电子束辐照对素鸡杀菌效果及品质特性影响的研究

以素鸡为试验对象,研究电子束辐照对素鸡杀菌效果及其营养品质和感官品质的影响。结果表明,电子束辐照对素鸡的杀菌效果显著,D10=0．48kGy;8．8kGy以下电子束辐照对素鸡蛋白质、脂肪、脂肪酸、氨基酸的影响在5％水平上差异不显著,在水分含量方面差异显著;经8．8kGy电子束辐照处理的素鸡与对照素鸡相比,其感官品质未呈现显著差异。综合考虑,2．4kGy电子束辐照处理可以有效控制素鸡中的细菌而不影响其营养和感官品质,其货架期可达8d;电子束辐照素鸡的最高耐受剂量至少为8．8kGy。     

辐照处理对鲜切圆生菜减菌效果及品质的影响

本研究将60Co-γ辐照技术引入到圆生菜的鲜切加工过程,研究不同剂量辐照对圆生菜减菌效果及其营养和感官品质的影响,以达到延长鲜切圆生菜贮藏期的目的.结果表明:辐照对鲜切圆生菜具有显著的减菌效果.辐照剂量≥0.68 kGy的处理对圆生菜细菌、大肠菌群、霉菌和酵母均有显著的杀灭效果.辐照剂量≤2.32kGy的处理,圆生菜的失重率、可溶性固形物含量、亚硝酸盐含量在5％水平上无显著影响;对圆生菜在贮藏期间Vc含量的下降起延缓作用,对其色泽、气味、质地和滋味、组织状态等感官方面总体可接受性没有显著影响.因此,0.68 ～ 2.32kGy剂量范围内的辐照可有效控制鲜切圆生菜中的微生物而不影响其食用和感官品质,货架期可达6d.本文探索了辐照保鲜在鲜切菜生产加工过程中的可行性,为以后的研究提供了一定的科学依据.     

高能电子束辐照对鲜切哈密瓜生理生化品质的影响

通过0．5、1．0、1．5和2．0kGy剂量的电子柬辐照处理鲜切哈密瓜,采用聚丙烯（PP）材质托盘和聚乙烯（PE）保鲜膜包装,置于5℃,相对湿度85％-95％的冷库中贮藏,研究高能电子束辐照对鲜切哈密瓜生理生化品质的影响。结果表明,电子束辐照能显著降低呼吸速率,显著抑制Vc、可溶性固形物的含量的下降,减少丙二醛积累,降低多酚氧化酶和过氧化物酶活性,并提高苯丙氨酸解氨酶活性。1．5kGv辐照处理的鲜切哈密瓜在贮藏至第13天时,感官品质保持良好。综合电子束辐照对鲜切哈密瓜的保鲜效果,确定最佳处理剂量为1．5kGy。     

芹菜花生冷食菜的辐照杀菌研究

研究了芹菜花生冷食菜的辐照杀菌效果和接种于其中的致病菌(Listeria innocua L83和Salmonellaenteritidis500041)的辐照效应,以及辐照处理对芹菜花生冷食菜营养品质和感官品质的影响。结果表明,2kGy辐照处理能有效降低冷食菜中微生物的含量,辐照接种于其中的沙门氏菌和李斯特菌的D10值分别为0.284和0.296 kGy,2.0kGy以下的辐照剂量对其感官品质和蛋白质的营养品质没有明显的影响。2.0kGy剂量能使冷食菜中的微生物降低10-2~10-3,使接种于其中的致病菌降低10-6以上,能有效地提高芹菜花生冷食菜的卫生安全。     

辐照杀菌对核桃粉品质的影响

研究了60Co γ辐照杀菌对核桃粉主要营养成分变化及感官品质的影响。结果表明：剂量为2.0～8.0kGy时,辐照对核桃粉中的总糖、粗蛋白和粗脂肪含量无显著影响;辐照后的粗纤维含量有一定的增加,但不显著;辐照对核桃粉中的月桂酸和肉豆蔻酸含量基本没有影响,对棕榈酸、棕榈油酸、硬脂酸、亚油酸、花生酸和亚麻酸含量有一定的影响,但不显著;辐照后核桃粉中的油酸含量随辐照剂量的上升而显著增加,剂量达到8.0kGy时,油酸含量增加了4.3%。8.0kGy以下辐照对核桃粉色泽、气味、口感无明显改变。可以得出结论低于8.0kGy的辐照不会对核桃粉的营养品质和感官品质有不良影响。     

蛋清粉辐照杀菌研究

本文研究了60 Co-γ射线辐照蛋清粉的杀菌效果、对蛋清粉的主要营养成分及感官品质的影响.结果表明,经4kGy辐照的蛋清粉样品中微生物指标达到食品卫生国家标准,8kGy辐照杀菌率达到95％以上.与对照相比,剂量为4～10kGy的辐照对蛋清粉中蛋白质、粗纤维、氨基酸含量的影响不明显,6kGy以下剂量辐照对蛋清粉色泽、气味等感官品质无明显改变.综合试验结果,确定了蛋清粉辐照杀菌的适宜工艺剂量范围为4 ～6kGy.     

