白粉菌侵染后田间小麦叶绿素含量与冠层光谱反射率的关系

 本文对白粉菌侵染后田间小麦叶片叶绿素含量与光谱反射率的关系进行了研究。用不同浓度的药液控制田间病害的发生梯度,于灌浆期对不同严重度小麦冠层的光谱反射率进行了测量,同时测定小麦叶绿素含量并调查病情指数,分析叶绿素含量与病情指数、冠层光谱反射率的关系。结果表明,药剂对叶绿素含量无显著影响;受白粉病危害后,小麦叶片叶绿素含量明显降低,抗性不同的品种之间下降速度存在差异,与病情指数之间也有极显著的相关性。绿光波段与叶绿素含量之间的相关性达到了显著水平;基于多波段建立的模型要优于单波段,可以利用绿光、红光波段的反射率估计叶绿素含量。红边参数与叶绿素含量之间也有较好的相关性,其中以红边面积的相关系数最大。     

不同水稻品种受褐飞虱危害后体内生理指标的变化

以不同耐虫性的水稻品种为试验材料，研究了水稻品种受褐飞虱危害后体内生理指标的变化。结果表明，稻株受害后感虫品种TN1、秀水11、汕优63的叶片叶绿素含量下降率达20％以上，而抗虫品种ASD7、IR64和具有较强耐虫性品种培矮64S／32E的叶绿素含量下降率在10％以下；受害稻株的三种保护酶活性变化不同，SOD酶活性均增加，其中以汕优63和IR64增加最显著。POD酶和CAT酶活性有增有减，除TN1、ASD7、培矮64S／32E品种的POD酶活性和秀水11的CAT酶活性下降外，其他品种的POD和CAT酶活性均增加。受害稻株叶片可溶性蛋白质、非可溶性蛋白质和蛋白质总量均下降；受害稻株游离脯氨酸含量的变化也不同，培矮64S／32E和IR64两个品种的脯氨酸含量减少，其他品种的游离脯氨酸含量都明显增加，且与稻株受害程度呈正相关。     

人参红皮病根部生物化学变化及病参质量综合评价

 对人参红皮病根部和健参根体内多种有机物含量的测定结果表明,病参根比健参根体内的总皂甙、淀粉、总糖含量减少,而还原糖、果胶质含量增加。所测病根体内17种氨基酸总含量、必需氨基酸含量比健根减少。病根无机元素Fe、Al、Mn的含量比健根显著增加而导致参根质量下降。红皮病的危害主要是降低人参产品的质量。严重度Ⅱ级以上的病参,使鲜参、红参的商品等级下降2~3级,其内在质量也显著降低。     

猕猴桃品种中糖分及木质素含量 与抗溃疡病的关系

以安徽省猕猴桃主栽品种金魁、早鲜、魁蜜和金丰为研究对象，于展叶孕蕾期分别取发病的枝条、叶片，以未发病的健株相应组织为对照，采用生理生化的方法，分析枝条、叶片中木质素和可溶性糖的含量变化以及与抗溃疡病的关系。结果表明：抗病品种金魁健株枝条、叶片中可溶性糖及木质素含量显著高于感病品种金丰。自然发病后，抗感病品种枝条、叶片中可溶性糖含量都降低，感病品种降低更多，金魁叶片可溶性糖含量下降4．20％，金丰叶片可溶性糖含量下降55.35％；木质素含量都升高，且抗病品种金魁叶片中的木质素含量比感病品种金丰高得多，其变化率分别为7．17％、3．01％，枝条中的木质素含量变化率分别为110．39％、68．98％，其差异达到显著水平。相关分析表明，枝条中木质素、可溶性糖含量与品种发病率也呈负相关，γ分别为-0．9583和-0．9282；叶片中木质素、可溶性糖含量与品种发病率呈负相关，γ分别为-0．8099和-0、8266。从而说明枝条、叶片中可溶性糖及木质素含量与品种抗性呈正相关。抗感品种淀粉含量无明显规律性变化，与品种抗性关系不大。     

