施用硒内源调控剂对水稻吸收硒、镉和砷的影响

为探讨不同硒内源调控剂对水稻吸收硒（Se）、镉（Cd）、砷（As）及土壤中Se、Cd、As形态的影响,将多种复合调理剂添加到富硒土壤中开展盆栽试验。结果表明,施用1%或2%蒙脱复合调理剂（MT）均可获得水稻增Se降Cd的效果,2%添加量效果更佳;在高硒土（土壤Se含量1.99 mg/kg）条件下,添加钙镁磷肥+磷矿粉+活性硅（GLG）可获得水稻Se过量减毒和同时降As的双重效果;在中硒土（土壤Se含量0.83 mg/kg）条件下,添加钙镁磷肥+骨粉+活性硅（GGG）,水稻的增Se降As效果最佳;而在低硒土壤（土壤Se含量0.46～0.47 mg/kg）条件下,添加钙镁磷肥+生物炭+有机菌肥+活性硅（GTJG）和添加钙镁磷肥+石灰+活性硅的增Se降As效果较好。研究表明,施加适量Se内源调控剂可实现水稻增Se、降Cd和As,同时减毒的效果。     

麦饭石肥对水稻产量及安全性影响的研究

麦饭石肥在一定施用数量范围内能增加水稻的有效穗数和结实率，从而提高水稻的产量，但并不是施用量越大水稻的各项产量构成因子越合理，产量越高。试验表明，麦饭石每hm^2施750kg时水稻产量最高，达10445．2kg／hm^2。在水稻生产过程中施用麦饭石肥，生产的稻米按NY／T419—2000标准进行检验，质量合格。氰化物、磷化物、铅等农药残留和重金属未检出，黄曲霉毒素B1、As、Hg、Cd、F等对人体有害的化学物质和重金属虽检出，但检测结果都在标准要求范围内，各项判定均为合格，达到A级绿色优质大米的卫生要求。施用麦饭石肥生产的稻米锰、钙、钠、锌、硒均不同程度的增加了含量，说明了使用麦饭石肥生产的大米中含有许多对人体有益的中量元素和微量元素，这证实了麦饭石具有较强的溶出性。     

As(Ⅲ)胁迫对不同小麦品种种子萌发及幼苗As含量的影响

为了探讨As(Ⅲ)胁迫对不同小麦品种的毒害效应,选取郑麦9023、豫麦18、周麦16三个小麦品种为材料,采用室内水培方法,研究了As(Ⅲ)胁迫对小麦种子萌发、幼苗生长及幼苗芽和根中As含量的影响,分析了不同小麦品种耐As能力的差异。结果表明,随As(Ⅲ)浓度的增加,小麦种子的发芽势、发芽率、发芽指数、活力指数和幼苗的芽长、根长、芽重、根重均呈明显下降趋势,且不同浓度间的差异均达到显著或极显著水平。As(Ⅲ)胁迫对小麦根生长的抑制作用明显大于对芽生长的抑制。小麦幼苗芽和根中As含量随As(Ⅲ)胁迫浓度的增大而增大。三个小麦品种种子萌发和幼苗生长对As(Ⅲ)胁迫的反应趋势相同,当As(Ⅲ)浓度≥20 mg/kg时,幼芽中As含量表现为周麦16最低;当As(Ⅲ)浓度≥40 mg/kg时,幼根中As含量也表现为周麦16最低。综合来看,郑麦9023和豫麦18种子活力较高,幼苗长势较旺,但对As耐受能力较弱;周麦16种子活力较低,幼苗长势不旺,但对As耐受能力最强。     

紧压茶中无机元素的含量及其浸出率的分析

紧压茶大多是以黑毛茶为原料压制加工而成,以边销为主。而西北各民族以农牧业为主,生活上多食肉乳,饮用黑茶能解油腻,帮助消化,解渴生津和补充人体所需的微量元素。因此,了解紧压茶中无机元素的含量,以及茶汤中无机元素的浸出情况,对提高紧压茶的品质,开发和利用紧压茶,有着十分重要的意义。     

