Plant Anatomy and Physiology

1. Plant Anatomy and Physiology Just the Concepts

2. Environmental Factors On Plant Growth

3. 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. Objectives

4. 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 Functions of Water

5. 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 Functions of Water

6. 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 Functions of Water

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

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

9. 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 Using Water Efficiently

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

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

12. 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? Using Water Efficiently

13. 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 Temperature

14. 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. Temperature

15. 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 Temperature

16. 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 Temperature

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

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

19. 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 Temperature

20. 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 Light

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

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

23. 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 Light

24. 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 Light

25. 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 Light