不同作物对土壤中Cd的富集特征及低累积品种筛选

为探究镉(Cd)污染土壤中农作物的食用安全性,以上海市常见农作物(青椒、黄瓜、豇豆、菠菜、花菜、西红柿、水稻和小麦)为实验材料,采用温室盆栽土培实验方法研究了不同土壤Cd含量梯级(0. 23、0. 6、1. 2、1. 8、2. 4和3. 0 mg·kg-1)下不同作物生物量变化以及可食部分Cd富集特征,建立不同种类作物与土壤Cd含量相关关系,探讨不同作物对应的土壤Cd安全限量值,筛选Cd低累积作物品种.结果表明:①随着土壤中Cd含量增加,作物地上生物量表现为先增加后减少,青椒耐受性最强,西红柿、菠菜耐受性最差.②不同作物可食部位Cd的富集系数由大到小依次为小麦菠菜水稻青椒花菜西红柿黄瓜豇豆.③作物可食部分Cd含量与土壤中Cd含量都呈显著正相关(P 0. 05),相关系数大小依次为菠菜小麦西红柿黄瓜青椒水稻花菜豇豆.④不同作物对应的土壤Cd安全限量值大小依次为:豇豆黄瓜花菜青椒西红柿水稻菠菜小麦.依据作物对土壤中Cd的耐受性、富集能力及食用安全限量值,筛选出黄瓜、豇豆、花菜为Cd低累积品种.     

Differential N uptake by maize cultivars and soil nitrate dynamics under N fertilization in West Africa

Nitrate is prone to leaching in the sandy soils of the West African moist savannas. Better management of nitrogen (N) resources and maize cultivars with enhanced genetic capacity to capture and utilize soil and fertilizer N are strategies that could improve N-use efficiency. In two field experiments conducted at Zaria, northern Nigeria, five maize (Zea mays L.) cultivars planted early in the season were assessed under various N levels for differences in N uptake, soil N dynamics, and related N losses. Cultivar TZB-SR accumulated more N in the aboveground plant parts in both years than the other cultivars. All, except the semi-prolific late (SPL) variety, met about 50–60% of their N demand by the time of silking (64–69 DAP). In both years, SPL had the greatest capacity to take up N during the grain filling period, and it had the highest grain-N concentration and the least apparent N loss through leaching in the second year. There were no significant differences in soil N dynamics among cultivars in both years. At harvest, the residual N in the upper 90 cm of the profile under all the cultivars ranged from 56 to 72 kg ha⁻¹ in the first year and from 73 to 83 kg ha⁻¹ in the second year. Apparent N loss from 0 to 90 cm soil profile through leaching ranged from 35 to 122 kg ha⁻¹ in both years. N application significantly increased N uptake by more than 30% at all sampling dates in the second year of the experiment, but had no effect on apparent N loss. Results indicate that the use of maize cultivars with high N uptake capacity during the grain filling period when maximum leaching losses occur could enhance N recovery and may be effective in reducing leaching losses of mineral N in the moist savanna soils.     

不同品种水稻对Cu积累分配的差异

以21个水稻品种（包括常规稻、二系杂交稻、三系杂交稻）为材料,通过室内盆栽试验探讨了Cu在不同品种水稻根-茎-叶-籽粒（糙米）中的积累分配的差异。结果表明,供试水稻品种根、茎、叶、籽粒中Cu含量的均值分别是67.35、16.24、8.29、11.62mg·kg-1,多数水稻品种Cu的含量顺序是根茎籽粒（糙米）叶,但也有少部分水稻品种Cu的含量顺序是根籽粒（糙米）茎叶。各器官的Cu含量在不同品种间存在显著差异,其中以根和籽粒Cu含量的差异最大,茎次之,叶最小。常规稻根部Cu含量显著低于杂交稻,而叶中Cu含量显著高于杂交稻,但两者的茎和籽粒中Cu含量没有明显的差异。三系杂交稻根、茎、籽粒Cu含量显著高于二系杂交稻,而叶的Cu含量两者差异不显著。不同遗传背景的水稻各器官对Cu积累也存在不同程度的差异。相关分析结果表明,不同品种水稻相邻器官（根与茎,茎与叶）的Cu含量呈极显著正相关,相间器官（根与叶、籽粒,茎与籽粒）的Cu含量呈显著正相关,地上部各器官Cu的转运系数相互之间呈极显著的正相关。     

