小麦白粉病菌对小麦幼苗MDA含量及防御酶活性的影响

为探讨小麦白粉病菌对小麦叶片防御酶活性的影响,揭示不同小麦品种对小麦白粉病菌的互作与抗性表现,以高抗小麦白粉病品种青春38、高感小麦白粉病品种龙麦33为实验材料,于小麦苗期采用白粉病强致病力生理小种E09感染小麦叶片,研究接菌后0、1 d、3 d、5 d、7 d、9 d时,小麦叶片细胞内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)活性及丙二醛(MDA)含量变化规律。结果表明:接种前,抗病品种的POD、CAT、PAL活性及MDA含量高于感病品种,而SOD、PPO活性略低于感病品种。接菌后,5种防御酶活性及MDA含量均不同程度的升高,除SOD活性峰值及MDA含量升高幅度为龙麦33高于青春38外,其他4种防御酶活性增加幅度均为青春38高于龙麦33。接菌初期,5种防御酶活性均表现为龙麦33的升高较慢或滞后于青春38,而MDA含量的增加则表现为龙麦33显著高于青春38。研究结果为探讨小麦白粉病菌与小麦的互作机理提供了一定的理论参考依据。     

桃褐腐病菌拮抗细菌的分离筛选与鉴定

为了筛选和鉴定桃园土壤中对桃褐腐病菌有拮抗作用的细菌,本研究采用了对峙培养法,16SrDNA基因分析以及生理生化反应等方法。从北京平谷区桃园土样中分离的42株细菌中筛选出了11株对桃褐腐病菌（Monilinia fructicola）有明显抑制作用的拮抗细菌。其中F3和Y4的拮抗效果最好,抑菌带的宽度分别为13.83 mm和14.67 mm, F1 和F4 抑菌效果次之,抑菌带宽度分别为11.83mm和12.00mm。在显微镜下观察发现,F3和Y4对桃褐腐病菌的菌丝有致畸作用,并且F3和Y4 的培养滤液还能够抑制桃褐腐病菌分生孢子的产生和萌发。经鉴定表明：F1 、F3、F4和Y4均为枯草芽孢杆菌（Bacillus subtilis）     

桃褐腐病菌的拮抗细菌CE的发酵条件研究

通过单因素及正交试验确定了桃褐腐病菌的拮抗细菌CE的最佳发酵液的组成和发酵的最佳条件。实验结果表明：发酵液中的C、N源的组合、C、N源的含量、金属离子对拮抗细菌CE的生长量和抑菌活性都有不同的影响,用4.5%的玉米粉和0.15%的酵母浸膏配制的发酵液对拮抗细菌CE生长量和抑菌效果都相对较好,另外Fe3+的添加能同时促进拮抗细菌的生长量和抑菌效果。在研究的几个发酵条件中,拮抗细菌CE的生长量和抑菌效果在一定范围内成正相关,即随生长量增大抑菌效果增强,说明抑菌物质的产生与活菌量的多少有关,最适的发酵条件为30℃,pH7,140r/min,接种量为10%,发酵时间为60h。     

黑痣病菌毒素诱导马铃薯幼苗体内防御酶活性的变化

试验选取对黑痣病菌抗性不同的马铃薯材料,研究黑痣病菌毒素处理后马铃薯幼苗体内防御酶活性的变化及其与抗黑痣病的关系,以探讨马铃薯抗黑痣病机制。结果表明,经毒素处理一定时间,POD、PPO、SOD和CAT这4种防御酶活性都有不同程度的提高。处理36～96 h时,POD、PPO、SOD活性快速升高,抗病品种底西芮酶活性的增加值明显大于感病品种大西洋的增加值;CAT活性先降低后升高,60 h达到最高,但处理时间内酶活性的增加值和品种抗病性不相关。处理96 h以后,POD和SOD的活性仍升高,但酶活性增加值在抗感品种之间没有显著差异,PPO和CAT的活性增加值降低。     

