Where is the Ecology in Molecular Ecology

物种辅助迁移问题的生态伦理考量当今物种灭绝的趋势正随着生态危机的加重而呈现持续恶化，使得一些传统物种保护手段（如划定自然保护区、栖息地复位等）的效用减弱，特别是随着社会各界对全球气候变暖的重视，以原位保护为主的策略也逐渐向异地保护的形式转向，物种辅助迁移就属于这类转向的典型代表。

辅助迁移保护策略采取的方式是将保护对象从原生环境转移到异地生存的保护模式，虽然它在当下应用广泛，但也存在诸多问题的争议。

本文对辅助迁移问题的生态伦理考量主要由三部分内容组成。

第一，对物种辅助迁移的历史和发展现状进行考察，明确它在众多保护策略中的地位，以及大致整理出它在保护生态位、缓解利益冲突、保护濒危物种三类情境中的应用状况。

第二，在此基础上，针对这三类情境所涉及的各种问题纷争，梳理总结了关于物种辅助迁移在生态风险和保护效用两方面的争论。

第三，将两类争论纳入生态伦理的视域中，分别从物种保护的道德动机与保护主旨、物种保护的道德关怀与辅助迁移效用的局限性以及辅助迁移应有道德语境与适用对象这三个层面，对一些非必要争论的问题域进行澄清，特别是为我国一些物种骤减严重的地区借鉴国外物种辅助迁移的实践应用提供有益的选择性导向。

一、物种辅助迁移的历史及发展现状迁移本身并不是什么新概念，人类迁移野生动物的历史已有数千年，类似物种迁移的方案也早在20世纪80年代就已经被提出。

①国际自然保护联盟（IUCN）更是早在1987年就将迁移（translocation）的概念明确定义为：“生物从一个地区迁移到另一个地区，将其放生并还以自由。

”②但直到21世纪，当全球变暖已然成为新形势下生态危机的代名词时，物种辅助迁移的保护策略才得以受到最为广泛的关注。

物种迁移的实际应用所涉及的意图很多，其中就包括商业目的或娱乐等，本文主要针对保护性质上的物种迁移（conservation translocation），大致有以下三类情况。

