猪粪沼液理化性质对玉米种子萌发的影响

明确沼液理化性质对种子萌发的影响是确定沼液合理灌溉量的前提。该研究以猪粪厌氧发酵的沼液为研究对象,分析了新鲜沼液及预处理后沼液的理化性质,并将沼液理化性质与相对发芽率、相对根长和萌发指数建立函数关系,筛选了沼液中的植物毒性因子及安全阈值。对于秋田MD311这一玉米品种来说,铵态氮与乳酸是沼液中的植物毒性因子。种子达到最大萌发指数对应的铵态氮与乳酸的浓度分别为186与35.8 mg·L^-1;二者浓度高于336与61 mg·L^-1时,具备植物毒性(萌发指数(70%),不可直接还田。通过静置和曝气过程可降低二种毒性因子的含量。研究表明,沼液还田时将铵态氮与乳酸含量控制在安全阈值内时可降低植物毒性,促进作物生长,最大限度地发挥沼液对无机肥的替代作用。     

Comparisons of terrestrial and aquatic bioassays for oil-contaminated soil toxicity

Background  Petroleum products are widely used in various sections of industry and they are one of the most abundant sources of environmental contamination. These products are classified by their physico-chemical properties such as boiling point, density and viscosity. Oil contamination in the environment is primarily evaluated by measuring the chemical concentrations of petroleum products in the solid or water phase. The results of chemical analyses do not correspond directly with the harmful environmental effects of petroleum products on the soil flora and fauna, because the interactions between oil compounds and the production of their methabolites in soil are not measured in chemical assessments. These kinds of effects of complex chemical mixtures in soil can be estimated by bioassays. Therefore, ecotoxicological tests are important for estimating soil quality in the risk assessment of oil-contaminated soil sites. Objectives  The objective of this study was to examine the oil-contaminated soil site of a closed petrol station with both chemical and ecotoxicological methods. The goals of this study were to compare the sensitivity of the terrestrial and aquatic bioassays and to compare the toxicity responses of aquatic bioassays determined from three different extraction procedures. In addition, our aim was to characterise a cost-effective battery of bioassays that could be applied to a comparison of oil-contaminated soils. It was in our interest to investigate oil-contaminated soil with oil concentrations of 2500–12000 mg/kg and to find out the possible differences between terrestrial and aquatic toxicity tests. Methods  Six soil samples from a closed petrol station were examined for toxicity with terrestrial and aquatic tests. Terrestrial tests includedEnchytraeus albidus survival and reproduction assays and seed germination assays using wheat, cress, lettuce, and red clover seeds and growth inhibition assays of onions. The toxicities of the water-extractable fractions of the soil samples obtained from three different extractions were tested with aquatic bioassays based on plants (onion and duckweed growth inhibition tests), microbes (luminescent bacteria test), and enzyme inhibition (reverse electron transport test, RET). Chemical analyses of the solid samples were carried out simultaneously. Results. Oil concentrations ranged from 2500 to 12000 mg/kg, BTEX varied from 300 to 2800 mg/kg, and fuel additives: MTBE and TAME from 0.0 1 to 260 mg/kg. Only the sample contain-ing 12000 mg/kg oil had a significant toxic impact on all test organisms. Soil samples with oil concentrations 2500–6200 mg/ kg had no or only slight adverse effects on the test organisms with one exception, theE. albidus reproduction test. TheE. albidus survival and reproduction tests were the most sensitive bioassays of the terrestrial tests, and the luminescent bacteria test of the aquatic tests.     

Iodine biofortification in tomato

Iodine is an essential element in the human diet, and iodine deficiency is a significant health problem. No attempts to increase iodine content in plant‐derived food (biofortification) have so far been particularly effective. We studied iodine uptake in tomato (Solanum lycopersicum L.) to evaluate whether it is possible to increase the iodine concentration in its fruits. Iodine translocation and storage inside tomato tissues were studied using radioactive iodine. Potassium iodide was also supplied at different concentrations to tomato plants to evaluate the resulting iodide concentration both in the vegetative tissues and the fruits. The results indicate that iodine was taken up better when supplied to the roots using hydroponically grown plants. However, a considerable amount of iodine was also stored after leaf treatment, suggesting that iodine transport through phloem also occurred. We found that tomato plants can tolerate high levels of iodine, stored both in the vegetative tissues and fruits at concentrations that are more than sufficient for the human diet. We conclude that tomato is an excellent crop for iodine‐biofortification programs.     