啶菌恶唑能有效抑制桃褐腐病菌菌丝生长及孢子萌发

<正>桃树褐腐病是大连桃产区重要病害之一,流行年份常常造成极大的经济损失,目前用于桃病害的杀菌剂存在不规范化,防治桃褐腐病菌的抗性问题比较严重。为了解啶菌恶唑对桃褐腐病的抑菌率和田间防效,辽宁省瓦房店市农业技术推广中心农技人员在实验室用25%啶菌恶唑乳油、对照药剂24%腈苯唑悬浮剂,浓度为0.25、0.125、0.063、0.031、0.016mg/L;对照药剂70%丙森     

啶菌恶唑能有效抑制桃褐腐病菌菌丝生长及孢子萌发

<正>桃树褐腐病是大连桃产区重要病害之一,流行年份常常造成极大的经济损失,目前用于桃病害的杀菌剂存在不规范化,防治桃褐腐病菌的抗性问题比较严重。为了解啶菌恶唑对桃褐腐病的抑菌率和田间防效,辽宁省瓦房店市农业技术推广中心农技人员在实验室用25%啶菌恶唑乳油、对照药剂24%腈苯唑悬浮剂,浓度为     

根腐病菌侵染对黄芪苯丙烷途径关键酶活性的影响

以蒙古黄芪-根腐病菌(Fusarium solani和F. acuminatum)为互作体系,测定苯丙烷途径关键酶苯丙氨酸解氨酶(PAL)、肉桂酸-4-羟化酶(C4H)及4-香豆酸-辅酶A连接酶(4CL)活性的变化,以期获得黄芪抗根腐病菌侵染机制的信息,为抗病育种工作提供参考。试验采用幼苗浸根法接种病菌,分光光度法测定3种酶的动态变化。结果表明,F. solani侵染黄芪后,PAL和C4H活性与对照相比明显升高,并在7、21天出现2个酶活高峰;4CL活性则随着时间的延长持续上升,7、21天时也显著高于对照。F.acuminatum侵染黄芪后,PAL、C4H和4CL的活性均在21天显著高于对照。可见2种病原菌在侵染黄芪过程中,苯丙烷途径的关键酶被不同程度地激活,但2种病菌激活各酶的时间和规律有所差异,表明黄芪对这2种病菌的抗性机制明显不同。     

香蕉枯萎病菌对不同香蕉品种防御酶系的影响

摘要：本文研究了不同香蕉品种在接种香蕉枯萎病菌后防御酶系的变化。结果表明,经病原菌接种后,SOD酶活性的大小与不同香蕉品种的耐、感病之间呈负相关;PO酶和内切几丁质酶活性的变化趋势与香蕉品种的抗病性之间不存在相关性;PAL酶、β-1, 3-葡聚糖酶和外切几丁质酶的活性变化趋势与香蕉品种抗、感病品种关系密切,可以作为香蕉品种抗枯萎病一个重要的生物化学指标。     

中草药提取物对桃褐腐菌抑制作用增效组合筛选

用菌丝生长速率法测定了虎杖、黄柏、厚朴、松萝等4种中草药提取物对桃褐腐菌的抑制作 用,经线性回归计算50％抑制时的有效浓度(EC50)分别为133．8μ g/ml、40.6μ g/ml、90．6μ g/ml、 3．4p g/ml。根据EC50,用等效线法相加作用线的6等分点设置配比,共毒因子法判断增效标准。结果 表明,各种配比的混配剂中黄柏 松萝为最佳增效作用组合,其中以8:1增效作用最显著。     