第一类，以保护生态位为目的，用以修复某区域生态系统关键生态位的缺失。

植物氮代谢及其环境调节研究进展3许振柱　周广胜33(中国科学院植物研究所植被数量生态学重点实验室,北京100093)【摘要】　氮代谢是植物的基本生理过程之一,也是参与地球化学循环的重要组成部分.植物氮素同化的主要途径是经过硝酸盐还原为铵后直接参与氨基酸的合成与转化,期间硝酸还原酶(NR )、谷氨酰胺合成酶(GS )、谷氨酰胺合酶(G O G A T )、天冬酰胺转氨酶(AspA T )等关键酶参与了催化和调节.以氨基酸为主要底物在细胞中合成蛋白质,再经过对蛋白质的修饰、分类、转运及储存等,成为植物有机体的组成部分,同时与植物的碳代谢等协调统一,共同成为植物生命活动的基本过程.文中概述了植物氮素同化的途径、几种关键酶的特性和调控机制,简述了氮素代谢的信号传导、植物细胞蛋白质的形成、转运、储存和降解过程.基于水分胁迫等关键生态因子对氮代谢的影响及其调节机制的评述,强调了未来需加强研究的7个方面.关键词　氮代谢　环境调节　水分胁迫　关键酶　途径文章编号　1001-9332(2004)03-0511-06　中图分类号　Q945,Q949　文献标识码　AR esearch advance in nitrogen metabolism of plant and its environmental regulation.XU Zhenzhu ,ZHOU Guangsheng (L aboratory of Quantitative V egetation Ecology ,Institute of Botany ,Chinese Academy of Sci 2ences ,Beijing 100093,China ).2Chin.J.A ppl.Ecol .,2004,15(3):511～516.Nitrogen metabolism is not only one of the basic processes of plant physiology ,but also one of the important parts of global chemical cycle.Plant nitrogen assimilation directly takes part in the synthesis and conversion of amino acid through the reduction of nitrate.During this stage ,some key enzymes ,e.g.,nitrate reductase (NR ),glu 2tamine systhetase (GS ),glutamate dehydrogenase (G DH ),glutamine synthase (G O G A T ),aspargine synthetase (AS ),and aspartate aminotransferase (AspA T )participate these processes.The protein is assimilated in plant cell through amino acid ,and becomes a part of plant organism through modifying ,classifying ,transporting and storing processes ,etc.The nitrogen metabolism is associated with carbonic metabolism through key enzyme regulations and the conversion of products ,which consists of basic life process.Among these amino acids in plant cell ,glutam 2ic acid (G lu ),glutamine (G ln ),aspartic acid (Asp )and asparagines (Asn ),etc.,play a key role ,which regulates their conversion each other and their contents in the plant cell through regulating formation and activity of those key enzymes.Environmental factors also affect the conversion and recycle of the key amino acids through regulat 2ing gene expression of the key enzymes and their activities.Nitrate and light intensity positively regulate the gene transcription of NR ,but ammonium ions and G lu ,G ln do the negative way.Water deficit is a very serious con 2straint on N 2fixation rate and soybean (Glycine m ax Merr.)grain yield ,in which ,ureide accumulation and degradation under water deficit appear to be the key issues of feedback mechanism on nitrogen fixation.Water stress decreases NR activity ,but increases proteinase activity ,and thus ,they regulate plant nitrogen metabolism ,although there are some different effects among species and cultivars.Water stress also decreases plant tissue pro 2tein content ,ratio of protein and amino acid ,and reduces the absorption of amino acid by plant.On the contrary ,soil flooding decreases the content and accumulation amount of root nitrogen in winter wheat by 11.9%from booting to flowering stages and 39.1%during grain filling stage ,and reduces the ratio of carbon and nitrogen by 79.6%.The results misadjust the metabolism between carbon and nitrogen ,and result in the end of the root growth.Elevated CO 2level could decrease plant leaf nitrogen content under well 2watered condition ,but almost maintain stable under water deficit condition.The radiation of UV 2B significantly reduces the partitioning coeffi 2cient and synthetic rate of Rubisco ,which significantly decreases the photosynthetic rate.This paper reviewed the pathway of plant nitrogen assimilation ,characteristics of key enzymes and their regulating mechanisms with pic 2turing the regulating mode of NR ,and described the signal sensing and conduct of plant nitrogen metabolism and the formation ,transportation ,storage and degradation of plant cell protein with picturing the schedule of protein transport of membrane system in plant cell.Seven key tasks are emphasized in this paper in terms of the review on the effects and mechanisms of key ecological factors including water stress on plant nitrogen metabolism.They are :1)the absorption mechanism of plant based on different nitrogen sources and environmental regulations ,2)the localization and compartmentalization of the key enzymes of nitrogen mechanism in plant cell ,3)the gene and environmental regulating model and their