托夫勒20世纪70年代在《未来的冲击》中写到：几千年人类经济发展的总历史将表现为三个阶段：即产品经济时代（包括前产品经济时代和后产品经济时代）、服务经济时代和体验经济时代。美国战略地平线LLP顾问公司的创始人帕恩二世和吉尔摩认为，经济价值演变过程可分为四个阶段：商品、货品、服务和体验。他们在《哈佛商业评论》中写到：“随着服务像它以前的货品一样越来越商品化，比如只有价格的长途电话服务，体验逐渐成为所谓的经济价值的下一步……欢迎来到体验式经济时代”。任何时代经济活动的产生和发展，都是生产力发展与人们需求不断升级相互作用的产物。经过了以产品生产为核心的产品经济时代，再经历营销策略核心由产品至上转为服务第一，由生产商和分销商合作完成的高效有序的服务体系为核心竞争力的服务经济时代。体验经济是以客户为中心的经济，它反映人类的消费行为和消费心理正在进入一种新的高级形态。体验经济时代是人类需求层次升华的必然趋势。体验营销与传统营销方式相比，有共性，也有其特殊性。相同点就是它们都是为了满足消费者的需求。它们的区别主要在于提供物、提供方式等不同。体验营销主要有个性化、无形性、延续性、互动性、主观性等特点。个性化：产品营销中强调提供标准化的产品，服务营销强调产品和服务的定制，而在体验营销中，由于个体存在巨大差异性，要吸引个体参与达到互动，在营销活动设计中就必须体现较强的个性化。当然消费者也乐意为所获得的体验价值承受相对高的价格。无形性：服务营销中服务的无形性是以商品为依托，制造商们通常的做法是将商品和服务捆绑销售，以达到更好的服务于消费者，当然许多服务本身也是一种体验。在体验营销中的无形性更强调顾客所能感受到的一种难忘的、身临其境的体验，一种被感知的效果。延续性：消费者所获得的感受并不会因一次体验的完成而马上消失，具有一定的延续性，如消费者对体验的各种回忆等，有时消费者事后甚至会对这种体验重新评价，产生新的感受。因此体验营销的效果是长期性的，一旦消费者对体验满意，他们对公司往往产生高度忠诚。互动性：在产品营销中，消费者是企业的“用户”；在服务营销中，消费者被称为“客户”；而在体验营销中，消费者是企业的“客人”，也是体验活动的“主人”。因为体验活动必须要有消费者的参与，进而在消费者和企业之间发生一种互动行为。体验营销效果是消费者在互动活动中的感知效果。主观性：在产品营销中，企业用价格或其他差异化手段区别于其他企业，在服务营销中企业通过服务价值的让渡使顾客获得更大的利益；而体验营销活动的最终效果是建立在个人主体印象（主要包括时间、空间、技术、真实性、质地、规格等方面的特征）的基础上的，它包含了个体差异的影响，对不同的个体有不同的感受，表现为一种个体的主观性。所有这些体验经济时代的消费需求变化趋势，对于企业而言，既是机遇，又是挑战。针对体验经济时代消费需求的变化趋势，企业如果不能跟上时代的步伐，意识不到营销规则的变化，任你曾经如何辉煌终将走向毁灭。鉴于此，为适应体验经济时代的营销环境新变化，企业营销战略必须做出相应调整，需进行系统的体验营销整合和实施。某制药有限公司推广上市的国际新型儿科止泻药乐度消旋卡多曲颗粒，由负责推广上市的品牌经理负责，从体验营销与品牌互动的角度入手，进行了乐度的体验营销模型的构造及实施。乐度消旋卡多曲颗粒是SFDA批准的四类新药，为肠道脑啡肽酶抑制剂——世界上第一个抗分泌药。1993年由法国Bioprojet Pharma公司开发成功并上市，1995年进入欧盟市场，1999年进入北美市场。2003年被加拿大儿科协会推荐为治疗婴幼儿腹泻常规用药。美国疾病预防控制中心在《急性小儿胃肠道疾病诊治手册》中也将该产品推荐作为临床验证有效的儿科止泻药。现阶段传统营销模式下的新药产品上市是在生产商的配合下，各级分销商经常组织医院药剂科人员及部分主治医师召开产品发布会。但是乐度为国内第二家上市的消旋卡多曲颗粒，竞争对手已占据了国内大部分重点儿童医院，采用传统的新药上市模式，可能无法在短期打开销售局面。而体验营销能带来的营销学上的变革，解决营销的差异化问题。运用体验营销，可以提炼品牌，表现消费个性；可以传播品牌创意与执行，建立消费理解和尊重；可以吸引顾客参与品牌互动，实现品牌认同的忠诚。针对乐度上市背景，采用体验营销，可避免与直接竞争对手的价格战，能在市场份额及销量持续增长方面有所突破。体验就是指人们用一种从本质上说以个人化的方式来度过一段时间，并从中获得过程中呈现出的一系列可回忆的事件。体验营销是满足消费者体验需求的营销模式。体验营销模式构造基础是站在消费者感官、情感、思考、行动、关联5个方面研究消费者购买行为，这种思考方式突破了传统上的“理性”消费者假设。传统营销过分强调产品的功能利益，而忽视了顾客所需要的感受和体验。体验营销的核心观念是，不仅为顾客提供满意的产品和服务，还要为他们创造和提供有价值的体验。体验营销模式的结构体验营销模式措施影响个人的三种模式。第一种是关系干预，这是最佳的干预模式，是在建立贴近于目标人物的关系之后，获得进行引导的优势地位；第二种是利益干预，主要通过利益引导，展示产品的卖点。在商业行为中，要塑造符合消费者功能与情感需要的主题；第三种是规则干预，这种干预是有强制性的，它的利益空间小，但简单易做。夸耀型的和对于对手排斥型的信息通常属于这类。因此，体验营销最接近关系干预与情感利益干预。体验消费行为模式都是由四个环节构成：看（See）→听（Hear）→使用（Use）→参与（Participate），即SHUP模型，这四个环节在时间维度上恰成先后序列，可以先后衔接为持续的多个循环圈。看就是信息受众通过广告和公开场合的传播获得感受。传播方式一种是直接传播主要是通过实物传播，另一种是间接传播，即通过广告来传播。乐度消旋卡多曲颗粒，设计了卡通形象的乐度宝宝，以及经典传播口号“无泻可急，全家开心”两者相配合，贯穿其包装、杂志平面广告、广告宣传片，就医生及患儿家长对腹泻儿童希望快速止泻的需求进行了从用药指导手册，品牌提示物，广告等系统传播。听，也就是由别人之口介绍来的信息，是已经被假定为是实际的使用总结。听来自两方面，一是间接，即多环节的传说；另一种是直接，即实际用户或者消费者的分享。乐度上市伊始，就选择重点儿童医院，进行上市后拓展性研究，请权威专家试用乐度后写出专业临床研究总结报告，在专业杂志上发表，并召开乐度临床经验分享会。另外编写乐度的科普文章，指导患儿父母选择止泻药及进行患儿护理等。使用包括他人使用和自己试用。实际使用效果则影响着重复购买的可能性。他人使用是一种间接的体验，自己试用是卖方向消费者展示产品的售点。乐度在各大药店终端，开展万人大赠药活动，万名患儿及父母共同体验乐度的“30分钟开始起效，平均治愈时间28小时”的快效性的特点。参与包括情景设置和实物展示。情景设置包括路演和展会展示，是卖方设置的一个情景，要消费者参与到设置好的情景中，以带动消费者的购买欲望。乐度开展以直销营销（联谊会营销）为主的系列上市会。在SHUP模型各个环节中，广告的传播度最广，但是信用度是低的，消费者口碑的传播能力与信用都在中高水平；实际使用在消费者中产生的信用度最高，但传播广度有限；试用的信用度较高，且传播的广度较实用为高，他人使用的信用度与传播的广度都属于中等；情景设置的信用度较高的，传播度较低。基于上述分析，乐度的推广框架以直效营销（联谊会营销）、循环服务、数据库营销为主。直效营销就是集中性解决目标群体疑虑、增强目标群体全方位信心。循环服务就是稳定目标群体、建设长期忠诚客户，并坚持“扶上马，送一程”的服务准则，例如把对客户的一对一服务延伸到客户的家庭中（情感建设）。数据库营销内容包括收集客户信息（需求的现实状况、消费能力、消费方向、消费影响力），互动区域市场（渠道的掌握控制、活动效果的反馈与控制），活动实施反馈控制、加强沟通。直效营销为乐度上市初期推广活动的重点，下面就直效营销的意义及乐度具体开展的直效营销进行说明。首先，建设目标群体信任度，集中解决顾客疑虑（对公司、产品、营销方式）。因在传统方式下（一对一）存在一些疑问，比如：一般人认为销售人员对产品功效方面的解释和引导缺乏权威性，即使在接受（开处方）了产品以后也不可能彻底消除；此外，对产品功效偶然性和必然性存在疑虑，这是偶然性服务还是存在一般性的科学原理、具有普遍性的适应性？这些可以通过各种人员、各个方面的结果分享会消除。在联谊活动这种热烈的气氛中，单个顾客的情绪和思维一定会受到群体情绪和思维的影响。其次，解决并消除不信任感。不信任来自于对他人充满恐惧；自身利益受到损害、被他人所欺骗、在活动中受到尴尬。真诚、坚持用产品与目标群体对话，坚持群体的自身体验来确定对产品价值的评定、活动的目的是联谊不是推销。再次，提升目标群体的忠诚度。在联谊会营销中，在所有与会人员都充分肯定产品的氛围中，在使用、销售产品者的分享与感激中，目标群体彼此之间的内心会受到进一步的震撼与强化。联谊会营销把与会客户的信任与感激都凝聚到一起，产生一个共同的磁场。在这个磁场中客户始终不会愿意把目光从这种体验营销的企业和系统上挪开，会继续保持忠诚。最后，促进企业美誉度。通过对产品功效、包装、价值、原理等多方面生动详细的分析，让与会人员在心中对它重新定位，容易形成比较全面的印象，形成产品形象的立体化；体验营销服务是多对一的网络式服务和基地服务，它使全方位、全过程、亲情化、家庭化、人性化得到充分体现，消除了纯粹凸现的商业概念；对这种充分人性化的营销模式，通过彼此沟通感受更切身服务。无论是对产品、服务还是营销推广模式的认同，最后都会归结为对企业美誉度的提升。乐度主要针对药剂科人员、主治医师、分销商，以联谊会形式进行。在联谊会中，主要安排简单的专家讲座、使用者分享、文体活动（主）、公司经营理念的简单表述等。在比较有规模或准备良好的联谊会，可以主张适度邀请部分嘉宾。嘉宾可以是产品方面的、营销方面的、健康环保方面的，也可以是行业领导、社区领导。他们的论证会使目标群体确信不移，并在这种基础上能在会场之外形成持续不断、确信不移的口碑。也可以通过热烈真实的会场气氛，突出经验分享，形成对企业、产品良好的印象。此外作为乐度品牌的负责人，还应针对乐度的体验营销进行阶段性评估。体验营销的阶段性评估是一些产品在营销过程中容易忽视的重要环节，也是众多品牌难以做大的原因之一。缺少阶段评估一方面难以认识到不足，更重要的是会渐渐失去改进和增强体验营销的决心和意志而使营销活动流于形式。在体验营销实施的过程中品牌经理应长期对其效果进行阶段性评估，通过事实让营销团队切实看到体验营销的成效，真正感到体验营销的魅力。总而言之，体验营销并不是“空中楼阁”，它是一种更深入分析顾客体验的全新的科学方法。其不仅可以避免大量无效的广告投入，防止陷入无休止的价格战中，而且很容易锁住客户。最重要的是，体验营销对于乐度在上市初期能快速获得市场信息，取得一部分客户的信任和尝试，进而在医院覆盖和销量上有所突破起到了事半功倍的作用。也许体验营销是长期的、渐进的，不会一鸣惊人，但它确实为乐度品牌的长期健康发展打下基础。主要参考文献1.伯恩德·H.施密特.体验式营销.北京：中国三峡出版社，20012.刘凤军.品牌运营论.北京：经济科学出版社，20003.盛琦.新时期“一对一”顾客定制化旅游营销战略.南开管理评论.1999（3）

建筑施工企业项目成本控制是指在项目成本的形成过程中，对生产经营所耗费的人力资源、物质资料和费用开支进行指导、监督、调节和限制，及时纠正将要发生和已经发生的偏差，把各项生产费用控制在计划成本的范围之间，以保证成本目标的实现。按照现代企业制度产权明晰、所有权与经营权分离、职责明确的要求，项目的成本控制责任主体应当以能否对成本费用进行控制分别采取措施。本文依据控制权限分别从公司和项目部角度进行论述，对项目部能够控制的费用，应当由项目部进行控制；而对项目部无法控制的成本，则应当由公司采取措施予以控制。招标价格低于成本，是指即使按照劳动定额、材料消耗定额、机械台班定额和建筑市场人工的平均工资水平、材料、设备的市场价格计算出来的总成本，且不计算间接费和计划利润，也比工程的招标价格高。企业承揽了这样的工程，定额消耗与实际消耗之间的差额数量没有了，管理费、劳动保险费和财务费用没有了，计划利润没有了，而这几项费用通常要占正常的建筑造价的25%左右，项目部要想在这样的中标价格基础上不亏损，无论怎么努力都难以达到。因此，企业除非有进入某个行业的意图，否则必须坚决避免承揽招标价格低于成本的工程。一旦承揽了这样的工程，企业应按照正常的成本控制方法，明确项目部允许开支的成本目标，而不能把总成本限制在中标价格以内。同时，企业在考核项目部的业绩时，必须以正常的总成本目标为依据。企业在工程项目开工后，必须对标书中的施工组织设计进行优化，或者重新编制实施性的施工组织设计，使施工组织设计更加科学、合理，完全符合工程项目的实际，尽量避免无效的工作量和重复劳动；注重帮助项目部采取先进的劳动组织形式，合理配置劳动力、材料、设备和资金等资源，最大限度地发挥各种资源的作用，提高劳动效率，降低劳动消耗；指导项目部采取先进的施工技术，并在不降低工程质量的前提下，改变一些传统落后的施工方法，使用节能降耗新型材料或可替代的工程材料和固定资产，以提高施工效益，加快工程进度。因非项目部主观原因而发生的成本或亏损，比如因设计变更（扣除增加的计价收入后的净成本）、施工组织设计的不合理、气候变化、项目部息工等因素而增加的成本，以及因中标价过低而企业又未予补充内部预算所形成的亏损，必须由企业负责。这样做的目的是为了分清责任，避免项目部因企业不承担非主观原因而发生的成本或亏损，放弃成本控制的责任，从而引发更加巨大的主观因素亏损。企业应对经营规模问题进行深入、细致的分析，在保证在册员工的工资水平在同行业平均水平之上的前提下，适当控制经营规模，向管理而不是单纯向规模要效益；在加强管理的前提下，对所属的项目部进行整合，使每一个项目部都具有较雄厚的管理基础，使所承担的工程项目都能够取得良好的经济效益。下面用一个例子说明上述问题。如果一个项目部一年完成3000万元产值可以实现利润总额（包括上交给企业的管理费）300万元，在完成价格水平相近的工程5000万元产值时仅可以实现利润总额330万元，那么就决不去完成5000万元产值。因为按照项目部的生产能力和管理水平，以及现行的工程价款结算方式，虽然多完成2000万元产值增加了30万元利润总额，但在多完成产值的同时，却使项目部的产值利润率降低（前者为10%，而后者仅为6.6%）和应收账款增加、完成的工程项目增加，从而使坏账的风险、工程项目不能按期完工的风险、发生工程质量和安全事故的风险增加，而这些风险在转化为损失时，则可能最终冲抵多增加的利润，甚至减少原有的利润。在自行施工项目部的成本中，固定资产（含施工机械、运输设备、生产设备和各种管理用固定资产，不包括房屋、建筑物）折旧费约占5%，而目前项目部和企业的各级管理机构所使用的固定资产，以招标形式实行购买的微乎其微。如果企业的设备全部实行招标采购，则其采购价格预计可降低10%左右，不但每年的固定资产的折旧费可因此降低10%，企业还可以用节余的资金办更多的事情。因此，企业在系统内也应全部实行招标采购固定资产。企业对每一中标的工程，在正式开工后半年内应当派出工作组，确定该工程项目的总成本目标和分项的成本目标，确定该工程项目和分项工程所需的人工工天、各种主要材料的数量、各种设备的台班数量，同时确定该工程项目和分项工程的人工费、材料费、机械使用费和间接费。在此基础上，确定该工程项目的总盈亏指标。确定成本目标时，各分项工程的人工工天，以省、部颁劳动定额或现场测定的定额数据进行确定，工天单价按照企业的平均工天单价或其他标准进行修正后确定；各分项工程的各种主要材料的数量，按照施工图纸和省、部颁材料消耗定额或现场测定的定额数据进行确定，材料单价按照中标时的价格或企业制定的计划价格进行确定。各分项工程的各种设备的台班数量，按照实施性施工组织设计和省、部颁机械台班定额，结合上场设备的状况进行确定，台班单价按照省、部颁机械台班定额和上述方法确定的材料单价进行确定；或者根据施工组织设计中安排的上场设备种类、数量、价值和国家、企业规定的固定资产折旧率，先计算出固定资产的折旧费和大修费，然后再根据按照省、部颁机械台班定额和上述方法确定的材料单价确定机械台班单价（可变费用部分）。各分项工程的间接费，可采取费率、费用定额等方式确定。工程项目的间接费总额可根据确定的该工程项目管理人员数量、管理人员的工资水平、管理所需的各种办公设备、用具数量以及日常的办公用品费用、应当提取或交纳的各项费用（如职工福利费、养老保险费、医疗保险费、失业保险金、住房公积金、工会经费等）进行确定。工程项目的税金可根据国家规定的税种、税率和合同价值进行确定。工程项目的财务费用可根据项目融资的数额和国家规定的利率、企业规定的资金占用费率进行确定。工程项目的盈亏指标按照中标价格减去总成本指标，在考虑一定比例或数额的变动因素后进行确定。项目部实现的盈亏数额由企业收缴或进行弥补。项目部按照总成本指标和实际发生的成本计算的盈亏，由项目部留用或自行承担。材料费和机械使用费中的燃料、配件等费用（以下简称为材料费），是工程成本中最主要的组成部分，其比例约占项目部总成本的70%以上；控制住了材料费，就能够控制住项目部总成本的绝大部分。材料费是由材料单价（含运杂费，下同）和消耗的材料数量两个因素决定的，其中材料单价的高低又直接决定了工程项目成本的高低，是成本控制的主要方面。