Abstract: The experiment was conducted using three rice hybrid combinations by ³H-isotope tracer technique. The results showed that at 10 days after labeling, 7.6%–9.8% of ³H-assimilates of stem and sheath labeled at 4 days after transplanting transported to new roots, 6.7%–15.6% to new leaf blades of main stem, and 6.9%–9.9% to the stem and leaf of tillers; at 30 days after labeling, about 12% to new roots, and 10%–14% to the stem and leaf of tillers. The ³H-assimilates of redistribution during 10–30 days after labeling was mainly from stem and sheath of main stem, and imported to tillers and new roots. There was 19%–28% of leaf-labeled-³H-assimilates distributed to new leaves of main stem at 10 days after labeling, and about 4.6%–13.4% to tillers, moreover, still 3%–5% to new roots. Gangyou 22 had a higher percentage of ³H-assimilates distributed to main stem, Kyou 047 had a higher percentage to tillers and Ⅱyou 162 had a higher percentage to new leaf blades.

Key words: Rice (Oryza sativa L.), Seedling stage, Photosynthate