relationships in various key enzymes of nitrogen metabolism ,4)the function of main cell organs and their responses to environmental factors in nitrogen metabolism process ,5)phys 2iological and chemical mechanism of nitrogen and the relationship between the mechanism and protein formation during crop grain filling ,6)improving gene structure of special species or cultivars using gene engineering meth 2ods to enhance the resistance to environmental factor stress and the efficiency of absorption and transportation of nitrogen ,and 7)the mechanism of natural nitrogen cycle and its response to human activity disturbance.K ey w ords Nitrogen metabolism ,Environmental regulation ,Water stress ,K ey enzymes ,Pathway.3国家重点基础研究发展规划项目(G1999043407)、国家自然科学基金重点项目(39730110)和中国科学院知识创新工程资助项目(KSCX221207,KZCX12SW 201212).33通讯联系人.E 2mail :zhougs @ 2002-08-07收稿,2002-11-27接受.应用生态学报　2004年3月　第15卷　第3期 CHIN ESE JOURNAL OF APPL IED ECOLO GY ,Mar.2004,15(3)∶511～5161　引 言植物从外界环境获得N主要是通过3条途径,通过NO-3还原把无机氮转化为生命体可用的有机氮,通过固氮菌对N2的固定,直接吸收土壤中的铵或有机氮.有研究者指出,每年经硝酸盐同化的N达10×1010t,而固氮菌固定的N 只有10×108t,前者是后者的100倍.而且硝酸盐还原与C 代谢密切相关,估计光合作用能量的25%用于硝酸盐还原[41].光合碳代谢与NO-2同化都发生在叶绿体内,二者都消耗来自碳同化和光合及电子传递链的有机碳和能量.研究表明在某些组织中N代谢甚至可消耗掉光合作用能量的55%[42].毫无疑问,研究其生理生化过程及其环境调节机制是揭示植物生命活动过程机制的关键.无机氮被吸收还原后,在植物体内经运输、合成、转化及再循环等各种生理活动过程后,与蛋白质代谢共同构成其生命活动的基本过程.2　氮素同化的途径一般认为植物同化的主要途径是[41,46]:NO-3NRNO-2NiRNH+4(NR:NO-3还原酶,NiR:NO-2还原酶).而NH+4同化需要经过一系列酶促反应的复杂过程,Lam等[17]总结了氨同化及其循环的生化反应过程:G lu+NH+4+A TP GSG ln+ADP+PiG ln+α-Oxo+2Fd(red)Fd-GO GAT2G lu+2Fd(Ox)G ln+α-Oxo+NADH NADH-GO GAT2G lu+NADG lu+H2O+NAD/NADP G DHNH+4+α-Oxo+NADH/NADPHG lu+Oxo AspATAsp+α-OxoG lu+Asp+A TP AsAsn+G lu+AMP+PPiAS有另一种作用形式是[4]NH+4+Asp+A TP AsAsn+ADP+Pi其中,GS为谷氨酰胺合成酶;G O G A T为谷氨酰胺合酶;G DH 为谷氨酸脱氢酶;AspA T为天冬氨酸转氨酶;As为天冬酰胺合成酶;α2Oxo为α2酮戊二酸;Pi为磷酸;PPi为焦磷酸.植株内所有的无机氮首先被逐步还原,经过再循环后变成有机氮形态[14].3　氮素同化过程中的关键酶及其调节311　硝酸还原酶(NR)NR是植物N代谢关键步骤硝酸盐同化中的限速酶,为了阐明其催化特性、效率及其调节的研究倍受关注[12,41].对各种环境条件下NR调节作用的研究仍较少.图1描绘了NR的调节模型[1,31,41,50].312　谷氨酰胺合成酶(GS)GS有两种同工酶,即分别定位于胞质和叶绿体的GS1图1　硝酸还原酶的调节模型Fig.1Regulating mode of nitrate reductase.和GS2,分别执行不同的生理功能.位于叶绿体中的GS2的主要功能是把叶绿体和光呼吸再合成的NH+4合成为谷氨酰胺(G ln)[23],而处在根中的GS1则主要是参与根部N的合成,但同时GS2也参与了这一过程[24].研究表明,GS2基因表达与光密切相关,受到光敏素的激活[9].同时也受到组织状况、碳水化合物、氨基酸供应和光呼吸的影响[24].GS在植物N代谢中的地位和作用是复杂的,具有不同同工酶表达类型及生物功能[17].313　谷氨酸脱氢酶(G DH) G DH具有两种形式,一种是在线粒体中发现的依赖于NADH的G DH,另一种是叶绿体中发现的依赖于NADPH的G DH[8].G DH在NH+4的合成及G lu的代谢中具有十分独特的作用.它在NH+4的合成和再合成中起初始性作用,并在G lu合成循环中起补充作用,但是它在高等植物中的生理作用仍有争议[17].植物在适应暗环境后积累较多的G DH的mRNA,并会受到光和蔗糖的抑制[17].有证据表明,有2种相互制约的基因参与了光与糖对G DH的调节作用[22].当C代谢受限时,G DH的活性会增加[27].这表明C代谢及其代谢物参与G DH的调节.314　天冬酰胺合成酶(AS)虽然天冬酰胺(Asn)是已在190多年前被分离出来的氨基酸[51],但有关其合成机制最近才被阐明.普遍认为AS是植物合成Asn的主要途径[34].环境条件和代谢信号控制Asn 的水平和AS活性.当需光植物适应于暗环境时,使AS活性升高和Asn含量增加,其中光敏素在起作用[16].也有报告指出光和(或)蔗糖会降低AS的活性[3,7].添加外源氨基酸如谷氨酸(G lu)、G ln、Asn等能免除庶糖的抑制作用.表明无机氮对C的比率可能是其基因表达的最终影响因子.在提供的碳架较多而无机氮源不足的条件下,Asn的合成储存作用则比较显著[16].215应　用　生　态　学　报 15卷315　谷氨酰胺合酶(G O G A T )G O G A T 也有两种形式,一种是以NADH 作为电子供体的NADH —G O G A T ,另一种则是以铁氧还蛋白作为供体的Fd 2G O G A [38].后者在植物叶片中处于主导地位,占全部G O G A T 活性的95%[17].Fd 2G O G A T 存在于叶绿体中,光诱导它的生物合成,并与光合作用和光呼吸有关[38].光诱导使其mRNA 水平升高,而外源蔗糖则能使由于缺乏光照导致的Fd -G O G A T 蛋白的减少得以逆转[17].说明有利光合作用的因素亦有利于Fd 2G O G A T 的表达和合成.316　天冬酰胺转氨酶(AspA T )AspA T 的作用是以G lu 和草酰乙酸为底物,生成Asp 和α2酮戊二酸.它有多种不同形式的同功酶.其在不同环境中的生理生化作用不同[17].在豆科作物苜蓿(M.sativa )中,随着有效根瘤的发育,其叶片中AspA T 的mRNA 水平提高[48].有效氮对胞质和线粒体中的AspA T 的基因转录过程起正效应,而对质体中的基因表达无此效果[47].4　植物细胞蛋白质的形成、转运及储存植物从外界吸收NH +4或NO -3后合成为氨基酸,之后经过相互转化,生成合成蛋白质的各种底物,根据基因的遗传信息,在mRNA 、tRNA 和rRNA 以及氨基酸活化酶等生物功能物质参与下,在核糖核蛋白体上合成肽链,再经过折叠等生化过程最后形成具各种生物功能活性的蛋白质[52].Okita 和Rogers[28]在总结前人工作基础上,描绘出了植物内膜系统蛋白转运模型(图2).图2　植物细胞内膜系统蛋白质转化过程图Fig.2Schedule of protein transport of membrane system in plant cell.AP :自体吞噬路径Autophagic pathway ;CCVs :外套格子小泡Clathrin 2coated vesicle ;CW :细胞壁Cell wall ;;ER :内质网Endoplasmic reticu 2lum ;G olgi :高基体G olgi body ;PM :胞间连丝Plasmodesma ;PSV :贮存蛋白质液泡Protein storage vacuole ;SDVs :光滑小泡Smooth “dense ”vesicles ;V :液泡Vacuolar. 蛋白质在内质网(ER )中合成后分泌于膜腔内,按照细胞内的区域化特定顺序运转:包括从ER 到高尔基体(G ol 2gi )[29](后者分为Cis 2G olgi 网、G olgi 垛和传输G olgi 网[44]).蛋白质在ER 和G olgi 区格化传输过程中被浓缩了200倍[36],这个过程也可能始于ER 的出口[2],蛋白质在ER 内被分类后进入贮存蛋白质的液泡(PSV ),或在G olgi 体内分类后分泌出光滑小泡(SDVs )或外套格子小泡(CCVs )后进入PSV.ER 可通过自体吞噬路径(AP )直接进入液泡形成蛋白质体(PBs ).其间需要一些特殊的相关氨基酸残基,或不具相邻残基折叠成的三维结构[30].其分类决定了蛋白质在细胞内区格化内膜系统的位置.然后,由ER 直接或在液泡[52]内形成大的蛋白质分子,甚至形成蛋白质体,并存在着ER 参与下通过胞间连丝(PM )细胞间的分子水平上的传导[11].