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HIGH TEMPERATURE EFFECTS ON PLANTS

 

HOW HIGH TEMPERATURE DAMAGES PLANTS
A) Dies quickly

     1) Denatures proteins (unfolding of proteins) - at 130 oF

B) Dies slowly or just poor growth

    1) Desiccation - causes excessive drying-out

    2) Sun scald or scorch - desiccation followed by death of tissue

    3) Respiration exceeds photosynthesis - depletes stored food
 
 
 
 

METHODS USED TO DECREASE HIGH TEMPERATURES
A) Soil temperatures

    1) mulch - insulates and blocks out light

B) Air temperatures

    1) Decrease light intensity (decrease both visible and infrared if possible)

        a) lath covering over nursery crops

        b) shade cloth or saran over nursery crops or greenhouses

        c) shading compound or white wash painted on greenhouse roof

        d) colored solution flowing through a double-layered greenhouse roof (primarily decreases IR)

    2) Evaporative cooling (relies on heat of vaporization)

        a) spray foliage and physical structures during mid-afternoon

        b) fine mist or fog injected into a greenhouse

        c) fan-and-pad cooling system in a greenhouse