材料单价是由市场的供需决定的，供给大于需求，材料单价就会下降，需求大于供给，材料单价就会上升；而目前企业所需要的各种材料，绝大部分是供给大于需求的产品，只是由于供应渠道不畅、市场信息不灵、材料采购人员业务不熟、采购数量偏小、选择的供应商偏散、付款时间拖后等原因，导致许多材料的价格偏高，因此，必须彻底改变以往的购货方式，在企业内的所有工程项目，其主要材料包括地材全部实行招标采购的方式，选择同样价格但质量好或同样质量而价格低的同品种、同规格的材料供应商，以降低材料的采购单价。同时，要充分考虑资金的时间价值，在不提高材料价格的前提下尽量晚付款，而在现金购买与赊购价格悬殊较大（相差5%以上）且付款时间不能延期半年以上时，即使是借款，也要优先选择现金购买。项目部对施工队和员工，要按照成本的可控原则，分清项目部、施工队和员工对各项成本的责任，按照市场情况、项目部实际和机械台班定额，制定出合理的责任单价，包括工天单价、材料单价、机械台班单价和间接费费率或定额；以劳动定额、材料消耗定额和机械台班定额为基础，确定单位工程量应当消耗的工天、材料和机械台班数量。在施工过程中，项目部要随时监控各种生产要素的使用和消耗情况，与所完成的施工任务进行对比分析，发现问题及时纠正处理。要严格执行内部验工计价制度，及时向施工队和员工兑现经济利益，不得以任何借口拒绝兑现。项目部要树立安全、质量就是效益的大效益观念，积极预防和避免可能发生的安全、质量事故，对安全、质量事故的多发区域时刻监控，减少或避免发生安全、质量事故。要严格执行对安全、质量事故责任人员的惩罚制度，使全体员工树立起清醒的安全、质量意识，从源头上消除安全、质量事故隐患。所有的项目部，特别是以分包工程为主的项目部，必须制定专人负责合同管理，对所有已经签订且正在履行的合同进行审查，不符合《合同法》规定的要与对方协商变更合同；不同意变更的要签订补充协议，或者对有关条款进行修订；对方要求变更合同时，必须坚持协商一致的原则。除能够及时结算或者处理的事项外，其他的与外单位或个人的买卖、供用水电气热、借贷款、租赁、融资租赁、承揽、建设工程、运输、技术、保管、仓储、委托等事项，都必须签订正式的合同，不得以口头形式约定。在合同履行过程中，要严格按照合同的有关条款进行处理，不得随意更改或变相更改。项目部要结合实际，制定与控制成本有关的规章制度，如材料采购、保管、验收、出库、消耗制度，劳动报酬管理制度，设备管理办法，财务管理办法，会计核算规定，安全、质量管理办法，验工计价办法等，并建立起项目部的成本控制和内部监督机制。要重视上述制度的落实工作，加强对业务部门执行制度的检查，对执行不好的部门和个人要进行批评教育，对不执行的部门和个人要进行处罚，必要时要坚决撤换有关人员。要努力提高业务人员的政治素质和专业水平，指导和督促他们做好各项业务工作，保证成本控制的质量。其具体操作过程是：第一，按照确定工程项目总成本的方法和分包单位承担的工程量，确定分包工程的项目直接费和现场经费，这样就扣除了预算定额与劳动定额、材料消耗定额、机械台班定额之间的差额（约为项目直接费和现场经费预算费用的5%）；第二，按照分包单位的资质等级，将其应当计取的企业管理费、劳动保险费和财务费用的费率降低30%～50%，也可以考虑不对分包单位计取财务费用；第三，按照上述确定的项目直接费、现场经费、企业管理费、劳动保险费和财务费用总额，把该工程项目的计划利润率降低60%以上计取计划利润；第四，按照国家或改工程项目规定的税种、税率，以1～3项的费用总额为基数计取税金；第五，将上述费用相加，即为分包工程的总价款。按照此方法确定分包工程价款，其差额约为工程正常预算价值的18%～20%。如果所有以分包工程为主的项目部全部按照这个方法分包工程，就可以控制住分包工程的成本，杜绝效益的流失。项目部必须按照合同规定的工程价款结算方式，对分包单位完成的合格工程量按月进行验工计价，然后结算工程款，不得对分包单位预付备料款和工程款。在结算工程款时，必须及时扣除分包单位在项目部领取的材料费、项目部代付的各项费用。要建立结算工程款的联签制度，即在结算工程款时，除了验工计价报表外，还要有分包单位业务有关的各业务部门是否扣款的意见，如物资、设备、安全质量、综合办公室等部门的意见。要严格禁止分包单位以项目部或企业的名义到外部采购材料、设备，不得向分包单位出具没有填写任何用途的单位证明和盖有本单位印章的空白信笺，防止分包单位进行各项诈骗活动。项目部必须按照企业的要求，禁止外部单位以各种形式挂靠企业对外施工。无论是项目部与建设单位直接接触中标的工程项目，还是项目部通过其他单位与建设单位间接接触中标的工程项目，或者是其他单位与建设单位通过各种关系中标、但需要企业挂名的工程项目，凡是以企业名义中标的工程，必须由企业直接与建设单位签订合同，由项目部与建设单位验工计价和结算工程款。任何项目部都不得让外部单位以企业的名义承揽工程、验工计价和结算工程款，而项目部仅象征性地收取一定比例的管理费。随着市场经济的不断发展，以建设工程招投标为主要特征的建筑市场已经形成，企业间竞争将逐渐过渡到合理低价竞争。企业的对外经营和对内管理的理念发生了深刻的变化，加强施工项目成本控制管理，减支增效，将成为大多数企业的长期经营战略。施工企业要提高市场竞争力，最重要的是在项目施工中，以尽量少的物化消耗和劳动力消耗来降低企业成本，把影响企业成本的各项耗费控制在计划范围之内。所以施工企业只有加强成本控制管理，才能增强市场适应能力和竞争能力。

Konjac glucomannan(KGM),derived from the tuber of Amorphophallus konjac C.koch,has traditionally been consumed as rubbery jelly,noodles,and other food products in Asia for centuries.It is also used as food additives in Western countries.Clinical studies have indicated KGM supplement normalizes the mouth-to-cecum transit time and relieves constipation for children and adults[1].In order to meet the increasing demand for konjac,more area is employed to plant A.konjac C.koch.With the increase of plant area,some diseases have appeared,and soft rot is the severest one.Huang et al.[2] showed that konjac soft rot was caused by Erwinia carotovora subsp.carotovora.E.carotovora subsp.carotovora is a plant pathogen responsible for producing soft rots in many vegetable and floricultural crops,and responsible for significant economic losses to the konjac industry each year for the causal agent of tuber soft rot[3].Tuber contamination can occur in field and in storage.Infection may occur at any stage of post-harvest handling including washing,grading and packing.Symptoms may develop slowly during cold storage;as temperature increases and conditions become favorable for disease development,thepathogen proliferates,resulting in rapid tissue breakdown.Contaminated tubers that are used as seed,may cause disease problems in field[4].Bacterial soft rot caused by E.carotovora subsp.carotovora occurs worldwide and is one of the most destructive diseases of plant's tubers(e.g.,potato,konjac).Many researchers have demonstrated the potential of control of soft rot of potato etc.Several salt compounds were tested in vitro as inhibitors of E.carotovora subsp.Carotovora[4].Acidified Oxine was demonstrated to be potentially effective in preventing potato spoilage(caused by E.carotovora)without any significant risks of chemical residual or change of skin color[5].Harris[6] found a chemical compound of 5-nitro-8-hydroxyquinoline was the most effective in control of potato soft rot.Biological control is an alternative[7].Cladera-Olivera et al.[8] showed that the soft rot bacterium E.carotovora from potato was inhibited by a novel bacteriocin-like substance produced by Bacillus licheniformis P40.Biological control offers an environmentally friendly alternative to the use of pesticides for controlling plant diseases.Unfortunately,growers continue to use chemical control over biological agents,and lack of knowledge often contributes to the downfall of a biocontrol agent.Knowledge of the biological environment in which the agent will be used and of how to produce a stable formulation are both critical to successful biocontrol[9]. And also,biological products may not consistently provide a high level of disease control[10].Therefore agricultural disease is controlled mainly with pesticides.Numerous pesticides have been tested for efficacy against soft rot E.carotovora on potatoes[11,12],but little was done on the soft rot of konjac tubers.Current control strategies aim to reduce soft rot of konjac tubers in field and storage by employing pesticides.In China,a wide range of pesticides is registered for control of bacterial soft rot of crops.However,there is no special pesticide for konjac soft rot,and most pesticides didn't control konjac soft rot effectively.Therefore,growers were driven to use pesticides blindly.Unreasonable use of pesticides has not only given rise to serious environmental problems,but also caused great waste of resources.The aim of this research was to evaluate seven pesticides and their effect on inhibition of soft-rotting bacterium from Konjac.Strains of E.carotovora subsp.carotovora were provided by Hubei Key Laboratory of Natural Product Research and Development,China Three Gorges University,Hubei Province,China.Pesticides were bought from a pesticide market in Yichang city,Hubei Province,China.The active constituent of each pesticide was Streptomycin,Carbendazim,Kasugamycin,Thiophanate+methyl,Oxadixyl+Mancozeb,Mancozeb or Phosethyl-Al+Mancozeb.Pesticides were prepared according to their instructions using sterile pure water to obtain the maximum concentrations.The in vitro screening trial of antimicrobial activity of seven pesticides was carried out by disk diffusion test[13] using 100μl of suspension containing 108 CFU/ml of bacterium spread on nutrient agar.Small filter disks were generated using a standard 6mm hole puncher andsterilized by autoclaving,and then dried at 80℃.Paper disks were dipped into each solution for 1min in order to assure that paper disks had been saturated with a pesticide solution,whereas those of the controls were dipped into sterile pure water.The inoculated plates with E.carotovora subsp.carotovora were incubated at 27℃ for 24h.The diameter of the clear zone around the disk was measured and expressed in millimeters as its antibacterial activity.The net zone of inhibition was displayed by subtracting the disk diameter(6mm)from the total zone of inhibition around the disk.Five disk per plate and three plates were used,and each test was run in triplicate[14].The MIC and MBC were determined by a modification of the broth microdilution method as previously described by Fazeli et al.