北京昌平地区草莓根腐病菌种类鉴定

明确草莓根腐病的主要致病真菌种类,可正确有效地指导草莓根腐病的防治。本试验采用单孢分离法和组织分离法从昌平地区所采集的草莓根腐病株中共分离得到41个菌株。采用病土定植法测定菌株对草莓幼苗的致病性,结果表明所分离的菌株均可引起草莓根腐病,致使草莓根部及根茎基部发育受阻,缢缩变黑,腐烂折断;造成地上部生长不良,叶片变黄,甚至死亡。通过形态学、分子生物学手段对菌株的分类地位进行鉴定,其中39株可以鉴定到种,分别属于10个属的15个种,另外有1株只鉴定到属,1株只鉴定到科。在41个菌株中,立枯丝核菌(Rhizoctonia solani)、胶孢炭疽菌(Colletotrichum gloeosporioides)、木贼镰刀菌(Fusarium equiseti)、尖孢镰刀菌(Fusarium oxysporum)等4个种所占比例较高,分别占菌株总量的29.25%、12.20%、12.20%、9.75%;致病力最强的种类为伏革菌科真菌、棒形拟盘多毛孢和胶孢炭疽菌,其次为尖孢镰刀菌、立枯丝核菌、木贼镰刀菌、茄病镰刀菌,发病率均可达50%;淡色生赤壳、伏革菌科菌、Plectosphaerella cucumerina、Stachybotrys chartarum、Neonectria radicicola等为首次报道的草莓根腐病致病菌。研究结果可以指导北京昌平地区草莓主产区中草莓根腐病的防治,并为草莓根腐病快速检测方法的研发提供参考。     

Effect of short term cold stress on rice seedlings

A method was developed for exposing riceseedlings to low temperatures for shortperiods. These seedlings were from 70F₉ inbred lines derived originallyfrom a hybrid of a salt tolerant cultivar,which provided a source of resistance toabiotic stress, and a non salt tolerantcultivar as the other parent. Seedlingswere grown hydroponically in a warm growthroom then placed in the air above afreezing bath for 6 hours at –0.2 ^°C,–1.0 ^°C or –2.0 ^°C beforereturning them to the growth room for a7–10 day period. Seedling survival in theinbred lines of rice was compared afterexposure to these temperature treatments toidentify the presence of low temperaturetolerance. An average survival of 93%occurred 7days after exposures to –0.2, and–1.0 ^°C and a survival of 35% afteran exposure of –2.0 ^°C. The non-salttolerant parent cultivar was killed byexposure to –2.0 ^°C but the salttolerant parent survived. The effect of lowtemperature exposure was examined in moredetail in lines selected for lowtemperature tolerance and susceptibility.Alterations to the total leaf proteinprofile, including fragmentation ofRubisco, were observed in these lines butno obvious difference was detected betweensusceptible and tolerant individuals.     

赤霉素处理影响草莓成花的解剖学研究

赤霉素（GA3）处理茎尖分生组织处于成花诱导前后的草莓植株，较全面地报告了由此引起的草莓植株发育状况、成花情况、花芽分化进程以及分化状态等内容，并且对不同时期处理所引起的成花逆转、成花抑制以及成花延迟等现象进行了分析，旨在为进一步深入研究激素调控草莓花芽分化奠定基础。     

Effect of heat treatments on gene expression and enzyme activities associated to cell wall degradation in strawberry fruit

Strawberries at white ripening stage were heat treated at 45 °C for 3 h in an air oven and then stored at 20 °C for 72 h. Firmness, activity of enzymes associated to cell wall degradation, and expression of related genes were determined during the storage. Fruit firmness decreased during the incubation time, and after 24 h of storage the heat-treated fruit softened less than the control fruit. However, after 3 days at 20 °C no differences in firmness were detected between control and heat-treated fruit. Immediately after heat treatment application, the activity of endo-1,4-β-d-glucanase (EGase), β-xylosidase and β-galactosidase decreased, while polygalacturonase activity remained at a level similar to the control fruit. However, lower activities of all these enzymes, including polygalacturonase, were detected in heat-treated fruit after 24 h at 20 °C. The enzyme activity of β-xylosidase, β-galactosidase and polygalacturonase increased after 72 h up to similar or higher values than those of controls. However, endo-1,4-β-d-glucanase activity remained lower in heat-treated samples even after 72 h at 20 °C. The expression of genes encoding endoglucanase (FaCel1), β-xylosidase (FaXyl1), polygalacturonase (FaPG1) and expansin (FaExp2) was reduced immediately after treatment and during the following 4 h, and then increased after 24 h to levels similar to or higher than those of control fruit.

Therefore, the selected treatment (45 °C, 3 h in air) effectively reduced strawberry softening and caused a temporary reduction of both the expression of above-mentioned genes and the activity of a set of enzymes involved in cell wall disassembly.     

