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Satoru Ishikawa 《Soil Science and Plant Nutrition》2020,66(1):28-33
ABSTRACT Cadmium (Cd) has an important impact on agriculture, as the excessive consumption of this element from contaminated food crops leads to toxicity in humans. Rice is the greatest source of dietary Cd intake in populations consuming rice as a staple food. Therefore, reducing the Cd concentration of rice grains for diminishing the potential risk of Cd for human health is a major challenge. This review summarizes the main achievements on Cd accumulation in rice by our research group. Using a positron-emitting tracer imaging system, we succeeded to visualize differences in real-time Cd dynamics from roots to panicles in rice varieties with different Cd accumulation abilities. Several loci or genes responsible for Cd accumulation in rice were found through quantitative trait loci (QTLs) analysis. Using the QTL qCdp7 responsible for efficiently extracting Cd from paddy soils, practical rice varieties for Cd-phytoextraction were developed by DNA marker-assisted breeding. A rice variety named ‘Koshihikari Kan No.1? carrying a mutant allele of OsNramp5 for reducing Cd concentration in rice grains was produced by mutant breeding with ion-beams, and breeding programs have been implemented to transfer this allele into many Japanese rice varieties by DNA marker-assisted breeding. Growing low-Cd varieties aerobically would be a feasible way to simultaneously reduce inorganic arsenic and Cd concentrations in rice grains. These results provide basis for reducing Cd concentration in rice through breeding new varieties. 相似文献
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【目的】研究根系分泌物对蕹菜 Cd 吸收积累的影响。【方法】采用水培 - 土培联合的方法,通
过水培种植蕹菜(Ipomoea aquatica Forsk.)典型低 Cd 积累品种 (QLQ) 和高 Cd 积累品种 (T308) 收集根系分泌物,
将 QLQ 根系分泌物施入种植 T308 的土壤中,将 T308 根系分泌物施入种植 QLQ 的土壤中。【结果】蕹菜两个
品种的生长差异不显著;QLQ 茎叶 Cd 质量浓度显著低于 T308。施加典型品种的根系分泌物,总体上不影响两
个蕹菜品种的生长。根系分泌物的施入总体上提高了供试蕹菜品种的茎叶、根 Cd 质量浓度和 Cd 积累量,表现
为促进植株对 Cd 的积累,原因主要在于根系分泌物提高了植株对土壤 Cd 的吸收能力。不同 Cd 质量浓度处理收
集的蕹菜根系分泌物对植株 Cd 积累的影响存在差异。低 Cd 品种 QLQ 的根系分泌物显著降低了高 Cd 品种 T308
的 Cd 转运系数,0 mg/L Cd 条件下的转运系数降低 30.23%;而 T308 根系分泌物对 QLQ 的 Cd 转运系数并未产生
显著影响。【结论】根系分泌物的施加促进植株对 Cd 的积累;低 Cd 品种 QLQ 表现出极强的低 Cd 转运能力。 相似文献
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Kenzo Miura Kazuki Togami Kayo Yoshizumi Kazuaki Kudo Kazuhiko Aoki Kentaro Matsuo 《Soil Science and Plant Nutrition》2016,62(2):201-211
To reduce the availability of soil cadmium (Cd) to soybeans (Glycine max (L.) Merr.), we employed a liming by partial mixing (PM) technique in two drained paddy fields on Gray Lowland soils, which had 0.1 mol L–1 hydrochloric acid-extractable Cd concentrations as high as 1.08 and 1.40 mg kg–1. Among the different application methods tested, PM application (PM2) using a width of 20 cm and a depth of 20 cm was found to be most appropriate for reducing the seed Cd concentration and to obtain the optimum yield at Site A. Under PM2, a liming rate of 38% of that for broadcast incorporated into the surface 15 cm layer (Bc) was suitable to reduce the seed Cd concentration at Site A, whereas the lime rate with PM2 was set at 50% of that for Bc (PM2-50) at Site B due to the higher