Temperature Topic 2163 Created By Torey Birchmeier

Definition of Temperature Temperature is the measure of the relative hotness or coldness of an object Temperature is also a measure of the heat energy present

Temperature Temperature controls the rate of many biological reactions –Reactions are slower at lower temperatures and faster at warmer temperatures –The relative humidity increases as the temperature increases

Temperature Reactions in the plant controlled by temperature are following: –Photosynthesis increases up to a point at high temperatures during the day –Respiration is reduced during cooler temperatures at night –Water use increases with temperature increases –Transpiration rate increases as temperature increases

Morphology of the Plant Flowering is enhanced by cooling, or delayed depending on the species Excess warmth may delay or speed up flowering, depending on the species

Temperatures in Greenhouses Cool temperature crops45 to 55 0 F Moderate55 to 65 0 F Warm Temperature Crops65 to 75 0 F

DIF MSU doctors Heins, Karlsson, Erwin and Berghage discovered a relationship between day and night The relationship was temperature differential and plant height

DIF DIF equals the day temperature minus night temperature Height changes in relationship to DIF DIF plus to DIF zero results in a large reduction in height DIF zero to DIF minus, less height reduction When DIF is not used, height is controlled by chemicals

Methods to Control Temperature Shading Thermostat to regulate heating units Pad and fan Air mixing Overhead unit heaters or fan jets with horizontal fans

Methods to Control Temperature Overhead unit heaters or fans with perforated convection tubes Horizontal fans Adding heat

References Thermometer – Sunflowers – Field Photo – Green House –