The Photocontrol of Respiration in Light-Sensitive Lettuce Seeds

The rate of respiration of positively photoblastic lettuce (Lactucasativa L. cv. Cannington Forcing) at 25 °C is increasedfollowing brief exposure to red light and is under phytochromecontrol. The higher rate is maintained until radicle emergencebegins, at which time a further increase takes place. At 30°C the rate of respiration is higher than at 25°C butno red light promotion occurs and very few-seeds germinate.