发酵床养猪垫料的养分转化与植物毒性研究

发酵床养殖技术也被称为原位堆肥技术,是一种值得推荐的控制畜场粪便排放与污染的生态养殖模式。本研究检测了发酵床的水分、温度和pH值变化以及在连续饲养两批猪后垫料中碳、氮和磷的组成与含量变化情况及其对植物毒性的强弱。结果表明,发酵床使用期间水分为58%-61%,垫料内部温度维持在40-55℃;在连续饲养两批猪后,垫料的pH值升高至8.16,氮、磷含量显著提高,铵态氮、亚硝态氮和硝态氮浓度显著升高,C/N比由养猪前的84∶1下降至31∶1,N/P比由2.8∶1下降至1.26∶1;垫料中的总铜浓度由7mg·kg^-1升高至89mg·kg^-1。以白菜种子作发芽试验考察废弃垫料的植物毒性,其相对发芽率为86.67%,相对根长为132.95%,发芽指数（Germination Index,GI）为115.23%,说明饲养了两批肥猪的发酵床垫料无植物毒性作用,对根的生长有促进作用,可作为有机肥还田。     

碳纳米颗粒诱发植物毒性效应及其机理的研究进展

对碳纳米颗粒植物毒性的研究是推广碳纳米技术应用及规避其可能引起的生态风险的重要前提,在相关研究的基础上,结合国内外研究进展,从研究植物对碳纳米颗粒物的吸附、吸收入手,阐述了碳纳米颗粒物在植物体内的迁移,分析了碳纳米颗粒物对植物产生的毒性效应,进而概述了碳纳米颗粒物毒性效应的影响因素以及产生这些毒性作用的分子机理,提出了碳纳米颗粒物在植物毒理学方面的研究重点.     

Root cation exchange capacity of cotton cultivars in relation to aluminum toxicity

Root cation exchange capacity (CEC) was analyzed for four cotton cultivars (Pima S‐5, Stoneville 825, Deltapine 41 and Auburn 56) within tvo species (Gossypium barbadense and G. hirsutum) grown in control (O Al) and Al (1.5 mg/l) solution. Pima S‐5, a G. barbadense variety, had significantly (P < 0.10) lower root CEC than G. hirsutum cultivars in control (O Al) solution. Root CEC of Stoneville 825 was numerically but not significantly lower than Auburn 56 and Deltapine Al in control solution. Root CEC was significantly reduced in all cultivars when grown in Al solution. Compared to controls, Pima S‐5 and Stoneville 825 had either numerically or significantly less reduction in root CEC than Auburn 56 or Deltapine 41 in Al solution. Aluminum content of roots after CEC analysis was numerically greater in the former cultivars than the latter.

The lower root CEC of Pima S‐5 and Stoneville 825 in non‐toxic conditions could provide an initially greater Al tolerance when roots grow into marginally Al toxic soil. Under sustained, Al toxic conditions, root CEC becomes altered and is more of an indirect indicator of root growth as affected by as yet undetermined Al tolerance mechanism(s).

The steady‐state technique to determine root CEC virtually eliminated the inherent problems of CO. effects on pH and titrating to an end point in a specific period of time in a dynamic system.     

Differences in shoot growth and zinc concentration of 164 bread wheat genotypes in a zinc‐deficient calcareous soil

Abstract

A greenhouse experiment was carried out to study severity of the zinc (Zn) deficiency symptoms on leaves, shoot dry weight and shoot content and concentration of Zn in 164 winter type bread wheat genotypes (Triticunt aestivum L.) grown in a Zn‐deficient calcareous soil with (+Zn=10 mg Zn kg^?1 soil) and without (‐Zn) Zn supply for 45 days. Tolerance of the genotypes to Zn deficiency was ranked based on the relative shoot growth (Zn efficiency ratio), calculated as the ratio of the shoot dry weight produced under Zn deficiency to that produced under adequate Zn supply. There was a substantial difference in genotypic tolerance to Zn deficiency. Among the 164 genotypes, 108 genotypes had severe visible symptoms of Zn deficiency (whitish‐brown necrotic patches) on leaves, while in 25 genotypes Zn deficiency symptoms were slight or absent, and the remaining genotypes (e.g., 31 genotypes) showed mild deficiency symptoms. Generally, the genotypes with higher tolerance to Zn deficiency originated from Balkan countries and Turkey, while genotypes originating from the breeding programs in the Great Plains of the United States were mostly sensitive to Zn deficiency. Among the 164 wheat genotypes, Zn efficiency ratio varied from 0.33 to 0.77. The differences in tolerance to Zn deficiency were totally independent of shoot Zn concentrations, but showed a close relationship to the total amount (content) of Zn per shoot. The absolute shoot growth of the genotypes under Zn deficiency corresponded very well with the differences in tolerance to Zn deficiency. Under adequate Zn supply, the 10 most Zn‐ inefficient genotypes and the 10 most Zn‐efficient genotypes were very similar in their shoot dry weight. However, under Zn deficiency, shoot dry weight of the Zn‐efficient genotypes was, on average, 1.6‐fold higher compared to the Zn‐inefficient genotypes. The results of this study show large, exploitable genotypic variation for tolerance to Zn deficiency in bread wheat. Based on this data, total amount of Zn per shoot, absolute shoot growth under Zn deficiency, and relative shoot growth can be used as reliable plant parameters for assessing genotypic variation in tolerance to Zn deficiency in bread wheat.     