[15].And there were five dose points(by two-fold serial dilutions from maximum concentrations according to the instructions)tested in this study.Pesticide was prepared in sterile Nutrient broth to reach a series of two-fold dilutions.Bacterial cultures were diluted in Nutrient broth from the stock of 108 CFU/ml before they were added to the pesticide preparations.Final concentration of bacteria in individual tubes was 1~5×105 CFU/ml.Control tubes contained no pesticide.After 24h incubation at 28℃ the test tubes were examined for possible growth and MIC of each pesticide were determined as the lowest concentration that ended with no growth.Tubes containing pesticide concentrations above the MIC were streaked onto nutrient agar plates to achieve MBC of pesticide against the tested strain.Each experiment was performed in triplicate.The data were statistically analysed by using the one-way ANOVA(SPSS 12.0 for Windows),and were expressed as mean±standard deviation(SD).The differences between treatments were also compared.A P value of less than 0.05 was considered statistically significant.According to the results(Table 1),both Oxadixyl-Mancozeb and Mancozeb showed antibacterial activities at the maximum concentrations within the applied concentration range according to the instructions.The growth of E.carotovora subsp.carotovora was inhibited by Oxadixyl+Mancozeb at concentration of 1μg/ml,and the inhibition zone reached(5.33±0.71)mm.At the concentration of 1μg/ml,Mancozeb inhibited the growth of tested bacteria,and the inhibition zone diameter was(4.22±0.83)mm.Streptomycin,Carbendazim,Kasugamycin,Thiophanate+methyl and Phosethyl-Al+Mancozeb didn't expressed antibacterial activity against E.carotovora subsp.carotovora.MIC and MBC of Oxadixyl+Mancozeb and Mancozeb were determined.Oxadixyl+Mancozeb and Mancozeb were found to have the same MICs and the same MBCs.The MICs of both pesticides were 0.25μg/ml,and MBCs were 1μg/ml(Table 2).ActiveconstituentsoftestedpesticidesInhibitionzone(mm)Streptomycin(0.18μg/mla)0bCarbendazim(0.8μg/ml)0Kasugamycin(0.4μg/ml)0Thiophanate+methyl(0.5μg/ml)0Oxadixyl+Mancozeb(1μg/ml)5.33±0.71cMancozeb(1μg/ml)4.22±0.83Phosethyl-Al+Mancozeb(0.4μg/ml)0Table 1 Antibacterial activities of seven pesticides agaist E.carotovora subsp.carotovoraAccording to the results(Table 2),both Oxadixyl-Mancozeb and Mancozeb showed strong bactericidal activity with the MBC at 1μg/ml.E.carotovora subsp.carotovora was sensitive to both Oxadixyl+Mancozeb and Mancozeb.ActiveconstituentsofpesticideMIC(μg/ml)MBC(μg/ml)Oxadixyl+Mancozeb0.251Mancozeb0.251Table 2 MIC and MBC of Oxadixyl-Mancozeb and Mancozeb against tested bacteriumMany studies showed that Streptomycin,Carbendazim,Kasugamycin,Thiophanate+methyl,Oxadixyl+Mancozeb,Mancozeb and Phosethyl-Al+Mancozeb could control konjac soft rot caused by E.carotovora subsp.Carotovora[16~19].But,the bacterial soft rot is still a major problem encountered in konjac during postharvest storage and in field.The soft rot bacterium Erwinia carotovora was not inhibited by some pesticides used by people.This problem could be attributed to unreasable use of pesticides,so it is necessary to assess effect of each pesticide before application.Seven pesticides were screened against the soft rot pathogens of konjac tubers.Oxadixyl+Mancozeb and Mancozeb were the only pesticides which completely prevented infection at concentration of 1μg/ml according to their instructions.Nevertheless,Streptomycin,Carbendazim,Kasugamycin,Thiophanate+methyl and Phosethyl-Al+Mancozeb didn't exhibit antibacterial activities against soft-rot causing strain at their higher applied concentrations.Therefore when growers faced severe problems with soft rot,they employed a lot of pesticides to protect konjac tuber,but the disease couldn't be controlled effectively.Oxadixyl+Mancozeb and Mancozeb inhibited soft rot bacterium at 0.25μg/ml,but did not give complete protection against infection for longer time.In order to control konjac soft rot,these pesticides could not be used at a concentration lower than 1μg/ml.According to these observations,we can speculate that Oxadixyl+Mancozeb and Mancozeb could be used to control konjac soft rot in field and storage conditions.Even though Mancozeb had the same MIC and MBC as Oxadixyl+Mancozeb,its diameter of the net zone of inhibition was significant differences from that of Oxadixyl+Mancozeb at 1μg/ml(P<0.05).Oxadixyl+Mancozeb expressed strongerbactericidal activity against E.carotovora subsp.carotovora.Mixtures of certain pesticides may act synergistically to augment the inhibition of disease development[4].Study of the antibacterial activity of compounds in vitro may have application in protecting plant from developing disease[20~22].Pesticides that showed no inhibition of soft rot bacterium in the present study included Streptomycin,Carbendazim,Kasugamycin,Thiophanate+methyl and Phosethyl-Al+Mancozeb.Therefore,although all of these pesticides were always employed to prevent and cure soft rot disease,the loss of soft rot is still severe.When used at the manufacturer's recommended concentration,Oxadixyl+Mancozeb and Mancozeb all displayed antibacterial activities against soft-rot causing bacterium.There is no special pesticide for konjac soft rot in China,and the database(a list of marketing companies is available on the database)does not give details of what problems each pesticide controls from the company that produces the pesticide,in vitro study maybe give the growers suggestions about choosing pesticides.Before growers buy or use any pesticide,ask themselves whether it is really necessary to control the disease that they want to get rid of.Therefore protection of konjac with suitable pesticides becomes a necessity.Chemical pesticides play a great role in eliminating agricultual pathogens,but because pesticides are used blindly and not scientifically,environment are polluted seriously.This paper approached ways of selecting pesticides to control konjac soft rot,using scientifically and effectively chemical pesticides,for the purpose of reducing environmental pollution,and protecting environment.Although the current study indicates that there is potential for the use of several pesticides as chemical agents to control disease caused by E.carotovora subsp.carotovora,further studies are needed to examine possible inhibitory effects in vivo.More research is also needed on the delivery methods for effective use strategies including spray application during post-harvest handling,application timing at growth stage or application as preservatives in storage facilities[4].In summary,our data demonstrate that pesticides of Oxadixyl+Mancozeb and Mancozeb inhibited the activity of konjac soft-rot causing bacterium.This disease could be controlled with chemicals such as Oxadixyl+Mancozeb and Mancozeb.Moreover,Oxadixyl+Mancozeb expressed stronger antibacterial activity than Mancozeb.Even though pesticides of various kinds(e.g.,Streptomycin,Carbendazim,Kasugamycin,Thiophanate+methyl,Phosethyl-Al+Mancozeb)have been used on a large scale in China to protect crops from damages inflicted by diseases,none of them were inhibitors of the soft rot pathogen at their recommended concentrations.This work was supported by the Scientific Research Foundation of China Three Gorges University(No.0620060113)and Hubei Provincial Department of Education(No.Q200713002).