2种常规水稻Cd、Zn吸收与器官分配的生育期变化：品种、土壤和Cd处理的影响

Cd在土壤-作物-膳食食物链中的迁移是人类对环境Cd暴露及其健康风险的主要途径,而水稻是子粒Cd积累最强的大宗作物之一.采用全生育期淹水盆栽试验研究了2种常规水稻(高Cd吸收品种“苏香粳1号”和低Cd吸收品种“99-22”)在添加Cd(2mg·kg-1)和不添加Cd处理下对2种土壤(红沙泥田,乌栅土)中Cd、Zn的吸收及其生育期变化.结果表明:1)常规水稻对Cd、Zn的吸收积累受土壤、品种和外源Cd的影响.Cd处理、土壤、品种间的正交互作用(高Cd吸收品种植于高Cd处理且Cd有效性高的红壤中)使常规稻植株Cd/Zn比成数十倍提高,从而使子粒Cd/Zn比产生强烈升高;2)水稻对Cd、Zn的吸收强度因不同生育期而异,Cd吸收的主要时期是分蘖期和成熟期,而Zn吸收的主要时期则是分蘖期、抽穗期和灌浆期.在整个生育期中,水稻Cd吸收伴随着对Zn的排斥现象,这在高Cd吸收下尤为强烈;3)水稻各器官对Cd、Zn的吸收分配无论是同品种的生育期间抑或同生育期时的不同品种间均有显著差异.Cd积累量为根系>穗粒>茎叶,而Zn却表现为茎叶>根系、穗粒.观察到水稻吸收的Cd在生育后期向穗粒的强烈运移.相对于低Cd吸收品种来说,Cd向穗粒转运较强,而Zn的转运较弱是高Cd吸收品种子粒Cd积累强而Cd/Zn比高的植株因素.     

Variation in composition of predator-attracting allelochemicals emitted by herbivore-infested plants: Relative influence of plant and herbivore

Summary During foraging, natural enemies of herbivores may employ volatile allelochemicals that originate from an interaction of the herbivore and its host plant. The composition of allelochemical blends emitted by herbivore-infested plants is known to be affected by both the herbivore and the plant. Our chemical data add new evidence to the recent notion that the plants are more important than the herbivore in affecting the composition of the volatile blends. Blends emitted by apple leaves infested with spider mites of 2 different species,T. urticae andP. ulmi, differed less in composition (principally quantitative differences for some compounds) than blends emitted by leaves of two apple cultivars infested by the same spider-mite species,T. urticae (many quantitative and a few qualitative differences). Comparison between three plant species — apple, cucumber and Lima bean — reveals even larger differences between volatile blends emitted upon spider-mite damage (many quantitative differences and several qualitative differences).     

水稻土中外源Cd老化的动力学特征与老化因子

选择5种不同性质的水稻土,通过外源添加制备了6个不同浓度梯度的Cd污染土壤,研究了外源Cd在几种水稻土中的老化动力学特征与影响因子;同时利用盆栽实验,结合Log-logistic分布模型,研究了5个不同老化时间(14、30、60、90和180d)与土壤中Cd对二种不同Cd敏感性水稻生长毒性的影响.结果表明,不同浓度外源Cd进入土壤后,0.05mol/L EDTA-2Na浸提的有效态Cd含量随着老化时间的增加而逐渐下降;与14d处理相比,老化30d后土壤中有效态Cd降幅达21.5%(红壤)~38.0%(黑土);老化90d后,土壤中Cd进入慢反应阶段. 基于二级动力学方程的拟合参数显示,土壤中Cd的老化特征表现为有效态Cd含量在30~60d内快速降低,随后变化减缓,经过90d的老化后,土壤中有效态Cd含量逐渐趋于平衡.基于老化动力学方程参数(C∞及K2)与土壤性质间的相关性分析表明,土壤pH值是影响Cd有效态含量变化的主控因子,其次是土壤CEC和OC含量.在不同性质土壤中,随着老化时间的增加,土壤中外源Cd对水稻生长毒性的半抑制浓度(EC50)值显著升高;与14d老化处理相比,经过180d老化后土壤中Cd对水稻生长毒性的EC50增加72.1%~195.0%;在大于90d的长期老化过程中,土壤pH值对Cd老化过程的影响逐渐降低,而CEC的影响逐渐上升,尽管如此,土壤中Cd老化过程的主要影响因子仍然是土壤pH,而与测试的2种水稻品种无关.     

