番茄筋腐病的识别与防治

番茄筋腐病又称条腐病或带腐病,主要危害番茄果实.近几年在重庆市万州区普遍发生,特别足九池乡黄梅村发生较重,如果不及时预防,将给菜农带来较大的经济损失,甚至绝收.现将番茄筋腐病的防治方法介绍如下.     

鸡传染性支气管炎病毒肾致病株的分离和鉴定

从广西13个鸡场,有呼吸道症状及尿石症的病鸡中分离出 C、G、Z、Q4株病毒。病毒经电镜观察,其大小在94～108nm 之间,囊膜外有特征性疏松排列的刺突。敏感鸡接种16～36小时后出现呼吸道症状,剖检病鸡时大多数鸡肾肿大并有尿酸盐沉积。各毒株接种鸡胚都能产生体儒胚;被56℃1小时灭活;在鸡胚中均能干扰鸡新城疫病毒 LaSota 株的生长。C_(19)株可被鸡传染性支气管炎病毒标准阳性血清所中和。G_3不被 IUDR 所抑制,属 RNA 病毒;对乙醚敏感,证明属有囊膜病毒。从以上各项鉴定指标证明,所分离的4株病毒是引起鸡尿石症的传染性支气管炎病毒。据作者的经验,提出分离鸡传染性支气管炎病毒较为合理的模式。     

影响猪病治疗效果的因素及对策探析

在生猪养殖时,猪病是养殖过程中经常出现的一种问题,其危害性较大,影响范围较广。猪病会导致生猪的生理免疫力下降,还会对其之后的生长及繁殖造成较大影响。因此,需要明确养猪户猪病的治疗效果,并根据猪病发生原因确定治疗对策。     

中西医结合治疗猪喘气病的效果分析

猪喘气病是由猪肺炎支原体所引起的慢性呼吸道传染病。从近些年猪养殖的情况来看,猪容易患喘气病,这使猪身体健康受到威胁,影响养殖户的经济效益。为了避免此种情况长期发生,应当采用中西医结合治疗方法将病菌从猪体内清除,有效治疗此病,从而保证猪健康的生长。重点分析猪喘气病,进而探究猪喘气病的中西医结合治疗方案,希望可以为猪养殖户提供帮助。     

柑橘黄龙病防控的实践对策

通过连续多年的防控示范实践,总结出柑橘黄龙病发生扩展与病(树)源基数、木虱数量、迁移速度密切相关,病树多、虫量大,迁移快,柑橘黄龙病发生蔓延快、为害重,反之则为害轻.为此,清除传染源病树和防治传媒木虱是防控关键.本文针对福建省建阳市柑橘黄龙病和木虱发生特点,提出“冬季清园彻底砍除病树,秋梢萌发重点防治木虱做到统一防控”的对策.     

水稻秆腐病的发生特点及防治措施

水稻秆腐病也叫菌核秆腐病。2009年在吉林省大安市有零星发生,2010年个别乡（镇）发生严重且有扩展的趋势,如果不认真对待及时防治,将成为抑制大安市水稻夺取高产的主要因素之一。因此,各级农业科技人员要加大工作力度,抓好防病宣传,     

氯化钾抑制玉米茎腐病发生与土壤微生物关系初探

十二年的钾肥长期定位试验表明,氯化钾能够显著降低玉米茎腐病的发生率。为了探讨其机理,通过室内培养试验,研究了PDA培养基中添加氯化钾和土壤浸提液对禾谷镰刀菌(Fusarium.graminearum)生长速度的影响,分析了长期施用氯化钾条件下玉米各生育期根际真菌、细菌和放线菌数目的变化。结果发现,一定浓度的氯化钾不能直接抑制禾谷镰刀菌的生长;与不施氯化钾处理相比,施氯化钾处理的土壤浸提液对禾谷镰刀菌生长具有明显的抑制效果,表明土壤浸提液在病原菌与玉米互作中发挥一定作用。长期施氯化钾显著影响玉米生育前期根际土壤真菌和放线菌数目,对根际土壤细菌数目影响不明显,而且真菌数目与茎腐病的发生率呈显著负相关。各处理根际土壤真菌与放线菌数目差异显著时期正处于病原菌的主要浸染时期,因此,施氯化钾引起的玉米根际土壤微生物区系(尤其是真菌数目)的变化是抑制玉米茎腐病发生的机制之一。     

舍饲环境对奶牛蹄病影响的研究进展

奶牛蹄病是危害奶牛生产的三大疾病之一.该文在参阅国内外大量文献的基础上,从品种、管理,尤其是养殖环境等因素对奶牛蹄病发生的影响进行了论述,发现影响奶牛蹄病发生与奶牛舍地面材质及牛床空间尺寸大小有着密切的关系.其目的在于引起行业内对奶牛舍设计、建造科学性的重视,为奶牛生产创造良好的环境条件,以促进我国奶业的健康发展.     

