Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
dissolves solutes;
- the cytosol of the cytoplasm is a water solution of dissolved solutes. |
|
|
Term
|
Definition
| water is used in biochemical reactions, such as photosynthesis. |
|
|
Term
|
Definition
| water translocates solutes in xylem and phloem. |
|
|
Term
|
Definition
water is very important in regulating temperature.
a) stabilizes plants and environment (due to high specific heat)
b) evaporative cooling (due to heat of vaporization)
c) releases heat when freezes (due to heat of fusion)
d) constant temperature during phase change - freezing/melting water/ice stays at 32 oF. |
|
|
Term
|
Definition
the positive pressure inside of cells due to water uptake.
a) due to osmosis.
b) keeps cells expanded
c) keeps herbaceous plants and plant parts erect
d) the driving force for growth in size by causing cell expansion |
|
|
Term
|
Definition
| shrinkage of individual cells due to loss of turgor pressure that causes a cell to become flaccid. |
|
|
Term
|
Definition
excessive water loss that causes loss of plant rigidity.
- caused by plasmolysis of enough individual cells to cause the organ to be limp. |
|
|
Term
|
Definition
| amount of water vapor in air expressed as grams water per cubic meter of air (g/m3) |
|
|
Term
|
Definition
| amount of water vapor in air expressed as grams water per kilogram of air (g/kg) |
|
|
Term
|
Definition
| amount of water vapor in air expressed as a percentage of the amount of water vapor that could be held at saturation. |
|
|
Term
|
Definition
| amount of water vapor in air expressed as the downward pressure exerted by the water vapor present in the atmosphere. (1-55 mm Hg). |
|
|
Term
|
Definition
| the temperature where relative humidity equals 100%. |
|
|
Term
|
Definition
| condensation of water into small droplets that stay suspended in air close to the earth's surface |
|
|
Term
|
Definition
| condensation of water into small droplets that stay suspended in air high in the atmosphere. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| movement of water through plants, mainly through xylem. |
|
|
Term
|
Definition
-loss of water vapor from leaves and other above ground plant parts;
- mainly occurs through the stomata. |
|
|
Term
|
Definition
loss of liquid water from leaves;
- occurs through hydathodes (similar to stomata, but they do not close). |
|
|
Term
|
Definition
most absorption, mainly through root hairs due to:
a) very numerous - 14 billion on a typical rye plant.
b) large surface area -14,000 ft2 (1310 m2) on a typical rye plant
c) rapidly and constantly produced - 975 linear ft (300 m) per day on a squash plant |
|
|
Term
|
Definition
little absorption due to:
a) suberization of endodermis
b) periderm (bark) formation |
|
|
Term
| Cohesion Theory of translocation in the xylem |
|
Definition
1) Transpiration occurs and is driving force
2) Causes negative pressure in leaves
3) Column of water is pulled up in the xylem and translocated due to:
a) H-bonding (hydrogen-bonding)
b) small size of xylem pores
c) negative charges on xylem walls |
|
|
Term
| driving force of translocation |
|
Definition
| transpiration causes a negative pressure in leaves, which "pulls" the water up the xylem. |
|
|
Term
| evaporative cooling of leaves |
|
Definition
| 540 cal of heat energy is dissipated for every gram of water that evaporates from leaves, which is a major contributor to the cooling of leaves. |
|
|
Term
| plant factors that effect transpiration |
|
Definition
1) leaf area - smaller leaf area decreases transpiration
2) leaf orientation - vertically orientated leaves decrease transpiration
3) leaf surface - waxy, hairy or shiny leaf surfaces decrease transpiration
4) stomata - when stomata are closed, transpiration decreases |
|
|
Term
| environmental factors that effect transpiration |
|
Definition
1) humidity- high humidity decreases transpiration
2) temperature
a) low temperature decreases transpiration.
b) high temperature increases transpiration, but when it gets too hot the stomata close, then transpiration may decrease
3)light intensity
a) darkness decreases, because stomata close, (except for CAM plants open at night)
b) high light intensity increases temperature which increases transpiration, until stomata close then transpiration may decrease; occurs midday during heat of summer
4) wind
a) as wind increases transpiration increases
b) if wind gets too high, then stomata close and transpiration may decrease
5) soil water
a) when soil is moist, transpiration occurs according to the above factors
b) when soil is too dry, stomata close causing transpiration to decrease (over rides above factors) |
|
|
Term
| techniques to decrease transpiration |
|
Definition
1) mistor spray foliage
a) in propagation an intermittent mist system is used
b) mid-afternoon sprinkler irrigate plants in greenhouses/nurseries
2) decrease light intensity - grow plants under shade
3) harden-off seedlings
a) decrease watering,
b) decrease temperature, or
c) decrease fertilizer, especially N.