availability of soil Cd. The root system was limited within the range of lime and fertilizer application for PM2 as well as PM2-50; thus, the lime and fertilizer were supplied successfully to the rooting zone. The soil pH value was lower under PM2 at Site A and PM2-50 at Site B compared with Bc, whereas the seed Cd concentration was lower for PM2 and PM2-50. This may be explained by the intensive uptake of calcium and magnesium with PM2 as well as PM2-50. The seed Cd concentration in the cultivar “Ryuhou” at the target pH of 6.5 was approximately 30% lower with PM2-50 than Bc at Site B. In addition, the average seed Cd concentrations in one cultivar and two lines, characterized by the lower Cd uptake with higher retention in roots and higher accumulation in leaves, were approximately 40% lower compared with “Ryuhou.” Thus, the combination of liming with PM2-50 at the target pH of 6.5 and a low-Cd cultivar (or lines) minimized the seed Cd concentration. The highest seed Cd concentration was found in the first year of soybean cultivation, which was considered to be caused by the release of Cd from organic nitrogen compounds during the nitrogen mineralization process. 相似文献
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镉污染耕地大豆安全生产模式的探究 总被引:1,自引:1,他引:0
为探索大豆在我国南方镉(Cd)污染耕地上安全可行的种植模式,本研究通过低积累品种筛选,结合钝化剂施用,在镉污染安全利用区[土壤总镉含量为(0.49±0.04)mg·kg-1,pH为6.31]开展田间试验。结果表明:各品种大豆籽粒镉含量均未超过国家限量标准,其中浙农6号、浙鲜9号、浙鲜12号和浙鲜19号具有镉低积累性状。将上述4个品种在镉污染严格管控区[土壤总镉含量为(1.69±0.25)mg·kg-1,pH为4.65]开展不同钝化剂施用量对大豆镉积累能力影响试验,发现1 500 kg·hm-2钝化剂施用下,4个品种大豆籽粒镉含量下降30.4%~79.0%,其中浙鲜9号、浙鲜12号籽粒镉含量降至0.13 mg·kg-1,符合国家食品安全限量标准(0.2mg·kg-1)。3 000 kg·hm-2钝化剂施用量下大豆籽粒镉积累能力与1 500 kg·hm-2无显著差异。1 500 kg·hm-2钝化剂处理分别使浙农6号、浙鲜9号和浙鲜12号的产量提高了14.7%、16.7%、16.1%。研究表明,施用1 500 kg·hm-2钝化剂可使浙鲜9号与浙鲜12号大豆籽粒中镉含量降低至国家食品安全限量标准内。 相似文献
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A Meta-Analysis on Phenotypic Variation in Cadmium Accumulation of Rice and Wheat: Implications for Food Cadmium Risk Control 总被引:3,自引:0,他引:3
In some densely-populated countries, farmland has been widely cadmium (Cd) contaminated, and the utilization of the contaminated farmland for crop production is currently unavoidable. This necessitates the use of low-Cd crops (i.e., pollution-safe cultivars, the crop varieties with the ability to accumulate a low level of Cd in their edible parts when grown on polluted soil) in these areas and highlights the importance of knowledge on phenotypic variation in crop Cd accumulation for food Cd risk control. Studies on phenotypic variation in heavy metal accumulation started decades ago for a wide range of crops, and synthesis of the scattered experimental results in the literature is in need. We built a Low-Cd Crops Database based on literature research, and relevant meta-analysis was performed to quantitatively explore the phenotypic variation in Cd uptake and translocation of rice and wheat. Considerable variability existed among rice (median grain Cd bioconcentration factor (BCF) of 0.10) and wheat (median grain Cd BCF of 0.21) phenotypes in grain Cd accumulation, and this variability was labile to soil pH and the level of Cd stress. Wheat statistically had a higher root-to-shoot Cd-translocating ability than rice, highlighting