1. Plant Processes and Factors That Affect Them Original Power Point Created by Mr. Morgan Modified by the GA Agriculture Education Curriculum Office July 2002

2. Why Plants are a Vital Part of CO 2 /O 2 Exchange u Animals breathe in air, use oxygen, and exhale carbon dioxide u Animals need oxygen to survive u Plants do the opposite- they take carbon dioxide from the air and give off oxygen u Through this cycle the correct balance of oxygen and carbon dioxide is maintained in the atmosphere

3. Why Plants are a Vital Part CO 2 /O 2 Exchange  The large-scale destruction of plants may lead to problems with the air we breathe

4. Why Photosynthesis is Essential to CO 2 /O 2 Exchange u The broad surface area of the leaf absorbs sunlight to be used as energy u Carbon dioxide is taken from the air and the other nutrients (including water) are taken from the soil and transported to the leaves in the water through the xylem u Chloroplasts participate in a chemical process that converts their raw materials into usable food for the plant

5. Why Photosynthesis is Essential to CO 2 /O 2 Exchange u The chemical reaction takes carbon dioxide and water and converts these materials to sugar and oxygen u 6CO 2 + 6H 2 O --> C 6 H 12 O 6 + 6O 2 -Photosynthesis occurs only in the presence of light

6. Respiration Importance in CO 2 /O 2 Exchange u Respiration is the reverse of photosynthesis u Sugar and oxygen are broken down, releasing carbon dioxide, water, and energy wC 6 H 12 O 6 + 6O 2 --> 6CO 2 + 6H 2 O + energy u Respiration occurs 24 hours a day

7. Plant Growth Requirements A.Nutrients B.Air C.Water D.Light E.Correct temperature

8. How Light and Temperature affect Plants u Light intensity- growth is greatly reduced at lower light intensities. Most plants cannot grow below 100-200 foot candles, about the level of light in an average room u The compensation point is the light intensity at which a plant will maintain itself but not grow u Temperatures at night are lower, therefore the plant goes through respiration

9. How Light and Temperature affect Plants u Light duration- the length of the day helps plants distinguish what time of year it is u Some plants will only flower in the spring but can be induced to flower in the winter (in a controlled environment) by extending the light duration u Temperatures during the day hours are higher and encourage plant development

10. Phototropism u Phototropism is the development responses of plants to the relative direction of the light

11. Thermotropism u Thermotropism is the plant characteristic in which a plant will grow towards areas with more desirable temperatures

12. Places where Plants Get Nutrients for Growth u Soil u Air

13. Functions of Primary Nutrients u Nitrogen: fast growth, synthesis of organic compounds- including amino acids, proteins, coenzymes, nucleic acids, and chlorophyll u Phosphorus: energy storage and transfer u Potassium: photosynthesis, sugar translocation, and enzyme activation

14. Functions of Secondary Nutrients u Calcium: components of cell walls, cell growth and division u Magnesium: central part of chlorophyll, photosynthesis u Sulfur: amino acids and vitamins

15. Functions of Micronutrients u Iron: synthesis of chlorophyll u Boron: regulation of metabolism u Zinc: protein synthesis u Manganese: respiration, photosynthesis u Copper: enzyme activation u Chlorine: photosynthetic processes  Sodium: plant-water relations

16. Effects of CO2 Fertilization on Plant Growth u Plant growth will increase as carbon dioxide increases, as long as carbon dioxide is the limiting nutrient

17. Five Types of Growth Regulators u Auxins: growth promoting hormone u Freshly cut stems are dipped into this u Gibberellins: stimulates growth in plants u Dwarf plants transform into normal sized plants u Kinins (cytokinins): influence in stimulation of cell division u Dormin: promotes flowering in some short day plants and promotes dormancy in buds and seeds u Ethylene: uniform ripening, sex conversion