1. Why and how the following weather elements are important and influence the growth and development of crop plants and yield? a. Rainfall b. Relative Humidity c. Sunshine d. Air-Temperature e. Wind velocity After successful completion of 5 Lessons in this Module, you have learned to answer: Virtual Academy for the Semi Arid Tropics Course on Crop-Weather Relationships Module IV: Weather and Plant Growth

2. Lesson 1: Rainfall and plant growth Lesson 2: Relative humidity and plant growth Lesson 3: Sunshine and plant growth Lesson 4: Air-Temperature and plant growth Lesson 5: Wind and plant growth The 5 Lessons in this Module are: Virtual Academy for the Semi Arid Tropics Course on Crop-Weather Relationships Module IV: Weather and Plant Growth

3. Virtual Academy for the Semi Arid Tropics Lesson 4- Air Temperature and plant growth Course on Crop-Weather Relationships Module IV: Weather and Plant Growth After successful completion of this Lesson, you will be able to answer: 1.Why air temperature is important for crop plants? 2.How plants respond to air temperature? 3.Why pearl millet do not grow well in hilly areas? 4.Why plants show wilting symptoms during afternoon hours in August in tropics? 5.What important plant processes are influenced by air temperature?

4. Virtual Academy for the Semi Arid Tropics Lesson 4- Air Temperature and plant growth Course on Crop-Weather Relationships Module IV: Weather and Plant Growth Why air temperature is important for crop plants?  The air temperature is a deciding factor in plant growth;  Each crop has its own optimum, maximum and minimum temperature conditions for their growth and development;  Some plants grow better in cooler temperatures, ex. Wheat, while others prefer warmer temperatures, ex. Pearl Millet.  The air temperature affects the amount of water a crop requires;

5. Virtual Academy for the Semi Arid Tropics Lesson 4- Air Temperature and plant growth Course on Crop-Weather Relationships Module IV: Weather and Plant Growth How air temperature affects crop plants?  The growth rate of most plants increases as the temperature increases favorably;  Influences the rate of physical and chemical reactions that determine a plant’s rate of growth and development.

6. Virtual Academy for the Semi Arid Tropics Lesson 4- Air Temperature and plant growth Course on Crop-Weather Relationships Module IV: Weather and Plant Growth How air temperature affects crop plants?  Regulates most plant processes – germination, flowering, photosynthesis, transpiration, respiration, etc.;photosynthesis transpirationrespiration  High air temperature generally increases loss of moisture from soil and from plants (evapotranspiration). When there is insufficient water in the soil to meet the plant water demand, the plant wilts.

7. This concludes Lesson 4- Air Temperature and plant growth - in this Module. The last Lesson in this module is about Wind velocity and plant growth. Select Lesson 5 from Module IV contents Virtual Academy for the Semi Arid Tropics Course on Crop-Weather Relationships Module IV: Weather and Plant Growth

8. One of the major differences between plants and animals is plants' ability to manufacture their own food. This process is called photosynthesis. Photosynthesis To produce food, a plant requires energy from the sun, carbon dioxide from the air, and water from the soil. During photosynthesis, it splits carbon dioxide into carbon and oxygen, adds water, and forms carbohydrates (starches and sugars). After producing carbohydrates, a plant either uses them as energy, stores them, or builds them into complex energy compounds such as oils and proteins.

9. Plants need energy for their life processes. Sugars are the fuel which provides the energy they need. Plants make their own sugars by a process called photosynthesis. The sugars release energy in a reaction which uses oxygen. This is called respiration. It happens in all living cells all of the time. The equation for the process is: sugar + oxygen == carbon dioxide + water + energy Respiration Sugar + Oxygen carbon dioxide + water + energy Respiration provides the power for plant growth and development

10. Transpiration is the process by which plants return water to the atmosphere. After absorbing water from the ground, plants release water through their leaves. Transpiration helps plants stay cool, in the same way perspiration keeps humans and animals cool. Transpiration