells and some plant cells) is the INability to grow beyond a certain genetically predetermined stage. Allows plasticity to handle environmental conditions.

Front 2

Indeterminate growth

Back 2

Continued capacity for vegetative growth. It allows plants plasticity to handle environmental conditions.

Front 3

Plasticity

Back 3

Is the ability of all organisms with the same genotype to irreversible change their phenotype (developmental pattern, behavior, form, or shape) in response to changes in the environment. Plasticity can evolve and be adaptive if fitness is increased by changing phenotype.

Front 4

Elasticity

Back 4

A reversible property such as when the vacuole swells and shrinks in response to water levels. This is important because it is adaptation to a changing environment.

Front 5

Phenology

Back 5

Is the study of the timing of events in order to predict outcimes. Phenological timing can be changed based on environmental conditions which may lead to better survival of an organism.

Front 6

Constitutive enzymes/genes

Back 6

The genes are always expressed and the proteins are always present. Sometimes referred to as "housekeeping" genes or proteins.

Front 7

Inducible enzymes/genes

Back 7

Genes can be turned on and new or more proteins can be produced when needed.
Signif: Allows plants to adjust to needs in the enviro such as defense, and it allows plants to conserve resources.

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Adaptation

Back 8

Adaptation to stress is an inherited level of stress resistance acquired by a process of genetic selection over many generations. This is why certain plants (sun v. shade) only grow in certain enviros which they are adapted to.

Front 9

Acclimation

Back 9

The increase in plant stress tolerance due to exposure to prior stress which may involve changes in gene expression (for example inducible enzymes or structures). Also called hardening. Plants can make short-term changes to survive a cold snap or temporary drought.

Front 10

Flora vs. Fauna

Back 10

Flora consists of plants and includes bacteria, fungi and other soil microorganisms whereas fauna consists of animal life. Example of flora would be plant roots, and fauna would be earthworms. These organisms help to determine soil structure and other soil characteristics and therefore affect plant life.

Front 11

Parent Materials (igneous, sedimentary, metemorphic)

Back 11

Parent materials impact chemical composition of soil which affects structure, nutrient content and pH
Igneous comes from cooled lava (granite, pumice) which can be changed into sedimentary and metamorphic rocks.
Sedimentary (sandstone, limestone, and shale) contains secondary minerals like quartz, lime and clay.
Metamorphic rock formed under pressure and temperature (quartzite, slate).

Front 12

Sand, silt, clay

Back 12

Different size particles that make up mineral fraction of soils. Sand is largest, silt in-between, and clay smallest. Affects cation exchange capacity, water retention which affects nutrient and water availability

Front 13

Cation Exchange Capacity

Back 13

Capacity of soil for ion exchange of positively charged ions between the soil and soil water. It is a measure of soil fertility and nutrient retention capacity.

Front 14

Phototroph vs. Heterotroph

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Phototrophs use the sun’s energy directly to make energy in form of carbon so are usually at the bottom of the food chain. Heterotrophs can’t make their own food, so they must eat other organisms to obtain their carbon.

Front 15

Saprophytes vs. parasites vs. obligate biotrophs

Back 15

Saprophytes take nutrients from non-living materials, useful for recycling of nutrients.
Parasites take nutrients from living organisms and give nothing in return.
Obligate biotrophs are organisms that require a living host for their food supply.

Front 16

Hydroponics

Back 16

Growth of plants in nutrient solutions. Allows specific nutrients to be added or removed for study of their effect on plants

Front 17

Macronutrients

Back 17

Macronutrients are needed in larger amounts than micronutrients.Macronutrients are C,O, H, N, S, P, K, Ca, Mg, and Si.
Biological roles in general are: C serves as backbone to starch and cellulose and used in photosynthesis as CO2,
O is necessary for aerobic respiration,
H, necessary component of sugars,
N, & S parts of carbon compounds (proteins),
P, Si involved in energy storage or structural integrity, K, Ca,Mg,Cl remain in ionic form serving in various functions

Front 18

Micronutrients

Back 18

Micronutrients are Cl,B, Fe, Mn, Zn,Cu, Mo,Ni, and Na.
Cl,Mn,Na remain in ionic form serving in various functions, and Fe, Zn, Cu, Mo, Ni nutrients involved in redox reactions.