4) antitranspirants - chemicals that close or clog stomata.
Two Types
a) physiologically cause stomatal closure
b) wax, resin or latex that clogs stomata |
|
|
Term
|
Definition
uses: rice, orchard, cranberries
advantages:
1. good wetting
2. Frost protection
disadvantages:
1. need level land
2. uses lots of water
3. some plants sensitive |
|
|
Term
|
Definition
Uses: rice, orchard, cranberries
advantages:
1. good wetting
2. frost protection
3. irrigate sections
disadvantages:
1. need level land
2. uses lots of water
3. upkeep of levees
4. slightly unleveled land |
|
|
Term
|
Definition
uses: row crops
advantages:
1. less water used
2. ideal for rows
disadvantages:
1. uneven distribution
2. supervise for erosion |
|
|
Term
|
Definition
uses: container plants, turf, high value fruits and vegetables
advantages:
1. irrigate section
2. can be automated
3. evaporative cooling
4. frost protection
disadvantages:
1. high cost
2. wind disrupts
3. nozzles clog |
|
|
Term
| Drip or Trickle irrigation |
|
Definition
uses: fruit (2.5 gal/hr/tree), row crops (300-400 gal/acre/day)
advantages:
1. most water efficient
2. less plant stress
3. low pressure equip
disadvantages
1. high cost
2. emitters clog |
|
|
Term
| chain tube or spaghetti tube |
|
Definition
uses: container plants
advantages:
1. keeps foliage dry
2. can be automated
disadvantages:
1. must use fine medium
2. gets tangled
3. high cost |
|
|
Term
|
Definition
uses: container plants
advantages:
1. constant moisture; maximum growth
2. keeps foliage dry
3. can be automated
disadvantages:
1. need fine medium
2. 6" or less pots
3. too wet for some
4. algae growth on mat |
|
|
Term
|
Definition
uses: bench crops
advantages:
1. can be automated
disadvantages:
1. moderate cost |
|
|
Term
| Subirrigation or Ebb & flow |
|
Definition
uses: container plants
advantages:
1. keeps foliage dry
2. can be automated
disadvantages:
1. high cost
2. disease may spread |
|
|
Term
|
Definition
uses: container plants, bench crops
advantages:
1. can be automated
2. evaporative cooling
disadvantages:
1. high cost
2. nozzles clog |
|
|
Term
|
Definition
| the weathered outer layer of the earth's crust |
|
|
Term
|
Definition
| the substrate in which plants grow. Usually applied to manufactured or synthetic soils, i.e. "potting soils", or highly amended soils, ex. landscape beds |
|
|
Term
| functions of water or growth medium |
|
Definition
1) Support and anchorage
2) Supplies mineral nutrients
3) Supplies water
4) Allows gas exchange - especially 0and CO, but also ethylene |
|
|
Term
|
Definition
| morphology of horizons (layers) in a soil. |
|
|
Term
|
Definition
- highly weathered
- abundant life, therefore, high in organic
matter
- dark colored
plow pan - a compacted impermeable
layer in the A horizon due to
repeated plowing or tilling
(approx. 6" deep) |
|
|
Term
|
Definition
- less weathered; higher in clay
- less life, therefore, low in organic matter
- lighter colored
clay pan - impermeable layer high in clay.
hard pan - impermeable layer high in iron. |
|
|
Term
| C horizon or parent material |
|
Definition
- little weathered
- little life, except deep rooted plants and
little to no organic matter |
|
|
Term
|
Definition
|
|
Term
|
Definition
| contain 20% or more organic matter |
|
|
Term
|
Definition
| contains greater than 65% organic matter |
|
|
Term
|
Definition
| contains 20-65% organic matter |
|
|
Term
| mineral soil (field soil) |
|
Definition
contains less than 20% organic matter.
