Roland-Story High School

Roland-Story High School Agriculture Technology Class Lesson 6.3 --Lighting it Up

Preface:

There are three main light requirements for plant growth including light quality, light intensity, and the duration of light exposure. Each of these factors influences the rate of photosynthesis and the physical structure of the plant. Growers must know how to regulate plant growth with light and protect against light related deformities.

This lesson begins by examining the role light plays in the growth and development of plants. Students will learn how plants are an essential member of the biological community because of their ability to conduct photosynthesis and transform carbon dioxide to oxygen.

Concepts: 1. Light is absorbed by chlorophyll and used by plants to convert carbon dioxide and water into glucose and oxygen through the process of photosynthesis. 2. Growth of plants is altered by light intensity and poor light exposure can create undesirable physical characteristics. 3. Photosynthetic rate is affected by environmental factors, such as light exposure, availability of carbon dioxide, and temperature. 4. The level of red and blue-violet light emitted in a spectrum determines the quality of a light source intended for plant use. 5. Plants respond to the length of daily dark periods to trigger physiological processes, such as flowering.

Essential Questions:

1. How does altering light intensity affect plants? 2. What happens if plant leaves are not exposed to light? 3. How does light exposure affect the rate of photosynthesis? 4. How can photosynthesis be measured? 5. Which artificial light sources are adequate for plant growth? 6. What is a light spectrum and how can knowledge of the spectrum be used for plant production? 7. How do colors of the light spectrum influence photosynthesis in plants? 8. Why do plants appear green? 9. Why is phototropism important to understand when raising plants? 10. How can plants be programmed to flower for seasonal markets? 11. Why is day length important for the physiology of plants? 12. How do plants react to the length of light or dark periods? Key Terms:

Chlorophyll Chloroplasts Chromatography Day-neutral plant Geotropism Light Long-day plant Photoperiod Photoperiodism Photosynthesis Phototropism Short-day plant Spectrometer Spectrum Tropism Wavelength