不同遮光时期对番茄褐变型筋腐病发生的影响

通过在番茄果实坐果期至白熟期之间设置的多个遮光起始点,研究了番茄坐果期、核桃大小、绿熟期和白熟期开始遮光对番茄褐变型筋腐病发生的影响,结果表明不论实际光照强度多大,在果实白熟期遮光均会显著促进筋腐病的发生,可以认为果实白熟期是番茄筋腐病对弱光诱导的敏感期.过早地进行遮光会使番茄植株生长势减弱,反而减轻了对筋腐病的诱发作用.     

综合诊断及治疗在樱桃谷肉鸭鸭疫里氏杆菌病并发传染性法氏囊病中的应用

鸭疫里氏杆菌病是由鸭疫里氏杆菌引发的一种鸭急性或者慢性的败血性传染病。其在2~3周龄的小鸭中较易发生,是养鸭业最为严重的危害性传染病之一。传染性法氏囊病为高度接触性感染疾病,是由双RNA病毒科禽双RNA病毒属病毒引起的一种急性、高度接触性和免疫抑制性的禽类传染病。鸭疫里氏杆菌病并发传染性法氏囊病时,如不及时诊断以及治疗,极易导致鸭的死亡,给养殖户造成严重的损失。为探讨综合诊断以及治疗在樱桃谷肉鸭鸭疫里氏杆菌病并发传染性法氏囊病中的应用效果,现进行一下综述,旨在提高樱桃谷肉鸭鸭疫里氏杆菌病并发传染性法氏囊病的诊治率,减轻养殖户的损失。     

Role of selenium in mitigation of cadmium toxicity in pepper grown in hydroponic condition

Selenium (Se) is an essential element for humans but is not considered as essential for plants. However, its beneficial role in improving plant growth and stress tolerances is well established. In order to study the role of Se in cadmium (Cd) toxicity in pepper (Capsicum frutescens cv. Suryankhi Cluster), this experiment was carried out in greenhouse conditions. Treatments comprised Cd [0, 0.25, and 0.5 mM cadmium chloride (CdCl₂)] and Se [0, 3, and 7 µM sodium selenite (Na₂SeO₃)] with three replications. The result showed that Cd decreased chlorophyll a, chlorophyll b, and carotenoids, whereas Se supplementation diminished Cd toxicity on photosynthetic pigment. Selenium at 7 µM significantly increased the leaf area in the plants grown at 0.25 mM Cd. The application of Se at 3 µM with 0.25 mM Cd and Se at 3 µM and Se at 7 µM with 0.5 mM Cd increased the activity of catalase (CAT). Selenium at 7 µM decreased the proline content of pepper leaves exposed to Cd at 0.5 mM (30%). Selenium significantly enhanced the antioxidant activity of leaves, which was diminished by Cd toxicity. In general, Se has a beneficial effect on plant growth and is an antioxidant enzyme of pepper cv. Suryankhi Cluster under Cd stress and non-stress conditions.     

Accumulation of copper in soils and leaves of tomato plants in greenhouses in Turkey

Copper (Cu)‐containing fertilizers, fungicides, and bactericides has been used extensively in the greenhouses in the Antalya province in recent decades with the use of such materials tending to increase year by year. The level of DTPA‐extractable Cu was determined in 210 soils (0–20 and 20–40 cm depth) and 105 leaf samples obtained from 105 tomato greenhouses. The DTPA‐extractable Cu contents of the soils taken from the 0–20 depth ranged between 0.76 and 88.03 mg kg^‐1 (mean 7.79 mg kg^‐1). The percentage of soils containing DTPA‐extractable Cu greater than the critical toxicity level (20 mg kg^‐1) was 8.1. The Cu content of tomato leaf samples ranged between 2.4 and 1,490 mg kg^‐1 (mean 166.5 mg kg^‐1). The Cu concentration in leaf samples was very high due to the intensive use of foliar applied Cu‐containing chemicals. As a consequence, 24.8% of the leaf tomato samples analyzed contained over 200 mg Cu kg^‐1, the maximum accepted tolerance level. Therefore, it may be necessary to reduce the use of Cu‐containing pesticides and fertilizers, or at least reduce the amount of Cu‐containing fertilizers being used in those greenhouses where Cu‐containing pesticides have been or are being used.     