植物的诱导抗病性，又称系统获得性抗性，是植物在一定的诱抗剂刺激下，对随后的病原菌侵染具有抵抗性的特征。植物诱抗剂又名激发子，一般将能够诱导寄主防卫反应的生物来源和非生物来源的物质统称为激发子。这些物质在很低浓度下即可被植物识别为信号物质，诱发植物自身的免疫系统，最终使植物获得抵御病害的能力。寡糖类激发子是人类研究的最早、最为充分的一类激发子，并且由于其具有良好的环境相容性，因此是很有发展潜力的生物农药。壳寡糖已经应用于生产，防治作物病害，但对其进行结构修饰的寡糖，其诱抗活性还不清楚。新的寡糖—褐藻酸钠寡糖诱抗活性也未见报道。本文研究了稀土络合的壳寡糖（壳寡糖-铈配合物）以及褐藻酸钠寡糖诱导烟草抗烟草花叶病毒，为其作为生物农药提供依据。1.1.1 供试药剂 壳寡糖-铈配合物、壳寡糖，由中国科学院大连化学物理研究所研制。褐藻酸钠寡糖，由中国农业科学院饲料所研制。1.1.2 供试植物 枯斑三生烟（Nicotiana tobacum L.SamSun NN）。1.1.3 供试毒源 烟草花叶病毒（TMV），本实验室保存于普通烟上。接种病毒汁液为每克含TMV的烟草病叶，加入5倍体积0.05mol/L的磷酸缓冲液（pH7.0），在研钵中研磨后纱布过滤。1.2.1 试验处理 供试药剂：对照药剂壳寡糖50μg/ml，喷雾。供试药剂壳寡糖-铈配合物浓度分别为1μg/ml，10μg/ml，25μg/ml，50μg/ml，100μg/ml，喷雾；供试药剂褐藻酸钠寡糖浓度为25μg/ml，50μg/ml，100μg/ml，喷雾。1.2.2 试验方法 选取大小一致6～8叶期的烟草植株，叶面喷雾施药。24h后汁液摩擦接种TMV病毒。在病毒汁液中加入少量石英砂，用毛笔蘸取汁液摩接种。枯斑三生烟苗采用半叶法接种，每株接4片叶。接种后每天观察发病情况。待全面发病后，调查病斑数。重复3次。抑制率（%）=[（对照叶片病斑数-处理叶片病斑数）/对照叶片病斑数]×100%最初的试验结果表明（表1），壳寡糖-铈配合物对抑制烟草花叶病毒引起的枯斑有抑制作用。在1～100μg/ml的浓度范围里，25μg/ml的诱抗效果最好，抑制率为55%，但是略低于阳性对照壳寡糖50μg/ml，抑制率63.9%。处理斑点数抑制率（%）壳寡糖-铈配合物1μg/ml43±18c37.025μg/ml31±13b55.050μg/ml38±18cd44.0100μg/ml42±19c37.7壳寡糖50μg/ml24±14b63.9CK68±26a—表1 壳寡糖-铈配合物不同浓度喷施对烟草花叶病毒病的防效 （P由于1μg/ml的壳寡糖-铈配合物依然有诱抗活性，并且25μg/ml的诱抗活性较好，因此将取浓度10μg/ml的壳寡糖-铈配合物，进行诱抗活性的检测试验。结果表明（表2），浓度为10μg/ml的壳寡糖-铈配合物比25μg/ml具有更好的诱抗活性，抑制病毒产生枯斑的抑制率为67.4%。但是与25μg/ml没有显著性差异。因此，10～25μg/ml的壳寡糖-铈配合物具有良好的诱抗活性，说明壳寡糖与稀土的络合物可以在低于壳寡糖的使用浓度时，依然具有较高的诱抗活性。处理斑点数抑制率（%）壳寡糖-铈配合物10μg/ml43±17c67.425μg/ml57±13cd56.750μg/ml73±22d45.0100μg/ml107±27a18.9壳寡糖50μg/ml28±13b78.7CK132±46a—表2 壳寡糖-铈配合物不同浓度喷施对烟草花叶病毒病的防效 （P在褐藻酸钠诱导抗性的试验中，试验结果表明，在25～100μg/ml的浓度范围内，褐藻酸钠具有诱抗活性，可以显著抑制病毒引起的枯斑的产生。其中浓度为50μg/ml诱导抗性效果最好，抑制率为71.8%，25μg/ml的褐藻酸钠也有较高的诱抗活性，抑制率为67.4%，均略高于壳寡糖50μg/ml（抑制率64.1%）。处理斑点数抑制率（%）褐藻酸钠25μg/ml59±27bc67.450μg/ml51±21c71.8100μg/ml74±32b59.1壳寡糖50μg/ml65±26b64.1CK181±32a—表3 褐藻酸钠不同浓度喷施对烟草花叶病毒病的防效（P多糖类化合物在自然界中分布广泛，是生命物质的重要组成成分。它不仅能够控制细胞的分化、分裂，调节细胞的生长和衰老以及维持生命有机体的正常代谢，还能够调节动植物细胞免疫以及其间信息的传递。目前，多糖作为生物激发子用于抗植物病害研究比较多，其中已报道氨基寡糖素、毛头鬼伞多糖、硫酸化的葡聚糖以及脱氧半乳聚糖[1～4]等具有诱导烟草抗烟草花叶病毒的生物活性。褐藻胶是一种来源于褐藻细胞壁的水溶性酸性多糖，主要从海带、巨藻、马尾藻等褐藻中提取得到，具有独特的结构和生物活性。褐藻胶由α-L-古罗糖醛酸和β-D-甘露糖醛酸通过1，4糖苷键连接而成的直链多糖[5]。褐藻胶还有很强的抗病毒活性，如抑制TMV，抑制程度随着褐藻胶浓度的增加而增强，且随着褐藻胶中古罗糖醛酸含量的增加而增强。电镜分析表明，TMV在培养基中呈单一分散悬浮，加入褐藻胶后则形成团聚物。团聚物的形成阻止了TMV在被感染细胞表面的脱衣壳过程，而阻止了TMV的RNA穿过细胞膜，从而防止感染[6]。但由于其凝胶性强，不容易被吸收，在应用方面收到很大的限制，将其水解为寡糖后，水溶性好，利于吸收。因此本文研究褐藻酸钠水解为褐藻酸钠寡糖后的生物活性，以期在生产实践中具有更加广泛的应用。结果发现褐藻酸钠寡糖具有良好的诱抗活性，并且好于阳性对照壳寡糖，但是其具体机理还有待于进一步的研究。近几年研究发现，稀土离子，尤其是Ce，有较广泛的抑菌作用，而且有降解有机磷的能力。壳聚糖-铈配合物对黄瓜中的硫磷农药残留有一定的降解作用，其降解产物是氨基对硫磷，基本解除了毒性[7]。研究已经发现壳寡糖能够诱导烟草抗烟草花叶病毒，本文研究了壳寡糖-铈配合物是否依然保持具有诱导抗性的活性。结果表明，壳寡糖-铈配合物尽管诱抗效果不如壳寡糖明显，但仍然具有较高的诱抗活性，至于是否有降解有机硫磷的作用，需要进一步的研究。经过化学修饰的壳寡糖-铈配合物可以改变壳寡糖的理化特征，产生新的活性，这对于加强寡糖应用的广泛性和多功能性具有重要的价值。

Rice stripe(RSV)has been known to distribute in rice areas all over the world,and it is very hard virus,transmitted by insect vectors,small brown planthopper(SBPH),Laodelphax striatellus,Fallen.Once the rice is infested,there is still no very effective measures to control,even the chemicals.The chemicals'effect is not ideal and more or less they could cause some environmental risks,so there is the common opinion in the IPM system that the rice varieties having resistance to rice stripe is one of the basic and effective measures to control this disease.In 2006 and 2007 for finding the resistant rice varieties that could be used for large scale in the field,the evaluation and screening of rice varieties were conducted in Jiaxing,Zhejiang Province.In 2006,there were 40 varieties provided for the experiement,just like Chunjiang 050,Xiushui 63,Y1,Zheda 510,Tai 03126,HZ586 and so on,and Jia 991 was set to be the control.Similar to 2006 studies,in 2007,there were 20 varieties used in 2006,and newly introduced into 17 varieties,just like Leyou 2,Jiaheyou 261,Bing 04～123,Jiashao 3.The control was still Jia 991.In 2006,the experiment was conducted in the yard of Shuangqiao Academic of Agricultural Science,Xiuzhou,Jiaxing.Last year in this plot rice was planted,and in winter no crop was planted.The water and fertilizer condition was good.The rice was seeded in 2th June,and transplanted to the field in 1st July.Randomed blocking design,and the size of every plot is 30m2,with three replications.The field management was as usual,except for no chemicals use for controlling the SBPH and RSV.In 2007,the experimental field was chose to north suburb of Jiaxing,where last year the RSV occurred hard.The experimental field condition and design were familiar with 2006,and total 111plots.Investigated Methods In 2006,after 5d from 1st July when the rice were transplanted,the investigation was conducted every 5d in field,till the diseases was stable,at that time the total rice tiller and the diseased tiller amount were recorded.Num.VarietiesDiseasepercentageinthefield(%)SSRP=0.05P=0.011Jiahe2156.03aA2Y25.33bB3Jiajing36485.24bB4Y33.9cC5Shaojing04-463.49dD6Jia991(CK)3.07eE7Yongjing04683.02efEF8Y62.88fgEFG9Tai04-42.83gFG10Xiushui032.73ghGH11Qianghu9142.73ghGH12Y102.59hiHI1336You7482.52ijHI14Xiushui092.51ijHI15ZH2512.42jkIJ16Xiushui1102.27klJK17Jingzhi202.27klJK18Y42.23lmJKL19Jia04-332.14lmnKLM20Jiahua12.11mnKLM21Xiushui632.04nLM22Jiahe2182nM23Zheda5101.99nM24Bing01-1131.74oN25R41011.69oN26Y51.59oN27Jingzhi270.94pO28Chunjiang0500.91pO29Chunjiang0510.91pO30Bing03-1230.88pO31Jiaheyou28880.87pO32Zheda5320.86pO33Y80.86pO34Y10.81pO35Ning04-450.45qP36Tai031260.44qP37HZ5860rR38Y70rR39Y90rR40JiaheyouTR0rRTable 1In 2007,after 15th May,when the seeds were seminated,the investigation was conducted periodically in seedling stage till 20th June,when the rice was transplanted,the total rice tiller and the diseased tiller amount were recorded.And in field,30th July,when the disease was stable,the same indexes were recorded.By the total rice tiller and the diseased tiller amount,the disease