秸秆还田对水稻镉积累及其亚细胞分布的影响

发布时间：2018-05-03 03:12

本文选题：水稻 + 镉　；参考：《环境科学》2017年09期

【摘要】：镉(Cd)是人类一级致癌物,大米食用是以大米为主食人群摄入Cd的主要途径.秸秆还田是秸秆处理中主要方式,在Cd污染稻田被广泛应用,其对水稻Cd吸收及水稻体内Cd的分布产生的影响不可忽视.本研究选用Cd水稻土,通过盆栽和大田试验分析了不同的秸秆还田用量(0.0%、1.0%、2.5%和5.0%)对Cd的亚细胞分布以及在水稻籽粒中积累的影响.结果表明水稻根细胞中的Cd主要分布在细胞壁中,占总Cd的86%~95%,茎叶细胞的细胞壁与可溶部分中的Cd含量相当,分别占总Cd的30%~51%和35%~61%.秸秆按1%和2.5%比例还田能显著提高根中Cd含量,以及细胞壁中Cd含量及其分配比例,并降低水稻体内Cd由根向茎叶转运;但5%的秸秆还田,分蘖期根中Cd含量和细胞壁中Cd含量显著降低,Cd由根向茎叶转运系数提高,灌浆期的根中Cd含量和细胞壁中Cd含量均显著提高,转运系数没有显著变化.大田试验前茬的水稻秸秆和油菜秸秆中Cd含量均较高,分别是0.49 mg·kg~(-1)和0.67 mg·kg~(-1);油菜秸秆单独还田或与石灰一起还田均没有显著影响水稻糙米或秸秆中Cd的积累;水稻秸秆单独还田也没有显著改变水稻糙米或秸秆中Cd的积累,但与石灰一起还田时能显著降低糙米和秸秆中的Cd积累;生物炭添加能显著降低水稻体内的Cd积累,且与石灰一起添加降Cd效果更显著.因此,当用Cd污染稻田前茬所产水稻秸秆还田时,建议与石灰一起添加可达到显著降Cd的效果.该研究将为Cd污染稻田的水稻安全生产与秸秆循环利用提供理论与实践指导.
[Abstract]:Cadmium (CD) is a first-class carcinogen in human. Rice consumption is the main way to ingest CD in the population with rice as the main food. Straw returning to the field is the main way of straw treatment. It is widely used in CD polluted rice fields. Its effect on CD uptake and CD distribution in rice can not be ignored. In this study, CD paddy soil was used to study the effects of different straw application rates on CD subcellular distribution and accumulation in rice grains by pot and field experiments. The results showed that CD in root cells of rice was mainly distributed in the cell wall, which accounted for 86% of total CD. The cell wall of stem and leaf cells was about the same as that of soluble part, accounting for 30% and 35% of CD, respectively. Returning straw to the field at the ratio of 1% and 2.5% could significantly increase the CD content in the root, the CD content in the cell wall and its distribution ratio, and reduce the CD transport from root to stem and leaf in rice, but 5% straw could be returned to the field. CD content in root and cell wall decreased significantly at tillering stage, CD transport coefficient increased from root to stem and leaf, CD content in root and cell wall increased significantly at filling stage, but transport coefficient did not change significantly. The CD contents of rice straw and rape straw were 0.49 mg / kg ~ (-1) and 0.67 mg / kg ~ (-1) respectively, but the accumulation of CD in brown rice or straw was not significantly affected by returning rape straw to the field either alone or together with lime in the field, and the content of CD in rice straw was 0.49 mg / kg ~ (-1) and 0.67 mg / kg ~ (-1) respectively. The accumulation of CD in brown rice or straw was not significantly changed by the application of rice straw alone, but the CD accumulation in brown rice and straw was significantly decreased when returning to the field with lime, and CD accumulation in rice was significantly decreased by adding biological carbon. The effect of decreasing CD with lime was more remarkable. Therefore, when the rice straw from the previous stubble was polluted by CD, it was suggested that the effect of CD reduction could be achieved by adding it together with lime. This study will provide theoretical and practical guidance for the safe production of rice and the recycling of straw in CD polluted rice fields.
【作者单位】：中国科学院生态环境研究中心;中国地质大学地球科学与资源学院;首都师范大学资源环境与旅游学院;浙江省嘉兴市农业科学研究院;湖南省攸县农业局;
【基金】：公益性行业(农业)科研专项(201403015) 浙江省自然科学基金项目(LY15D010001) 浙江省嘉兴市科技计划项目(2014AZ21001)
【分类号】：X173

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