西洋参叶二醇组皂甙中无机元素分析

本文采用原子吸收分光光度法测定了西洋参叶二醇组皂甙中10种无机元素,其中含有 Na、K、Ca、Mg以及Fe、Cu、Zn、Mn等人体必需微量元素,而有害元素 Pb、As含量极低。同时对西洋参总甙中这些元素也进行测定。     

几种重金属(Cd、Cr、As)在玉米植株中的分布研究

从株洲市某社区玉米园中采集玉米植株及其生长的土壤样品,利用ICP等离子法测定铬(Cr)、砷(As)、镉(Cd)3种重金属元素的含量,对玉米不同器官积累重金属的特性进行初步研究。结果表明:(1)玉米园土壤受重金属As中度污染,重金属Cd重度污染;(2)3种重金属在玉米植株中的分布规律大致为根叶茎;(3)玉米对土壤中3种重金属的平均富集系数大小排列顺序为CdCrAs;(4)玉米对土壤As元素有较强的耐性;(5)玉米茎中Cr元素含量与根中Cr达到了显著负相关,而茎、叶中Cd含量与根部Cd呈正相关。     

砷胁迫下磷用量对不同磷效率水稻苗生长、磷和砷吸收的影响

 通过盆栽试验研究了苗期砷胁迫下磷用量对磷高效水稻99011和磷低效水稻99056生长以及对P、As吸收的影响。试验设3个磷水平（0、30、150 mg/kg）和5个砷水平（0、25、50、100、200 mg/kg）。结果表明,苗期施砷显著增加了两个水稻品种地上部及地下部砷的含量,降低了两个水稻品种的株高、分蘖数、地上部及地下部干质量;施磷不但促进了两个水稻品种的生长,而且还增加了根系对砷的吸收量。当土壤砷浓度为25 mg/kg和50 mg/kg时,施用30 mg/kg磷抑制了两个水稻品种砷向地上部的转移,但施用150 mg/kg磷却促进了砷向地上部的转移。相同的处理,磷高效水稻99011地上部干质量和根干质量均显著高于磷低效水稻99056。施砷后,在30 mg/kg磷水平上磷低效水稻99056的砷转移系数最低。     

维生素锌硒肥对水稻产量及品质的影响

在水稻上喷施维生素锌硒肥试验结果表明,水稻喷施维生素锌硒肥后,其经济性状改善,产量明显提高;大米中的硒、锌、钙、镁、锰等矿物元素及维生素B1、B2、B6含量明显增加,大米品质提升。     

一个水稻铜锌SOD酶基因在应答亚砷酸盐胁迫中的作用

【目的】水稻Os08g44770.1基因编码一个铜锌SOD酶,但其在响应亚砷酸盐[As(Ⅲ)]胁迫中的生物学功能未知。本研究旨在深入揭示由该基因调控水稻砷耐性改变的分子机理并为水稻抗逆育种提供理论参考。【方法】以野生型日本晴(WT)和2个Os08g44770.1过表达转基因株系为试材,通过胁迫处理、生理指标测定和基因表达分析等,系统探究了转基因植株对As(Ⅲ)的耐受性表现,并初步揭示了其调控水稻砷耐性的生理和分子机理。【结果】与WT相比,过表达转基因株系对As(Ⅲ)更加敏感;转基因植株在砷胁迫下的根系相对伸长量、生物量(干质量)、叶绿素含量、根系细胞质膜完整性、叶片抗氧化程度等均显著低于WT;Os08g44770.1在砷处理后的WT和转基因植株叶片中的表达模式略有不同,但均表现为处理24 h时被显著诱导表达。【结论】过度表达Os08g44770.1基因可导致水稻的砷耐受性极显著下降。     