4 Major Components (in a well watered, but well drained loam soil)
1) air - approximately 25% of volume; in larger pores
2)water - approximately 25% of volume; in smaller pores
3) mineral particles - 44-49% of volume
4) organic matter - typically about 1% in nature |
|
|
Term
|
Definition
| partially decayed organic matter on the soil surface. |
|
|
Term
|
Definition
| highly decomposed, fine, amorphous organic matter in the soil. |
|
|
Term
| functions of organic matter |
|
Definition
1) stabilizes soil structure
2) increases water retention and availability
3) increases drainage and aeration
4) increases cation exchange capacity
5) supplies nutrients upon decay (only if low C:N ratio)
6) stabilizes pH
7) food source for microorganisms |
|
|
Term
|
Definition
1)Physical - structurally simple; relatively unweathered, physically broken down parent material
2) Chemical - relatively inert; results in:
a) little effect on soil chemistry and pH
b) poor nutrient holding capacity (i.e. CEC)
3)Pore Space
a) less total pore space
b) more large (macro) pores, fewer small (capillary) pores; thus sand causes:
1) increased aeration
2) increased drainage
3) decreased water holding capacity |
|
|
Term
|
Definition
1)Physical - structurally complex
a) colloidal - sub-microscopic and held in suspension in solution
b) when wet - viscous and gelatinous, sticky; when dry - hard, packed and cohesive
c) composed of micelles = flat, sheet-like plates laminated into stacks
d) very large internal and external surface area
e) very small internal and external pores
2) Chemical - very complex; negatively charged
a) very high cation exchange capacity (CEC); hence, nutrient holding capacity
b) charge allows flocculation (aggregation) or de-flocculation (spread-out)
1) Ca+2 promotes flocculation of soil, and good soil structure
2) Na+ promotes de-flocculation of soil, and poor soil structure
3)Pore Space
a) greater total pore space
b) more small (capillary) pores; fewer large (macro) pores; thus clay causes:
1) decreased aeration
2) decreased drainage
3) increased water holding capacity
4) but not all water is available |
|
|
Term
| cation exchange capacity (CEC) |
|
Definition
| milliequivalents per 100 grams dry soil; meq/100 g. |
|
|
Term
|
Definition
| % of total CEC occupied by basic nutrients |
|
|
Term
|
Definition
below pH 5.5
Fe, Zn, Cu, Mn, B |
|
|
Term
|
Definition
above 6.5
N, K, Mg, Ca, S, Mo |
|
|
Term
| chemicals that increase pH |
|
Definition
calcitic lime
dolomite
hydrated lime
burned lime
basic fertilizers (nitrate) |
|
|
Term
| chemicals that decrease pH |
|
Definition
elemental sulfur
aluminum sulfate
iron sulfate
acidic fertilizers (ammonia, urea, ammonium) |
|
|
Term
|
Definition
| soils with acid pH; in regions of high rainfall |
|
|
Term
|
Definition
| soils with basic pH; in arid regions |
|
|
Term
|
Definition
| pH 7-8.5, and has greater than 2,000 ppm total soluble salts. |
|
|
Term
|
Definition
| pH 8.5-10, low to moderate total salts, but 15% or more of CEC is occupied by Na |
|
|
Term
|
Definition
| pH 8-8.5, greater than 2,000 ppm total soluble salts and 15% or more of CEC occupied by Na. |
|
|
Term
| how to improve basic soils |
|
Definition
a)leach - application of large volumes of water to removes excess soluble salts.
b) add elemental sulfur (S) - acidifies the soil
c) add gypsum (CaSO4) - Ca promotes good soil structure, drainage and Na leaching |
|
|
Term
| typical growing medium should contain |
|
Definition
50-75% organic amendments - usually sphagnum peat moss, composted bark or coir
25-50% inorganic amendments - usually vermiculite, perlite, sand or styrofoam
plus: lime, starter fertilizer and sometimes a wetting agent and gypsum |
|
|
Term
|
Definition
| occurs as a water shell around compounds and particles in soil; plants cannot utilize |
|
|
Term
|
Definition
| water adsorbed onto soil particles, held at less than -31 bars of tension; plants cannot utilize |
|
|
Term
|
Definition
| water held by capillary attraction in the capillary pores in soils; held at -1/3 to -31 bars; plants can extract water in the larger capillary pores down to approximately -15 bars. |
|
|
Term
|
Definition
| water in large pores immediately after watering or a rain, which drains from the soil (within 24 hr.) by the force of gravity; held at greater than -1/3 bars (0 to -1/3 bars); plants can utilize when present. |
|
|
Term
|
Definition
the amount of water a soil can hold against the force of gravity;
- at field capacity, water is held -1/3 bars. |
|
|
Term
|
Definition
| when a plant wilts, but recovers when placed in a saturated atmosphere (100% R. H.), ex. overnight. |
|
|
Term
|
Definition
| the soil moisture content when a plant wilts, but recovers when placed in a saturated atmosphere (100% R. H.), ex. overnight |
|
|
Term
|
Definition
| when a plant wilts, but cannot recover when placed in a saturated atmosphere (100% R.H.) |
|
|
Term
|
Definition
| the soil moisture content when a plant wilts, but cannot recover when placed in a saturated atmosphere (100% R.H.). |
|
|
Term
|
Definition
| an instrument that is inserted in the soil and measures the soil moisture tension. |
|
|
Term
|
Definition
-any material applied to the surface of the soil or growing medium
-almost always beneficial to use, and their use is highly recommended.