Occurrence of Sexual Hormones in Sediments of Mangrove in Brazil

The presence of sexual hormones (female estrogens) was assessed in sediments of a mangrove located in the urban region of southern Brazil. The estrogens are involved in human sexual reproduction. They act as the chemical messengers, and they are classified as natural and synthetic. The estrogens inputs in the environment are from treated and untreated sewage. The presence of estrogens in sewage is excretion from the female due to natural production and use of contraceptives (synthetic estrogens). With the indiscriminate release of sewage into the environment, estrogens can be found in rivers, lakes, and even in oceans. In this work, the presence of estrone (E1), 17-??-estradiol (E2), and 17-??-ethynilestradiol (EE2) in eight sedimentary stations in Itacorubi mangrove located on Santa Catarina Island, south Brazil, was investigated. Historically, the Itacorubi mangrove has been impacted by anthropogenic activities because the mangrove is inserted in the urban area of the Florianopolis. The estrogen EE2, used as contraceptive, had the highest concentration in mangrove sediment, 129.75?±?3.89 ng/g. E2 was also found, with its concentration ranging from 0.90?±?0.03 to 39.77?±?1.19 ng/g. Following the mechanism, under aerobic or anaerobic conditions, E2 will first be oxidized to E1, which is further oxidized to unknown metabolites and finally to CO₂ and water (mineralized). EE2 is oxidized to unknown metabolites and also finally mineralized. Theoretically, under anaerobic conditions, EE2 can be reduced to E1 even in environments such as mangrove which is essentially anaerobic.     

红壤区不同肥力水稻土根际硝化作用特征

通过根际培养箱(三室)——速冻切片技术研究了红壤地区高、低两种肥力下水稻苗期根表、根际和土体土壤矿质态氮含量和硝化强度,以及水稻生长、氮素积累的差异。结果表明,肥力水平对水稻根表和根际土壤铵态氮(NH4+-N)含量无显著影响,但高肥力显著提高土体土壤NH4+-N含量,以及根表、根际和土体土壤硝态氮(NO3--N)含量及硝化强度。两种肥力水稻土硝化强度最大值均出现在距根表2 mm处,分别为0.20和0.31μmol kg-1 h-1。土体土壤硝化强度随距根表距离增加而降低,低肥力土壤在距根表10～40mm处时硝化强度接近本底值,而高肥力土壤在距根表20～40 mm处时接近本底值。与不种水稻的CK相比,种植水稻显著提高根际土壤硝化强度。高肥力能显著改善水稻生长,增加植株氮素积累量,尤其显著促进根系生长及通气组织发育。由于红壤稻田肥力水平的差异造成水稻根际硝化强度以及水稻吸收NO3-的差异,导致高肥条件下水稻显示出更强的生长势和氮素吸收利用能力。因此,合理提高红壤稻田肥力水平对改善红壤区水稻根际土壤硝化作用及水稻氮素营养具有重要意义。     

Meta-analysis in the Selection of Groups in Varieties of Citrus

Brazil is the largest producer of oranges (Citrus sinensis) in the world. The nutrient management of tree orchards is designed from experiments with a limited number of varieties. This knowledge is transferred to other varieties by diagnosing tissue nutrient composition and tree demand. Compositional data analysis has been first applied to tissue analysis of agricultural crops using centered log ratios with compositional nutrient diagnosis (CND-clr). The isometric log ratio (ilr) transformation is a new approach based on binary nutrient ratios and the principle of orthogonality (CND-ilr). We analyzed eleven nutrients: nitrogen (N), sulfur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) in leaf tissue samples across 108 commercial plots (thirty-one grow Valencia, twenty-two Hamlim, twenty Pera, and thirty-five Natal). Nutrients were partitioned between macro- and micronutrients as well as anionic and cationic species. The effect size of varieties over Valencia was quantified by the mean and standard deviation of ilr values across ilr coordinates. Specific varietal nutrient profiles and ilr norms were defined. The nutrient profile of orange varieties could be classified into homogeneous groups to take advantage of fertilizer trials conducted on varieties of the same group. The Aitchison distance and a perturbation vector could be instrumental for diagnostic purposes and nutrient management.     

