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Plant Growth Requirements

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Title: Plant Growth Requirements


1
Plant Growth Requirements
http//expage.com/page/waxnsteel
  • Topic 2019
  • By Torey Birchmeier

http//199.212.16.18/msc/as/index_e.html
2
Major Factors for Plant Growth
  • Temperature
  • Light
  • Moisture
  • Carbon Dioxide
  • Hormones

http//home.earthlink.net/bob4mvg/Time_n_Temperat
ure.htm
3
Temperature
  • As temperature increases, reaction rates increase
  • ie-Photosynthesis is slower at lower
    temperatures however the rate increases up to a
    cerain point as the temperature goes up
  • Plant growth functions such as absorption of
    minerals and water are determined by temperature

4
Temperature
  • Plants have an optional temperature range at
    which they function best
  • Plants have a minimum temperature tolerance below
    which the plant may be injured or killed
  • Monocots have an advantage because the growth
    point remains below the ground
  • Dicots growing point is pushed above the ground
    and do not tolerate fluctuating temperatures or
    frost

5
Temperature
http//expage.com/page/waxnsteel
  • Sun scald can occur at high temperatures
  • High temperatures cause desiccation or may may
    directly kill protoplasm of cells
  • Plants should be selected according to the growth
    conditions and climate of the area
  • An exception is the greenhouse where temperature
    conditions can be controlled

6
Light effects plants based on its quality,
intensity and duration.
  • Quality
  • The major source of light is the sun
  • Normal plant growth requires white light or
    sunlight
  • Chlorophyll absorbs the red and blue portions of
    the light spectrum. Leaves are green, since the
    chlorophyll reflects green light

7
Quality
  • Light is important and must contain important
    wavelenghts
  • These wavelengths are represented by the rainbow

http//204.97.147.10/card/paper.htm
8
Light Intensity provides energy for photosynthesis
  • Rate of photosynthesis is effected by water,
    carbon dioxide and sunlight
  • In the absence of light, plants will grow until
    there food reserves are exhausted
  • This growth will be elongated and abnormal

9
Light Intensity
  • Phototropism is the tendency to grow in the
    direction of the greatest light intensity
  • Plants vary in the intensity of light that they
    need
  • ie-Impatiens grow better in shade with indirect
    light
  • Zinnias grow best in full sunlight

10
Light Duration
  • Photoperiodism is a growth response to the length
    of dark period
  • This determines if a plants is growing
    vegetatively or is in the flowering stage
  • In a greenhouse we can force a plant to bloom by
    controlling the duration of light

11
Flowering plants include short-day, long-day and
day-neutral plants
  • Short-day Plants-must be exposed to light periods
    shorter than some critical length for flowering
    to occur
  • ie-Poinsettia
  • Long-day Plants-must be exposed to light periods
    longer than some critical length for flowering to
    occur
  • ie-Azalea

12
Long-day, Short-day and Day-nuetral
  • Day-neutral Plants-These plants flower regardless
    the day length
  • ie-Dandelion

http//home.jtan.com/russ/terri/trash.htm
13
Ways to influence blooming or vegetative growth
  • Use a black cloth to shorten days. This involves
    covering the plants with an opaque cover to
    shorten days
  • Artificial light stimulates long days by adding
    light in the evening hours

14
Other Light Effects
  • Phototropism is the growth response in which
    plants turn or bend in the direction of the light
    soource
  • Geotropism is the growth response in which plants
    turn or bend in response to gravity

http//biosci.cbs.umn.edu/labs/koukkari/teaching/c
ourses/Angiosperms_30May.html
15
Moisture is also essential for plant growth
  • Water carries essential nutrients from the roots
    and acts as a solvent for salts and minerals
  • Water translocates photosynthetic products from
    the leaves via the phloem
  • Water is a chemical reactant in may plant
    processes including photosynthesis and respiration

16
Moisture
  • Water quality is important to plants
  • Excessive salt can cause leaf burn, root
    corrosion, poor seed germination, wilting and
    killing
  • Capillary water is used by the plants
  • Capillary is when the water makes contact with
    the soil and it is elevated of depressed
    depending on the relative attraction of the
    molecules or water

17
Moisture
  • Capillary continued
  • Water moves freely in the soil and can move up or
    down, horizontally
  • ie-dip the end of a napkin into a glass of water
    and observe water as it moves up through the
    napkin

http//199.212.16.18/msc/as/index_e.html
18
Moisture Not Available To Plants
  • Gravity water-which is lost due to drainage
  • Hygroscopic water that bonds to soil particles
  • The bonding is ionic charge related to the size
    of the soil particle and its electrical charge
  • The charge is opposite that if water and will
    attract or hold the water in the soil making it
    unavailable to plants

19
Moisture
  • Plants with large thin leaves lose water more
    readily and have high water requirements
  • Plants with small waxy leaves have a tendency to
    lose less water to transpiration and have less
    water requirements
  • Desert plants have small leaf surfaces while
    tropical plants have a large leaf surface

20
Carbon Dioxide is Required for Photosynthesis
  • Carbon Dioxide is taken in through the stomata
  • Air contains .03 Carbon Dioxide
  • Greenhouses need to have CO2 added
  • Roses, carnations and tomatoes need 12
  • This can be accomplished by using gas burners

http//csee.lbl.gov/ScienceEd/Tony/chemistry/html
21
Carbon Dioxide
  • Plants use 16 essential nutrients and are
    available in the soil
  • Primary nutrients-N, P, K
  • Secondary nutrients-Ca, S, Mg
  • Trace nutrients-Mn, Fe, Zn, Cu, Cl, B, Mo
  • C, H, O-usually not limited since they are freely
    available in the air and water

22
Hormones
  • Hormones are low molecular weight chemicals
    produced in the plant to regulate growth
  • Auxin-promotes cell elongation, apical dominance,
    induces roots on cuttings, stimulates fruit
    development and stimulates ethylene synthesis

23
Hormones
  • ABA-Stimulates stomatal closure, may be necessary
    for abscission and dormancy in some species
  • Cytokinin-Promotes apical dominance, shoot growth
    and fruit development
  • Giberellins-GA-Flowering stimulation in long-day
    plants and biennials, shoot elongation and
    regulates production of seed enzymes in cereals

24
Hormones
  • Ethylene-Promotes fruit ripening, leaf and flower
    senescence and abscission

25
References
  • Carbon Dioxide Picture http//csee.lbl.gov/Scienc
    eEd/Tony/chemistry/html
  • Dandelion Picture http//home.jtan.com/russ/ter
    ri/trash.htm
  • Rain Drop Picture http//199.212.16.18/msc/as/in
    dex_e.html
  • Rainbow Picture http//204.97.147.10/card/paper.
    htm
  • Sunflower Picture http//biosci.cbs.umn.edu/labs/
    koukkari/teaching/course/Angiosperms_30May.html
  • Sun Picture http//expage.com/page/waxsteel
  • Thermometer Picture http//home.earthlink.net/b
    ob4mvg/Time_n_Temperature.htm

26
Conclusion
  • Moisture, Temperature, Light, Carbon Dioxide and
    Hormones are required in various amounts for
    different plants but are all requirements for a
    plant to grow.
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