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

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 /courses/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/ScienceEd/Tony/chemistry/htmlhttp://csee.lbl.gov/ScienceEd/Tony/chemistry/html Dandelion Picture: http://home.jtan.com/`russ/terri/trash.htmhttp://home.jtan.com/`russ/terri/trash.htm Rain Drop Picture: http://199.212.16.18/msc/as/index_e.htmlhttp://199.212.16.18/msc/as/index_e.html Rainbow Picture: http://204.97.147.10/card/paper.htmhttp://204.97.147.10/card/paper.htm Sunflower Picture: http://biosci.cbs.umn.edu/labs/koukkari/teaching/course/Angiosperms_30May.html http://biosci.cbs.umn.edu/labs/koukkari/teaching/course/Angiosperms_30May.html Sun Picture: http://expage.com/page/waxsteelhttp://expage.com/page/waxsteel Thermometer Picture: http://home.earthlink.net/`bob4mvg/Time_n_Temperature.htmhttp://home.earthlink.net/`bob4mvg/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.