Human disturbance and nesting success of Common Eiders: interaction between visitors and gulls

Common Eider colonies often are subjected to human visitors, such as down collectors, recreationists and researchers. However, the effects of frequency and timing of disturbance, and the abundance of nearby avian predators on eider nesting success have been studied only partly. We used three experimental treatments and six eider colonies over 3 years (1993-1995) to test the effects of these factors on eider nesting success, while controlling results for associated gull nest density. Treatments consisted of (1) high frequency visits (once every 3 days) starting early in the incubation period (HFE), (2) low frequency visits (once every 15 days) starting early in the incubation period (LFE), and (3) high frequency visits starting late in the incubation period (HFL). Analysis of covariance indicated that both disturbance treatments and associated gull nest density had a significant effect on eider nesting success probability. Nesting success probabilities were similar for eiders under HFE and LFE treatments (means=0.317±0.166 [SE] and 0.434±0.172 respectively), indicating that changes in frequency of visits had little impact on nesting success. In contrast, timing of visits had a major influence on nesting success, as the HFL treatment resulted in a significant higher nesting success probability (mean=0.981±0.191) than the HFE treatment. Most nest failures occurred after the first visit in all treatments, although the impact of the first visit was lowest in the HFL treatment. Researchers and wildlife managers should visit eider colonies as late as possible, and avoid visiting colonies associated with high densities of eider egg predators.     

生姜茎尖组织培养和污染率控制的研究

以生姜茎尖为外植体,筛选了愈伤组织和芽分化的最适培养基和培养方式,并探讨了生姜组织培养过程中污染率的控制方法.试验结果表明,将表面消毒与抗生素浸泡处理相结合,能有效降低污染率.培养基MS 6-BA 1 mg/L IAA 1 mg/L是愈伤组织诱导与芽分化的最适培养基.     

Conservation of natural enemies in cotton: comparative selectivity of acetamiprid in the management of Bemisia tabaci

The integrated control concept emphasizes the importance of both chemical and biological control for pest suppression in agricultural systems. A two-year field study was conducted to evaluate the selectivity of acetamiprid for the control of Bemisia tabaci (Gennadius) in cotton compared with a proven selective regime based on the insect growth regulators (IGRs) pyriproxyfen and buprofezin. Acetamiprid was highly effective in controlling all stages of B tabaci compared with an untreated control, and generally produced lower pest densities than the IGR regime. Univariate analyses indicated that nine of 17 taxa of arthropod predators were significantly depressed with the use of acetamiprid compared with an untreated control, including common species such as Geocoris punctipes (Say), Orius tristicolor (White), Chrysoperla carnea Stephens sensu lato, Collops vittatus (Say), Hippodamia convergens Guérin-Méneville, and Drapetis nr divergens. Compared with results from independent, concurrent studies using mixtures of broad-spectrum insecticides at the same research site, acetamiprid depressed populations of fewer predator taxa; but, for eight predator taxa significantly affected by both regimes, the average population reduction was roughly equal. In contrast, only four taxa were significantly reduced in the IGR regime compared with the untreated control and three of these were omnivores that function primarily as plant pests. Principal response curves analyses (a time-dependent, multivariate ordination method) confirmed these patterns of population change for the entire predator community. Predator:prey ratios generally increased with the use of both IGRs and acetamiprid compared with an untreated control, but ratios were consistently higher with IGRs. Parasitism by aphelinid parasitoids was unaffected or depressed slightly in all insecticide regimes compared with the control. Because of its high efficacy, acetamiprid may play an important role in later stages of B tabaci control where less emphasis is placed on selectivity. However, our results suggest that acetamiprid would be a poor substitute for the currently used IGRs in the initial stage of control where insecticide selectivity is crucial to a functional integrated control program for B tabaci in cotton.     

A Survey (1992–1996) of natural enemies of diaspididae species in Antalya, Turkey

Natural enemies associated with armoured scale insects were surveyed in Antalya province during the years 1992-1996. The surveys yielded 16 species of predators and 11 species of parasitoids associated with 11 species of scale insects. One predator species—Lestodiplosisaonidiellae Harris, one hyperparasite species—Ablerusperspeciosus Girault, and one parasitoid species—Coccophagoidesmoeris (Walker), are recorded for the first time in Turkey. Three coleopterans, namely,Chilocorus bipustulatus (Linnaeus),Cybocephalus fodori- minor Endrödy-Younga andRhyzobius lophanthae (Blaisdell), were found to be the most common predators and to be associated with the diverse species of diaspidids in Antalya and are known so also in other parts of Turkey. Among the parasitoids found,Aphytis chrysomphali (Mercet) andAphytis melinus DeBach are known to be relatively important onAonidiella aurantii (Maskell),Aphytis maculicornis (Masi) onParlatoria oleae (Colvée),Aphytis mytilaspidis (LeBaron) onLepidosaphes ulmi (Linnaeus), andEncarsia berlesei (Howard) onPseudaulacaspis pentagona (Targioni Tozzetti), in Antalya and/or other parts of Turkey.     

