1. Plant Anatomy and Physiology Just the Concepts

2. Environmental Factors On Plant Growth

3. Objectives  Describe the functions of water in plant growth;  Explain plant responses to a shortage or excess of water;  Describe efficient use of water in plant production;  Describe the effects of temperature on plant growth;  Describe plant responses to temperature extremes;  Explain the qualities of light that affect plant growth, including color, intensity, and duration; and  Explain plant responses to light.

4. Functions of Water  Water covers three-fourths of the earth’s surface and it is available for plants in most areas of the world.  It is a major component of plants and animals.  Humans are about 70 percent water and cacti are about 90 percent water

5. Functions of Water  Water Plays an important role in all plant functions  Needed for turgor – gives a plant rigidity and shape  Provides internal pressure to help roots push through soil  Aides in cell division and growth  Used in photosynthesis  Release oxygen  Use hydrogen to manufacture carbohydrates

6. Functions of Water  Water Plays an important role in all plant functions  Transport nutrients and energy through the plant  Movement of materials through plants is called Translocation  Transpiration is the process of evaporating water from the stomates to pull in new water through the roots  This process helps stabilize the temperature of the plant

7. Response to Shortage and Excess  Shortage  Transpiration continues even though water is not absorbed  Wilting occurs due to loss of turgor  Color changes

8. Response to Shortage and Excess  Excess  Root hairs die due to saturated soil (no oxygen)  Can no longer absorb water and nutrients

9. Using Water Efficiently  What determines the frequency and the amount of irrigation water that we use?  The plant is the factor  Type of soil is next  Irrigation is artificial application of water to a crop

10. Using Water Efficiently  Who is the least efficient Irrigator?  Why The home owner

11. Using Water Efficiently  What is the goal of efficient water use?  There can be several  Greater production  Conservation of water  Conservation of soil

12. Using Water Efficiently  Greater Production  Got to have water to make a good crop.  Conservation of Water  Why?  How?  Conservation of Soil  What does this have to do with using water efficiently?

13. Temperature  Temperature is one factor that contributes to plant growth  Metabolism: all of the chemical reactions in a plant  Photosynthesis, respiration  Temperature affects the speed of metabolism

14. Temperature  Most plants show optimum growth when night temps are 10˚ -15˚ cooler than day temps  Photosynthesis occurs mostly during the day  Cool temperatures slow down respiration  Photosynthesis > Respiration = growth  Most plants will stop photosynthesis at temps above 86˚  At that time they begin using stored reserves.

15. Temperature  The daily change in temp. is a thermoperiod  When thermoperiod influences plant functions they are called thermoperiodic  Begin to flower when the days get shorter and the temps are cooler

16. Temperature  Some plants are cool season crops  Wheat, barley, rye, spinach, lettuce  They grow best in cooler weather and are tolerant to frost  They begin to flower when the temps get warmer and the days are longer

17. Temperature  Warm season crops grow best in warmer temps  Cotton, Corn, Soybeans, Sorghum  Tomatoes will absolutely not flower in cool temps

18. Temperature  Plants like tulips or winter wheat require Vernalization  Period of cold temperatures, often below freezing, in order for physiological processes to occur

19. Temperature  Some seeds will remain dormant until it has been subjected to a period of cold temperatures  This is called stratification  If a plant is hardy it can withstand cold weather  There are categories of hardiness  Plants are usually classified into hardiness categories by the zone of the country where they grow best

20. Light  Light Quality  Color or wavelengths  Wave length range is placed on the electromagnetic spectrum  Visible light is a very small portion of the spectrum  It is what drives photosynthesis

21. Light  Red and blue are the most effective for plant growth  Why?  Readily absorbed by chlorophyll  Green is the least effective  Why?  It gets reflected

22. Light  What type of lights are best for plants?  Fluorescent or incandescent  Fluorescent  Blue wave lengths  Cool  Incandescent  Red wave lengths  Hot

23. Light  Light Quantity  Intensity of light  More intense at high altitudes and near the equator  The greater the intensity the more food produced through photosynthesis  What will a plant do if it prefers full sun but is grown in shady area?  It stretches  Internodes become longer to push the plant towards more sunlight

24. Light  Light duration is called Photoperiod  Many plants respond to changes in day length  They are called photoperiodic  Usually this affects flowering  Long day, short day, day neutral

25. Light  Long-day  Initiate flowering when nights grow shorter  Short-day  Initiate flowering when nights grow longer  Day-neutral  Don’t respond to changes in day length