Starch accumulation associated with growth reduction at low temperatures in a tropical plant.

Growth of Digitaria decumbens is severely reduced by night temperatures of 10 degrees C or below. Ultra-structure of leaves and chemical analyses show a high starch content in chloroplasts of plants illuminated and kept at a temperature of 30 degrees C. This starch disappears after a period in the dark at 30 degrees C, but it remains if the temperature during the dark period is 10 degrees C. The inhibition or slowing of starch translocation out of chloroplasts appears to account for reduced photo-synthesis and growth at low night temperatures.