盒装豆腐辐照杀菌的研究

研究了接种于盒装豆腐中致病菌（Listeria innocua L83和Salmonella）的辐照效应和盒装豆腐的辐照杀菌效果,以及辐照对包装豆腐的营养品质和感官品质的影响。结果表明,接种于盒装豆腐中的李斯特氏菌和沙门氏菌的D10值分别为0.225和0.240 kGy,2.0 kGy以下的剂量辐照能有效降低盒装豆腐中微生物的含量,提高豆腐的食用安全。该剂量辐照处理的盒装豆腐的感官品质能为人们所接受,蛋白质等营养品质没有明显的影响。     

辐照对发酵甘薯保鲜效果和功能活性的影响

采用0、2、4和6kGy剂量辐照甘薯茎尖,研究辐照对发酵甘薯茎尖感官品质、理化性质、微生物指标以及功能活性的影响。结果表明,经2和4kGy辐照后,发酵甘薯茎尖的感官品质变化不显著,6kGy辐照后则显著劣变。4kGy辐照后,发酵甘薯茎尖中游离氨基酸总量无显著变化;6kGy辐照后,其游离氨基酸总量显著上升。2、4和6kGy...     

电子束辐照对美国红鱼杀菌保鲜效果的研究

以美国红鱼为对象,利用不同剂量电子束处理,对冷藏期内鱼肉菌落总数、总挥发性盐基氮（TVB-N）、过氧化值（POV）及鲜度指标K值进行测定,分析不同剂量电子束辐照对美国红鱼肉的杀菌效果及品质影响。结果表明：电子束辐照能有效降低美国红鱼肉的菌落总数,其中D10=161kGy,D=540kGy,冷藏期间辐照组样品菌落生长缓慢,且辐照剂量越大,杀菌效果越强;电子束处理后美国红鱼肉TVB-N值、POV均有不同程度增加,但在冷藏期内对照组TVB-N值、POV、K值的上升速度大于辐照组样品;辐照对美国红鱼肉感官影响不明显,但6kGy辐照组鱼肉色泽略微变红。综合考虑,美国红鱼肉经4kGy 电子束辐照,能有效杀灭其中的微生物,冷藏条件下保质期可达到14d,比对照延长5d左右。     

辐照对泡椒凤爪感官品质的影响

辐照可以有效的控制泡椒凤爪中的乳酸菌含量,从而延长其货架期。本文根据相关的标准和调研,以色泽及形态（权重30%）、香气（权重30%）、质地及滋味（权重40%）为评价指标,制定了泡椒凤爪的感官分析标准,并用此标准对辐照处理后的泡椒凤爪进行了感官品质分析。结果表明贮藏3d后的3、5、8、12kGy辐照的样品,其感官评价结果与对照相比无显著差异,辐照剂量为10 kGy的样品感官评价结果还显著优于对照组。贮藏11d后,样品的感官品质也未降低。由此得出结论：辐照不会影响泡椒凤爪的感官品质,适当剂量的辐照还有助于提高泡椒凤爪的被接受程度。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.     

细菌、真菌及植物氮营养信号研究进展

氮素吸收代谢是所有生物生命活动的核心部分,因此,各种生物对氮的吸收与同化过程都有精细的调节。这种调节依赖于生物对体内氮素状况信号及体外（生长介质中）氮素信号的感受。过去几十年中,在细菌、真菌中已经对氮素营养信号有了较好的研究,而植物中则相对缓慢,但也有了一定的认识。本文重点比较细菌、真菌及植物中氮信号系统的组成,以期为进一步认识植物中的氮信号接受与转导系统提供启示。     

Aircraft operations near concentrations of birds in Antarctica: The development of practical guidelines

Aircraft operations have the potential to disturb and to impact negatively on bird life. A gradient of increasing behavioural response is evident in birds when exposed to increasing aircraft stimulus. The most major disturbance is likely to lead to impacts on the health, breeding performance and survival of individual birds, and perhaps bird colonies. A process of revision to policies on aircraft operations contained in management plans for a number of specially protected areas in Antarctica by the United Kingdom, accompanied by consultations made within the scientific community through the Scientific Committee on Antarctic Research (SCAR) and with operational interests through the Council of Managers of National Antarctic Programmes (COMNAP) resulted in new guidelines being adopted by the Antarctic Treaty Consultative Parties in June 2004. The principal recommendations of the guidelines are that bird colonies should not be overflown below 2000 ft (∼610 m) above ground level and landings within 1/2 nautical mile (∼930 m) of bird colonies should be avoided wherever possible. These guidelines are less stringent and less specific than those that were recommended by the SCAR specialist group on birds, and represent a compromise to accommodate operational needs. While the adoption of clear and consistent guidelines for the operation of aircraft in Antarctica is welcome in that this provides practical advice that is likely to reduce incidences of close aircraft/bird encounters, there remains insufficient knowledge of the interactions between aircraft and birds in Antarctica, and the consequent impacts on individual birds and on bird populations. It is important, therefore, that the guidelines adopted are considered interim, and should be kept under scrutiny with revisions made as new and improved research results appear.     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.