香橼优良单株半同胞家系子代抗寒性研究

在南京六合地区对3年生24个香橼优良单株半同胞家系子代进行抗寒性测定研究,结果表明家系子代间抗寒性存在着显著的差异。田间观测-11℃自然低温下春江4#和香橼4#的抗寒性最强,受冻株率分别为86.67%和100%,平均受冻级别均为Ⅰ级,耐寒指数均为2.00;新世纪8#、春江7#和新世纪2#的抗寒性最差,受冻株率均为100%,平均受冻级别均达Ⅲ级,耐寒指数均大于3.00。室内抗寒力测定供试家系子代的半致死温度在-14.84℃～-7.05℃之间。春江4#和香橼4#的抗寒力最强,半致死温度分别为-14.84℃和-13.94℃;春江7#和新世纪2#的抗寒力最差,半致死温度分别为-7.91℃和-7.05℃。抗寒性评估结果一致。根据半致死温度,结合田间抗寒性观测,供试香橼家系子代抗寒性评估排序为春江4#>香橼4#>春江6#>春江5#>新世纪9#>新世纪10#>新世纪3#>香橼1#>新世纪7#>香橼7#>新世纪8#>香橼6#>香橼5#>春江3#>新世纪4#>新世纪6#>香橼2#>春江8#>新世纪5#>春江1#>新世纪1#>春江2#>春江7#>新世纪2#。     

低温胁迫对淡竹2个抗寒性生理指标的影响

选择13个区域的淡竹叶片为试材,分别在0、-5、-10、-15、-20、-25℃下进行低温胁迫处理,测定其电导率和脯氨酸含量的变化,电导率结合Logistic方程计算出淡竹的半致死温度。通过脯氨酸含量分析和半致死温度的计算,综合分析不同区域淡竹抗寒性的生理生化指标,推测其抗寒性强弱:来源于烟台林科院、烟台昆嵛山、潍坊的淡竹抗寒性较强,来源于日照、沂源、东营、济南、临沂、胶南、泰安的淡竹抗寒性中等,来自浙江、江西、江苏的淡竹抗寒性最弱。     

Toxicity and neurophysiological effects of selected insecticides on the mole cricket, Scapteriscus vicinus (Orthoptera: Gryllotalpidae)

Mole crickets (Scapteriscus spp.) are severe subterranean pests of turfgrasses, commonly targeted with neurotoxic insecticides. Ideally insecticides used against mole crickets should induce quick knockdown or mortality to minimize damage caused by their tunneling. However, neurophysiological effects of insecticides on mole crickets are mostly unknown. The aims of this study were to investigate neurophysiological and toxic effects of several insecticides on tawny mole cricket (Scapteriscus vicinus Scudder) adults and nymphs, and potential synergy between pyrethroid and neonicotinoid insecticides. Bifenthrin, fipronil, and the combination of bifenthrin + imidacloprid provided the fastest median mortality when injected. The combination of bifenthrin + imidacloprid elicited faster toxicity than either active ingredient alone. Imidacloprid, bifenthrin, and bifenthrin + imidacloprid caused immediate knockdown, whereas fipronil immobilized mole crickets within 1-2 h. Acephate, bifenthrin, fipronil, imidacloprid, and bifenthrin + imidacloprid caused significant neuroexcitation. Bifenthrin + imidacloprid resulted in greater increases of spontaneous neural activity than the additive effects of imidacloprid and bifenthrin alone. Excitatory compounds acting at sodium and chloride channels (bifenthrin and fipronil) were the most toxic against S. vicinus. Combining a sodium channel toxin (bifenthrin) and a synaptic toxin (imidacloprid) led to greater than additive neurophysiological and toxic effects, which to our knowledge provides the first documented evidence of synergistic neurological “potentiation”.     

Differences in winter-hardening between phenotypes of Lolium perenne with contrasting water-soluble carbohydrate concentrations

Carbohydrates are essential for the winter-hardening of temperate grasses, affecting both rate of hardening and level of frost hardiness. The rate and extent of winter-hardening of contrasting phenotypes of two Lolium perenne cultivars targeted for differences in water-soluble carbohydrates concentration were quantified under controlled hardening conditions and standardized freeze testing. The phenotype with the lowest water-soluble carbohydrates concentration had a lower rate of hardening and tolerated less frost than the other phenotypes but the effect of water-soluble carbohydrate concentrations on the hardening processes levelled off at increasing water-soluble carbohydrate concentrations, indicating a threshold. Contrasting responses to freezing were found for survival and for potential for tillering and regrowth. Mortality was little affected by the higher test temperatures, while tillering was negatively affected, even at −5°C. Compensatory regrowth of tillers surviving the lower test temperatures partially compensated for the effects of loss of tillers on regrowth. The hardiest phenotypes had a rapid lowering of LT₅₀ during the first 3 d (−1·65°C d⁻¹), acquiring LT₅₀ values at −15°C or below in 10 d. The hypothesis that rate and maximum level of hardening increase with water-soluble carbohydrates concentrations in stubble is supported by the results.     

