气雾剂对肉鸡大肠杆菌感染的保护作用

本研究开展了3个试验探讨气雾噬菌体对感染大肠杆菌肉鸡的保护作用。3个试验均包含9个处理组,每组3个重复,每个重复10只鸡。9个处理组中有3个未感染大肠杆菌组,其中1组不做任何处理,另外2组喷雾PBS或噬菌体气雾剂,其余6个组分别在第7、8和10天感染大肠杆菌,并分别进行PBS喷雾或噬菌体气雾剂。致病性大肠杆菌噬菌体是从城市污水处理设施或家禽加工厂分离出来的。试验1:与对照组相比,第7天感染大肠杆菌接受噬菌体喷雾的肉鸡在第1周体重显著降低(P<0.05),与对照组相比,第7天感染大肠杆菌接受PBS喷雾、第8天感染大肠杆菌接受噬菌体喷雾的3周龄肉鸡体重显著降低(P<0.05)。感染大肠杆菌的肉鸡死亡率均显著高于未感染组(P<0.05)。试验2:感染大肠杆菌的肉鸡在第2周的体重均显著低于未感染组(P<0.05),除了第8天感染大肠杆菌的肉鸡,其他感染组均较未感染组显著降低了第3周体重(P<0.05)。第10天感染大肠杆菌的肉鸡接受噬菌体喷雾较接受PBS喷雾显著降低了死亡率(P<0.05)。试验3:第10天感染大肠杆菌的肉鸡接受噬菌体喷雾较对照组显著提高了第1周龄的体重(P<0.05),接受噬菌体喷雾但未感染大肠杆菌的肉鸡死亡率较对照组以及接受PBS喷雾组显著降低(P<0.05)。本试验结果显示,通过气喷噬菌体对保护肉鸡呼吸道感染大肠杆菌具有重要作用,使用孵化场和家禽舍内的现有设备,在气溶胶喷雾剂中使用噬菌体可适用于家禽养殖业,并可替代抗生素控制家禽细菌性疾病。     

Effects of five vegetable oils on the sweetpotato whiteflyBemisia tabaci

The effects of five economically important vegetable (seed) oils, peanut, cottonseed, castor, soybean and sunflower, on adult and immature stages of the sweetpotato whitefly(Bemisia tabaci (Gennadius) [Hemiptera: Aleyrodidae]) were studied in the laboratory. Irrespective of origin, oil residues had similar effects on immature stages and adult mortality, and on settling and oviposition deterrence. Trends for 5-h settling, 24-h oviposition and 24-h survival of adults on treated plants were similar for oils applied at the same concentration range. Settling deterrence was strong enough to cause adult death due to starvation or dehydration under no-choice conditions, and caused greater mortality than direct physical toxicity; similar results were obtained when adult survival on oil residues was compared to survival of starved adults. Adults recovered when transferred from oil-treated to untreated plants. All oils produced similar effects when sprayed on immatures; the egg and fourth instar (pupa) were the most tolerant stages. The oil concentration required for significant effects on whitefly mortality and behavior was relatively high (>0.3%) compared with published efficacy data for synthetic pesticides, and varied to some extent with oil origin. All tested oils were active as direct and residual larvicides. Peanut oil was the most effective for all tested effects, followed by cottonseed oil, which was significantly less effective than peanut and castor oils when applied-directly to eggs. Only by this latter parameter was castor oil more effective than cottonseed oil and similar to peanut oil. As direct sprays to larvae, soybean and sunflower oils resembled castor oils, but their residues were less effective against all stages.     

靶向硫酸庆大霉素的制备及体外抗菌试验

将硫酸庆大霉素与抗大肠埃希菌抗体用化学修饰剂进行偶联,再经化学方法处理,按制剂学原理制备成靶向硫酸庆大霉素。用硫酸庆大霉素做对照,进行体外抗菌试验,检测靶向硫酸庆大霉素对大肠埃希菌的抗菌效果。结果表明,靶向硫酸庆大霉素的最低抑菌浓度(MIC)为0.02μg/mL,硫酸庆大霉素的最低抑菌浓度(MIC)为0.4μg/mL,靶向硫酸庆大霉素的抑菌效果明显优于硫酸庆大霉素。     

Seasonal variation and low-cost agronomic practices effect growth and yield of moth bean (Vigna aconitifolia) in the extreme arid Thar desert

An experiment was laid out at Jaisalmer for three consecutive rainy seasons (2007 to 2009) to evaluate the effect of season and the efficacy of low-cost agronomic practices on the performance of moth bean (Vigna aconitifolia L.) in the extreme arid Indian Thar. Skip row planting (skipping every third row) significantly improved pods and seed weight per plant, and consequently seed yield, over normal planting. Total readily available water and moisture availability at critical growth stages of the crop significantly influenced plant attributes and thus biological and seed yield. Relative leaf water content (RWC) at sunrise in the pre- and post-flowering stages remained above the moisture stress level. However, at midday, plants experienced moderate stress in RWC during pre-flowering and severe stress during the post-flowering stages. Foliar application of 1% urea was found to be effective only when midday RWC is more than the critical threshold value of 84%. Therefore, foliar application of 1% urea at the pre-flowering stage significantly increased almost all plant attributes and yields, whereas second foliar application at post-flowering stage when midday RWC was <84% has no impact on plant attributes and yield.     