Influence of short-term irrigation of textile mill wastewater on the growth of chickpea cultivars

The effect of textile mill wastewater on germination, delay index, physiological growth parameters, and plant pigments of two cultivars of chickpea was studied. The aim of this study was to evaluate the suitability of textile mill wastewater (treated and untreated) at different concentrations (0, 6.25, 12.5, 25, 50, 75, and 100%) for irrigational purposes. The textile effluent did not show any inhibitory effect on seed germination at a lower concentration (6.25%). The other reported plant parameters (delay index, root length, shoot length, dry weight, chlorophyll, and carotenoid) also followed a similar trend. Seeds germinated in 100% effluents but did not survive for longer periods. It has also been concluded that the effect of the textile effluent is cultivar-specific, and due care should be taken before using the textile mill wastewater for irrigation purposes.     

外加Cd对两水稻品种细胞超微结构的影响研究

为了研究Cd在不同水稻品种(Oryza sativa L.)细胞中的分布位点及其耐Cd的具体表征状况,以子粒Cd积累水平不同的两水稻品种(品种A:中浙优1号,子粒高Cd含量品种;品种C:J196,子粒低Cd含量品种)为材料,进行盆栽实验,设不加Cd处理(CK)和加Cd处理(25mg·kg-1),采用透射电镜技术研究了外加Cd对两水稻品种细胞超微结构的影响.结果表明:Cd处理下两水稻品种的部分根细胞有Cd沉积现象,但不同品种的沉积部位表现不同,品种A主要在液泡边缘而品种C则在细胞壁和细胞间隙,表明不同水稻品种根系的耐Cd机制不同,品种A主要表现为液泡区室化,而品种C主要表现为细胞壁上有特定沉积.水稻叶肉细胞器中的叶绿体和线粒体是对Cd胁迫较为敏感的细胞器,外加Cd对茎叶细胞超微结构造成的伤害主要表现在使叶绿体上淀粉粒消失,叶绿体空泡化,部分线粒体出现肿胀或解体现象,品种C的受害程度高于品种A。     

方解石基组配钝化剂与低积累玉米协同修复效果

针对典型北方碱性镉和铅复合污染农田土壤,开展土壤钝化与低积累农作物协同修复田间试验,以方解石作为主量钝化材料,分别复配少量熟石灰、沸石粉和生物炭形成组配钝化剂.研究在CL(方解石+熟石灰)、 CZ(方解石+沸石)、 CB(方解石+生物炭)和CLZB(方解石+熟石灰+沸石+生物炭)不同组配条件下,对土壤理化性质、重金属Cd和Pb生物有效性的影响,以及对低积累玉米产量和植株(茎叶和籽粒)重金属Cd和Pb含量的影响.结果表明：(1)施用钝化剂均能保障玉米正常生长,小幅提升玉米千粒重与玉米产量.(2)不同方解石基组配钝化剂处理对土壤理化性质的影响具有一定的差异性,CL、 CZ、 CB和CLZB处理对土壤pH分别提升0.46、 0.25、 0.12和0.13个单位,对土壤肥力指标无显著相关性(P>0.05).(3)不同方解石基组配钝化剂处理均能显著降低土壤Cd和Pb的DTPA浸提态和离子交换态含量,其中CLZB处理对DTPA浸提态Cd和Pb含量降低率分别为49.36%和72.55%,对离子交换态Cd和Pb含量降低率分别为55.39%和78.52%.(4)在不同组配钝化剂处理后可使低积累玉米...     

Iron and Zinc status in soils, water and staple food cultivars in Itakpe, Kogi State of Nigeria

The levels of iron (Fe) and zinc (Zn) were quantitatively determined in soil and water samples as well as in staple food cultivars in Itakpe, Nigeria's major iron mining town. The survey was conducted to establish a baseline pollution index for Fe and Zn in the Itakpe environment and to evaluate the role of foods as an exogenous source of these metals among the inhabitants. Exceedingly high levels of both metals characterized the staple food cultivars in the town.