水稻抗病性的研究Ⅳ、水稻品种耐肥性与对白叶枯病抗病性的关系

 用人工接种的方法测定水稻品种在不同氮肥水平下的抗病性变化,发现最感染白叶枯病的品种,发病程度一般都随氮肥水平的增加而显著提高;比较抵抗的品种,发病程度虽然亦有所增加,但是幅度要小得多。品种叶片的蛋白质氮的含量,都随着氮肥水平的提高而增加,但是其中游离氨基酸含量则根据品种抗病性的强弱而不同,感病品种一般都随着氮肥水平的提高而增加,而此较抗病的品种则在氮肥水平过高的情况下反而降低,或者始终保持在较低的水平。因此,水稻品种对氮肥水平的生理反应是不同的,其中游离氨基酸的变化可能在一定程度上反应了品种的耐肥性。水稻对胡麻斑病的反应,除品种农垦58以外,发病程度都是随着氮肥水平的提高而降低。与植株蛋白质氮量的高低呈反此,与游离氨基酸含量的变化无一定规律。     

沙子空心李主要病害的发生与防治技术

<正>沙子空心李是沿河县的支柱产业之一,主要病害有李子红点病、细菌性穿孔病、李树流胶病、李树膏药病、李疮痂病、李褐腐病等。在管理条件差的情况下,李树易感染病害。轻者影响树体发育,果实品质差,产量低;重者造成树体衰弱,果实不能食用。笔者介绍沙子空心李主要病害的发生规律和防治技术,以供参考。1李子红点病1.1症状红点病初期为害李树叶片,后期为害果实。为害叶片时,在叶面上产生红色圆形微隆起的病斑,其边缘与健部界限清     

几种辣椒品种次生物质与抗侧多食跗线螨的关系

为探讨辣椒品种次生物质与抗侧多食跗线螨Polyphagotarsonemus latus(Banks)的关系,以叶片危害指数为抗性评价指标,利用分光光度法检测了6个辣椒品种在侧多食跗线螨取食前后辣椒碱、多酚和单宁含量的变化。结果显示,在接螨前和接螨后7 d,未在辣椒叶片中检测到辣椒碱;接螨后14 d和21 d,叶片辣椒碱含量上升,但与叶片危害指数之间无显著相关性。接螨前辣椒叶片多酚和单宁含量与接螨后叶片危害指数之间存在显著负相关性,相关系数分别为-0.8410和-0.8714。与接螨前相比,接螨后7 d,抗性品种叶片多酚和单宁含量显著上升,而非抗性品种则显著下降;接螨后14 d和21 d,酚类含量开始下降;接螨后7、14和21 d叶片多酚和单宁含量平均上升率与叶片危害指数之间均存在极显著负相关性,相关系数分别为-0.9826和-0.9133。表明辣椒品种对侧多食跗线螨的抗性表现出组成和诱导抗性2种机制,辣椒品种多酚和单宁含量与抗性大小呈正相关。     

土壤盐分对小麦籽粒蛋白质含量及产量性状的影响

分析了栽培在4块含盐量不同的土壤中的4个春小麦品种（系）的籽粒蛋白质含量及产量性状与土壤盐分含量及各盐离子含量的关系。结果表明：随土壤全盐含量的提高，各品种籽粒的蛋白质含量都有显著提高，千粒重和产量有所下降，各品种的产量在土壤全盐含量小于0.3％时下降不明显，只有当各时期土壤平均含盐量达到0.36％时才会显著下降；籽粒蛋白质含量与其产量的负相关不显著，说明低浓度的土壤盐分对春小麦蛋白质含量的影响要大于对产量的影响，籽粒蛋白质与产量的矛盾不是绝对的，大多数土壤盐离子含量与春小麦籽粒蛋白质含量间存在着正相关关系，而与产量和千粒重呈负相关。对籽粒蛋白质影响最大的离子是：Na^ 、K^ 和SO4^2-，对产量影响最大的离子是Mg^2＋和Cl^-；SO4^2-，Ca^2 ，K^ 和Na^ 对千粒重有显著的影响。     

褐飞虱侵害对不同水稻品种根及叶片赤霉素含量的影响

应用酶联免疫吸附法(ELISA)研究褐飞虱若虫侵害分蘖期水稻超级培矮64S/E32和TN1后根及叶片赤霉素(gibberellin,GA)含量变化,以探讨褐飞虱侵害后水稻品种耐虫性与植物体内源激素的关系。结果显示:虫口密度60和90头/株侵害超级培矮64S/E323天后根GA含量显著上升;30、60和90头/株侵害TN13天后根、叶片GA含量显著上升。30、60和90头/株侵害超级培矮64S/E326天后叶片GA含量显著下降;30头/株侵害TN1后根GA含量显著下降。表明耐虫品种与感虫品种变化一致,根、叶片GA含量均在褐飞虱侵害3天后上升,6天后下降,但耐虫品种变化幅度较感虫品种大,持续期较感虫品种短;根冠比变化无明显规律。     