Inducing Salt Tolerance in Wheat by Exogenously Applied Ascorbic Acid through Different Modes

ABSTRACT

In order to assess whether exogenous application of ascorbic acid (AsA) through different ways could alleviate the adverse effects of salt-induced adverse effects on two wheat cultivars differing in salinity tolerance, plants of a salt tolerant (‘S-24’) and a moderately salt sensitive (‘MH-97’) cultivar were grown at 0 or 120 mM sodium chloride (NaCl). Ascorbic acid (100 mg L^?1) was applied through the rooting medium, or as seed soaking or as foliar spray to non-stressed and salt stressed plants of wheat. Salt stress-induced reduction in growth was ameliorated by exogenous application of ascorbic acid through different ways. However, root applied AsA caused more growth enhancement under saline conditions. Leaf ascorbic acid, catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities were also maximal in salt stressed plants of both cultivars treated with AsA through the rooting medium. Furthermore, leaf ascorbic acid, CAT, POD, and SOD activities were higher in salt stressed plants of ‘S-24’ than those of ‘MH-97’. Root applied AsA caused more enhancements in photosynthetic rate. Root applied AsA caused more reduction in leaf sodium (Na⁺) compared with AsA applied as a seed soaking or foliar spray. Overall, AsA-induced growth improvement in these two wheat cultivars under saline conditions was cultivar specific and seemed to be associated with higher endogenous AsA, which triggered the antioxidant system and enhanced photosynthetic capacity.     

EFFECT OF AUTUMN CALCIUM SPRAY AT A HIGH RATE ON ‘GRANNY SMITH’ APPLE QUALITY AND STORABILITY

The aim of the study was to examine effect of autumn calcium (Ca) spray at a high rate on apple quality and storability. The investigation was carried out during 2005–2006 in Isparta district, Turkey, under semi-arid conditions, on mature ‘Granny Smith’ apple trees/M.9 EMLA, planted at a spacing of 3.5 × 1.5 m on fine-textured soil rich in Ca. The trees were sprayed with Ca in summer and/or in autumn, using organically complexed Ca to avoid possible leaf and fruit injuries. In autumn (10 days before harvest), the trees were sprayed with Ca at a rate of 8 kg ha^?1. In summer, the another trees were sprayed with Ca six times at a rate of 1.5 kg ha^?1 in each measure; the first spray treatment was performed 6 weeks after full bloom, and the others at 7–9 day intervals. The third part of the trees was sprayed with Ca in summer as well as in autumn, at the same terms and rates as given above. Trees unsprayed with Ca served as the control. It was found that Ca sprays in autumn or in summer plus in autumn damaged leaves; however those treatments did not caused defoliation. Calcium sprays had no effect on apple yield, mean fruit weight, fruit skin russeting, and firmness, soluble solids concentration and titratable acidity of fruit at harvest. Fruit flesh Ca concentrations of the control trees were high. However, the highest fruit Ca concentration was recorded on the trees sprayed with Ca in summer plus in autumn. Calcium sprays in summer or in autumn increased fruit Ca concentrations but their effects were weaker than summer plus autumn Ca applications. After 100 days of refrigerated air storage, soluble solids concentration of fruit did not differ between the studied combinations. Only apples sprayed with Ca in summer plus in autumn were firmer and contained more organic acids than the control fruit. During storage, there were neither pathogenic diseases nor physiological disorders. Based on the obtained results we conclude that Ca sprays in summer plus in autumn at high rate can prolong ‘Granny Smith’ apple storage even thought initial fruit Ca concentration is as high as 502–504 mg Ca kg^?1 DW or 84.1–84.8 mg Ca kg^?1 FW.     

Urea retention and uptake by avocado and apple leaves

Solution retention by avocado (Persea americana cv. Fuerte) and apple (Mallus domestica Burkh. cv. Anna) leaves was measured by weight gain of detached leaves after dipping them in solutions of two surfactants and by analysis of various concentrations of urea retained at zero time on surfaces of attached leaves. Linear regression equations were calulated, relating leaf area and retention of solution. The slope of the equation represents the retention of solution on the leaf surface, and its intercept represents the value retained on the leaf margin. Solution retained on leaf surface was 2.5–2.6 and 5.4–6.4 mg/cm² for ‘old’ avocado and apple leaves, respectively. Retention on the serrated leaf margin of the apple was greater than on the smooth margin of the avocado. The abaxial leaf surfaces retained approximately 62% and 83% of the total solution retained by the avocado and the apple leaves, respectively.

The rate of urea uptake was proportional to the applied concentration and reached in avocado 65–85% within 2–5 days and over 90% in apple within 2 days. The rate of urea uptake by avocado was similar on ‘Young’ and ‘old’ leaves, similar from either Triton X‐100 or L‐77 surfactants, and similar through abaxial and adaxial surfaces. The nitrogen enrichment from foliar application of urea was related to retention and threshold of phytotoxicity rather than to rate of uptake. Older leaves of avocado showed some phytoxicity to 4% urea. Young leaves were damaged by repeated 2% application and flowers by 0.5–1.0%.

The actual nitrogen enrichment in avocado, which could be predicted accurately from measurement of urea retention, was 43% following three successive applications of 3% urea in 12 days.     

可吸尘风压喷雾擦洗机

设计了一种可吸尘风压喷雾擦洗机，它含有携带风叶组和滤尘器的永磁式直流电动机，超声波发生器上方设贮水箱，贮水箱的顶部是压力喷雾腔，贮水箱与压力喷雾腔之间设水雾过滤网，携带风叶组和滤尘器的永磁式直流电动机出风口连接过渡送风道一端，过渡送风道另一端连接压力喷雾腔一端，压力喷雾腔外壁连接框架。框架上装内置减速器的电动机。电动机转轴的端部连接电动擦洗盘。本机实用新型，集冲洗、擦净和吸尘三种功能为一体．具有便于携带、节水、重量轻、体积小巧、制造成本低、使用成本低、使用安全可靠、可直接使用车上蓄电池的电源等特点。