H. Usuda et K. Shimogawara, THE EFFECTS OF INCREASED ATMOSPHERIC CARBON-DIOXIDE ON GROWTH, CARBOHYDRATES, AND PHOTOSYNTHESIS IN RADISH, RAPHANUS-SATIVUS, Plant and Cell Physiology, 39(1), 1998, pp. 1-7
The effects of sink capacity on the regulation of the acclimation of p
hotosynthetic capacity to elevated levels of carbon dioxide are import
ant from a global perspective. We investigated the effeocts of elevate
d (750 mu mol mol(-1)) and ambient (350 mu mol mol(-1)) atmospheric CO
2 on growth, carbohydrate levels, and photosynthesis in radish seedlin
gs from 15 to 46 d after planting. In radish, a major sink is the stor
age root, and its thickening is initiated early. Elevated CO2 increase
d the accumulation of dry matter by 111% but had no effect on the accl
imation of the rate of photosynthesis or on the levels of carbohydrate
s in leaves at dawn, Elevated CO2 increased the dry weight in storage
roots by 105% by 46 d after planting, apparently enhancing the sink ca
pacity, This enhanced capacity seemed to be responsible for absorption
of elevated levels of photosynthate and to result in the absence of a
ny over-accumulation of carbohydrates in source leaves and the absence
of negative acclimation of photosynthetic capacity at the elevated le
vel of CO2.