Even short-duration heat waves could lead to failure of coffee crops.
A study by OSU’s College of Forestry showed that when Coffea arabica plants were subjected to short-duration heat waves, they became unable to produce flowers and fruit.
C. arabica is the globe’s dominant coffee-plant species, accounting for 65 percent of the commercial production of the nearly 20 billion pounds of coffee consumed globally each year.
Continually producing new flushes of leaves year-round, C. arabica grows on 80 countries in four continents in the tropics.
The OSU research investigated how leaf age and heat duration affected C. arabica’s recovery from heat stress during greenhouse testing.
"This emphasizes how sensitive Coffea arabica is to temperature," said lead author Danielle Marias, a plant physiologist with OSU’s Department of Forest Ecosystems and Society.
"Heat is very stressful to the plants and is often associated with drought.
However, in regions where coffee is grown, it may not just be hotter and drier, it could be hotter and wetter, so in this research we wanted to isolate the effects of heat."
In the OSU study, C. arabica plants were exposed to heat that produced leaf temperatures of a little over 120 degrees Fahrenheit, for either 45 or 90 minutes.
"In both treatments, photosynthesis of expanding leaves recovered more slowly than in mature leaves, and stomatal conductance of expanding leaves was reduced in both heat treatments," Marias said.