水稻结实期籽粒和根系中玉米素与玉米素核苷含量的变化及其与籽粒充实的关系

在水培和盆栽条件下，研究了6个水稻品种(含籼/粳杂交组合、新株型品系)结实期强、弱势粒和根系中玉米素(Z)与玉米素核苷(ZR)含量的变化及其与籽粒充实的关系。籽粒中Z+ZR含量在开始灌浆时很低，随灌浆进程Z+ZR含量增加，达到峰值(强势粒在花后9～15d，弱势粒在花后12～21d)后迅速下降。根系中Z+ZR含量在抽穗时就很高，在花后

Changes in Zeatin and Zeatin Riboside Content in Rice Grains and Roots during Grain Filling and the Relationship to Grain Plumpness

Six rice cultivars (including 2 japonica/indica hybrid combinations and 1 new plant type line ) were grown in water culture in the green house /or in pots in the screen house. Zeatin (Z) and Zeatin riboside (ZR) contents in grains and roots during grain filling were measured with an enzyme-linked immunosorbent assay (ELISA), and the relationship to the grain filling were examined. Z ZR content in grains was rather low at initial filling stage, and quickly increased with the filling process , and reached the peak at 9-15 days after flowering (DAF) for superior grains and 12- 21 DAF for inferior ones, and sharply decreased thereafter. Z ZR content in roots was rather high at heading, and reached the peak at 3-9 DAF. Z ZR content in grains and roots, and the time reached the peak were associated with grain filling patterns of the cultivars. The cultivar with good grain plumpness and high grain filling rate had high Z ZR content in grains and roots at early filling stage (3-12 DAF), and early reached the peak. Z ZR content in grains and roots at early filling stage, the maximum content, and the mean content in whole filling period significantly or very significantly correlated with Fertilized grainfilling percentage (FGFP), grain weight, the maximum filling rate, and with mean filling rate. Z ZR content in grains and roots, FGFP and grain weight were obviously decreased when roots were treated with NaN3 at heading, and the result was reversed when roots with 10-6mol/L zeatin. The results suggested that the grain filling pattern may be determined by the changing pattern of cytokinins (Z ZR) in the grains and roots, and it is an effective approach to improving grain filling by regulating cytokinin levels in the grains and roots during grain filling, especially at early filling stage.