Understanding how plants use sunlight
Plants protect themselves from intense sunlight by rejecting much of it as heat — sometimes far more than needed to prevent damage. Engineering plants to be less cautious could significantly increase yields of biomass for fuel and crops for food, but exactly how the photoprotection system turns on and off has remained unclear. MIT researchers have now gathered new insights into the protein that controls the switch. They zapped individual copies of that protein with a laser and used a highly sensitive microscope to measure the fluorescence emitted by each protein in response. Based on those tests, they concluded that there are two distinct mechanisms by which the dissipation of heat begins. One is a split-second response to a sudden increase in sunlight, say, after a cloud passes by, while the other activates over minutes to hours as light gradually changes during sunrise or sunset. In both cases, the response is...