percentage could be got,and by DPS software the resistance of different rice varieties could be made with ANOVA method.From table 1,we could get that in 2006 the RSV occurred softly in the experimental field,the CK,Jia 991'disease percentage was just 3.07%.Shaonuo 04~46,Y3,Jiajing 3648,Y2,Jiahe 215's were higher than CK;but there were four varieties,Jiaheyou TR,Y9,Y7,HZ586,which no typical RSV was found.By ANOVA analysis,the resisstance of rice varieties were obviously different.Jiaheyou TR,Y9,Y7,HZ586,which no typical RSV was found,the resistance were the highest;the Yongjing 0468,Y6 and CK were in the same level and at P=0.01 there were no obvious difference;and Shaonuo 04～46,Y3,Jiajing 3648,Y2,Jiahe 215 resistance were weak.In 2007,in the field the RSV occurred seriously in the experimental field,the CK,Jia 991'disease percentage was 19.12%(Table 2).Disease percentage of Shi 1 and Yongjing 0468 were 27.8%and 25.65%,respectively;there were 16 varieties,for example Jia 991,the disease percentage were above 10%;and the disease percentage of HZ586,Chunjiang 051,Jiahe 218,Jiaheyou 555 and Y9 were below 2%.By ANOVA analysis,the resistance of these rice varieties were seriously different.Disease percentage of Shi 1 and Yongjing 0468 were obviously higher than CK,their resistance were weak;the disease percentage of HZ586,Chunjiang 051,Jiahe 218,Jiaheyou 555 and Y9 were far below from other variety,their resistance were high;and others resistance were in the middle level.In 2007,in the seedling field the disease percentage of Bing 04～132,Zheda532,Xiushui 09,Xiuishui 110 and Bing 05～15 were all above 5%;the disease percentage of was just 0.07%,and in the Chunjiang 051 there was no RSV found;Other varieties percentage of disease were in the middle of 5%and 0.07%(Table 2).Num.VarietiesDiseasepercentageinthefield(%)SSRP=0.05P=0.01VarietiesDiseasepercentageintheseedlingfield(%)SSRP=0.05P=0.011Shi127.8aABing04-1325.68aA2Yongjing046825.65aAZheda5325.6aA3Bing04-0819.62bBXiushui095.39aAB4Jia991(CK)19.12bBXiushui335.24abAB5Xiushui11018.5bBXiushui1104.85abcABCTable 2 Evaluation of rice varieties resistance to RSV (Jiaxing, 2007)Num.VarietiesDiseasepercentageinthefield（%）SSRP=0.05P=0.01VarietiesDiseasepercentageintheseedlingfield（%）SSRP=0.05P=0.016Bing05-1517.83bBCShi14.34abcdABCD7Bing01-11317.76bcBCJiahua14.34abcdABCD8Y517.33bcBCYongjing04684.24abcdABCDE9Jiahua116.5bcdBCBing05-154.15abcdeABCDEF10Xiushui3316.4bcdBCY53.78abcdefABCDEFG11Ning04-4516.26bcdBCBing04-083.66abcdefgABCDEFGH12Bing04-13215.75bcdBCJia991（CK）2.9bcdefghABCDEFGHI13Zheda53215.69bcdBCY22.88bcdefghABCDEFGHI14Y215.18bcdBCDBing01-1132.81bcdefghiABCDEFGHI15Shi215.06bcdBCDNing04-452.77cdefghijABCDEFGHI16Xiushui0914.99bcdBCDY12.66cdefghijABCDEFGHI17Y112.96cdeBCDEQianghu1712.52cdefghijkABCDEFGHI18Qianghu17112defCDEBing05-1142.48cdefghijkABCDEFGHI19Bing03-019.22efgDEFShi22.26defghijkBCDEFGHI20Bing04-1138.25fghEFGBing03-012.14defghijkBCDEFGHI21Jiaheyou6127.18ghiEFGHBing04-1131.69efghijkCDEFGHI22Bing03-1235.76ghijFGHJiaheyou2611.39fghijkDEFGHI23Leyou25.42ghijFGHJiaheyou6121.23ghijkDEFGHI24Jiaheyou2615.23ghijFGHBing03-1231.11hijkDEFGHI25Jiaheyou16204.76ghijFGHY71hijkEFGHI26Shaonuo04-464.36hijFGHChunjiang0500.99hijkEFGHI27Jiashao34.3hijFGHJiahe2180.94hijkFGHI28Chunjiang0503.22ijFGHLeyou20.9hijkFGHI29Y73.18ijFGHJiaheyou62230.72hijkGHI30Jiaheyou62233.1ijFGHJiaheyou5550.7hijkGHI31台031262.97ijFGHJiaheyou16200.5hijkGHI32Bing05-1142.9ijFGHY90.38hijkHI33HZ5861.83jGHHZ5860.32ijkI34Chunjiang0511.81jGHShaonuo04-460.24jkI35Jiahe2181.78jGHJiashao30.24jkI36Jiaheyou5551.53jHTai031260.07kI37Y90.94jHChunjiang0510kI续表2By ANOVA analysis,the different resistance of these rice varieties also existed.the disease percentage of Bing 04～132,Zheda532 and Xiushui 09 were higher,and their resistance were weak;the disease percentage of six varieties,Chunjiang 051,Tai 03126,HZ586,Shaonuo 04～46,Jiashao 3 and Y9,were lower,and they had comparatively high resistance.Through the rice varieties screening for resistance to rice stripe virus(RSV)in the seedlingstage and in the field in Jiaxing,in 2006 and 2007,the difference of rice varieties resistance to RSV could be found,and the resistance trends between different developmental stage and different year kept in the same trends.Chunjiang 051,Y9,Jiahe218,Jiaheyou 555,Tai 03126 and Bing 03~123,and so on,had the high resistance to RSV.Though most of the results showed that the varieties resistance behave the same in different developmental stage and different year,we also should notice that few varieties did not obey this trends,for example,Shaonuo04～46,in 2006 in the field it showed very weak resistance,but in 2007 in the seedling field it showed high resistance.This perhaps tell us that just use the index of disease percentage is not enough,and at the same time we could ignore that there is still no very clear criterion to evaluate the varieties resistance to RSV.These factors could influence our evaluation.In 2006 the RSV occurred softly in the experimental field,the CK,Jia 991 disease percentage was just 3.07%,but in 2007 the CK,Jia 991's disease percentage was 19.12%,far higher than that in 2006.That is because in 2007 we chose the field where in year before the RSV occurred seriously,and advanced the seeding date and transplanted date accordingly,which the two steps could make the optimal RSV occurring conditions.On other hands,in the same cultivated condition,the disease percentage different varieties could behave 10-folder difference,it could show us clearly that the varieties resistance could exert important role in the RSV IPM system.Research was funded by a grant from Zhejiang province Science and Technology Bureau.