干旱胁迫对苗期木薯内源激素含量的影响

以SC124、KU50、C4和SC8四个木薯品种为试验材料,运用酶联免疫吸附测定法,研究了盆栽条件下干旱胁迫对苗期木薯根系与叶片中内源激素脱落酸（ABA）、吲哚乙酸（IAA）、赤霉素（GA）和玉米素核苷（ZR）的含量以及四种激素间平衡关系的影响。结果表明：随着干旱程度的加强,四种激素的含量在不同木薯品种内呈现不同的变化趋势。干旱至第10天时,ABA含量在苗期木薯叶片内增加,在根系内含量也增加（KU50除外）;IAA在叶片中含量下降,根系内含量因品种不同,变化趋势相差明显,其中SC124和KU50中IAA含量显著下降,而在SC8和C4中含量上升;GA含量在四种品种的根系中均下降,叶片GA含量在C4和KU50中略有下降而在SC124和SC8中上升;ZR含量在四种品种的根系中均下降,叶片中ZR含量在C4中上升,SC8中下降,而在KU50和SC124中无明显变化。IAA/ABA ,ZR/ABA在根系中比值下降,SC124降幅最大,SC8降幅最小,KU50、C4降幅居中,说明IAA/ABA ,ZR/ABA与木薯的抗旱能力具有一定相关性。该研究结果解释了苗期木薯根系和叶片内源激素对干旱胁迫的适应性反应,为筛选不同木薯抗旱品种提供了理论依据。     

绿盲蝽为害对不同空间位置桃叶生理指标的影响

为明确绿盲蝽为害不同时期桃树的应激反应发生发展过程,采用生化测定方法分析了桃树上、中、下部不同受害程度叶片内的可溶性糖、蛋白质、游离氨基酸含量以及防御性酶活性的变化。结果表明,绿盲蝽为害后,随着时间的延长,受轻度为害的桃树叶片内可溶性糖含量由28.61 mg/g减少至19.21 mg/g,蛋白质含量由1.29 mg/g先增加至2.01 mg/g,后减少至1.66 mg/g,游离氨基酸含量由0.49 mg/g增加至0.72 mg/g;而受重度为害的叶片内可溶性糖和蛋白质的含量均先减少后增加,游离氨基酸含量则先增加后减少。防御性酶活性随绿盲蝽为害程度的加重也发生了不同程度的变化,随着时间的延长,受轻度为害的叶片内超氧化物歧化酶活性降低,过氧化物酶和过氧化氢酶活性有所升高;而受重度为害的叶片内超氧化物歧化酶活性先降低后升高,过氧化物酶活性升高,过氧化氢酶活性降低。说明不同位置桃树叶片对绿盲蝽的为害胁迫产生了应激反应,通过调整其体内各种防御性物质的含量,对绿盲蝽为害产生诱导抗性,且与为害程度有一定的相关性。     

李果实细菌性穿孔病发生规律及防治

在辽宁省多数李树品种的果实上发生细菌性穿孔病,病斑近圆形、暗紫色、边缘具水渍状晕环,使果实去失商品价值。研究结果发现果实自落花后１５ｄ至采收前都可被侵染;雨日多、雨量大、品种感病、树势旺盛为病害流行的因素;防治该病有效措施是栽植抗病品种,消灭初侵染源,加强栽培管理,生长期用药控制病害发生。     

Bioassays on the role of tomato,potato and sweet pepper as sources of <Emphasis Type="Italic">Tomato chlorosis virus</Emphasis> transmitted by <Emphasis Type="Italic">Bemisia tabaci</Emphasis> MEAM1