在大麦醇溶蛋白的积累过程中,蛋白质体在液泡内积累包装后形成,但也发现由内质网直接形成的蛋白质体,当胚乳发育到较晚阶段后其快速积累的醇溶蛋白几乎全部是在内质网中进行[33].在豆科作物上也得到类似的结果[25].另一种情况是,在蛋白质积累过程中,许多内质网潴泡聚集浓缩,进一步形成蛋白质体[13,18].Robinson 等[35]的研究证实豌豆子叶缺乏核糖体的内质网可能直接形成贮存蛋白质的液胞,并在其周围有嗜锇的蛋白质沉积物.5　氮代谢的信号硝酸钾对植物生长的作用在16世纪已被人们所认识.硝酸根本身就是植物吸收硝酸根和诱导N 代谢的正信号.而其代谢产物铵、合成产物G lu 和G ln 是负信号.基因分析的研究方法也证明了这一点[6].但实际情况较复杂,例如硝酸根可通过抑制淀粉合成关键酶的基因表达使碳架向着用于N 合成的方向转化[37].研究表明,烟草NR 突变体具有低水平的活性,失去了野生型的诱导作用,分离出的相关基因ANRI 在根系扩展中扮演了重要角色[59].基因标记的研究结果表明,野生型烟草和一种NR 缺陷型烟草Nia30(145)相比,前者可在高硝酸根水平条件下合成较多的蛋白质、氨基酸和G ln ,消耗的硝酸根也较多,后者则相反,表明由于基因缺失而导致了硝酸根诱导作用的丧失[37].Wang 等[54]的研究表明,根据硝酸根诱导NR 的mRNA 快慢,可把NR 克隆基因分为两类,一类是对低浓度硝酸根的快速(20min )响应基因,另一类是对高浓度硝酸根的慢速(2h )响应基因.相比而言,以铵及其衍生物氨基酸作为分子信号的证据较少.认为铵及其衍生物氨基酸(G lu/G ln )是硝酸根和铵吸收的负调节物.在分子水平上的证据是,一种铵转运子基因(AM T1)在调节铵信号中起作用,铵及其合成产物G ln 可抑制其表达[54].N 和C 代谢在植物生化代谢途径中紧密相连.C 代谢调节基因介入和CN 代谢调节过程是显而易见的.葡萄糖和蔗糖的比值(G lc/Suc )可影响NR 的活性,而蔗糖能诱导经暗适应的绿色幼苗NR 的产生.在分子信号感知、传递和接受过程中,C 和N 代谢存在着相互制约的关系.光可诱导NR 活性及使mRNA 水平升高,C 代谢产物及引起NR 活性降低的N 代谢产物亦可达到同样的效果[6].6　环境调节611　水分胁迫水分是影响N 生物地球化学循环的关键因子之一.有研3153期 许振柱等:植物氮代谢及其环境调节研究进展 究表明,水分胁迫严重影响了豆科植物(如大豆)对大气中的N2的固定,从而减少了植物对无机氮的利用,最近的实验结果指出,水分胁迫后大豆根部的酰脲含量积累或降解揭示了其对水分亏缺适应的线索.这方面的研究刚刚起步,可望有进一步的成果报道[39,49].以植物的水分关系为例评述环境条件对N代谢的调节过程.Hsiao[15]的报告指出,水分胁迫显著地降低了NR的活性,中度胁迫仅1d便使提取液中的NR活性降低20%,严重或长时间的胁迫降低50%或更多,但此过程是可逆的,复水后24h便能恢复到其对照水平.NR活性的降低也表现在水分胁迫影响了NR的合成过程.最近Y adav等[56]研究结果表明,小麦在PEG轻度胁迫下,NR的活性提高,而在严重胁迫下,NR的活性开始下降.这或许表现出了其对水分胁迫的适应性.而Neeru[26]报道小麦在PEG渗透胁迫下,叶片的NR活性很快下降,并指出在胁迫初期下降的原因主要是活性的失活,不是合成量的减少.蒽玉芹等[55]在大田中的试验结果表明,降低土壤水分导致小麦NR活性急剧下降,提高土壤水分含量后又可显著地提高其活性,当处在孕穗期小麦的土壤水分达18%以上时,NR活性可成倍提高.水分胁迫的影响在品种间差异明显,抗旱品种活性降低速率低于敏感品种.并存在翻译水平上的差异.另一方面,由于干旱抑制光合和呼吸,导致NADH水平降低,而在NO-3的还原过程中需要其NADH提供电子,其水平的降低必会导致NR活性的下降[10,12,60].总之,不同土壤水分条件对植物NR活性的影响有差异,土壤水分条件不同(如干旱方式、长度等)影响机制可能不同,这方面还有待进一步研究.一般认为,水分胁迫使蛋白酶等一系列水解酶的活性增加,促进分解.Srivali[43]研究认为,水分胁迫能促进小麦老化,同时提高内肽酶和外肽酶的活性,从而导致一些蛋白质的水解.最近,陈立松等[5]对荔枝叶片的研究表明,在中度水分胁迫下,蛋白酶活性迅速提高,抗旱性强的品种提高幅度显著超过抗旱性弱的品种.在严重水分胁迫下,活性增大更多,2个供试品种蛋白酶的活性均极显著大于中度水分胁迫下的蛋白酶活性,抗旱性弱的品种增幅更大.经分析,叶片中的总可溶性蛋白质含量与蛋白酶活性呈显著负相关.这表明总可溶性蛋白质含量的下降是由于蛋白酶活性升高引起蛋白质水解所致.岳艳玲等[57]在小麦叶片上的研究表明,随着水分胁迫时间的延长,小麦叶片水溶性蛋白和非水溶性蛋白含量均显著降低,蛋白酶活性明显升高,并指出多胺参与了对蛋白酶的调控.多数研究者认为,水分胁迫导致蛋白质与氨基酸的比率或蛋白质含量减少[5,15].以甜菜叶片为例,干旱胁迫数天后,单位干重的可溶性蛋白和总蛋白含量都逐渐减少,在小麦叶片上的研究结果也表明,当相对含水量(RWC)降低到60%时,可溶性蛋白的含量显著减少.标记氨基酸渗入蛋白质的试验表明,短期的中度或严重胁迫阻碍了对氨基酸的吸收和渗入,从而影响到蛋白质合成[15].张慧等[58]采用示踪技术测定了渗透胁迫下小麦叶片蛋白质合成的能力,表明胁迫降低了叶片、特别是生长叶片蛋白质固定14CO2及由根系吸收的14C2G ly的掺入率,且抗旱性强的品种降低幅度较小.612　其它环境条件的影响土壤滞水对冬小麦影响的研究结果表明,根系中N含量和N积累量在不同生育时期的反应不同.前期影响较小,扬花后则随着滞水时间的延长逐渐下降,孕穗至扬花期间下降11.9%,灌浆期则下降39.1%,CN比下降79.6%,造成CN 代谢失调,根系走向衰亡[61].大雨会导致土壤N的损失[40].研究指出,在适宜的水分和土壤N供应条件下,高CO2水平降低植物叶片的含N量,原因是高CO2水平增加的生物量的幅度高于N增加的幅度,导致稀释效应的发生[19,21].但在草原上用小麦的研究试验表明,在水分亏缺条件下CO2水平的提高对N吸收和含量的影响不大.而低土壤N降低了叶片含N量,进一步加剧了高CO2浓度的稀释效应[40].UV2B辐射增强使叶N在Rubisco的分配系数明显降低,其合成明显减少,引起光合速率的明显降低.UV2B可能改变香蕉植株对不同氮源的吸收利用能力,从而引起CN比代谢和酸碱代谢调节的变化,导致CN比增高[45].杜仲叶片NR、GS、G DH和谷丙转氨酶(GPT)活性随酸雨p H值降低而降低,可溶性蛋白质和总N含量也呈类似趋势[32].7　结 语尽管近年来人们对植物N的合成途径、利用效率及其植物体内的转化过程展开了大量的研究,取得了一系列新的认识,但研究结果仍较分散,并没有绘制出植物界N代谢的完整过程和途径,许多难点和疑点还有待阐明:1)植物对不同氮源吸收机制及其环境调节;2)N代谢过程中关键酶在细胞内的定位、区域化及其作用,例如定位在不同细胞器中的酶的结构差异性如何,所起作用有何异同等;3)不同N代谢关键酶基因调控和环境调节模型及其相互间的关系;4)N代谢过程中参与的有关细胞器的功能及其环境影响;5)作物籽粒中N生理生化代谢过程及其与蛋白质体形成的关系;6)利用基因工程的手段改善特定植物物种或品种的基因结构,提高植物对N亏缺或富集等胁迫环境下的抗性,最大限度地提高N的吸收、转运效率;7)研究自然界N循环的内在机制及其人类活动的干扰影响,为维护和改善生态环境,促进可持续利用提供策略.相信随着植物生理学、生态学、细胞生物学、生物化学、分子生物学等学科的不断发展和综合交叉,人们对植物N代谢的认识将会进一步深入,从而达到有效控制植物对N的利用、合成和转化及分解过程的目的.参考文献1　Baki 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n(作物学报),27(5):673～679(in Chinese)作者简介许振柱,男,1965年生,博士,副研究员,主要从事陆地生态系统氮素循环和水分生理生态方面的研究,撰写专著1部(副主编),发表论文15篇.Tel:0102625914312 6289,E2mail:xuzz@致　读　者　・　作　者 《应用生态学报》系中国科学院沈阳应用生态研究所和中国生态学会主办的国内外公开发行的学术性期刊,科学出版社出版.国际标准刊号为ISSN100129332.专门刊载有关应用生态学(主要包括森林生态学、农业生态学、草地牧业生态学、渔业生态学、自然资源生态学、景观生态学、全球生态学、城市生态学、污染生态学、化学生态学、生态工程学等)的具有创新性的综合性论文、研究报告和研究简报等. 本刊创刊于1990年,现为月刊,采用国际标准开本(210mm×285mm),176面,每期39万字.本刊系中国自然科学核心期刊,曾荣获全国优秀科技期刊和中国科学院优秀期刊称号.本刊整体质量和水平已达到相当高度,在国内外应用生态学界的影响日益扩大.《中国科学引文索引》、《中国生物学文摘》、美国《生物学文摘》(BA)、美国《化学文摘》(CA)、英国《生态学文摘》(EA)、日本《科学技术文献速报》(CBST)和俄罗斯《文摘杂志》(РЖ)等数十种权威检索刊物均收录本刊的论文摘要(中英文). 据悉,您们正在从事有关生态与环境科学研究项目(如国家基础科学人才培养基金项目、国家杰出青年科学基金项目、国家自然科学基金重大和重点项目、国家攀登计划项目、国家“863”和“973”计划项目、国家重点科技攻关项目、“百人计划”项目、“长江学者计划”项目和国际合作研究项目等),并有望取得重大研究成果和产生一系列创新论文,本刊编辑同仁热切希望您及您的同行们充分利用这一科学园地,竭诚为您们提供优质跟踪服务,本刊将及时发表您们的创新成果论文(或以特刊、专刊及增刊等形式发表,或以专刊形式发表优秀英文创新论文).我们相信这一承诺一定能得到您们的积极响应,愿我们迎着新世纪的曙光,为应用生态学的发展协同奋进! 我们的目的: 读者———广泛订阅这一优秀期刊 作者———充分利用这一科学园地 编者———精心编制这一信息精品《应用生态学报》编辑部615应　用　生　态　学　报 15卷。