低温胁迫对油棕幼苗光合作用及叶绿素荧光特性的影响

在30 μmol/(m2.s)的弱光条件下,以25℃、10℃、7℃、4℃、1℃各处理油棕幼苗3天,测定了油棕幼苗叶片光合参数及叶绿素荧光参数的变化。结果表明：温度由 25℃降至4℃,净光合速率（Pn）显著下降的同时,气孔导度(Gs)、蒸腾速率(Tr)、胞间CO2浓度（Ci）也显著下降,但气孔限制值(Ls)和水分利用效率(WUE)却显著增加,说明光合作用的下降主要由气孔因素引起;之后随温度下降至1 ℃,净光合速率、气孔导度、蒸腾速率、水分利用效率、气孔限制值均出现显著下降,但胞间CO2浓度却显著上升,说明光合作用的下降主要由非气孔因素引起。叶绿素荧光参数显示,随温度下降,初始荧光(Fo)不断上升,PSⅡ最大光化学效率（Fv/Fm）、光化学猝灭系数(qP)、非光化学猝灭系数（qN）不断下降,其中以4 ℃以下的低温胁迫,这些参数的变化最为显著。表明严重低温对油棕幼苗产生了显著的光抑制,过剩的激发能不能通过热耗散途径散失,大量积累于PSⅡ反应中心,使光合机构遭受了较大程度的破坏,最终导致油棕幼苗光合能力的急剧降低。     

The use of synthetic octoploids in strawberry breeding

Summary A number of methods of producing synthetic octoploids from Fragaria species of lower levels of ploidy are described. Six synthetic octoploids were produced from various combinations involving one hexaploid species, two tetraploid species and four diploid species. Three of the synthetic octoploids are male fertile and were used successfully as male parents in crosses with octoploid strawberry cultivars.     

球孢白僵菌代谢产物对植物幼苗的影响研究

通过研究球孢白僵菌代谢产物对植物幼苗的影响,结果表明：球孢白僵菌代谢产物对不同植物的影响不同;不同培养基培养和不同溶剂抽提的球孢白僵菌代谢产物对植物的幼苗影响不同;不同浓度球孢白僵菌代谢产物对植物幼苗生长影响不同.     

Injuries induced in different strawberry genotypes by winter freeze and their effect on subsequent yield

Severe frosts without snow cover are disastrous for the garden strawberry, Fragaria × ananassa Duch. The objectives of this study were to determine injuries, caused by freeze to crowns and roots of 13 and five different cultivars/lines in 2002 and 2003, respectively; to observe subsequent plant behaviour; to measure yield and to find out its dependence upon the injuries. Based on percentages of injured branch crowns and roots, estimates of plant growth and yields, the relationships between the indices have been established. Root injury has had a stronger effect on plant growth compared with crown injury. Yield has been found to be correlated only with plant growth, root damage and root‐to‐crown ratio of per cent survival when root damage was heavy. Two different strategies of the cultivars/lines, associated with their morphological characteristics and physiological peculiarities influencing plant survival, growth and yield, have been revealed. To discern the characters and cultivar types that can be valuable in such extreme conditions, differences in the genotypes responses to freeze are examined and thoroughly analysed in the paper.     

日光温室草莓栽培技术措施

在日光温室内栽培草莓,宜选择耐弱光、不徒长、休眠期短、早熟高产、鲜食口味好的品种进行栽植.如明宝、宝交早生、丰香等品种皆适宜温室栽培.为了从根本上保证草莓的优质高产,最好选用这些品种的脱毒苗进行栽培.脱毒草莓苗生长快,长势旺,抗病性强,结果期延长,果大色红,畸形果少,其产量和品质比同品种的普通草莓苗都有显著的提高,一般 667m2增产草莓 500kg以上.     

北京市草莓鲜果消费模式的初步研究

本研究的目的是掌握北京市草莓鲜果消费的特点,分析消费者行为的诸因素对其购买行为的影响。采取发放调查问卷的形式收集相关数据,再采用分层取样法、结构分析法和比较分析法等研究方法,对相关数据进行收集、整理,并分析,初步探明了北京市草莓鲜果的消费模式。