源库调节对小麦不同品种籽粒微量元素及蛋白质含量的影响

为了解小麦籽粒微量营养元素含量的调控机制及其与籽粒重和蛋白质含量的关系, 以9个冬小麦品种为材料, 通过开花后减源(去叶、穗遮光)、减库(去50%小穗)处理, 分析了成熟籽粒中Fe、Zn、Mn、Cu等微量元素含量与籽粒重、蛋白质含量变化及其相互关系, 并探讨了籽粒微营养素积累的源库调控作用。结果表明, 籽粒中Fe、Zn、Mn、Cu、蛋白质含量和籽粒重均在品种间和源库处理间存在显著差异。去叶源不仅使籽粒重和籽粒蛋白质含量显著降低, 而且使籽粒Fe、Zn、Mn和Cu含量明显降低; 穗遮光使籽粒重显著降低, 蛋白质含量略有提高, 籽粒微量元素含量的变化因品种和元素类型而异, 总体趋势为Fe、Zn和Cu含量增加, Mn含量降低; 去小穗减少库, 使各品种剩余籽粒粒重略有增加, 而蛋白质含量提高, 籽粒Fe、Zn、Mn和Cu含量均较大幅度提高。籽粒Fe、Zn、Mn和Cu含量主要受各元素供源的限制, 不同元素受供源影响程度不同, 且与品种基因型有关。籽粒中4种微量元素含量之间及其与粒重和蛋白质含量之间具有一定的正相关性, 说明籽粒微量元素含量与籽粒重和蛋白质含量存在同步提高的可 能性。

Effects of Source and Sink Reductions on Micronutrient and Protein Contents of Grain in Wheat

Micronutrient content in wheat (Triticum aestivum L.) grains directly affects human health. However, the regulatory mechanism of micronutrient in grains is not clear.The effect of source and sink manipulation on micronutrient content has not been reported. In this study, 9 winter wheat cultivars were selected to study the regulatory mechanism of micronutrient in wheat grains by reducing source (defoliation and spike shaded) or sink (50% spikelet removal) after anthesis. Changes of Fe, Zn, Mn, Cu, and protein contents in grains and grain weight at maturity were investigated. There were significant differences (P<0.001) on Fe, Zn, Mn, Cu, and protein contents in grains and grain weight among cultivars and among source and sink treatments. In the defoliation treatment, accompanied by the reductions of grain weight (31.9%) and protein content in grains (8.6%), the contents of Fe, Zn, Mn, and Cu in grains were reduced by 1.4%, 4.5%, 7.4%, and 3.7%, respectively. In the spike shaded treatment, grain weight decreased (22.8%) while grain protein content increased slightly (7.9%). The micronutrient contents in grains changed with culti-vars and elements, but the average contents showed increases in Fe (15.8%), Zn (7.1%), and Cu (4.2%) and a decrease in Mn (1.1%). In the treatment of 50% spikelet removal, grain weight was slightly increased by 2.6%, while the grain protein content and Fe, Zn, Mn, and Cu contents rose more obviously by 23.9%, 55.0%, 39.7%, 36.2%, and 13.3%, respectively. The contents of Fe, Zn, Mn, and Cu in grains were restricted by source supplies of the corresponding element, but the effects of the source supply were different across the elements and wheat genotypes. Correlation analysis showed that all coefficients of correlation (r) were significantly positive (r = 0.431-0.785, P<0.01) except that between grain weight and the contents of Cu (r = 0.291, P>0.05) and Fe (r = 0.255, P>0.05). This implies that the 4 micronutrients in grains can be adjusted accordantly and their contents are possibly increased with grain weight and protein content simultaneously.