Abstract: 【Objective】In order to elucidate the relationship between root chemical signals and the quality of rice.【Method】Using various rice genotypes as materials, zeatin (Z) + zeatin riboside (ZR), abscisic acid (ABA), 1-aminocylopropane -1-carboxylic acid (ACC) and organic acids in roots during grain filing period and the appearance quality, cooking/eating quality were investigated. The correlations among them were analyzed.【Result】The results showed that Z+ZR concentrations in the roots at mid and late grain filling stages were significantly and positively correlated with the gel consistency and alkali spreading value (r＝0.72* to 0.90**), whereas negatively correlated with the amylose content (r＝-0.68* to -0.78**). ABA concentrations in roots at mid grain filling stage were significantly and negatively correlated with gel consistency and alkali spreading value (r＝-0.90** to -0.91**), and positively correlated with the amylose content (r＝0.87**). ACC concentrations in root exudates at mid grain filling stage were very significantly correlated with the percentage of chalky grains and chalkiness (r = 0.97** to 0.98**), and those at late grain filling stage were significantly correlated with chalkiness and chalky size (r = 0.69* to 0.96**). The more the malic acid and succinic acid exuded from roots for a cultivar, the greater the breakdown values and smaller the setback values in the starch profile, and the results were reversed for a cultivar with more tartaric acid and citric acid exuded from roots during the grain filling period. The cultivar with more lactic acid in exudates had smaller gel consistency and alkali spreading values, but had greater amylose content. When roots were treated with exogenous ZR, ABA and ACC during grain filling period, the effects of the chemicals on the rice quality were consistent with the relationships of the endogenous hormones (Z+ZR, ABA and ACC) with the quality indexes.【Conclusion】The results suggest that root chemical signals play important roles in the formation of rice quality, and rice quality could be improved through regulating the signals.

Key words: Rice, Root, Chemical signals, Appearance quality, Cooking and eating quality