武夷山茶园土壤汞、镉和砷形态及茶叶有效性特征

通过测试武夷山19个茶园土壤及茶叶中的Hg、Cd和As元素全量及土壤元素化学形态组成,分析3种元素对茶叶的有效性。结果表明:土壤Hg存在一定程度的富集,以残渣态和强有机态为优势形态;Cd富集最严重,且以离子交换态为优势形态;As符合无公害茶产地环境标准(NY/T 853-2004),且以残渣态为主,占总量的70.35%。茶叶Hg、Cd、As含量属于安全范围内,均值远低于《茶叶中铬、镉、汞、砷及氟化物限量(NY659-2003)》标准限值。土壤Hg、Cd和As的生物可利用性系数及富集系数值比较得出,土壤Cd生物可利用能力最强,As次之,Hg最弱;茶叶对土壤Cd、Hg富集能力较强,对As富集较弱。总之,土壤元素种类和化学形态组成更大程度上决定了元素活性、迁移与转移能力。     

Proteomic analysis of a disease-resistance-enhanced lesion mimic mutant spotted leaf 5 in rice

Background

Rice is a major source of dietary intake of arsenic (As) for the populations that consume rice as a staple food. Therefore, it is necessary to reduce the As concentration in rice to avoid the potential risk to human health. In this study, the genetic diversity in As accumulation and As speciation in rice grains was investigated using a world rice core collection (WRC) comprising 69 accessions grown over a 3-year period. Moreover, quantitative trait locus (QTL) analysis was conducted to identify QTLs controlling the dimethylarsinic acid (DMA) content of rice grains.

Results

There was a 3-fold difference in the grain As concentration of WRC. Concentrations of total-As, inorganic As, and DMA were significantly affected by genotype, year, and genotype-year interaction effects. Among the WRC accessions, Local Basmati and Tima (indica type) were identified as cultivars with the lowest stable total-As and inorganic As concentrations. Using an F₂ population derived from Padi Perak (a high-DMA accession) and Koshihikari (a low-DMA cultivar), we identified two QTLs on chromosome 6 (qDMAs6.1 and qDMAs6.2) and one QTL on chromosome 8 (qDMAs8) that were responsible for variations in the grain DMA concentration. Approximately 73% of total phenotypic variance in DMA was explained by the three QTLs.

Conclusions

Based on the results provided, one strategy for developing rice cultivars with a low level of toxic As would be to change the proportion of organic As on the basis of a low level of total As content.     

高砷煤矿污染土壤的小麦砷累积研究

为了解砷污染土壤对小麦品质的影响及食用砷污染土壤种植的小麦对人群健康的影响,以贵州省兴仁县交乐高砷煤矿区砷污染农田的土壤-小麦系统为研究对象,采用氢化物发生-原子荧光光度法测定土壤和小麦砷含量,并对砷污染土壤及小麦中砷分布特征进行研究。结果表明,受污染农田土壤(区域Ⅰ、区域Ⅱ)的砷含量显著高于周边未受污染农田(区域Ⅲ),区域Ⅰ土壤pH值最低(4.57),土壤砷含量分别是区域Ⅱ、区域Ⅲ的1.94和2.13倍,土壤砷含量与土壤pH值呈显著负相关关系;区域Ⅰ小麦样品不同器官的砷含量为1.37mg·kg~(-1)(根)、0.74mg·kg~(-1)(茎叶)、0.85mg·kg~(-1)(籽粒);受试样品中,67%的小麦籽粒砷含量高于GB2762-2012中规定的小麦砷含量限值(0.5mg·kg~(-1))。采用USEPA推荐健康风险评价模型对当地居民以小麦为砷摄入途径的健康风险评价结果显示,区域Ⅰ、区域Ⅱ小麦的HQ值分别为2.82和1.19,区域Ⅲ为0.97。受试土壤砷污染已对小麦品质产生影响,食用矿区附近砷污染农田种植的小麦可能对居民健康有影响。     

