Hatching of Globodera pallida is inhibited by 2-propenyl isothiocyanate in vitro but not by incorporation of Brassica juncea tissue in soil

The aim of this study was to assess the feasibility of controlling the potato cyst nematode Globodera pallida through biofumigation with glucosinolate-rich Brassica juncea genotypes. The main glucosinolate of B. juncea is 2-propenyl glucosinolate which is the precursor of 2-propenyl isothiocyanate. Toxicity of 2-propenyl isothiocyanate to encysted G. pallida was tested in vitro. Fifty percent reduction in hatching was found within 2 h of exposure to 0.002% 2-propenyl isothiocyanate. Based on the in vitro results, we hypothesized that biofumigation with B. juncea would reduce hatching of G. pallida in vivo and higher 2-propenyl glucosinolate levels would have a stronger effect. Plant genotype, sulfur fertilization and insect herbivory affected 2-propenyl glucosinolate concentration of B. juncea. However, increasing 2-propenyl glucosinolate concentration of B. juncea did not affect G. pallida hatching after biofumigation. The absence of a biofumigation effect was most likely due to lower concentrations of 2-propenyl isothiocyanate in vivo compared to in vitro conditions. These results show that it is difficult to reach sufficiently high levels of toxicity to reduce hatching of G. pallida under realistic conditions.     

Cytotoxicity of Senecio in macrophages is mediated via its induction of oxidative stress

In Arunachal Pradesh and other sub-Himalayan areas of India, accidental consumption of Senecio plants by yaks is often fatal as the plant contains toxic alkaloids like Seneciophylline. The present investigation was undertaken to demonstrate the pro-oxidant effects of an ethanolic extract of Seneciochrysanthemoides (S-EtOH). S-EtOH impaired viability in macrophages, the IC₅₀ being 13.8 ± 1.11 μg/mL. The effect of S-EtOH (1 μg/mL) on generation of reactive oxygen species (ROS) in macrophages was measured by flow cytometry using 2′,7′-dichlorofluorescein diacetate (H₂DCFDA) where it caused a significant increase in the mean fluorescence channel (MFC) from 8.55 ± 0.03 to 47.32 ± 2.25 (p < 0.001). S-EtOH also effected a 3.8-fold increase in extracellular nitric oxide (NO) generation from 4.90 ± 0.72 μM to 18.79 ± 0.32 μM (p < 0.001), a 2.2-fold increase in intracellular NO production, the MFC increasing from 14.95 ± 0.48 to 33.34 ± 1.66 (p < 0.001), and concomitantly depleted non protein thiols as analyzed by flow cytometry using mercury orange, with a reduction in MFC from 632.5 ± 49.44 to 407.4 ± 12.61 (p < 0.01). Additionally, S-EtOH (14 μg/mL, 24 h) caused apoptosis as evident by increased Annexin V binding and terminal deoxynucleotidyl transferase mediated dUTP DNA nick end labeling. Taken together, the cytotoxicity of S-EtOH can be partly attributed to its capacity to inflict oxidative damage via generation of both reactive oxygen and nitrogen species culminating in apoptosis.     

20.00%辣根素对草莓白粉病防治效果评价

通过对草莓白粉病喷施20.00%辣根素水乳剂处理,检验辣根素对白粉病的防效试验,结果表明,20.00%辣根素对草莓白粉病有明显的防治效果。     

Greenhouse gas production and emission from a forest nursery soil following fumigation with chloropicrin and methyl isothiocyanate

Soil fumigation is commonly used to control soil-borne pathogens and weeds. Our aim was to examine the effects of soil fumigation with chloropicrin (CP) and methyl isothiocyanate (MITC) on CH₄, N₂O and CO₂ production and emission. These effects on a SE USA forest nursery soil were examined in field and laboratory experiments. Following field fumigation, CH₄ surface emissions and concentrations in the soil atmosphere were unaffected. Both fumigants increased N₂O emissions rates significantly compared to non-fumigated controls, and the effects were still evident after 48 d. These findings are in contrast to fertilizer-induced N₂O emissions, which generally return to background within 2 wk after application. Depths of N₂O production were different for the two fumigants as determined by soil gas sampling, suggesting fumigant-specific stimulation mechanisms. CO₂ emissions (0-15 d) were not altered significantly, although sub-surface CO₂ concentrations did increase following fumigation with CP or MITC and remained elevated for CP treatment on d 48. CP-induced N₂O production was also stimulated in aerobic laboratory incubation studies, with surface soils exhibiting 10 to 100-fold greater production rates. MITC and a combination of CP/MITC also stimulated N₂O production, but the effect was significantly less than for CP alone. MITC suppressed and CP did not effect CO₂ production in the laboratory incubation. By comparing sterilized to non-sterile soils, >95% of these effects appear to be of biotic origin.     