Shot hole disease of stone fruits caused by Thyrostroma carpophilum has become a major threat to stone fruit industry of Jammu and Kashmir, India because of the failure in its management with fungicides. To understand the diversity in shot hole pathogen, a combination of conventional (morphological, cultural and pathological) and molecular (ISSR and ITS markers) approaches were employed to discern variability in 25 isolates of T. carpophilum isolated from peach, plum, apricot, almond and cherry leaves collected from Srinagar, Ganderbal, and Baramulla districts of Jammu and Kashmir, India. The studies revealed a high level of variability among the pathogen. Based on the morpho-cultural and pathological studies, the isolates were grouped into different categories based on colony growth, texture, margin and colour besides change in media colour, incubation period, leaf area infected, etc. Using ISSR markers, a high level of polymorphism in different isolates of T. carpophilum was observed which indicated that these markers are suitable for studying the genetic diversity in this pathogen. Based on dendrogram, the isolates were grouped irrespective of their geographical origin or host species. Phylogenetic analysis of the 25 sequences based on ITS region showed maximum similarity with T. carpophilum (Syn. Wilsonomyces carpophilus) sequences retrieved from NCBI and grouped them in a single clade which proved it as a powerful tool for authentic identification. The pathogen was highly variable based on morpho-cultural, pathological and molecular (ISSR) characterisation.     

First report of Plum pox virus on plum in Finland

In July 2014, leaves showing symptoms of a viral infection were collected from a plum tree serving as a mother tree in a Finnish nursery and found to be infected by Plum pox virus (PPV). A subsequent survey revealed additional infected trees originating from the infected mother tree. This paper provides the first report of PPV, the causal agent of the most destructive viral disease of Prunus, in Finland.     

Adaptation of spray dosage in stone-fruit orchards on the basis of tree row volume

The tree row volume (TRV) model was adapted for use in stone-fruit orchards. The number of leaves, leaf area and TRV were determined in apricot, peach, cherry and plum orchards in France and Switzerland. The number of leaves per tree ranged from 2500 to 25900, and TRV values ranged from 5400 to 28600 m³ ha⁻¹. Trees were sprayed with a fluorescent tracer, according to TRV, in order to determine the quantity and distribution of tracer deposition in the crown of the trees. For large trees with TRV values above 15000 m³ ha⁻¹, tracer deposits on leaves were lower in the upper half of the crown than in the lower half. The TRV formula developed for pome-fruit trees was accordingly used for spraying stone-fruit trees, but with a 15% increase in spray volume for large trees. Under these conditions, disease control was efficient, and residues of difenoconazole, penconazole and dithianon were below the maximum residue limit. The TRV method was thus found to allow adaptation of spray dosage and volume to the volume of the trees, on condition that sprayers are carefully calibrated and adjusted for each orchard. The TRV concept can be applied to a wide range of pome and stone-fruit orchards and can help to harmonize registration protocols for fungicides and insecticides.     

干旱与复水对马铃薯块茎膨大期碳氮转运的影响

为探讨干旱及复水对马铃薯块茎膨大期碳氮物质转运影响的生理机制,采用盆栽控水法研究了干旱胁迫、旱后复水过程中马铃薯叶片与块茎中碳水化合物、氮素同化物以及碳氮转运相关酶活性的变化规律。结果表明：干旱胁迫下马铃薯叶片蔗糖磷酸合成酶（SPS）活性显著增强,增幅为54.9%,可溶性糖与蔗糖含量显著增加,分别增加84%、25%;块茎蔗糖与淀粉含量显著下降,分别降低25%、11.8%。复水后叶片可溶性糖含量变化较小,叶片SPS活性仍保持较高水平;块茎中蔗糖合成酶（SS）活性下降6.25%(P＜0.05),蔗糖与淀粉含量分别增加21.8%、29.8%。干旱胁迫下马铃薯叶片中硝酸还原酶（NR）活性下降49.3%,谷氨酰胺合成酶（GS）活性与对照差异不显著,叶片游离氨基酸与可溶性蛋白质含量分别降低29.4%、38.4%,全氮含量降低13%;块茎中游离氨基酸与可溶性蛋白质含量增加16.8%、270.9%。复水后叶片中NR与GS活性高出对照3.5%、12.1%,叶片游离氨基酸、可溶性蛋白质以及全氮含量仍保持较低水平;块茎游离氨基酸、可溶性蛋白含量较高,增幅分别为24.6%、178.4%,全氮含量增加,与对照差异不显著。说明干旱胁迫显著阻碍了马铃薯碳水化合物与氮素同化物的合成与转运,使马铃薯叶片碳水化合物积累,但干旱促进了氮素向块茎转运,块茎中的碳氮比下降;复水后马铃薯植株能够快速修复干旱胁迫造成的损伤,表现为块茎中淀粉含量增多,块茎碳氮比增加。     

