促进4种野生花卉种子萌发的方法研究

野生花卉金莲花(Trollius chinensis)、牛扁(Aconitum barbatum vat.puberulum)、野罂粟(Papaver naudicaule)和草本威灵仙(Veronicastrum sibiricum)发芽率低,采用不同的温度、赤霉索浓度和光周期组合处理,明显提高了这些花卉种子的发芽率和发芽势,加快种子萌发进程.结果表明:(1)采用500 ms/L GA3,25℃和8 h光照16 h黑暗组合处理,可以使金莲花种子发芽率由对照的4%提高到84%;(2)采用500 ms/L GA3,15℃、12 h光照12 h黑暗组合处理,可以使牛扁种子萌发率由对照的20%提高到82.4%;使草本威灵仙种子发芽率由对照的17.3%提高到100%.(3)采用125mg/L GA3,15℃,24 h光照萌组合处理,可以使野罂粟种子萌发率由对照的29.3%提高到61.3%.     

Control of fungal pathogens — preharvest Use of coniothyrium minitans and pythium oligandrum as disease biocontrol agents

When disease levels are low,Coniothyrium minitans gives biological control of Sclerotinia disease in lettuce andPythium oligandrum control of damping-off in cress and sugar beet equivalent to standard fungicide treatments, but both fail as the inoculum potential of the pathogens increases. Possible approaches for improving the use and efficacy of these biocontrol agents are discussed.     

Suppression of development of Callosobruchus maculatus (F.) (Col.: Bruchidae) in bambara groundnut seeds exposed to solar heat in the Nigerian savanna

The effect of solarization on the development of Callosobruchus maculatus was investigated in the Nigerian savanna during the hot season from April to May, 1999. Development of C. maculatus adult progeny was completely suppressed in seeds of bambara groundnut, Vigna subterranea bearing bruchid eggs or harbouring first and second instar larvae that were exposed to the sun in metal tins, clay pots or polypropylene sacks for 7, 14 or 28 h. Adults of C. maculatus developed only in seeds that were not exposed to sun. Solarization did not have a significant adverse effect on germinability of bambara groundnut seeds.     

Effect of mitochondrial ATP sensitive potassium channels opening on translocation of protein kinase C epsilon in cultured adult rat ventricular myocytes

AIM: To investigate the effects of mitochondrial ATP sensitive potassium (MitoKATP) channel opening on translocation of protein kinase C epsilon (PKCε) and the relationship between the translocation of PKCε and the production of reactive oxygen species. METHODS: The expression of PKCε in cultured adult rat ventricular myocytes was investigated with immunofluorescence and Western blotting techniques. RESULTS: （1） Diazoxide, a selective MitoKATP channel opener, caused a significant translocation to myofibrillar-like structures in cultured adult rat ventricular myocytes. (2) The N-2-mercaptopropionylglycine (MPG), a free radical scavenger, partly inhibited the translocation of PKCε caused by diazoxide. (3) Chelerythrine, a selective protein kinase C (PKC) inhibitor, completely blocked the translocation of PKCε caused by diazoxide. CONCLUSION: Opening of MitoKATP channel might activate PKCε and make it translocation to myofibrillar-like structures. PKCε activation occurs downstream of MitoKATP channel, and might be caused by production of reactive oxygen species after opening of MitoKATP channel.     

Keyword Index to Volume 10 (2002)

Other Index

Keyword Index to Volume 10 (2002)     

Meteorus rubens—Steinernema carpocapsae interaction, field studies

The entomogenous nematode,Steinernema carpocapsae was applied in three forms in two fields cultivated with cotton and tomato, under each cotton seedling or tomato plant: a bait like form, a suspension and in irrigation water. High concentrations of 2000 and 1000 IJS/seedling induced 100% mortality (after 5 days), while lower concentrations showed the same result but after 15 days or later. Under all doses of nematode, bait form application was more effective than suspension or irrigated water.     

Isotope-dilution technique for determination of endogenous faecal excretion and true absorption of iodine in 125I labelled rats

Introduction In studies on the quantitative mineral metabolism the separation of total faecal mineral excretion into the fraction of dietary and of endogenous origin is often a methodical barrier. Both components cannot be distinguished by standard chemical procedures. But their separation is essential to the quantification of the mineral flux from the diet into the organism and back from tissues into the faecal excretion as it is necessary for example to quantify the bioavailability of dietary mineral sources (K irchgessner et al. 1993). For this purpose, the use of isotopes is an appropriate means. During the last decades, several techniques employing radioactive or stable isotopes have been developed, e.g. the ‘comparative balance method’, the ‘dual tracer’ or ‘double isotope’ technique, methods based on computerized ‘compartment analysis’ and the ‘isotope-dilution technique’ (e.g. A ubert et al. 1963; T hompson 1965; B elshaw et al. 1974; G ibson et al. 1988). Among these methods, the isotope-dilution technique, in particular, comprises direct and quantitative measurements of mineral fluxes and provides robust estimates of endogenous faecal excretions as has been shown for a series of macrominerals and trace elements (W eigand and K irchgessner 1976a,b; W eigand et al. 1986a,b; K reuzer and K irchgessner 1991; R euber et al. 1993; K irchgessner et al. 1994; W indisch and K irchgessner 1994; W indisch et al. 1997; G abler et al. 1997). For iodine however, there is no appropriate isotope method available. Therefore, the present experiment was designed to establish the isotope-dilution technique for iodine. The isotope-dilution technique is based on a single parenteral injection or a long-term oral administration of the tracer (W indisch and K irchgessner 1994). After the labelling procedure, all tracer that appears in the faeces is of endogenous origin. The calculation from the quantity of tracer recovered in the faeces to the total amount of endogenous faecal excretion of the respective element is performed by the use of a reference tissue from which the endogenous excretion originates or which is at least in very close physiological relationship to the endogenous excretion. Using ¹²⁵I as tracer the total amount of endogenous faecal iodine is calculated as follows: Endogenous faecal iodine (ng/day) = A_faeces/SA_{reference tissue}A_faeces = ¹²⁵I activity in the faeces (Bq/day)SA_{reference tissue} = specific ¹²⁵I activity of the reference tissue (Bq ¹²⁵I per ng of total iodine)True absorption of dietary iodine (ng/day) = Iodine intake – iodine in faeces (total – endogenous)In total, the present methodological study had to focus on two major aspects. Since the administered tracer needs time to reach steady-state kinetics within the excretory pool of iodine it was to be clarified at first, from which day after a single ¹²⁵I administration does the faecal ¹²⁵I excretion correctly represent the total endogenous excretion quantitatively. Secondly, it had to be clarified which tissue or body fluid may be used as a proper reference source to quantify the endogenous faecal excretion and thus to calculate true absorption of iodine.