Plant and fungal cells are surrounded by a cell wall rich in diverse polysaccharides and proteins.It has become apparent in recent years that the carbohydrates in the cell wall function not only to maintain cell shape and integrity,but also may serve as signals in plants(Mohnen et al.,1993).Oligogalacturonic acid(OGA),a well studied elicitor,is derived from plant cell walls(Nothnagel et al.,1983).When added to cultured plant cells,it induces an oxidative burst within minutes,releasing ROS via a pathway that involves receptor binding,activation of a G-protein,influx of Ca2+,stimulation of phospholipase C,and induction of a number of kinases(Apostol et al.,1989;Horn et al.,1989;Legendre et al.,1992;Chandra et al.,1995;Legendre et al.,1993).Purified OGAs 13 to at least 26 residues long stimulate pp34 thiophosphorylation in vitro(Philippe et al.,1995).OGAs are also involved in the induction of the jasmonate pathway during plant defense response to E.carotovora subsp.Carotovora attack(Cecilia et al.,1999).The first response observed after the addition of OGAs that is clearly involved in plant defense is the production of active oxygen species,including H2O2,and O2-.This response,termed the oxidative burst,occurs within a few minutes after the addition of OGAs to suspension-cultured soybean,tobacco,and tomato cells.Reactive oxygen species are thought to have direct(through cytotoxicity)and indirect(through signaling)roles in the plant cell death required for the HR.Reactive oxygen species induce the expression of defense related genes,and are implicated as second messengers that elicit other defense responses,including systemic acquired resistance(SAR)and the HR(Brent etal.,2001).Different elicitors are thought to activate different sets of second messengers.The two signaling events that appear to participate in the OGAs inducing plant defense include the oxidative burst and NO accumulation.Inhibitors of mammalian nitric oxide synthase reduced both OGA-induced NO ac-cumulation and NOS activity,suggesting that OGA-induced NO production occurs via a NOS-like enzyme(Hu et al.,2003). Nitric oxide(NO)is a highly reactive molecule that rapidly diffuses and permeates cell membranes.During the last few years NO has a significant role in plant resist-ance to pathogens by triggering resistance-associated cell death and by contributing to the local and systemic induction of defense genes.NO stimulates signal transduction pathways through protein ki-nases,cytosolic Ca2+mobilization and protein modification(María et al.,2004). Most of the ex-perimental data available on NO detection during plant-pathogen interactions come from studies of infections by biotrophic pathogens(María et al.,2004). Additionally,an increase in NOS activity correlated with the pathogen resistance response has been observed in resistant tobacco during TMV infection( Durner et al.,1998;Chandok et al.,2003).Here we report that OGAs induced a range of defense responses in tobacco,including oxidative burst,NO accumulation and stimulation of superoxide dismutase(SOD)activity and catalase(CAT)activity.Furthermore,we show that tobacco plant sprayed with OGAs developed a resistance against infection by tobacco mosaic virus.We also provide evidence that the defense response induced by OGAs was connected with H2O2 and NO pathway.Plants of tobacco(Nicotiana tabacum var.sam sun NN)were grown from seeds in a greenhouse and were used at the 4~6-leaf stage after 2 months in culture.The plants were kept in a growth chamber at(23±1)℃ with a photoperiod of 16 h and 70%~80%relative humidity for several days before treatments.Diphenylene iodonium(DPI),2-(N-morpholino)ethanesulfonic acid(MES),Sodium nitroprusside(SNP),catalase(CAT,from bovine liver),NG-nitro-L-arginine-methyl eater(L-NAME)and 4,5-diaminofluorescein diacetate(DAF-2 DA)were obtained from Sigma.2′,7′-dichlorofluorescin diacetate(H2DCF-DA)from Biotium.All other reagents were from Shanghai Chemical Reagent CO.,LTD,Tianjin Kermel Chemical Development Centre,or Beijing Chemical Plant.OGAs was prepared from enzymatic hydrolysis of pectin and separated with membrane according to the report(H Zhang et al.,1999).An aliquot of OGAs was dissolved in water and analyzed with a matrix-assisted laser desorption-ionization time-of-flight mass spectrometer(MALID-TOF-MS,Bruker,Germany).Tobacco mosaic virus(TMV)that came from our collection was multiplied in N.tabacum.TMV was extracted from systemic infected plants by homogenization of infected leaves in 0.05mol/LH3PO4 buffer(0.05mol/L KH2PO4,0.05 M Na2HPO4 pH 6.8)with subsequent clarification of the extract by centrifugation at 2000g for 6 min.The supernatant extract was used for mechanical inoculation.All leaves of plant were sprayed with 50μg/ml of OGAs,the control plants were sprayed with water.24h~25d after OGAs application,plants were inoculated mechanically with TMV.The lesion caused by TMV was investigated at 7d after inoculation.Results were analyzed using Duncan's multiple range test at P= 0.05.For measurements of SOD and CAT activities,tobacco leaves treated with OGAs were kept in liquid nitrogen.The enzymes in the frozen powders were extracted by adding 0.05g polyvinylpyrrolidone and 5ml 0.05mol/L sodium borate buffer at pH 8.8 and homogenized at 4℃.SOD activities were measured as described by Zhu Guanglian(Zhu Guanglian et al.,1990).CAT activity was determined using the method of Beers&Sizers(Beer et al.,1952).NO and H2O2 measurement was performed using their fluorescent indicator dye DAF-2 DA and H2DCF-DA as described previously by H.Kojima(H.Kojima et al.,1998)with slight modifications.The epidermis was peeled carefully from abaxial surface of the leaves and cut into 5-mm length.Epidermal strips were placed into Tris/KCl buffer(Tris 10 mmol/L and KCl 50mmol/L,pH 7.2)containing DAF-2 DA at a final concentration of 10μmol/L for 30min,or H2DCF-DA at 50μmol/L for 10min,at 26℃ in the dark.The epidermal sections were removed and transferred to a dish of fresh Tris/KCl buffer(without probe)to wash off excess fluorophore apart from light.Then the epidermal strips were placed in Tris/KCl buffer containing OGAs and inhibitors.Examination of peels was performed using laser scanning confocal microscopy(Leica,TCS SP2)with exciting wavelength 488 nm,emitting wavelength 505~530nm.Plants were sprayed with 0.01 and 0.1 mmol/L of sodium nitroprusside(SNP),50μg/ml of OGAs,1 mmol/L,10mmol/L and 100 mmol/L H2O2,H2O2 scavenger catalase(CAT,100unit/ml)and OGAs cotreatment,H2O2 scavenger ascorbic acid(0.1mmol/L)and OGAs cotreatment and NOS inhibitor L-NAME(1mmol/L)for 30min before OGAs respectively.The control plants were sprayed with water.In all cases,24h after OGAs and other materials applications,plants were inoculated with TMV.The lesion caused by TMV was investigated at 7d after inoculation.The effect of OGAs,SNP and H2O2 on local infection was calculated from the ratio of the number of local lesion produced on the treated leaves to that on the control leaves treated with water.The TOF-MS profiles of OGAs sample were showed in Figure 1.The mass spectrum indicated that peaks corresponding to the mass numbers of( M+ Na)+of trimer to enneamer were detected.So the sample was composed mainly of OGAs having degree of polymerization( DP)2-8.Figure 1 TOF-MS of oligochitosan sampleThe results of control effects on TMV with OGAs at different concentration(50～100μg/ml)showed that the best concentration was 50 μg/ml(data not shown).The effects of application of OGAs at different time were summarized in Table 1.It was found that tobacco leaves treated with OGAs were protected against TMV infection.When the inoculation occurred at 19d after spraying 50μg/ml OGAs on tobacco plants,the relative control effect was 53.42%.We concluded that the resistance induced by OGAs became better with the inducing time until 19d.The resistance was reduced after 19d.Dayof50μg/mlgalacturonideappliedNumberoflesioncausedbyTMVRelativecontroleffect(%)vcdsaw1d125±5814.40a?4d116±3920.55a?7d120±4217.81a10d84±3742.47ab13d97±4433.56ab16d90±3238.36ab19d68±3453.42b22d71±3451.37b25d89±3739.04bck146±51—Table 1We examined the effects of OGAs on the activity of plant resistance correlated enzymes.The results(Figure 2 and Figure 3.)indicated that OGAs increased activity of