types:
1) organic - bark, leaves, sawdust, straw, hay, needles, paper
2) inorganic - plastic, gravel |
|
|
Term
| benefits and uses of mulch |
|
Definition
1) stabilizes soil temperature - cooler in summer; warmer in winter under a mulch
2) conserves water - decreases evaporation of water from soil surface
3) better water infiltration - more rain or irrigation water soaks-in due to slower runoff
4) controls erosion - due to slower runoff
5) mayadd nutrients - upon decomposition, if it is a) organic and b) has a low C:N ratio
6) decreases weed growth - decreases germination of weed seeds & growth of weed seedlings
7) appearance - used for decorative purposes |
|
|
Term
|
Definition
| an element required by plants for normal growth, development and completion of its life cycle, and which cannot be substituted for by other chemical compounds; plants require 17 |
|
|
Term
| supplied naturally by water and air |
|
Definition
comprise the bulk of the plant
C, H, 0 |
|
|
Term
|
Definition
required at 0.1 to 6% of the dry weight of plants
N, P, K, S, Ca, Mg |
|
|
Term
|
Definition
required at 1 to 300 ppm of the dry weight of plants
Fe, Zn, Cu, Mo, B, Mn, Cl, Ni |
|
|
Term
|
Definition
| means towards the apex; transport up the in xylem |
|
|
Term
|
Definition
| means towards the base; transport down in the phloem |
|
|
Term
|
Definition
moves both up and down the plant by both acropetal and basipetal transport (in both the xylem and the phloem).
-Deficiency appears on older leaves first.
-N, P, K, Mg, S (macro) |
|
|
Term
|
Definition
moves up the plant by only acropetal (in the xylem) transport
Deficiency appears on new leaves first.
Ca, Fe, Zn, Mo, B, Cu, Mn (micro) |
|
|
Term
|
Definition
slightly acid:
a) around 6.5 for field soil
b) around 5.5-6.0 for artificial growing media made with peat moss or composted bark |
|
|
Term
|
Definition
| sequence of 3 numbers on the fertilizer label that gives the percent composition of N-P205-K20 in a fertilizer; required by law to be on the label of every fertilizer sold. |
|
|
Term
|
Definition
| the relative proportion of N to P205 to K20 in a fertilizer. |
|
|
Term
|
Definition
use a high N, low P and K fertilizer
● for example, use a 2-1-1 or 3-1-1 ratio fertilizer (higher 1st number) |
|
|
Term
| favor flowering/root growth |
|
Definition
use a low N, high P and/or K fertilizer
●for example, use a 1-2-2 or 1-3-2 ratio fertilizer (higher 2nd and/or 3rd number) |
|
|
Term
| mineralization or ammonification |
|
Definition
the conversion of organic nitrogen (in the -NH2 form) to inorganic nitrogen (in the NH4 form).
- the speed of conversion depends on the C:N ratio |
|
|
Term
|
Definition
a two step process converting ammonium to nitrite, then nitrite to nitrate.
- the soil bacterium Nitrosomonas converts ammonium to nitrite
- the soil bacterium Nitrobacter converts nitrite to nitrate
- this occurs very quickly so little ammonium (which can be toxic if high) and virtually no nitrite (which is highly toxic) accumulates in the soil. |
|
|
Term
|
Definition
| the conversion of nitrate in the soil to gaseous nitrogen that escapes into the atmosphere. |
|
|
Term
|
Definition
the conversion of gaseous nitrogen to ammonia.
- only nitrogen fixing microorganisms can cause nitrogen fixation; some form symbiotic relationships with plants (see table below) |
|
|
Term
|
Definition
| proportion of carbon to nitrogen present in organic matter. |
|
|
Term
|
Definition
- wood, sawdust, uncomposted bark
- microbes use up all nitrogen in organic matter when consuming carbon,
- then the microbes use up the nitrogen in the soil |
|
|
Term
|
Definition
- manure, bone meal, fish emulsion, organic fertilizers
- microbes consume carbon,
- then release excess nitrogen from the organic matter into the soil
- acts as an organic nitrogen fertilizer |
|
|