生态学的英语Ecology is a fascinating field of study that explores the interactions between living organisms and their environment. It encompasses a wide range of topics, from the relationships between species in a community to the global processes that shape our planet. In this document, I will delve into the intricacies of ecology and discuss the key concepts and principles that govern this discipline.One of the fundamental principles of ecology is the concept of interdependence. In nature, all living organisms are interconnected in complex webs of relationships. Each species relies on other species for resources such as food, shelter, and protection. For example, plants depend on bees for pollination, while bees rely on plants for nectar and pollen. This interdependence ensures the stability and resilience of ecosystems, as changes in one species can have ripple effects throughout the entire ecosystem.Another key concept in ecology is the idea of energy flow and nutrient cycling. In any ecosystem, energy is constantly being transferred from one organism to another through the food chain. Producers, such as plants, capture sunlight and convert it into energy through photosynthesis. This energy is then passed on to herbivores, which are consumed by carnivores, creating a flow of energy through the ecosystem. At each step of the food chain, energy is lost in the form of heat, resulting in a pyramid-shaped structure with fewer organisms at higher trophic levels.Nutrient cycling is another essential process in ecology, as it ensures that essential elements such as carbon, nitrogen, and phosphorus are recycled within ecosystems. Decomposers, such as fungi and bacteria, break down dead organic matter and release nutrients back into the soil, where they can be taken up by plants. This cycle of nutrient recycling is crucial for the health and productivity of ecosystems, as it allows nutrients to be reused rather than lost from the system.One of the most pressing issues in ecology today is the impact of human activities on the environment. Climate change, deforestation, pollution, and overexploitation of natural resources are threatening the delicate balance of ecosystems around the world. These human-induced changes are leading to biodiversity loss, habitat destruction, and disruptions in ecosystem services that are vital for human well-being. It is essential for us to understand the interconnectedness of all life on Earth and work towards sustainable solutions that protect the environment for future generations.In conclusion, ecology is a complex and dynamic field that explores the relationships between living organisms and their environment. By studying the principles of interdependence, energy flow, and nutrient cycling, we can gain a deeper understanding of the intricate workings of ecosystems. As we face unprecedented challenges such as climate change and habitat destruction, it is more important than ever to apply the principles of ecology to promote environmental conservation and sustainability. Let us strive to protect and preserve the natural world for thebenefit of all life on Earth.。