Ertragsleistung, Standorteignung und Qualitatseigenschaften von Sareptasenf (Brassica juncea L. Czern.)

Yield and Qualitative Characteristics of Indian Mustard ( Brassica juncea L. Czern.)
Indian mustard is required as raw material for the production of mustard. In field trials, farm trials and processing tests during several years evidence could be furnished, that the cultivation of the up to now foreign crop is possible on suitable sites in central Germany. On loess soils (soil value number more than 50) in regions with milder climatic conditions the grain yields attained in using of intensive specific cultivation methods on an average of about 30 dt/hectare. The results of the field trials confirmed by average yields of 14 16 dt/hectare in agricultural practice. The best farms attained grain yields up to 25 dt/hectare. With regard to raw material with a content of allyl mustard oil of more than 1.00 % also the demands of the food processing industry could be fulfilled by all lots produced on farms (the attained content of allyl mustard oil amounted to 1.00 1.40 %).
Climatic factors but also the observance of correct cultivation methods influence first of all the processing quality.     

A simple and effective method for linking field investigations of earthworms and water infiltration rate into soil at pedon‐scale

Earthworm density and activity may significantly contribute, amongst others, to soil physical properties such as water infiltration rate and permeability, and thus provide a desirable ecosystem service. In environmental field studies, investigations of the two soil physical properties are highly recommended. In practice, they are carried out separately in terms of time and space and, therefore, are typically closely connected. Therefore, the aim of this study was to test the feasibility of a combined investigation of earthworm population and infiltration rate in soil in field studies. The idea was to use an aqueous solution of allyl isothiocyanate (AITC) and a double‐ring cylinder for simultaneous measurements at the same pedon and, thus, without any spatio‐temporal deviation. Tap water was used as a control for the infiltration measurements with AITC. Another aim was to evaluate the plausibility of earthworm data received from those combined investigations. This was tested for some arable and grassland soils derived from various parent materials in W‐Germany differing in soil chemical and physical properties. Infiltration rates of AITC in soil were not significant different from tap water, neither for the different soils nor different land‐uses and at the different study sites. Earthworm population data revealed from AITC application with a double‐ring cylinder equipment were realistic and in line with previous investigations in the respected study area. Pearson correlation coefficient between earthworm biomass and infiltration rate of AITC was medium (R² = 0.363).     

Chemiluminescent detection of potato spindle tuber viroid in true potato seed using a digoxigenin labelled DNA probe

Summary The potential use of a simple, sensitive and non-radioactive method for detecting potato spindle tuber viroid (PSTVd) in germinated true potato seeds, based on nucleic acid hybridization with a PSTVd-specific DNA probe labelled with digoxigenin, was investigated. Two simple procedures for the clarification of plant extracts suitable for a non-radioactive detection system were also investigated. The nucleic acid hybridization technique could detect one PSTVd-infected seed in more than 150 healthy seeds. The benefits of this non-radioactive detection system are discussed.     

异硫氰酸甲酯对小麦网腥黑穗病菌杀灭效果研究

在20℃和60%温湿度条件下,分别测定了氧硫化碳、异硫氰酸甲酯(Methyl isothiocyanate,MITC)等7种新型熏蒸剂对小麦网腥黑穗病菌(Tilletia caries(DC.)Tul.,TCT)的熏蒸效果。结果表明,除MITC外,其他6种熏蒸剂均不能完全杀灭TCT病菌;MITC熏蒸120h可有效杀灭TCT病菌,其LD90、LD95、LD99、LD99.9963分别为15.438、17.046、20.530、32.414g/m3。但是,由于小麦对MITC的高吸附性导致熏蒸剂空间浓度过低,使得有载物熏蒸试验中投药50、100g/m3MITC均未能有效杀灭小麦中的TCT病菌。残留检测结果表明,散气16d后小麦中MITC残留量分别降至0.29、1.07mg/kg,残留较高。结论:MITC对TCT有很好的杀灭效果,但由于小麦对MITC的吸附性很强,需进一步研究熏蒸方式,方可实际应用。     

山药叶片总RNA提取方法的比较

[目的]提取高质量的山药叶片总RNA。[方法]以山药叶片为材料,采用异硫氰酸胍法、改良CTAB法提取山药叶片总RNA并进行比较分析,利用琼脂糖凝胶电泳分析所提RNA的完整性,并用紫外分光光度计分析RNA的纯度。[结果]改良CTAB法提取的总RNA的28S、18SrRNA条带清晰、整齐,测得A260/A280为1.72.0。[结论]改良的CTAB法适合山药叶片总RNA提取。