旱地果园水肥管理模式研究进展

分析了旱地果园水肥管理模式的研究进展和存在问题,指出水肥胁迫尤其是水钾已成为旱区果树高产稳产优质化的主要限制因子。在系统探讨旱地果园水分管理、养分管理、综合管理以及果树叶营养综合诊断施肥标准的基础上,提出了旱地果园的高效水肥管理模式。     

Effect of iron-quercetin complex on reduction of nitrite in in vitro and in vivo systems

This study investigated whether reducing agents such as quercetin and iron(II) facilitate formation of nitric oxide (NO) gas from orally ingested nitrite in an vivo study. When 3 mg/kg Na (15)NO2 was orally administered to rats with or without iron(II) or quercetin, Hb (15)NO, which is indicative of systemic (15)NO, was detected in the blood, with the maximum blood concentration of Hb (15)NO at 15 min after nitrite or nitrite plus quercetin treatment, whereas after administration of nitrite plus iron(II) or nitrite plus iron(II) and quercetin, the time was shortened to 10 min. Interestingly, iron(II), quercetin, or iron(II) plus quercetin did not affect the total amount of Hb (15)NO generated from orally administered Na (15)NO2. However, the systemic nitrite concentration was significantly decreased in the presence of iron(II) or iron(II) plus quercetin. These results may indicate that iron(II) is critical to the generation of NO gas from nitrite, whereas quercetin contributed little under the in vivo experimental conditions.     

Role of aldehyde oxidase in the hepatic in vitro metabolism of 3-methylindole in pigs

The metabolism of 3-hydroxy-3-methylindolenine (HMI), a recently discovered metabolite of 3-methylindole (3MI, skatole) produced by porcine liver microsomes, was investigated in vitro using porcine liver cytosol. HMI was rapidly metabolized to a single product, 3-hydroxy-3-methyloxindole (HMOI), by porcine cytosol. By the use of the selective inhibitors menadione and quinacrine, it was shown that the enzyme responsible for the oxidation of HMI into HMOI was aldehyde oxidase (AO; aldehyde:oxygen oxidoreductase, EC 1.2.3.1). The activity of AO in the conversion of HMI to HMOI was measured in a population of pigs (n = 30) with a wide range of 3MI levels in back fat (0.07-0.30 mg/kg). AO activity was found to be negatively correlated (r = -0.70; P < 0.001) with the level of 3MI in fat. The results of the present study suggest that AO plays an important role in the metabolism of 3MI in the pig and that its catalytic activity is related to an adequate 3MI clearance.     

Role of hydrocolloids in the creaming of oil in water emulsions

The influence of guar gum and xanthan gum on the creaming of 10% oil in water emulsions has been investigated. The presence of very low concentrations of the polysaccharides (typically < approximately 0.075%) was found to induce depletion flocculation of the emulsion droplets and increased the rate of creaming. However, at higher polysaccharide concentrations (typically > approximately 0.1%) the creaming rate was reduced due to the increased viscosity of the aqueous phase. For most systems a delay period was noted before creaming started, which was found to be dependent on the zero shear viscosity of the continuous phase and independent of polysaccharide type. The delay period increased significantly at zero shear viscosities approaching 1 Pa s. A mathematical model has been used to fit the creaming rate profiles and a simple exponential relationship obtained between delay time and polysaccharide concentration.     

响应面设计法在温室番茄栽培中的应用

为优化温室番茄的栽培条件,试验研究了不同栽培密度、施氮量和施钾量对日光温室番茄产量的影响。通过中心复合试验设计,构建三因素（栽培密度,氮肥,钾肥）五水平的响应面设计方法并建立番茄产量与三因子的二次回归数学模型。结果表明:三因素对温室番茄产量均有显著的影响（p0.01）,影响的大小顺序为栽培密度施钾量施氮量;栽培密度与施氮量、施钾量之间存在显著的交互作用（p0.01）,施氮量与施钾量之间的相互作用对番茄产量影响不显著（p0.05）;多元二次回归分析结果显示,栽培密度、施氮量、施钾量与番茄产量之间的回归模型高度显著（p0.01）。统计分析确定温室番茄的最佳栽培条件为:栽培密度4.83万株/hm2,施氮量262 kg/hm2,施钾量513kg/hm2;在此条件下,温室番茄产量的预测值为119381kg/hm2,验证试验所得产量为121005kg/hm2。本研究为日光温室番茄高产、稳产和优质提供了理论依据。