Front 19

Chlorosis

Back 19

Yellowing of plant tissues (leaves). Could be due to number of problems such as nutrient deficiency, pathogens, etc. but is an indicator that something is wrong. In nutrient deficiencies could be used to diagnose absence of nutrient based on mobility in phloem since older chlorotic leaves indicate mobility and could be due to N deficiency, etc.

Front 20

Necrosis

Back 20

Type of cell death resulting in dead tissue spots. Indication of plant health problem either through nutrient deficiencies or pathogens.

Front 21

Phloem immobile vs mobile nutrients

Back 21

Deficiencies in phloem mobile nutrients will result in symptoms that first appear in old leaves as the mineral like N which can move freely are taken away and sent to young leaves. Immobile nutrients such as S, Fe, Cu will show deficiency symptoms in young leaves first. One way to diagnose potential nutrient deficiencies.

Front 22

Rhizosphere

Back 22

Area of soil around the root where root-soil interactions occur. Root can modify the soil to promote nutrient uptake or attract symbiotic relationships.

Front 23

Quiescent center

Back 23

Central region of root meristem where cells divide more slowly than surrounding cells which serves as a backup in case damage to the meristem occurs.

Front 24

Endodermis

Back 24

Specialized layer of cells with a Casparian strip surrounding the vascular tissue in roots and some stems. Prevents flow of water and nutrients apoplastically into the stele and allows root pressure to build up.

Front 25

Casparian strip

Back 25

Band in cell walls of endodermis that is impregnated with a waxy suberin preventing water and solutes from entering xylem by moving between the endodermal cells (apoplastically).

Front 26

Apoplastic vs symplastic pathways

Back 26

Apoplastic pathway is route by which water and solutes move through the cell walls without crossing any membranes vs symplast pathway in which sap travels from cell to cell via plasmodesmata

Front 27

Passive vs active transport

Back 27

Passive transport does not require energy and molecules move from a higher concentration to a lower concentration via diffusion vs active transport which allows molecules to be concentrated against a concentration gradient and requires an input of energy. Both are useful in moving molelcules from cell to cell over short and long distances.

Front 28

Mineralization

Back 28

Process of breaking down organic compounds by soil microbes that releases mineral nutrients in forms that can be assimilated by plants

Front 29

Immobilization

Back 29

Microbial absorption and assimilation of ammonium or nitrate. One way nitrogen passes through the biogeochemical cycle

Front 30

CHATS vs IHATS vs LATS

Back 30

Constitutive High-affinity nitrate transporters – take up nitrate at low concentrations all the time vs Inducible High-affinity nitrate transporters which are induced by nitrate or nitrite. At high external nitrate concentrations the low-affinity transport system takes up nitrate.
All three work in concert to ensure adequate nitrate is available for the plant

Front 31

Transcription vs translation

Back 31

Transcription is copying DNA into mRNA for translation of mRNA to proteins. It was talked about in terms of inducible gene expression and protein production as well as two areas of regulation of protein activity.

Front 32

Nitrogenase

Back 32

Two component protein complex that carries out biological nitrogen fixation in which ammonia is produced from molecular nitrogen. Sensitive to high oxygen levels around enzyme which must be controlled.

Front 33

Leghemoglobin

Back 33

Oxygen binding heme protein found in cytoplasm of infected nodule cells that facilitates diffusion of oxygen to respiring symbiotic bacteria. Prevents inactivation of nitrogenase enzyme.

Front 34

Nodulin vs nodulation genes

Back 34

Nodulation (nod) genes are rhizobial (bacterial) genes, the products of which participate in nodule formation by encoding Nod factors which are lipochitooligosaccharides vs nodulin (Nod) genes that are plant genes specific to nodule formation such as infection and nodule development. Signals lead to symbiotic nitrogen fixation.