6种长效除草剂土壤残留致烟草药害 症状及其致害临界值

采用盆栽试验方法,测定氯嘧磺隆尧苯磺隆、烟嘧磺隆、莠去津、扑草净及氟磺胺草醚6种长效除草剂土壤残留致烟草药害症状及其致害临界值。结果表明：6种长效除草剂的施药方式均为土壤处理,所以均不同程度地抑制烟株的根、茎、叶的生长。氯嘧磺隆、苯磺隆、烟嘧磺隆3种磺酰脲类除草剂致使烟株药害症状显现时间长,持续时间长,不易恢复;而莠去津、扑草净尧氟磺胺草醚则显现时间短,轻者可恢复,严重者可使烟株迅速枯萎死亡。氯嘧磺隆、苯磺隆、烟嘧磺隆、莠去津、扑草净、氟磺胺草醚（有效成分）致烟株药害的临界值分别为：5.31×10-3、2.79×10-3、1.05×10-2、3.35×10-3、2.00×10-3、1.11×10-4 mg/kg。     

噻苯隆对莴笋产量、品质的影响及药害症状初步研究

在一定范围内,使用高浓度噻苯隆,会直接导致莴笋的功能叶、幼叶受害,同时会因为代谢导致新生叶片受害。在摘除死亡叶片后,正常管理下,莴笋植株可恢复生长,最终成熟;使用高浓度（〉0．10％）噻苯隆,会使成熟莴笋植株的株高、茎粗、叶片质量、叶中脉质量、叶片长宽比、根部质量、产量下降,而叶面积指数、品质提高;使用低浓度（0．05％）噻苯隆,可提高莴笋植株的叶片质量、叶中脉质量、茎部质量、株高、茎粗、产量。     

Sorption Characteristics of Chromium and Its Phytotoxic Effect with or without City Compost on Maize and Spinach in a Vertisol of Central India

Abstract

Phytotoxicity, due to chromium [Cr (VI)] additions from low to very high levels in a swell–shrink clayey soil (Haplustert), in maize and spinach was studied in a pot culture experiment. Six levels of Cr (VI) (0, 5, 10, 25, 50, and 75 mg kg^?1 soil) for maize and five levels for spinach (0, 2, 5, 10, and 25 mg kg^?1 soil) were applied singly and in combination with two doses (0 and 20 t ha^?1) of city compost. At levels of more than 75 mg Cr (VI) kg^?1 soil for maize there was virtually no growth after germination, whereas 25 mg Cr (VI) kg^?1 soil hindered the germination of spinach crop. Initial symptoms of Cr (VI) toxicity appeared as severe wilting of the tops of treated plants. Maize plants suffering from severe Cr (VI) toxicity had smaller roots and narrow brownish red leaves covered with small necrotic spots. In spinach, severe chlorosis was observed in leaves. Higher levels of Cr (VI) inhibited the growth and dry‐matter yield of the crops. However, application of city compost alleviated the toxic effect of Cr (VI). The concentration of Cr (VI) in plant parts increased when Cr (VI) was applied singly but decreased considerably when used in combination with city compost. There was evidence of an antagonistic effect of Cr (VI) on other heavy‐metal (Mn, Cu, Zn, and Fe) concentrations in plant tops. Thus, when Cr (VI) concentration increases, the concentration of other beneficial metals decreases. Chromium (VI) concentration in maize roots ranged from traces (control) to 30 mg kg^?1and were directly related to soil Cr (VI) concentration. At 25 mg Cr (VI) kg^?1 soil, yield of maize was reduced to 41% of control plants, whereas in spinach, 10 mg Cr (VI) kg^?1 soil caused a 33% yield reduction. Experimental results revealed that the maize top (cereal) is less effective in accumulating Cr (VI) than spinach (leafy vegetables). Laboratory studies were also conducted to know Cr (VI) sorption capacity of a swell–shrink clayey soil with and without city compost, and it was found that Cr (VI) sorption reaction was endothermic and spontaneous in nature.