Characterization of the pathogenicity of strains of Pseudomonas syringae towards cherry and plum

Bacterial canker is a major disease of Prunus avium (cherry), Prunus domestica (plum) and other stone fruits. It is caused by pathovars within the Pseudomonas syringae species complex including P. syringae pv. morsprunorum (Psm) race 1 (R1), Psm race 2 (R2) and P. syringae pv. syringae (Pss). Psm R1 and Psm R2 were originally designated as the same pathovar; however, phylogenetic analysis revealed them to be distantly related, falling into phylogroups 3 and 1, respectively. This study characterized the pathogenicity of 18 newly genome‐sequenced P. syringae strains on cherry and plum, in the field and laboratory. The field experiment confirmed that the cherry cultivar Merton Glory exhibited a broad resistance to all clades. Psm R1 contained strains with differential specificity on cherry and plum. The ability of tractable laboratory‐based assays to reproduce assessments on whole trees was examined. Good correlations were achieved with assays using cut shoots or leaves, although only the cut shoot assay was able to reliably discriminate cultivar differences seen in the field. Measuring bacterial multiplication in detached leaves differentiated pathogens from nonpathogens and was therefore suitable for routine testing. In cherry leaves, symptom appearance discriminated Psm races from nonpathogens, which triggered a hypersensitive reaction. Pathogenic strains of Pss rapidly induced disease lesions in all tissues and exhibited a more necrotrophic lifestyle than hemibiotrophic Psm. This in‐depth study of pathogenic interactions, identification of host resistance and optimization of laboratory assays provides a framework for future genetic dissection of host–pathogen interactions in the canker disease.     

一串红穿孔病病原鉴定和初侵染源分析

 2021年夏季,受台风“烟花”影响,上海市奉贤区海湾镇大面积一串红种苗突发穿孔病,本文按照柯赫氏法则鉴定病原物并进行初侵染源分析。从田间病样中分离出的黄色分离物YchA回接一串红形成穿孔症状,在非寄主本氏烟草上可激发过敏反应。16S rDNA序列分析显示YchA为黄单胞菌属;以持家基因fyuA、gyrB、rpoD进行多位点序列分析(Multi-locus sequence analysis, MLSA)发现,菌株YchA与核桃细菌性黑斑病菌(Xanthomonas arboricola pv. juglandis, Xaj)亲缘关系最近;Biolog鉴定系统分析显示,一串红穿孔病病原为Xaj的可能性约为68%。对育苗基质、种子和灌溉水的检测发现,种子和灌溉水带菌。这些结果表明,一串红细菌性穿孔病的病原为树生黄单胞菌(X. arboricola),可能是一个新致病变种;种子带菌是病害的初侵染来源,灌溉水带菌扩散。     

Recovery in apple trees infected with the apple proliferation phytoplasma: an ultrastructural and biochemical study

ABSTRACT Localization of hydrogen peroxide (H(2)O(2)) and the roles of peroxidases, malondialdehyde, and reduced glutathione in three apple cultivars were compared in healthy trees, trees infected with apple proliferation phytoplasma (APP), and trees that had recovered from the infection. In recovered apple trees, symptoms of the disease and the pathogen had disappeared from the canopy, but phytoplasmas remained in the roots. H(2)O(2) was detected cytochemically by its reaction with cerium chloride to produce electron-dense deposits of cerium perhydroxides.H(2)O(2) occurred in the plasmalemma of the phloem of leaves of recovered apple trees, but not in healthy or APP-infected leaves. In all cultivars, the peroxidase activity detected in tissue from APP-diseased trees was greater than or equal to that of tissue from recovered trees, which equaled or exceeded that of tissue from healthy trees, at two sampling times (May and September). In contrast, the glutathione content of leaves decreased in the reverse order. More malondialdehyde was observed in leaves from recovered trees than in leaves from healthy or APP-infected trees in three of six cultivar-date combinations; in the other three combinations, the malondialdehyde contents of leaves from healthy, infected, and recovered trees were not significantly different from one another. The results suggest that some components of the oxidant-scavenging system in recovered leaves are not very active, leading to an overproduction of H(2)O(2) and, possibly, to a membrane lipid peroxidation.The production of H(2)O(2) appears to be involved in counteracting pathogen virulence.