根系化学讯号与稻米品质的关系

【目的】试图阐明水稻根系化学讯号与米质形成的关系。【方法】试验采用不同基因型的水稻材料，测定结实期根系玉米素（Z）＋玉米素核苷（ZR）、脱落酸（ABA）、1-氨基环丙烷1-羧酸（ACC）和根系分泌的有机酸以及稻米外观品质和蒸煮食味品质，并进行相关分析。【结果】表明灌浆中、后期根系Z＋ZR浓度与胶稠度及碱化值呈显著或极显著正相关（r＝0.72*～0.90**），与直链淀粉含量呈显著或极显著负相关（r＝-0.68*～-0.78**）；灌浆中期根系ABA浓度与胶稠度及碱化值呈极显著负相关（r＝-0.90** ～-0.91**），与直链淀粉含量呈极显著正相关（r＝0.87**）；灌浆中期根系ACC浓度与垩白粒率和垩白度呈极显著正相关（r = 0.97**～0.98**），灌浆后期根系ACC浓度与米粒的垩白度和垩大小呈极显著正相关（r = 0.69*～0.96**）。结实期根系分泌的苹果酸和琥珀酸越多的品种，其稻米淀粉谱的崩解值越大，消解值越小；而根系分泌的酒石酸和柠檬酸越多的品种，结果则相反。根系分泌乳酸较多的品种，稻米的胶稠度和碱化值较小，直链淀粉含量较高。结实期外源ZR、ABA和ACC处理根系后对稻米品质的影响，与内源激素(Z+ZR, ABA, ACC)同稻米品质指标的关系基本吻合。施用菜籽饼作有机肥，可以提高根系苹果酸和琥珀酸浓度并增大崩解值和降低消解值。【结论】根系化学讯号对稻米品质的形成起重要作用，通过调控根系化学讯号，可以改善稻米品质。

Relationship Between Root Chemical Signals and Grain Quality of Rice

【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.