Abstract: Abstract The paddy rice in the field experiment, grown at three different altitude localities, viz. Yuanjiang (north tropic type about 400 m altitude), Yuxi ( middle subtropics type about 1600 m altitude) and Dali ( north subtropics type about 2000 m altitude) in Yunnan province in 1988, had been fed with the 14C to the paddy rice to have been treated with different levels of nitrogenous fertilizer, during the booting and grain filling stage, respectively. All the samples of the aerial plant parts had been collected at the yellow ripe stage, and divided into vegetative mass (included leaves, leaf sheath, stem, ear axis and pedicel and its dieback parts) , rice and chaff, and then determined dry weight and specific activity of the 14C, respectively, and that the percentages of the 14C in each part had been calculated by dry weigth.

Key words: Paddy rice