莱氏野村菌对棉铃虫致病力及田间控制作用初步研究

\t\t\t\t\t目的\t\t\t\t\t探明莱氏野村菌Nr0815对不同龄期斜纹夜蛾幼虫的毒力。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t采用浸渍法分别测定莱氏野村菌菌悬液对斜纹夜蛾2~5龄幼虫的致病死亡率。\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t从校正死亡率来看,对同一龄期斜纹夜蛾幼虫接种时,幼虫的校正死亡率均随着接种浓度的升高而增加,不同接种浓度间幼虫的校正死亡率均存在显著性差异(P<0.05);各龄期间的校正死亡率在10⁷ mL^–1接种密度下无显著性差异(P>0.05),10³~10⁶和10⁸ mL^–1接种密度下均存在显著性差异(P<0.05);且以2龄幼虫的校正死亡率最高。从致死中密度来看,不同龄期的致死中密度LC₅₀间存在极显著性差异(P<0.05)。且龄期敏感性随龄期的增大而减弱;对2~5龄幼虫的LC₅₀分别为(2.63±0.25)×10⁴、(4.79±0.18)×10⁵、(8.04±0.21)×10⁵、(2.20±0.25)×10⁶ mL^–1。从致死中时来看,接种密度为2.18×10⁸ mL^–1时,对2~5龄幼虫的致死中时LT₅₀分别为4.72、6.24、6.09、6.88 d。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t莱氏野村菌Nr0815对斜纹夜蛾2~5龄幼虫具有一定的致病效果,且对2龄幼虫的致病力最强。\t\t\t\t     

咖啡天蛾质型多角体病毒的生物活性测定

以不同浓度的咖啡天蛾(Cephonodes hylas)质型多角体病毒包含体悬液,浸渍栀子花叶,再喂食感染3龄初咖啡天蛾幼虫。感染浓度与死亡率回归方程式为y=2.690 7+0.464x,其致死中浓度LC50为9.483×10~4PIB/ml;5×10~7、5×10~6和5×10~5PIB/ml三种浓度的LT50值分别为:6.16、6.67和7.89天。 试验表明,同一浓度病毒(5×10~6PIB/ml)对不同龄期幼虫的感染力不同,幼虫死亡率随龄期增大而降低,从2龄的92.35％降到5龄的69.44％;其中LT50随着龄期递增而加大,从2龄的6.08天增加到5龄的7.63天。温度对幼虫感病死亡速度有一定影响,但对总死亡率影响不大,高温(35℃)对病毒的增殖起抑制作用,幼虫死亡率明显下降。     

不同日龄苏太仔猪LTβR基因组织表达谱及发育性表达规律分析

试验旨在探讨LTβR基因在仔猪出生至断奶期间的mRNA表达变化,为进一步研究该基因与F18大肠杆菌致病的相关性提供理论依据。本试验选取从初生到断奶的4个日龄(8、18、30和35日龄)苏太仔猪各4头,利用实时荧光定量PCR方法分别比较分析了LTβR基因在各个体11个组织(心脏、肝脏、脾脏、肺脏、肾脏、胃、肌肉、胸腺、淋巴结、十二指肠及空肠)间的表达规律。结果表明,LTβR基因在肝脏、脾脏、肺脏、肾脏、胃、淋巴结、十二指肠及空肠组织中呈现较高水平的表达,并且表现出明显的发育性表达差异。LTβR基因在8日龄仔猪淋巴、十二指肠和空肠组织中的表达极显著高于其他日龄(P<0.01);在8日龄仔猪肺脏组织中的表达极显著高于35日龄(P<0.01),且显著高于30日龄(P<0.05);在35日龄仔猪肝脏组织中的表达极显著高于其他日龄(P<0.01);在35日龄仔猪胃组织中的表达显著高于18日龄(P<0.05)。由此推测,8日龄左右为仔猪肠道免疫屏障快速形成期,LTβR基因的较高表达可能有利于仔猪对F18大肠杆菌抗性。     

球孢白僵菌MZ050724菌株对瓜实蝇的毒力测定

摘 要 本研究选用球孢白僵菌MZ050724菌株对瓜实蝇进行室内毒力测定,结果表明,在3.6?05-3.6?08个/ml 4个浓度中,成虫、幼虫和蛹的最大累计校正死亡率分别为(95.24?.55)%、(86.56?.88)%和(80.47?.86)%;其致死中浓度(LC50)分别为(2.544?.2846)?05个/ml、(2.9126?.4871)?05个/ml和(3.459?.4735)?05个/ml; 成虫、幼虫和蛹的致死中时间（LT50）分别为(4.643?.396)d(5.308?.225)d和 (6.139?.524)d。     

蜡蚧轮枝菌对桃蚜的室内毒力测定研究

[目的]筛选对桃蚜侵染致病力强的蜡蚧轮枝菌菌株,为该菌的进一步开发利用奠定基础.[方法]采用波特喷雾塔测定法,测定来源于俄罗斯的6株蜡蚧轮枝菌菌株对桃蚜的侵染致死情况.[结果]高浓度处理（＞1×106孢子/ml）,多数菌株在第5、6天达到死亡高峰;第7天结束观察时,所测定各菌株的最高浓度处理（1×108孢子/ml）若蚜校正死亡率均达到95％以上.V3、V4菌株在该浓度下致死中时间分别为4.25和4.11 d.[结论]参试菌株对桃蚜均表现出较高的致病性,V3、V4菌株为更优良的备用菌株.     

LPS和LT对肠黏膜VEC内分泌NO和ET的影响

研究LPS和LT引起肠黏膜微血管内皮细胞(VEC)损伤的作用机制。将所培养的肠黏膜VEC 60个孔分为空白对照组、LPS(1μg/mL)组和LT(50μg/mL)组3个组,每个组又分4个不同时间段:3h、6h、9h、12h。结果LPS导致肠黏膜VEC分泌NO明显升高,3 h后达到高峰,随后逐渐降低,而ET分泌急剧升高,9 h后达到高峰。LT导致肠黏膜VEC分泌NO明显升高,3 h达到高峰,随后逐渐降低,而ET在6 h前明显降低,随后逐渐升高到正常水平。