甘薯茎尖营养成分分析及评价

对7个不同品种的甘薯茎尖进行了营养成分和微量元素的测定,并且与常见蔬菜进行了对比。结果表明,甘薯茎尖的营养成分齐全,除总糖含量较低外,其它成分含量均较常见蔬菜要高;微量元素含量绝大多数比常见蔬菜含量要高,尤其是Mg、Mn、Fe和Zn,这为甘薯茎尖的菜用价值提供了科学依据。     

Comparing the impact of conventional pesticide and use of a transgenic pest-resistant crop on the beneficial carabid beetle Pterostichus melanarius

The potential impact of a chemical pesticide control method has been compared with that of transgenic plants expressing a protease inhibitor conferring insect resistance by utilising a tritrophic system comprising the crop plant Brassica napus (L.) (Oilseed rape), the pest mollusc Deroceras reticulatum (Müller) and the predatory carabid beetle Pterostichus melanarius (Illiger). Cypermethrin, as the most widely used pesticide in UK oilseed rape (OSR) cultivation, was selected as the conventional treatment. OSR expressing a cysteine protease inhibitor, oryzacystatin-1 (OC-1), was the transgenic comparator. In feeding trials, D. reticulatum showed no significant long-term effects on measured life history parameters (survival, weight gain, food consumption) as a result of exposure to either the cypermethrin or OC-1 treatment. However, D. reticulatum was able to respond to the presence of the dietary inhibitor by producing two novel proteases following exposure to OC-1-expressing OSR. Similarly, P. melanarius showed no detectable alterations in mortality, weight gain or food consumption when feeding on D. reticulatum previously fed either pesticide-contaminated or GM plant material. Furthermore, as with the slug, a novel form of protease, approximately M(r) 27 kDa, was induced in the carabid in response to feeding on slugs fed OC-1-expressing OSR.     

马铃薯茎尖脱毒培养关键因子分析

对马铃薯茎尖脱毒培养关键因子方面进行了分析,综合论述了马铃薯茎尖培养脱毒的原理,影响马铃薯茎尖培养脱毒的因素和培养条件的控制,并针对脱毒难的问题提出了提高脱毒率诸如结合化学处理等的有效措施,指出了茎尖培养脱毒中尚存在的一些问题以及相应对策。     

切花葱的再生

切花葱种球价格昂贵,目前通常一个种球的市场售价在20~38元之间。为了建立切花葱高效再生体系,以Lucy Ball和His Excellency两个切花葱品种为试验材料,研究了灭菌时间及灭菌剂浓度、外植体的选择、不同激素配比等因素对切花葱再生的影响。结果表明,最佳的灭菌方法为4%次氯酸钠处理20 min,污染率仅为18.2%,利用率达到了81.8%;最佳外植体为幼叶尖端,平均诱导率为92.6%;诱导不定芽直接再生效果最好的培养基为MS+NAA 1.0 mg/L+6-BA 0.2 mg/L,两个切花葱品种的诱导率分别为His Excellency85.71%,Lucy Ball 90.00%;最佳的生根培养基为1/2MS+0.2 mg/L NAA+0.2 mg/L IBA,生根率为41.67%。通过该方法即可利用切花葱幼叶尖端经直接再生途径诱导出新植株。     

贯叶连翘的离体培养与四倍体诱导

以贯叶连翘种子发芽后的无菌苗为外植体,进行了贯叶连翘的组织培养与四倍体诱导研究。结果表明,贯叶连翘的子叶和下胚轴具有较高的愈伤组织诱导率,在2,4-D 1.0 mg/L或NAA 0.5 mg/L配合6-BA0.5 mg/L使用,并添加500 mg/L CH时能提高愈伤组织诱导率,并提高愈伤的质量;分化培养基中添加6-BA0.5~1.0 mg/L和NAA0.05~0.1 mg/L的效果最好;培养基中添加0.5 mg/L 6-BA与500~800 mg/L CH能使丛生苗快速增殖,并生长粗壮,叶色浓绿;采用0.3%秋水仙碱溶液浸泡茎尖24 h,效果最佳,存活率28%,四倍体诱导率为6%。