Front 35

Phytosiderophores

Back 35

Plant derived chelating compounds that bind iron which is not readily available for uptake in plants and thus making it more available. Especially important in grasses.

Front 36

Hyphae

Back 36

Small tubular filaments of fungi. Used to branch and grow to roots to make connections and can act like root hairs to increase root surface area.

Front 37

Mycelium

Back 37

Mass of hyphae that form body of fungus. Some fungi form symbiotic relationships with plants, some act as saprophytes breaking down organic matter, and some can be pathogenic

Front 38

Hyphopodium

Back 38

Specialized hypha of arbuscular mycorrhizae often branched and swollen which adhere to the root epidermis before intracellular fungal penetration

Front 39

PPA

Back 39

Triggered by hyphopodium, the assembly of broad aggregation of cytoplasm underlying the cortical cell which gives the fungal hyphae a route to follow from the epidermis to the inner cortex.

Front 40

Intra- vs interspecific competition

Back 40

Intraspecific competition is competition between like plants (corn in field) where as interspecific is competition between different species (like crop and weed). Intraspecific is usually more intense.

Front 41

What six factors influence soil development?

Back 41

Parent materials (igneous, sedimentary, metamorphic), climate (rainfall, temperature), topography, organisms, time, and man (compaction, erosion, pollution)

Front 42

What horizons make up the soil profile?

Back 42

O is organic layer, A horizon is top soil where main root activity happens and maximum leaching occurs. B horizon or subsoil leached products accumulate, and C horizon is transition zone

Front 43

Identify three zones of activity in roots.

Back 43

Meristematic, elongation, maturation zones. Meristematic cells actively dividing, in elongation zone cells expand in size and push root through soil. In maturation zone, cells become fully differentiated with specialized functions. Also area where root hairs occur.

Front 44

Nitrate and ammonium assimilation in plant cells.

Back 44

Nitrate assimilation:
Nitrate reductase reduces nitrate to nitrite in the cytosol of the cell. Then, nitrite reductase reduces nitrite to ammonium ion in the chloroplast.

Ammonium Assimilation:Ammonium combines with glutamate to form glutamine in a reaction that is catalyzed by glutamine synthase in either the cytosol or the chloroplast. Glutamate synthase (GOGAT) transfers the amine group from glutamine to 2-oxoglutarate in the cytosol or chloroplast.

Front 45

Nitrate reductase regulation

Back 45

Nitrate reductase is regulated at the transcriptional level, and therefore also at the translational and posttranslational level. At the transcriptional/ translational level, nitrate reductase is activated by nitrate concentration, light, and sugars; and it is reduced by glutamate/ glutamine concentrations. Nitrate reductase can be regulated posttranslationally by reversible protein phosphorylation.

Front 46

Outline the process involved in nodule formation in plant roots beginning with the plant signal until the formation of the bacteroid

Back 46

1. Rhizobia are attracted to plant roots by chemical signals.
2. Rhizobia attach to root hairs.
3. The root hairs begin to curl and the rhizobia are trapped-- formation of infection pocket.
4. Rhizobia infect root hair by an infection thread that travels toward the root cortical cells.
5. Root cortical cells divide.
6. Rhizobia infect cortical cells.
7. A nodule is formed by the infected cortical cells.
8. The nodule matures and becomes a fully functional bacteroid.

Front 47

Outline the process involved in the association of arbuscular mycorrhizae with plant roots.

Back 47

1. A spore released chemical signals "exudates", and plant releases chemical signals "exudates".
2. Once they find each other, the spore starts growing and branching towards the plant. And the plant begins producing calcium in high concentrations.
3.When the fungus reaches the root, the hypophodium adheres to the root surface.
4. Cytoplasm aggregates in the cell to form a tunnel, called the prepenetration apparatus.
5. When the fungus penetrates the epidermal root cell, more PPAs are formed so the fungus can follow a path through the cells to the inner cortex.
6. More branching occurs within cells, allowing more surface area for nutrient exchange.