Arsenic-prone rice cultivars: a study in endemic region

Rice is prone to arsenic accumulation compared to other cereals as typically grown up under waterlogged situation favoring arsenic mobility. Arsenic in rice depends on arsenic availability to plants from irrigation water, even differs among cultivars and their plant parts. Present study was concentrated on arsenic accumulation in various plant parts of five common rice cultivars grown using irrigation water from different water sources in various fields in arsenic-endemic region. Additionally, dose response experiment under laboratory net house was conducted on the same cultivars excluding open environmental factors. The common cultivars were categorized according to high to low arsenic accumulator in rice grain, straw and root parts. The cultivar Shatabdi has shown highest arsenic accumulation in rice grain compared to other rice cultivars in fields and when grown at various soil arsenic doses. In field samples, a highest grain arsenic concentration ranged between 0.69 ± 0.04 and 0.78 ± 0.12 mg kg^?1 for Shatabdi, whereas lowest grain arsenic concentration ranged between 0.37 ± 0.07 and 0.41 ± 0.07 mg kg^?1 for the cultivars GB3 and Lalat. Speciation study detected more inorganic arsenic than organoarsenicals with a trend of arsenite > arsenate > DMA > MMA, which would be problem for consumers. The concluding remark is the characterization of common rice cultivars according to arsenic concentration to highlight an important remediation strand by changing to low arsenic cultivar.     

锌与有机物料配施对水稻吸收转运镉的影响

采用盆栽试验,研究了在重金属镉污染（5 mg/kg）下,2种锌源（硫酸锌、纳米氧化锌）与3种有机物料（蚕砂、菜籽饼、豆饼）配施对水稻吸收镉、锌及对土壤镉形态变化的影响。结果表明,有机物料与锌配施可以提高土壤pH值、阳离子交换量（CEC）,降低土壤DTPA提取态镉含量,增加DTPA提取态锌含量,改变镉赋存形态。与对照相比,配施处理均能降低糙米镉含量;当有机物料种类相同时,纳米氧化锌降镉效果优于硫酸锌,其中纳米氧化锌+菜籽饼处理使糙米镉含量降低至0.04 mg/kg,低于国家标准镉的安全限值。相关性分析表明,水稻糙米镉含量与锌含量呈极显著正相关,土壤DTPA提取态镉含量与水稻各器官中的锌含量呈负相关。有机物料与锌配施通过改变土壤DTPA提取态镉和锌含量、水稻各器官锌含量及镉形态影响水稻吸收积累镉的能力。     

Arsenic in irrigated water,soil, and rice: perspective of the cropping seasons

Arsenic contamination of shallow groundwater and related health problems are threats for the millions in endemic regions of West Bengal. Contamination of rice grain creates the food chain pathway of mineral arsenic besides drinking water contamination. Present study concentrated on association of arsenic concentration in irrigated water, paddy field soil and rice with the cropping seasons. Irrigated ground water arsenic concentration decreased significantly (p = 0.007) from summer (median 0.42 mg l^?1) to winter (median 0.35 mg l^?1). Carried over effect created significant decrease (p = 0.03) of paddy field soil arsenic concentration from summer (median 8.35 mg kg^?1) to winter (median 6.17 mg kg^?1). Seasonal variation was observed in rice straw (p = 0.03) but not in husk (p = 0.91). Arsenic concentration decreased significantly (p = 0.05) in the rice grains collected in winter season (median 0.23 mg kg^?1) than the samples collected in the summer season (median 0.30 mg kg^?1). In conclusion, seasonal effects need to be considered in case of human health risk assessment from arsenic consumption.     

Selenium Alleviates Carbohydrate Metabolism and Nutrient Composition in Arsenic Stressed Rice Plants