SOD and CAT compared with the H2O-treated ones.There are no distinct differences on the activity of POD and PPO of tobacco leaves treated with OGAs or water(data not shown).SOD and CAT are concerned with eliminating oxygen free radical.Within one hour,activities of CAT and SOD were induced to maximum.Figure 2 Time course of SOD activity in tobacco leaves treated by 50μg/ml OGAs or H2O as CKFigure 3 Time course of CAT activity in tobacco leaves treated by 50μg/ml OGAs or H2O as CKBecause of activity of SOD and CAT induced by OGAs and the two enzymes correlative with oxygen free radical,we examined the production of H2O2 induced by OGAs.To study the effects of OGAs on the production of H2O2 in tobacco cells,the H2O2-sensitive fluorophore H2DCF-DA were used.The results of production of H2O2 in epidermal cells of tobacco leaves induced by OGAs were shown in Figure 4.It was found that OGAs caused an increase of intracellular H2DCF-DA fluorescence in epidermal cells and guard cells of tobacco leaves,indicating the production of H2O2.Fluorescence became visible along the plasma membrane and in organelles in the epidermal cells of tobacco leaves treated with OGAs(Figure 4C),but the fluorescence was very faint in the epidermal cells only loaded with H2DCF-DA(Figure 4A).The Figure 4E and G showed that CAT and DPI could inhibit the level of H2DCF-DA fluorescence in the cells of tobacco leaves treated with OGAs.The results revealed that CAT and DPI could suppress the production of H2O2.Figure 4 Laser scanning confocal microscopy of OGA-induced production of H2O2 in epidermal cells of tobacco leaves. (A) The cells loaded with H2DCF-DA. (B) Bright field image of the cells loaded with H2DCF-DA. (C) The cells loaded with H2DCF-DA before treatment with OGA. (D)Bright field image of the cells loaded with H2DCF-DA before treatment with OGA. (E) The cells loaded with H2DCF-DA and elicited by OGA in the presence of the CAT. (F) Bright field image of the cells loaded with H2DCF-DA and elicited by OGA in the presence of the CAT. (G) The cells loaded with H2DCF-DA and elicited by OGA in the presence of the DPI. (H) Bright field image of the cells loaded with H2DCF-DA and elicited by OGA in the presence of the DPI.The NO-sensitive fluorophore DAF-2DA was used to observe NO accumulation.The observed LSCM results of OGAs-induced production of NO in epidermal cells of tobacco leaves were shown in Figure 5.It was found that OGAs could enhance the level of intracellular DAF-2DA fluorescence in epidermal cells of tobacco leaves,indicating massive production of NO.Production of NO and/or accumulation was observed in organelles and along the plasma membrane in the epidermal cells of tobacco leaves treated with OGAs(Figure 5C).However,the DAF-2DA fluorescence indicating production of NO was not observed in the epidermal cells only loaded with DAF-2DA(Figure 5A).The results also indicated that CPTIO and L-NAME could inhibit the level of H2DCF-DA fluorescence in the cells of tobacco leaves treated with OGAs(Figure 5E and G).The results representedthat CPTIO and L-NAME could suppress the production of NO.Figure 5 Laser scanning confocal microscopy of OGA-induced production of NO in epidermal cells of tobacco leaves. (A) The cells loaded with DAF-2 DA. (B) Bright field image of the cells loaded with DAF-2 DA. (C) The cells loaded with DAF-2 DA before treatment with OGA. (D) Bright field image of the cells loaded with DAF-2 DA before treatment with OGA. (E) The cells loaded with DAF-2DA and elicited by OGA in the presence of the CPTIO. (F) Bright field image of the cells loaded with DAF-2DA and elicited by OGA in the presence of the CPTIO. (G) The cells loaded with DAF-2DA and elicited by OGA in the presence of the L-NAME. (H) Bright field image of the cells loaded with DAF-2DA and elicited by OGA in the presence of the L-NAME.As H2O2 and NO appear to be a key factor associated with plant induced defense disease,it was interesting to test the effect of exogenous NO and H2O2.The effect of OGAs,NO donor SNP and H2O2 at different concentrations and some scavengers are summarized in Figure 6.It was found that treatment with OGAs,SNP and H2O2 protected tobacco leaves against TMV local infection.The least lesion was observed at the treatment of 50μg/ml OGAs among the all treatments.The inhibition effect of H2O2 showed dependence on the amount of H2O2.The lesion of co-treatment of OGAs and the H2O2 scavenger CAT or ascorbic acid on TMV infection was as high as CK.We also observed SNP inducing resistance was dose-dependent.When the tobacco plants were treated with L-NAME before OGAs,the induced resistance was depressed.Therefore,we can presume NO and H2O2 are important factors participating in OGAs inducing resistance to TMV.Figure 6 Effect of OGAs and exogenous NO and H2O2 on disease symptomPectic oligosaccharides,produced by microbial enzymes,are well-known oligosaccharins,eliciting defence responses in diseased plants(Dumville et al.,2000).A broad spectrum of OG-induced pathogenesis-related defense responses has been reported(M.T.Esquerré-Tugayé et al.,2000).Most defense and developmental responses are induced by OGAs with a degree of polymerization(DP)between 10 and 15 galacturonic acid residues.OGAs with a DP less than 8 can also trigger defense responses in plants:they induce accumulation of protease inhibitors(T.Moloshok et al.,1992),ethylene production(S.D.Simpson et al.,1998)and elicitation of genes involved in jasmonic acid metabolism in tomato(C.Norman et al.,1999).In this report,we observed the OGAs with a DP between 2~8 could induce tobacco resistance to TMV.The concentration of OGAs used was also discussed.OGAs-induced plant growth has been reported(LoSchiavo et al.,1991;Filippini et al.,1992),and the maximal effect to growth was about 10-4 M(Stephen et al.,1993).To elicit plant defense responses,OGAs concentration higher than those usually required for control developmental process.In our experiments,50μg/ml was the best concentration to induce resistance within 100μg/ml(data not shown).It showed the efficiency of the OGAs in inhibition of virus infection was not depended on the dose of OGAs.But the inhibition effect was dependent on the treatment time.We observed the inducing effect of resistance to TMV was gradually elevated before 19d,but the mechanism of this needed further study.Research showed that lag period of the induced resistance of glucohexaose was about 7days and the protection period was about 28 days(Li Hongxia et al.,2005).Furthermore,tobacco plants treated by sulfated fucan or linear β-1,3 glucan showed resistance to TMV or bacterium E.carotovora after 5 days(Olivier Klarzynski et al.,2003;2000).So far no oligosaccharides were reported to have so long time inducing effect.Therefore,OGAs have more predominance to be applied in agriculture.Experimental results also showed that NO and H2O2 played important roles in OGAs inducing tobacco resistance to TMV.NO and H2O2 as important signaling active molecules in pathogen defense reaction has been extensively studied(Levine et al.,1994;Mehdy et al.,1996;Baker et al.,1995;Jabs et al.,1996;Delledonne et al.,1998;Rout-Mayer et al.,1997?;Binet et al.,1998).First,we examine the activity of plant resistance correlated enzymes.Because the activity of PAL has been confirmed elevated by many reports(Messiaen et al.,1994;Lapous et al.,1998;Dixon et al.,1989;Tepper et al.,1990),we just mensurated the PPO,POD,SOD and CAT.This includes the activity of SOD and CAT elevated,so we estimated the extra H2O2 production.To evaluate the stimulatory effect of OGAs on tobacco cells,we measured the production of H2O2 and NO in tobacco cells.The data indicated that OGAs induced the production of H2O2 and NO in epidermal cells of tobacco within a short time.These results were in agreement with the reports by Xiangyang Hu,who claimed OGAs stimulated NO accumulation in the growth medium of ginseng suspension cultures(Hu et al.,2003).Rout-Mayer and Binet discovered respectively H2O2 production within a few minutes after the addition of OGAs to suspension-cultured tobacco cells(Rout-Mayer et al.,1997;Binet et al.,1998).Many reports show H2O2 and NO exist are correlated to plant defense.H2O2 is involved in the induction and/or execution of hypersensitive