Analysis of assimilate distribution by 3H-tracing during recovery period after rice seedling transplanting

In order to characterize assimilate distribution in rice (Oryza sativa L.) seedlings during recovery period after transplanting, the experiments were conducted by using ³H-isotope tracer technique with three rice hybrid combinations. The label introduced into the leaf sheath was distributed and redistributed to young roots, tillers, and young leaves, thus promoting these organs to grow at the initial stage after transplanting. During period from 10 to 30 days after labeling, ³H-assimilate redistribution occurred mainly from the sheath of the main stem; some radioactivity moved to tillers and roots emerged after transplanting. The activity and percentage of ³H-compounds transporting to rooting nodes and roots emerged after transplanting were higher in root-pruned plants than in control, indicating that growth of root-pruned seedlings more depended on the export of the compounds from the sheath of the main stem than growth of control seedlings.