海洋保护英语作文100字：篇1:Sea pollution is becoming an increasing problem for our planet and we have a responsibility to reduce sea pollution.I need to describe the problem. Our ship currently dumps all its rubbish into the sea.It's easy to result in huge endanger. First of all, Non-organic substances such as plastic bags kill fish and whales. Because fish get trapped and whales cannot digest them. Secondly some rubbish is inherently toxic.I can suggest some solutions. First and foremost we can create a better system of disposing of rubbish for instance. We ought to store rubbish. Next, we are supposed to make ships environmentally and friendly. A case in point is that we should stop providing plastic bags.We must act now before it is too late!篇2:The earth scale change of climate has brought a new kind of natural disaster and the developed and complicated city system is holding a latent risk of expanding the damage artificially. Also people has been spoiling the health since the immense quantity of chemicals have been produced and already used in pursuit of convenience and various toxicsubstances have been produced unintentionally and accumulated in environment. Therefore, We need some countermeasures from the viewpoint to prevent the city environment form disaster and to manage environmental risks. So we will develop and improve a new risk management system and a disaster prevention system to preserve and create the city environment where people feel easy and sound in their life.篇3：here are many kinds of animals in the world,but not only the humans.we live in the same world,and we should be friends.as everybody knows,the humans are the rulers of the world today,so we should protect our friends--the animals!But how to protect them?as first,i think we must stop killing the rare birds and animals,especially the young ones.the second,we have to protect the environment,to make the sky blue,to make the grass green,to give the animals a comfortable space to live.篇4：All things cannot be separated from water, and fish cannot leave water.The theme is: water, the root of all things.It is true that the seven parts of the sea are right. We are from one of the creatures in the sea, and we have the samegills of fish when we are young.Everything shows that we are connected to the sea.Maybe we were just a little fish, but now we are the greatest humans.The sea is so kind and mysterious, what is it that we humans are, the most intelligent creatures at the top, what are our ancestors?It's a low-grade fish or an advanced dinosaur, and everything is a mystery.Now the sea is being developed by us, the sea ranch, the Marine oil base is so amazing.The sea gave us life, and gave us so much energy, and we?Marine oil base causes large oil spill, resulting in Marine oil pollution!What are we doing with the indiscriminate killing of whales and the salivating of shark fins?Is the environmental protection or the destruction of the ecological balance?If the sea could wash everyone's heart like a shell, there would be no creatures in the world because of our indiscriminate killing.Is it a reward that the sea is our mother, and it has created the destruction of all that it has created?No, it isn't.What else can we do when black oil covers the ocean, and when black exhaust fills the sky?The sea belongs to nature, nature belongs to us?We belong to the sea, and the sea belong to us?What are we doing here?To kill for personal gain?Destroy for yourself?No, no, no.I do not believe that we will destroy our oceans, and I do not believe that people will despair when the oceans disappear.Because everyone is selfish.Is it humane that the oceans have created us and destroyed us?Although we're trying to protect the environment, it's too late, unless time goes backwards, unless there's a miracle, unless it's all over again.I believe we can get the ocean back to our youth, and we are the smartest intelligent creatures. Everyone, for the sake of the bright future of the sea, also protect the sea for ourselves.thank you.篇5：The ocean, a vast blue expanse, is the heart of our planet. Our oceans are a treasure, providing food and a habitat for countless species.It's under threat from pollution and overfishing. We must act now to preserve its beauty. Reducing plastic waste and supporting sustainable seafood are steps we can all take.Together, we can make a difference. Let's ensure a healthy ocean for future generations.The future of our oceans depends on our collective efforts.。