Front 48

Nodule formation vs. arbuscular mycorrhizae

Back 48

Both are symbiotic relationships that provide nutrients to plant (mainly N and P.)
AM differs from nodules in that it is very intrusive.The fungus invades and spreads to many cells of the root. Nodules only affect a few root cells that eventually grow and divide to form an external bacteroid.

Front 49

Ecto- vs. Endo-mycorrhizae

Back 49

Ectomycorrhizae colonize spaces between root cells (don’t actually go into cells) by creating the Hartig net which is a network of hyphae surrounding the roots. The sheath of mycelia make the mantle.
Endomycorrhizae develop inside the root cells (AM most common type) by inserting hyphae into cells, branching and forming arbuscles and/or vesicles.
Both take carbon from plant, but increase root surface area thus increasing water uptake as well as increased nutrient uptake, esp. phosphorus.

Front 50

What above ground and below ground resources do plants compete for?

Back 50

Above – space, light, carbon dioxide, pollinators
Below – nutrients, water, space, oxygen

Front 51

What does plant competitive success depend on?

Back 51

Seedling growth rates
Root architecture
Feeding diameter and area
Root depth
Symbiotic relationships
Growth and  internal recycling processes
Ability to modify soil environments

Front 52

What are phytochromes and cryptochromes?

Back 52

Plant pigments that detect light.
Phytochromes responsible for shade avoidance, germination.
Cryptochromes (phototropins) are responsible for chloroplast movement, sun tracking, guard cell opening, phototropism.
Both are used for: flowering, gene expression, and recognizing circadian rhythms.

Front 53

Shade avoidance system

Back 53

Using light signals like cry,phy, plants can sense increase Fr radiation caused by proximity of neighbors

Front 54

Phototropism

Back 54

growth response towards light. Made possible by cryptochromes.

Front 55

Characteristics of a plant trying to avoid shade

Back 55

Rapid internode, petiole, and leaf extension
Increased rate of flowering, but reduced seed set, and truncated fruit development.
Reduced germination, leaf development, and chlorophyll development

Front 56

Weed impact to crop physiology

Back 56

Cause crops to germinate under altered light quality (poor stand density)
Energy is used for resource capture (lower yield)
Modified internode length (higher probability of lodging-- falling over.)
Altered root:shoot ratio (lower yield.)

Front 57

Impacts of Invasive species on ecosystems

Back 57

Increased fire threat (number and intensity)
Imapcts human, livestock, and wildlife health
Exacerbates erosion and drought
Alterations in water flows and availability
Reduced access/utilization to recreation
Reduces property value

Front 58

Origins of Invasive Species

Back 58

Landscaping or Horticulture.. a few of agronomic origins

Front 59

Evolution of Parasitic Plants

Back 59

Independent evolution 11 to 13 times from autotrophic plants
13 families of parasitic plants.
Development of ability to draw resources from another plant.
Loss of structures: leaves, secondary roots, stems.
Loss of genes involved in photosynthesis: Holoparasitic plants have experienced a significant loss of the chloroplast gene.

Front 60

Hemi- vs. Holo- parasitic plants

Back 60

Hemiparisite: A plant which is only partially parasitic, possessing some capacity for photosynthesis.
Holoparasite: A plant which is totally parasitic, lacking chlorophyll and thus unable to make its own food.

Front 61

Haustorium

Back 61

The bridge of tissue connecting the host and parasite which acts as a conduit for the flow of water and nutrients from host to parasite.
A parasitic plant must have a haustorium to be considered parasitic.

Front 62

Parasite control strategies

Back 62

Using stimulants
"Trap Crops:" crops that are able to stimulate germination of the parasite seed, but will not allow themselves to be parasitized.
"Catch crops:" crops that act as hosts to stimulate germination of the parasites, but then crops and parasites are killed with herbicides or by other means.
Use synthetic stimulants to induce suicidal germination.

Front 63

How a parasite locates host

Back 63

A parasite seed needs to be preconditioned before it can perceive/ respond to germination. After this stage though, a germination stimulant is exuded from plant root. The seed recognized this exudate and grows toward the root.