reaction(C.S.Bestwick et al.,1997).H2O2 is required for the cross-linking of plant cell wall components as a part of the structural defense response(C.Lamb et al.,1997).The production of H2O2 may also lead to the development of an antimicrobial environment within the apoplast(M.Peng et al.,1992).In many cases,H2O2 collaborate with NO to execute invading pathogens.H2O2 and NO production were induced almost at the same time by cryptogein,a fungal elicitor(Foissner et al.,2000).NOS inhibitors compromise the hypersensitive resistance response in Arabidposis and tobacco(Delledonne et al.,1998?;Huang et al.,1998).TMV infection could elevate NOS(nitric oxide synthase)activity,and NO could induce PR-1 expression(Durner et al.,1998).NO,as well as other ROS,have been shown to stimulate the accumulation of SA(Durner et al.,1999),which play a critical signaling role in the activation of plant defense responses after pathogen attack.Furthermore,to test whether OGAs functions on inducing resistance in tobacco via NO and H2O2 pathway,we examined the effects of OGAs,exogenous NO donor SNP and H2O2 on inducing resistance to TMV.It was found that all of these treatments reduced lesion caused by TMV.But co-treatment with OGAs and H2O2 scavenger CAT or ascorbic acid blocked the inducing resistance.The tobacco plants inhibited NOS activity by L-NAME were not induced resistance by OGAs.So the defense response induced by OGAs was connected with NO and H2O2 pathway.The study reported herein reveals that OGAs can induce the production of H2O2 and NO,and induce the defense response against TMV.Our understanding of OGAs induced resistance is sketchy.The mechanisms of OGAs eliciting defense responses of tobacco need further investigation.

川成都植物病害是由植物—病原—环境三者在一定适宜条件下，引起植物体发病，构成对植物正常生长发育和新陈代谢的干扰与破坏，最终造成植物的生物产量和经济产量减产，品质降低，给人类的农业、林业生产造成重大损失。植物病害的病原物是指能寄生于植物体并导致侵染性病害发生的生物。植物病害分成菌物（真菌）性病害、细菌性病害、病毒类病害、线虫类病害以及其他因素引起的植物病害。植物细菌性病害是植物病害中发生为害较重、发病规律比较难以掌握、防治技术要求高、防治效果很难凑效的一类病害。植物病原细菌是属于原核生物中的一个生物类群，它与真核生物在细胞结构及组成成分方面存在着较大的差异，正是这种细胞结构和组分上的差异，导致了细菌性病害比真菌性病害更难以防治。植物细菌性病害中比较著名的病害有：水稻细菌性条斑病、水稻白叶枯病、白菜软腐病、番茄青枯病、玉米细菌性枯萎病、柑橘溃疡病、梨火疫病、马铃薯环腐病。还有近年来被国际柑橘病毒学家确认的柑橘黄龙病等，这些植物细菌性病害给我国农业、林业生产带来了巨大的影响和危害。本文将对植物细菌性病害做了以下6个方面的初步探讨。早在2000多年前我国《诗经》中已经将生物划分成了植物、动物和蕈类三大类。1593年李时珍在《本草纲目》中将生物分成了植物、动物和人类三大类。在近代科学发展史上，以林奈为代表的生物分类学家将生物分成两界（即动物界Animaliae和植物界Plantae），这两界系统被人类科技界沿用了200多年。16～18世纪，随着显微镜发明和细胞学说的建立，人类才发现了单细胞生物——细菌。对于细菌在生物进化过程中，专家们普遍认为：细菌的出现应该是在植物和动物出现之前就已经存在了。1969年魏泰克将生物界分成五界系统，即：（1）以细菌为主的原核生物界；（2）以单细胞原生动物和藻类为主的原生生物界；（3）多细胞生物中以光合作用制造营养的植物界；（4）以多细胞为主吸收营养的真菌界；（5）多细胞生物中以摄取食物为营养来源的动物界。1974年黎德勒认为：取消原生生物界，将生物化分成四界系统，即：原核生物界、真菌界、植物界和动物界。1977年我国科学家陈世骧提出了生物学界的三总界构成六界系统，即：无细胞总界——（病毒界）；原核生物总界——（细菌界、蓝藻界）；真核生物总界——（真菌界、植物界、动物界）。1988～1989年（Cavalier-Smith），将生物学界划分成：两个总界组成的八界系统，即：一、细菌总界：①真细菌界；②古细菌界；二、真核总界：③古菌界；④原生动物界；⑤植物界；⑥动物界；⑦真菌界；⑧藻界。到2003年，他取消了古细菌界和古菌界，改为二总界六界学说。许志刚教授在2005年正式提出三域七界的最新分类体系，即无细胞生物域的病毒界；原核生物域的细菌界；真核生物域的原生生物界、真菌界、藻物界、植物界和动物界。反映了当前人们的认识水平。从上述分类系统可以看出，细菌的分类始终处于原核生物界内，它与真核生物在细胞结构及其组成成分上存在着许多本质上的差异。原核生物是以单位膜为界的，细胞核质无核膜包围，呈原核状态。含肽聚糖的细胞壁有或无；核糖体在细胞质内70S。染色体的数目为1。细菌的质粒DNA游离于细胞质中。细菌都是单细胞生物，它们的细胞膜外都有一层主要由肽聚糖（革兰氏阳性细菌）或脂多糖（革兰氏阴性细菌）构成的坚韧细胞壁。真核生物：具有以单位膜为界的细胞器，细胞壁不含肽聚糖。细胞核有核膜包围，呈真核状态，核糖体80S，在细胞器内的核糖体70S。细胞内有内质网、高尔基体、溶酶体、叶绿体有或无、有微管系统。染色体中有组蛋白；有核仁；要发生有丝分裂；细胞器有DNA（如线粒体）；配子能够融合；DNA不单向转移形成部分二倍体。最典型的是真核生物具有真正的细胞核以及其他细胞器组成成分。核是细胞的控制中心，它由核膜包着与核外的细胞质分开。核膜内有核仁和核质。植物病理学家们长期以来将植物细菌性病原种与对寄主的致病性作为一个非常重要的因素，同时要依据病原细菌的生理生化性状和血清学性状等指标来综合确定植物病原细菌的种。在《伯杰氏细菌学手册》第七版出版时已经命名的植物病原细菌种有200多种。根据生物学命名中优先命名权不能侵犯的原则，确定每一个新种必须查阅大量文献，以避免同物异名的出现。在《伯杰氏细菌学手册》第八版中将植物病原细菌种由原来的200多种削减为几十种，以保证所有种都可以用生化试验来进行鉴定并尽量保证能在实验室条件下可以重复实验，使之更具有科学性和重复性。1994年，根据《伯杰氏细菌学手册》第九版的系统分类：将细菌分成了四大类35个群。2000年以后，《伯杰氏细菌学手册》第二版分五卷陆续出版发行，该版本的最新分类体系中将细菌界包括了16门、26组、27纲、62目、163科、814属，共计4727种。植物病原细菌属于细菌界中普罗特斯门、放线菌门和厚壁菌门。普罗特斯门细菌细胞壁主要由脂多糖组成，肽聚糖含量较少，因而革兰氏染色阴性。放线菌门细菌的细胞壁中肽聚糖含量高，革兰氏染色阳性。厚壁菌门中的病原生物包括植原体（Phytoplasma）和螺原体（Spiroplasma）。已经描述的引起植物病害的原核生物有28个属。植物细菌性病害的病原菌主要分成五大类别。第一类：黄单胞菌属（Xanthomonas）。黄单胞菌属是细菌中的特殊类群，目前文献中描述的黄单胞菌属的种几乎都是植物病原细菌。它可以为害120多种单子叶植物和270多种双子叶植物。黄单胞菌引起许多重要植物病害，比较典型的病害有：（1）甘蓝黑腐黄单胞菌（X.campestris pv.campestris）；（2）水稻白叶枯病（X.oryzae pv.oryzae）；（3）水稻细菌性条斑病（X.oryzae pv.oryzicda）；（4）柑橘溃疡病（X.campestris pv.citri）。由黄单胞菌属细菌引起的植物病害大多数症状为叶枯、坏死、萎蔫等症状。第二类：假单胞菌属（Pseudomonas）。假单胞菌属细菌大多数都是土壤、水、其他基质上的腐生菌，有些是植物病原细菌。它的生态适应性广，表型差异大，是一个非常异质的组群。丁香假单胞菌（Pseudomonas syringae）是重要的植物病原细菌，能为害多种植物。在《伯杰氏细菌学手册》第九版中正式命名的植物病原细菌有7个种。第三类：欧文氏菌属（Erwinia）。欧氏菌属细菌是人类第一个发现的植物病原细菌。有史以来所发现的欧氏菌属细菌一部分是植物病原细菌，最常见的是各种植物的软腐病，也有萎蔫和坏死。典型的病害有：梨火疫病（E.amylovora）；玉米细菌性枯萎病（E.stewartii）；马铃薯和大白菜的软腐病等。由欧氏菌引起的细菌性软腐病在全世界均有发生分布。第四类：土壤杆菌属（Agrobacterium）。土壤杆菌属细菌是一类习居于土壤的细菌，在土壤中广泛的分布。常见的致病性细菌种有根癌土壤杆菌和发根土壤杆菌。根癌土壤杆菌（A.tumefaciens）能为害多种双子叶植物，在近土根茎部形成恶性肿癌。发根土壤杆菌（A.rhizogens），在侵染双子叶植物幼根后形成丛生的毛发状根群，称之为发根。第五类：棒形杆菌属（Clavibacter）。它是从棒状杆菌属（Corynebacterium）中分列出来的一个新属。国内发现的植物病原棒形杆菌属细菌中，最典型的病害有马铃薯环腐病菌（C.m.pv.sepeadonicum）在国内马铃薯产区均有分布。由于该病菌是以种薯传带的，所以在调运马铃薯种薯时必须要实施检疫。小麦蜜穗病菌（C.tritici）在国内华北冬麦区、山东、安徽、江苏、浙江、贵州等省已有发生。植物病原细菌从植物的气孔、皮孔、蜜腺等自然孔口以及伤口侵入寄主。植物细菌性病害主要见于高等被子植物和栽培植物上较多。植物病害的症状包括病状和病症两个方面。所谓病状：是指感病植物的外部特征，主要表现有：（1）变色：指整个植株、叶片或叶片部分变色。（2）坏死：指植物体局部细胞和组织的死亡。（3）腐烂：整个植物的组织和细胞被破坏和消解。（4）萎蔫：植物病害中的萎蔫是指植物的输导系统被病原物毒害或病组织的产物阻塞而造成不可逆转性的萎蔫。（5）畸形：感病植物组织和器官所发生的皱缩、卷曲、萎缩、丛枝、发根、肿瘤，花器和种子变态。所谓病症：是指病原物在病株发病部位上所表现的特征。主要表现有：（1）霉状物。（2）粉状物。（3）锈状物。（4）粒状物。（5）根状菌索。（6）菌脓。菌脓：是指发病部位产生的胶黏脓状物，干燥后形成白色的薄膜或黄褐色的胶粒。菌脓是细菌性病害在田间特有的病症。从多年田间病害症状诊断的实践环节看，植物细菌性病害田间症状诊断上着重注意几点：细菌性病害往往会出现局部坏死斑点，如柑橘溃疡病的病斑。腐烂：很多蔬菜类作物上出现的软腐病、马铃薯环腐病等。萎蔫：作物上出现的青枯病，全株性萎蔫。菌脓：如水稻细菌性条斑病病叶上出现的胶黏脓状物。细菌性病害往往不会出现整株变色、叶片上不会出现霉状物、粉状物、丛枝、萎缩等症状。细菌性病害会出现发根和肿瘤等症状。这个问题是一个非常复杂的问题，要回答好这个问题并非易事。从理论上探讨，所有植物病原细菌都可以通过种子传带。细菌附着在种子表面，也可以存活于种皮内，以及块茎组织内部。细菌在植物种子上一般存活1～2年。植物病原细菌一般产生胞外多糖，且一般具有鞭毛结构。因而，雨水的溅射和细菌自身在水中的游动可导致其传播。此外，随着灌溉水的流动，细菌可以在田块间传播。在20世纪60～70年代，水稻白叶枯病在四川省水稻产区流行蔓延，造成水稻产量严重减产，损失惨重。植物病原细菌可以通过苗木、接穗传播。嫁接工具、人为操作不当的行为均可以传播植物细菌性病害。柑橘溃疡病在我国柑橘主产省区均有不同程度地发生为害。狂风暴雨夹带雨滴是沿海岸线柑橘产区柑橘溃疡病蔓延猖獗的主要环境因素。通过媒介昆虫可以传带细菌性病害。柑橘黄龙病传毒主要媒介是柑橘木虱。要使柑橘黄龙病发生蔓延的几大因素是：一是要有柑橘黄龙病病树存在；二是要有传毒的媒介昆虫；三是要有感病的寄主。同时，昆虫的越冬寄主枳壳、九里香等存在为病菌的越冬和第二年的病菌的侵染循环创造了条件。如何掌握植物细菌性病害发病规律，作者认为应该注意以下几点：（1）植物的种子、苗木、接穗等一切繁殖材料均有可能携带植物细菌性病害的病原，并能在植物体表或表皮内较长时期的存活，是远距离传播植物细菌性病害的主要原因。（2）由于植物病原细菌的细胞有胞外多糖，在有水膜存在下可以加快细菌侵染速度，为害程度由点到片逐步加重。在雨季、大风、甚至飓风条件下加快了点片发生与为害的程度。（3）有灌溉水存在的条件下可以加快植物细菌性病害的流行蔓延，是大面积造成为害损失的主要诱因。（4）有媒介昆虫的发生、越冬寄主的存在，为植物细菌性病害的再次侵染循环奠定了基础和创造了条件。（5）嫁接工具、农事活动操作不当均可以造成寄主大量伤口，有利于病原细菌的侵入，导致田间植物细菌性病害近距离传播为害。（6）适宜的温湿度条件，加速了植物细菌性病害的侵染循环。根据植物细菌性病害发病的诱因和发病基本规律可以看出：种子、苗木可以带菌；细菌繁殖速度快、侵染途径多；远距离传播与近距离扩散相辅相成，加快了细菌性病害点、片发生，具有暴发成灾、损失严重的特点。植物细菌性病害很难防治，药剂防治效果很难奏效。四川省在防治水稻白叶枯病、水稻细菌性条斑病、柑橘溃疡病、柑橘黄龙病等细菌性病害中都不是单一地采用药剂防治。药剂防治只能作为综合治理植物细菌性病害技术环节中的一个重要环节，特别是柑橘溃疡病防治技术中，国内外至今尚未见到仅仅依靠药剂防治来完全控制其为害蔓延的成功范例。柑橘黄龙病的综合治理更是如此。（1）建立无病虫种子、苗木繁殖基地，生产健康无检疫性病虫的种子苗木。（2）种子苗木调运前实施田间产地检疫和抽样实验室检验相结合，保证调出种子苗木是无病的。（3）调入地尽量集中成片种植，播种前进行种子消毒处理，有利于生产管理和病虫害综合治理。（4）加强田间病虫害预测预报，发现细菌性病害点、片发生时，及时拔除病株销毁，并用药剂对周围植株进行保护性防治。（5）严格对发病田块的肥水管理，防止有病田块流水串灌或漫灌。（6）对较大面积发生细菌性病害的发病区要及时隔离，防止上游流水继续向下游流传，造成更大面积的细菌性病害流行。同时对发病区要进行较大规模的药剂防治。（7）及时换种、加强轮作换茬，防止细菌性病害在田间菌量的不断积累和再次暴发成灾。（8）注意嫁接工具的消毒，防止农事活动中人为的传播感染。

豆瓣菜（Nasturtium officinale R.Br.）又名西洋菜、水蔊菜、水田芥，属十字花科豆瓣菜属植物。枝叶柔嫩青翠，性喜冷凉，较耐霜冻，是深受人们喜爱的冬春上市的水生绿叶蔬菜。有关豆瓣菜菌核病国内尚未有专门报道。该病1999年在武汉旱地栽种的豆瓣菜田中仅见零星发生，到2001年春发病田中的发病面积可达1.61%，甚至到10%左右，表明病害有增重的趋势。豆瓣菜的茎、叶、叶柄均可受害。以中、下部贴近地面匍匐或半匍匐生长的枝叶受害最重。田间病害呈点片状发生，不规则分布。因豆瓣菜分枝多，生长繁茂，茎呈匍匐或半匍匐丛生，故发病初期常需拨开丛生状植株，才能发现感病枝叶，后期因植株枯死而呈现近圆形至不规则形病区。茎部受害，水渍状，淡褐色，边缘不清晰，从病处向两端扩展，空气湿度大时生茂密的绵毛状白霉，继而在植株表面及病茎的空腔中菌丝集结成近球形、扁球形、鼠粪状或不规则的菌核。菌核初白色，成熟后黑色，内部白色。罹病植株病部软腐，但无恶臭，最后失水干枯而呈枯草黄色。叶柄症状与茎部同。病叶受侵处灰褐色或浅黄褐色，湿度大时亦生较稀疏的绵毛状白霉，最后病叶腐烂或干枯。该病一般在12月上中旬出现病株，1月下旬至2月上中旬是大棚中豆瓣菜菌核病的盛发期，大棚和露地均在3月上旬病情趋于稳定。在近几年的调查观察中，一直未见浅水栽植的豆瓣菜有菌核病发生，而旱地栽植的豆瓣菜，不论大棚或露地种植的条件下均可受害，并且大棚中的病情有较露地重的趋势。病茎失水干枯后，菌核极易脱落，而病茎空腔内的菌核则随病株残体遗留在土中。该病的初侵染，来自遗留在土中的菌核产生的子囊孢子。子囊孢子不能侵染健壮的枝叶，而极易侵染中下部贴近地面匍匐或半匍匐生长的衰老叶片，此后才能侵染健壮的枝叶。再侵染主要通过病患组织接触，由病部长出的绵毛状菌丝体完成。豆瓣菜的匍匐或半匍匐生长及分枝多、生长繁茂、枝叶交错的植物学性状和病原菌侵染循环特点，决定了其有利于菌核病菌的接触蔓延，而不利于子囊孢子的气流较远距离的传播，因而造成了植株中、下部枝叶发病的现象，这样就使豆瓣菜菌核病具有一定的“隐蔽性”，也导致田间病害呈点片状发生及不规则分布的特点。菌丝管状、无色，有分枝具隔膜，田间自然情况下菌丝体白色绵毛状，在病茎表面及被害茎的空腔里均可形成菌核。在测量的87个菌核中，其大小（长径）为2.0～7.0mm。菌核无休眠期。将菌核置培养皿中双层浸湿的滤纸上，13.5～16.0℃，室内散射光下培养很易萌发。一个菌核可生出一至数个子囊盘，子囊盘高足杯状，初淡褐色，后为暗褐色。柄长短因环境而异，在黑暗无光条件下，柄长可达6.0 cm以上。子囊盘中生有大量子囊和侧丝，子囊无色棒状，内生8个排列一行的子囊孢子。子囊孢子椭圆形，无色单胞，大小8.7～13.7μm×4.9～8.1μm。子囊孢子成熟后稍受震动（如打开供菌核萌发的培养皿的盖），即可看到状如烟雾的子囊孢子放射现象。据上鉴定，认为豆瓣菜菌核的分离物为Sclerotonia sclerotiorum（Lib.）de Bary。这是我们首次在豆瓣菜上发现有由核盘菌引起的菌核病。进一步研究发现该菌菌丝生长温度范围很广，其中在4～5℃时，菌落在PDA平皿上扩展速度为8.3mm/天、33℃时为2.0 mm/天、当温度达到35℃时，菌落几乎停止生长。病菌菌丝生长最适温度是21℃，在此温度下，菌落扩展速度达32.2 mm/天。