This study reported the influence of selenium (Se) on carbohydrate composition and some related enzymes and nutrient compositions of arsenic (As) stressed rice plants. Rice plants of cultivar PR126 were grown on soil amended with As in a range of 25–100 μmol/kg with and without 0.5 or 1.0 mg/kg Se. Total soluble sugars (TSS) and reducing sugars (RS) increased in leaves of As stressed plants at the tillering and grain filling stages whereas sucrose and starch contents showed the reverse trend. Se supplementation to As stressed plants further increased TSS and RS, and enhanced sucrose phosphate synthase activity in rice leaves, thus improving sucrose content and the tolerance to As stress of the plants. Se alone or in combination with As resulted in lower As accumulation in rice husk and grains, and the highest reduction was observed in Se applied at 1.0 mg/kg compared to the corresponding As treatments alone. As may limit the accumulations of Na, Mg, K, Ca, Fe, Zn and Mn in rice grains, which are essential for humans. Binary application of different combinations of As and Se protected the plants against As and increased the mineral content in rice grains. Addition of Se in As treated soil significantly alleviated As stress by enhancing grain yields compared to the corresponding As treatment. It is concluded that Se induced amelioration of the toxic impact of As in rice either by modulating carbohydrate composition and/or nutrient uptake is one of the mechanisms to alleviate As stress in plants.     

Simultaneous mitigation of arsenic and cadmium accumulation in rice (Oryza sativa L.) seedlings by silicon oxide nanoparticles under different water management schemes

Paddy and Water Environment - Arsenic (As) and cadmium (Cd) accumulation in rice is a great food safety concern. Simultaneous control of As and Cd accumulation in rice grown in co-contaminated rice...     

长期有机肥无机肥配施对水稻氮素吸收、转运及产量的影响

基于25年定位试验,设置6个大田试验处理（CK,不施肥;NPK,常规施用化肥;1/4M+3/4NPK,25%有机肥替代化肥;1/2M+1/2NPK, 50%有机肥替代化肥;M,100%有机肥替代化肥;MNPK, 100%化肥+100%有机肥）,研究了长期有机肥无机肥配施对水稻氮素吸收和利用的影响。结果表明,水稻地上部N素总积累量与产量大小均表现为MNPK>1/4M+3/4NPK> NPK>1/2M+1/2NPK>M>CK,与NPK处理相比,MNPK和1/4M+3/4NPK处理的地上部氮素总积累量增加20.11%~27.86%、产量增加2.04%~12.42%。各处理花前N素转运量对籽粒贡献率（69.54%~84.60%）显著高于花后积累量对籽粒贡献率（15.40%~30.46%）,花前N素积累是水稻植株N素的主要来源。1/4M+3/4NPK处理的氮肥偏生产力及氮收获指数均高于NPK处理,分别提高16.42%、10.29%。有机无机肥配施比单施化肥处理显著改善了稻米品质,提高了籽粒氨基酸含量,其中,非必需氨基酸含量是必需氨基酸含量的2倍左右。长期施肥条件下,25%有机肥替代化肥处理在化肥减施基础上,可以提高肥料利用率、促进水稻养分吸收,是黄壤性水稻土地区实现水稻增产、品质提升的最佳施肥措施。     

Arsenic Accumulation in Rice: Sources,Human Health Impact and Probable Mitigation Approaches

The human body loading with arsenic (As) through rice consumption is a global health concern. There is a crucial need to limit As build-up in rice, either by remediating As accumulation in soils or reducing As levels in irrigation water. Several conventional approaches have been utilized to alleviate the As accumulation in rice. However, except for some irrigation practices, those approaches success and the adoption rate are not remarkable. This review presents human health risks posed due to consumption of As contaminated rice, evaluates different biomarkers for tracing As loading in the human body, and discusses the latest advancement in As reducing technologies emphasizing the application of seed priming, nanotechnology, and biochar application for limiting As loading in rice grains. We also evaluate different irrigation techniques to reduce As accumulation in rice. Altering water management regimes significantly reduces grain As accumulation. Bio- and nano-priming of rice seeds improve germination and minimize As translocation in rice tissues by protecting cell membrane, building pool around seed coat, methylation and volatilization, or quenching harmful effects of reactive oxygen species. Nanoparticle application in the form of nano-adsorbents or nano-fertilizers facilitates nano-remediation of As through the formation of Fe plaque or sorption or oxidation process. Incorporating biochar in the rice fields significantly reduces As through immobilization, physical adsorption, or surface complexation. In conclusion, As content in cooked rice depends on irrigation source and raw rice As level.