苯乙锡·铜对稻田水绵的防除效果

田间试验结果表明:苯乙锡·铜对稻田水绵有优良防除效果,具有药效持久、稳定、对稻苗安全、施用简便、增产明显等特点,可作为推荐药剂与硫酸铜轮换使用.施药方法为,以20%苯乙锡·铜WP 100～150 g/667m2于水绵盛发初期对水45 kg喷雾.     

哈斯油梨贮藏保鲜技术研究

用0.1%施保功和热处理哈斯油梨进行贮藏防腐。结果表明,50℃、0.1%施保功浸泡5分钟对哈斯油梨的防腐效果最好,商品果率可达100%。11℃贮藏,哈斯油梨无冷害,缓慢后熟,但易发生病害;7℃贮藏发生轻微冷害和病害,3℃贮藏发生明显冷害,果肉褐变,不能正常后熟。50℃热水处理5分钟能减轻3℃贮藏冷害,但热水处理15分钟以及热空气处理12小时、24小时、36小时均不能减轻3℃贮藏冷害症状,甚至加剧冷害。     

Host suitability of three avocado cultivars (Persea americana Miller: Lauraceae) to oriental fruit fly (Bactrocera (invadens) dorsalis (Hendel) (Diptera: Tephritidae))

The oriental (invasive) fruit fly Bactrocera (invadens) dorsalis (Hendel) (Diptera: Tephritidae) has invaded Africa and is currently established in over 30 countries and has caused in massive fruit losses. Avocado (Persea americana Miller) is among the fruit with which the pest is associated. The aim of the study was to determine the host status of a ‘black-skinned’ cultivar “Hass” and two ‘green-skinned’ cultivars “Pinkerton” and “Fuerte” to B. (invadens) dorsalis. In the laboratory study conducted in Kenya in 2012 and 2013, punctured and unpunctured recently-harvested fruit were exposed to sexually-mature fruit fly in ‘no-choice’ experiments. B. (invadens) dorsalis readily developed in the punctured fruit but not in the uncompromised fruit (fruit not damaged by insects or handling). This result was confirmed in Tanzania in 2013 where flies were introduced to unpunctured fruit. In the field studies the fruit of each cultivar were caged in situ with flies for 72 h. On dissection only fruit damaged by false codling moth (Thaumatotibia leucotreta (Meyrick)) were found to harbor B. (invadens) dorsalis. In the light of these results the risk imposed for “Hass”, “Pinkerton” and “Fuerte” by B. (invadens) dorsalis is negligible under standard export conditions. The findings of this study and the implications to regional and international trade are discussed.     

Avocado rootstock influences scion leaf mineral content

ABSTRACT

To test the influence of avocado rootstocks on the scion leaf ionome, the nutritional status of avocado cultivars Hass and Ettinger grafted onto 15 rootstocks was compared over 3 years. The rootstocks were of different genetic origins (West Indian or Mexican) and were clonally or reproductively propagated. The trees were grown in a high-density orchard, and were continually fertigated as is common in modern avocado orchards. Leaf mineral composition was analysed and found to be correlated with crop load. ‘Hass’ leaves had significantly higher levels of B, Ca, Mg, Na, P and K than ‘Ettinger’ leaves. Rootstocks of Mexican origin produced higher foliar Cl levels, but lower levels of Mg and Mn. Rootstocks grown from seedlings conferred higher foliar K and lower B, Ca and Mg. The results demonstrate that avocado rootstocks affect the nutritional status of the tree, by a differential mineral transport, which is indicated by the scion leaf ionome.     

声音在人耳内部传递的统计规律——打击脉冲论与传递因子论

从物理学的基本原理出发，结合耳膜的特殊结构和振动模式，得出打击脉冲，比较麦克斯韦－玻尔兹曼的统计理论，得出声音在人耳内部出现传递因子Ｓ（ω）；在超声区，Ｓ（ω）出现截止频率ｗｃ，在次声区，打击脉冲不连续，出现临界频率ｆｃ（ｆｃ＝２０Ｈｚ）。这些结论与弗莱彻－蒙森和鲁宾森－达德森的等响应曲线的边界频率都符合得很好。     

桃金娘水提物抗肝脏纤维化作用的试验研究

本试验旨在研究桃金娘水提物对CCl₄复合因素造模法诱导的肝脏纤维化大鼠的保护作用,探讨其作用机制。取SD大鼠72只,随机分为模型组、秋水仙碱组（1×10^-4 mg/g）、桃金娘水提物低剂量（1.5 mg/g）、中剂量（3 mg/g）、高剂量（6 mg/g）组及正常组,每组12只。除正常组外,其余各组大鼠于第1~4周皮下注射40% CCl₄花生油溶液,注射剂量为0.3 mL/100 g体重,隔日1次,连续4周,同时第2~4周给予30%乙醇灌胃1 mL/只,隔日1次,连续3周。各组大鼠于第5周开始灌胃给药,灌胃体积量为1 mL/100 g体重,正常组、模型组给予等量生理盐水,桃金娘水提物组分别按照相应剂量灌胃给药,每日1次,连续给药4周,给药的同时仍继续造模。给药结束后,检测各组大鼠血清中丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）活性、总胆红素（TBil）、α-平滑肌肌动蛋白（α-SMA）、转化生长因子-β（TGF-β）等的水平、丙二醛（MDA）含量及超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活性;观察肝脏组织HE及Masson染色的变化。试验结果显示,桃金娘水提物可显著或极显著降低肝脏纤维化大鼠AST、ALT活性、TBil、TGF-β及α-SMA水平（P<0.05;P<0.01）,提高大鼠血清SOD、GSH-Px活性（P<0.05）,降低MDA含量（P<0.01;P<0.05）,减轻肝脏纤维化大鼠肝脏病理损伤程度。以上结果表明,桃金娘水提物对CCl₄复合因素所致肝脏纤维化大鼠的肝脏功能具有明显的恢复作用,可增强其抗氧化能力,减轻肝细胞损伤,具有较好的抗肝脏纤维化作用。