Quantification and spatial distribution of zinc in wheat grains by laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS） | 激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）定量分析小麦籽粒锌元素的空间分布

Chinese. 摘　　要：激光剥蚀电感耦合等离子体质谱（laser ablation inductively coupled plasma mass spectrometry,LA-ICP-MS）是用于测定植物组织中元素分布的最新技术。采用LA-ICP-MS技术对小麦成熟籽粒中锌的空间分布进行了定量分析。结果表明：成熟小麦籽粒锌浓度的空间分布差异明显。从浓度分布看,种皮、糊粉层和胚中的锌分别为192、432和292 mg.kg-1,而胚乳中的锌只有14 mg.kg-1;从积累量分布看,种皮、糊粉层、胚和胚乳中的锌积累量分别占籽粒总积累量的24%、47%、11%和18%,说明小麦籽粒经加工后锌含量锐减（下降约80%）。分别采用LA-ICP-MS和酸消解溶液雾化进样ICP-MS法测定了自制校正标准样和小麦整粒种子的锌浓度,结果两种方法的测定值很接近且重复间变异较小,证实了LA-ICP-MS这一空间分布定量分析方法的可靠性。

English. Laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS）is a recently developed technology for examining mineral elements distribution in plant tissue.In this paper,the spatial distribution of zinc in wheat grains was quantified by LA-ICP-MS.Results indicated large spatial variation of zinc concentration in wheat grains.Zinc concentration in seed coat,aleurone layer and ambryo is 192,432 and 292 mg・kg-1,respectively,only 14 mg・kg-1 in endosperm.As for zinc accumulation,zinc amount in seed coat,aleurone layer,ambryo and endosperm account for 24%,47%,11% and 18% of total zinc in grain,which implied that zinc content in grains decreased sharply after seed processing（polished）.By comparing the measured zinc value of two different methods（i.e.,LA-ICP-MS and ICP-MS after digestion）,we also found that the variation of measured zinc concentration between two methods as well as among replications were small,which suggested that LA-ICP-MS is a reliable method for quantifying the spatial distribution of elements in grains.