Ecology is the scientific study of the interactions of organisms and their environment.The biosphere is the part of Earth where life exists.All organisms live and interact in the biosphere.To understand relationships in biosphere, ecologists study events and organisms that range in complexity from a single individual to the entire biosphereBiotic factors that are living things that influence other organisms in an ecosystem.Abiotic factors are physical or nonliving factors that shape and ecosytem.Ecologists study many levels of organization.• individual organisms• species—a group of similar organisms that breed and produce fertile offspring• population—a group of individuals of the same species that live in the same area• community—a collection of different populations that live together in an area• ecosystem—all organisms living in a specific place, together with their physical environment• biome—a group of ecosystems with the same climate and similar dominant communities• biosphere—the part of the planet (land, water, and air) where all life exists.Scientists conduct ecological research using three basic approaches: \1.observing,2.experimenting,3.modeling.All of these approaches rely on the application of scientific methods to guide ecological inquiry.∙Observing is often the first step in asking ecological questions.∙Observations can also be used when designing experiments and making models.∙Experiments can be used to test hypotheses.∙They may be done in a laboratory or in the field.∙Modeling helps scientists understand complex processes.3–2 Energy FlowOrganisms use energy from the environment for life processes.Living things get energy in different ways.Sunlight is the main energy source for life on Earth.anisms that use the energy in sunlight or chemicals to make food are called autotrophs.Autotrophs, also called producers, make food in two ways.1.Some autotrophs use light energy to make food in a process called photosynthesis.o In photosynthesis, carbon dioxide and water are changed to carbohydrates and oxygen.o Plants, some algae, and certain bacteria carry out photosynthesis.o Some types of organisms rely on the energy stored in organic chemical compounds.2.Some autotrophs use chemical energy to make carbohydrates is called chemosynthesis.o Only certain types of bacteria carry out chemosynthesis.Organisms that rely on other organisms for energy and food are called heterotrophs.Heterotrophs also are called consumers.Types of heterotrophs.o Herbivores, such as cows, get energy by eating only plants.o Carnivores, such as snakes, get energy by eating only animals.o Omnivores, such as humans, get energy by eating both plants and animals.o Detritivores, such as earthworms, feed on the remains (dead matter) or wastes of other organisms.o Insectivores –such a anteaters, or some birds.o Scavengers an organism that feeds on dead or once living organismso Decomposers, such as fungi, break down organic matter.Energy flows through an ecosystem in one direction.It flows from the sun (or inorganic compounds) to autotrophs and then to heterotrophs.A food chain shows how living things transfer energy by eating and being eaten.For ex. a food chain might consist of grass (producer), an antelope (herbivore), and a coyote (carnivore).A food web links together all of the food chains in an ecosystem.For example, rabbits may also feed on the grass in the food chain above. These rabbits may be eaten by the coyotes. The feeding relationships of the grass, rabbits, antelopes, and coyotes make up a food web.Each step in a food chain or food web is called a trophic level.o Producers are at the first trophic levelo Consumers make up higher trophic levels.o Each consumer depends on the trophic level below it for energy.Ecological pyramids are diagrams that show the relative amounts of energy or matter at each trophic level.Only about 10 percent of the energy available at one trophic level is passed on to organisms at the next trophic level.Three types of ecological pyramids are1.Energy pyramids show how much energy is available at each trophic level.2.Biomass pyramidsshow the biomass, or total amount of living tissue, at each trophiclevel.3.Pyramid of numbers shows the relative number of individual organisms at each trophiclevel.3–3 Cycles of MatterEnergy and matter move through the biosphere very differently.Unlike the one-way flow of energy, matter is recycled within and between ecosystems. Matter, including water and nutrients, moves through organisms and parts of the biosphere through BIOCHEMICAL CYCLES.The Water Cycle.o All living things need water to survive.o Water cycles between the ocean, atmosphere, land, and living things.o Many processes part of the water cycle. Ex. during evaporation liquid water changes to gas.o Transpiration is the evaporation of water from the leaves of plants.o Water changes from a gas to a liquid through the process of condensation.o Water vapor in the atmosphere condenses into tiny droplets that form clouds.o When the droplets get large enough, they fall to Earth’s surface as precipitation.Nutrients are chemical substances that organisms need to survive.Lliving organism needs nutrients to build tissues and carry out essential life functions. Like water, nutrients are passed between organisms and the environment through biogeochemical cycles.The Carbon Cycle.o Carbon is a key part of living tissue.o Photosynthesis and cellular respiration are parts of the carbon cycle.o Human activities such as burning fossil fuels are also parts of the carbon cycle.The Nitrogen Cycle.o Organisms need nitrogen to build proteins.o Different forms of nitrogen cycle through the biosphere.o Nitrogen gas is the most abundant form of nitrogen on Earth.o However, only certain kinds of bacteria can use this form directly.o These bacteria change nitrogen gas into ammonia in a process called nitrogen fixation.o Other bacteria in the soil convert ammonia into nitrates and nitrites.o When organisms die, decomposers return nitrogen to the soil.o Other bacteria change nitrogen compounds called nitrates back into nitrogen gas.o This process is called denitrification.The Phosphorus Cycle.o Most phosphorus is stored in rocks and ocean sediments.o This phosphorus is slowly released into water and soil and then used by organisms.o Phosphorus is a key part of DNA and RNA.Primary productivityo It is the rate at which producers form organic matter in an ecosystem.o The availability of a nutrient affects primary productivity of a producer.o A nutrient that is scarce or cycles slowly through an ecosystem is a limiting nutrient.o A limiting nutrient can affect ecosystem health.。