potential food Cd risks and the importance of growing low-Cd wheat in slightly Cd-contaminated regions. Meanwhile, no correlations were detected among soil-to-root, root-to-shoot, and shoot-to-grain translocation factors, implying that Cd uptake and internal translocation in crops were probably controlled by different underlying genetic mechanisms. Root-to-shoot Cd transport could be a favorable target trait for selecting and breeding low-Cd rice and wheat. In all, this review provides a comprehensive low-Cd crop list for remediation practice and a systematic meta-analysis inferring food Cd risks based on plant capacity for Cd accumulation and desired traits for low-Cd crop breeding. 相似文献
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The mechanisms of low cadmium (Cd) accumulation in sweet potato cultivars are obscure. In this study, seedlings of a low-Cd (Nan88, N88) and a high-Cd cultivar (Xiang 16, X16) were grown in Hoagland’s solution containing Cd concentrations of 0 (control), 1 (Cd1), and 10 µM (Cd10) for 20 days. We analyzed the Cd accumulation, root morphology and low molecular weight organic acids (LMWOAs) excreted by the root tips (RTs). The total root length (RL) and specific root length (SRL) in X16 were greater than those in N88 following Cd treatments. In the Cd1 treatment, RL and surface area for root diameter was ≤0.2 mm, and RTs in X16 were also greater than those in N88. LMWOAs excreted from the RTs initially increased and then decreased as Cd concentration increased. The RTs of N88 were more efficient at excreting organic acids than were those of X16. The low-Cd cultivar with lower RL and SRL displayed greater ability to excrete organic acids in Cd treatments, which can decrease Cd translocation from roots to shoots. Furthermore, root morphology and some LMWOAs released from the root tips played an important role in the differing rates of Cd accumulation in the two sweet potato cultivars. 相似文献
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筛选和培育镉低积累水稻品种的进展和问题探讨 总被引:11,自引:0,他引:11
推广镉低积累品种是重金属污染农田安全利用的前提,筛选和培育镉低积累水稻品种已经成为水稻育种家的一个重要任务。近年来人们对镉低积累品种的筛选和培育工作投入较大的精力,但是由于稻米镉积累是一个复杂性状,受环境和基因型共同调控,人们对重金属低积累品种的定义、特征、筛选认定方法等并没有形成一致意见。本文主要介绍了最近几年国内外在镉低积累水稻品种筛选和定向培育方面的最新成果。在此基础上,从遗传学和农学角度提出了我们对镉低积累品种的定义及其特征的理解:镉低积累品种是指在相同环境条件下稻米镉积累量相对较低的品种,其在高镉(有效态)背景下稻米镉含量相对较低,中低镉背景下能达标,而低镉土壤背景下不超标。虽然稻米镉积累受环境和遗传因素共同调控,但镉积累特性遗传率高,降低稻米镉积累量不影响水稻的生育期、产量及其他必需微量元素的含量。镉低积累品种和镉高积累品种稻米镉积累量的差异随环境变化而变化,在高镉背景下相差较大,而在低镉土壤背景下差异变小。因此筛选认定镉低积累品种时,我们建议先在高镉背景下比较不同品种的相对镉含量,筛选镉积累相对较低的品种,然后在低镉条件下评价其产品的达标频率,确定其安全生产所需的环境条件。 相似文献
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为了解不同小麦品种灌浆期在镉污染农田中的生长情况和重金属镉积累的差异,本研究以30个小麦品种为材料,探明其在镉污染农田上的生长情况以及镉积累情况。结果表明,30个小麦品种在镉污染条件下能正常生长。不同小麦品种在灌浆期其株高、地上部和根部的生物量均存在着显著的差异,变化范围分别为48.87~77.47 cm、0.89~1.92 g·plant~(-1)、0.05~0.22 g·plant~(-1)。此外,不同小麦品种之间各部位吸收、积累镉的能力也存在明显差异。地上部和根部镉含量的变化范围分别为0.07~0.26、0.37~1.57mg·kg~(-1)。灌浆期镉在小麦体内的分配规律总体上为根地上部。地上部和根部镉积累量的变化范围分别为0.12~0.38、0.04~0.24μg·plant~(-1)。不同小麦品种各部位转运镉的能力存在明显差异,变化范围分别为0.08~0.47,其中淮麦23、冀麦738、宁麦17具有最低的根-地上部转运系数。成熟期的数据表明,淮麦23、冀麦738、宁麦17籽粒中镉的含量均远低于0.1 mg·kg~(-1)DW的国家限量标准,并具有很低的根-地上部转运系数,符合镉低积累小麦的标准。本文初步确定淮麦23、冀麦738、宁麦17作为低转运小麦品种的候选者,为低积累小麦品种的筛选提供科学依据。 相似文献
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