Thursday, August 18, 2011
Flour or Corn Tortillas?
Revisiting Climate and the Food Supply
Aug. 18, 2011
A Warming Planet Struggles to Feed Itself
June 4, 2011
Wheat is a C3 ("cool season") plant. When temperatures rise above 70 degrees Fahrenheit or so, C3 plants photosynthesize so quickly that oxygen builds up within the plant faster than the plant can obtain carbon dioxide for construction of sugars, starches, and fibers. Wheat then enters photorespiration, where the plant actually consumes oxygen and releases carbon dioxide in a much less efficient process of making carbohydrates. Photorespiration is when the plant "stalls" and has a difficult time growing.
Corn, sugar cane, and sorghum (milo) are C4 ("warm season") plants, as well as many other grasses. A C4 plant has a pathway that helps concentrate carbon dioxide within itself to continue the photosynthesis system to "feed forward", and therefore, continue CO2 sequestration and sugar production. These plants can keep growing and producing carbohydrates while exhaling oxygen in much higher temperatures than C3 plants can.
C4 plants are efficient in "warm seasons", while C3 plants are efficient in "cool seasons". If our world climate continues to warm, will there eventually be more production of corn, sugar cane, and sorghum (milo), while there will be less wheat planted and consumed? What do you Think?