我们应当保护海洋生物英语作文（精选6篇）我们应当保护海洋生物英语作文（精选6篇）无论在学习、工作或是生活中，大家都跟作文打过交道吧，作文要求篇章结构完整，一定要避免无结尾作文的出现。

为了让您在写作文时更加简单方便，下面是小编精心整理的.我们应当保护海洋生物英语作文，供大家参考借鉴，希望可以帮助到有需要的朋友。

我们应当保护海洋生物英语作文篇1Today，I saw a shop was selling the coral when I walk on the street.I was very angry.Perhaps many people still don't know that selling coral is illegal abroad expect in Indonesia.Because Indonesia is so poor that it has to earn money through digging and selling the coral,which accuse many marine organisms have to move from their home-ocean.As you known,if coral leave the ocean which they adapt,they might die.That's why I feel so angry. 我们应当保护海洋生物英语作文篇2Ocean refers to the protection of the marine environmental protection,including protection of marine resources and protection of the marine ecosystem.Marine organisms,including sea water is an environmental and water-capacity solution and suspended solids,sediments and marine life,the complexity of the system.Rich in marine biological resources,mineral resources,chemical and power resources,such as human resources indispensable treasure trove of resources,human survival and development of the relationship is extremely close.At present,the protection of the marine main objective is to protect the living marine resources,so that it will not be failure for the sustainable use of mankind.Special priority should be to protect those valuable and endangered marine life indanger.According to the survey departments of the United Nations,as a result of over-fishing,accidental killing of non-target to allow the killing marine life and coastal tidal flats of the project,the mangrove deforestation,pollution of the marine environment in general,at least 25 of the world's most valuable fisheries resources Exhausted,whales,sea turtles,manatees and other marine animals face extinction risk.With the expected expansion of the scale of ocean development,the possibility of living marine resources caused more damage.First of all,the protection of the marine task to put an end to the living marine resources over-exploitation,to be followed to protect marine life habitat or habitat,particularly their migration and spawning,feeding,Dihai to avoid the coast,tidal flats,estuaries,coral reefs,it is necessary to The prevention of heavy metals,pesticides,oil,organic produce and easy eutrophication of nutrients such as marine pollution.T o maintain living marine resources and renewable sources of natural water purification ability to maintain the ecological balance of oceans and the sea of humanity to ensure the continued development and use.我们应当保护海洋生物英语作文篇3The boundless sea gives people the expectation, the beauty, the warm maternal love.The sea is like a poem.Like a picture, the meaning is rich;Like a symphony, the vast...It is always calm, like a mirror;Now and then the rage, the surge of rage, can overturn the boat that sailed.In my mind, the sea is the blue world and the cradle of life.There are so many free and free lives.The sea is so mysterious, so charming!Now the sea has changed.The water is no longer clear, it'scloudy, it's dirty.The water washed up on the sand, leaving no more of a bouncing fish, but a pile of trash, and a lot of shrill little shrimps.Why is that?It's all because of us.While enjoying the beauty of the sea, someone threw the stinky rubbish into the sea.There are also people living on the coast who make toilet discharge pipes to the bottom of the sea.Even worse, the waste water from the factory poured into the sea, and the water became a strange color.Lead to give birth to a lot of lack of brain ` low IQ baby, our next generation - the eyes bright ` voice immature ` gorge through red face the next generation will never see the beautiful blue sea.Some people have done an experiment, he compared a basin of water to the sea, and drop a drop of ink into the "sea".At once, the ink spread slowly, shallower and disappeared, and the "sea water" was almost as clean as before.If the ink keeps dripping, "the color of the water will get darker and darker, and then it will turn into a basin of black water.The world's six billion people produce a lot of waste water and industrial pollution every day, just as the ink has been pouring into the pristine waters of the sea, and the sea is now a pool of sewage.For the sake of our human health, to see the beautiful and charming blue ocean for our children and grandchildren.Let us act immediately, love the sea as we love life, and love the common blue home of mankind.我们应当保护海洋生物英语作文篇4The seas and oceans receive the brunt of human waste, whether it is by deliberate dumping or by natural run-off from the land.In fact over 80% of all marine pollution comes from land-based activities and many pollutants are deposited in estuariesand coastal waters. Here the pollutants enter marine food chains, building up their concentrations until they reach toxic levels. It often takes human casualties to alert us to pollution and such was the case in Minimata Bay in Japan when many people died as a result of a pollutant building up in food chains. A factory was discharging waste containing methyl mercury in low concentrations into the sea and as this pollutant passed through food chains it became more concentrated in the tissues of marine organisms until it reached toxic levels.As a consequence 649 people died from eating fish and shellfish contaminated with mercury and 3500 people suffered from mercury poisoning.我们应当保护海洋生物英语作文篇5All things cannot be separated from water, and fish cannot leave water.The theme is: water, the root of all things.It is true that the seven parts of the sea are right. We are from one of the creatures in the sea, and we have the same gills of fish when we are young...Everything shows that we are connected to the sea.Maybe we were just a little fish, but now we are the greatest humans.The sea is so kind and mysterious, what is it that we humans are, the most intelligent creatures at the top, what are our ancestors?It's a low-grade fish or an advanced dinosaur, and everything is a mystery.Now the sea is being developed by us, the sea ranch, the Marine oil base is so amazing.The sea gave us life, and gave us so much energy, and we?Marine oil base causes large oil spill, resulting in Marine oil pollution!What are we doing with the indiscriminate killing of whales and the salivating of shark fins?Isthe environmental protection or the destruction of the ecological balance?If the sea could wash everyone's heart like a shell, there would be no creatures in the world because of our indiscriminate killing.Is it a reward that the sea is our mother, and it has created the destruction of all that it has created?No, it isn't.What else can we do when black oil covers the ocean, and when black exhaust fills the sky?The sea belongs to nature, nature belongs to us?We belong to the sea, and the sea belong to us?What are we doing here?T o kill for personal gain?Destroy for yourself?No, no, no.I do not believe that we will destroy our oceans, and I do not believe that people will despair when the oceans disappear.Because everyone is selfish.Is it humane that the oceans have created us and destroyed us?Although we're trying to protect the environment, it's too late, unless time goes backwards, unless there's a miracle, unless it's all over again.I believe we can get the ocean back to our youth, and we are the smartest intelligent creatures.Everyone, for the sake of the bright future of the sea, also protect the sea for ourselves.thank you我们应当保护海洋生物英语作文篇6Ocean refers to the protection of the marine environmental protection，including protection of marine resources and protection of the marine ecosystem。

生物多样性　第8卷,第3期,2000年8月CHIN ESE BIODIV ERSIT Y　8(3):337～342,August,2000分子生物学方法在微生物多样性研究中的应用Ξ杨永华　姚　健(南京大学生物科学与技术系,　南京　210093)摘　要　微生物多样性是生物多样性的重要组成部分。

由于微生物和大生物(动、植物)相比,存在着多种显著差异,因此其多样性研究、保护及利用也有所不同,尤其是研究方法亟待完善、提高。

近年来,分子生物学方法广泛用于微生物多样性的研究并取得了一系列研究成果。

本文从四个方面加以介绍:1)微生物总DNA制备及其遗传多样性检测方法;2)16S rRNA基因序列研究;3)核酸杂交分析技术;4) DNA动力学的研究。

今后的发展趋势是加强这些方法间及其与传统方法的有机结合,并发展新的方法,促进微生物多样性研究的深入开展。

关键词　微生物多样性,DNA扩增,遗传多样性,16S rRNA基因序列,核酸杂交,DNA动力学Molecular techniques and their application to the study of microbial diversity/YANGYong2H u a,YAO Jian Abstract　Microbial diversity is an important part of biodiversity.Microbial diversity research and its conser2 vation and utilization are quite different from those of macroorganisms including animals and plants.In particu2 lar,it is necessary to develop new techniques suitable for microbial diversity research.Recently,as the devel2 opment of modern molecular biology,several molecular techniques have been used to study microbial diversity, including1)total DNA extraction of microbe and its genetic diversity assay,2)16S rRNA gene sequence anal2 ysis,3)nucleic acid hybridization,and4)DNA kinetics.In order to promote extensive and intensive research on microbial diversity,it’s necessary to integrate these methods to enhance a combination of traditional and modern techniques,and to develop novel method.K ey w ords　microbial diversity,DNA amplification,genetic diversity,16S rRNA gene sequence,nucleic acid hybridization,DNA kineticsAuthor’s address　Department of Biological Sciences and Technology,Nanjing University,Nanjing　210093微生物包括了从原核到真核的不同类群的生物:细菌、放线菌、原生动物、真菌、部分藻类和病毒,是生物多样性的重要组成部分。