豇豆常见病害及其防治措施

豇豆根腐病俗称烂根、死藤、豇豆瘟,各地均有发生,为害较重。从苗期到收获期均可发病,主要侵害根和茎蔓。根部发病,呈典型根腐,主、侧根及茎基部变褐色腐烂,病部略凹陷,地上部叶片由基部向上逐渐萎黄,严重时全株枯死,有时根部及茎基部出现褐色纵向裂痕,剖视病部及附近的     

山东省玉米穗腐病病原菌的分离鉴定及优势种的系统发育分析

旨在明确山东省玉米穗腐病病原菌组成及优势病原菌的流行趋势。对2015-2017年在山东省采集的138份玉米穗腐病样品进行了病原菌的分离,采用形态学和分子生物学方法对分离物进行鉴定,并对优势病原菌进行系统发育分析,明确其发生发展规律。分离鉴定结果表明,分离到的真菌共有18种,其中镰孢属的拟轮枝镰孢菌分离频率为67.39%,为山东省优势病原菌;其次为层出镰孢菌,分离频率为10.87%;禾谷镰孢复合种、木贼镰孢菌和尖孢镰孢菌的分离频率分别为7.97%,5.80%,0.72%;木霉属的哈茨木霉分离频率为7.91%;青霉属的草酸青霉分离频率为6.52%;曲霉属黄曲霉和黑曲霉的分离频率分别为2.17%和5.07%。基于EF-1α基因序列构建了山东省2015-2017年拟轮枝镰孢菌的系统发育树,并分析了山东省菌株与河北省菌株的遗传进化关系。系统发育分析结果发现,89个拟轮枝镰孢菌菌株可以分为2个大群,其遗传距离较小,为0.002～0.016,表明山东省2015-2017年的菌株之间遗传关系较近;河北省和山东省拟轮枝镰孢菌菌株的遗传距离较小,相似性较高,亲缘关系较近,存在较为频繁的基因交流。研究结果为深入开展拟轮枝镰孢菌穗腐病的抗性育种、发生发展规律以及综合防治提供科学依据。     

茄子重茬地注意防止根腐病导致大面积死秧

<正>茄子根腐病是一种土传性病害。主要侵染茄子根部和茎基部。连年重茬种植,会出现茄子定植后大面积根腐死秧现象,发病率可达40%以上,甚至绝产绝收。高温、高湿有利于发病,连作地、低洼地、土壤黏重,发病重。一般在茄子定植后开始发病。1.发病症状病菌初期侵染茄子主根或茎基部,水渍状斑,然后病斑转为褐色,后又变为黑褐色。这时地面上植株还正常,随着茎或根部病斑不断扩大,当茎基部病斑绕茎一周时,病部的组织溃烂露出木     

甘薯茎基部腐烂病调查及病原鉴定

2012年以来浙江省台州市及其周边市县甘薯产区发生了大面积的甘薯茎基部腐烂病,导致当地甘薯种植面积大幅度下滑。为明确浙江省甘薯茎基部腐烂病的发生情况、病原组成及种类,本团队于2015年至2018年对浙江省11个县市区进行了田间调查并采集127份病样分离鉴定病原菌,结果表明浙江省甘薯茎基部腐烂病主要存在4种主要症状,根据病菌的致病性、形态特征、ITS和16S rDNA序列分析鉴定,主要鉴定到达旦提狄克氏菌(Dickeya dadantii)、齐整小核菌(Sclerotium rolfsii)、拟轮枝镰孢菌(Fusarium verticillioides )、腐皮镰刀菌(F. solani)、尖镰刀菌(F. oxysporum)、甘薯间座壳菌(Diaporthe batatas)、毁坏性拟茎点霉(Phomopsis destruens)和爪哇镰孢(F. javanicumS)等8种致病病菌,各地区病原菌组成分布均有所不同,采集的样品普遍为多种致病菌复合侵染危害。     

夏玉米常见病害及其防治

1玉米苗枯病 玉米苗枯病是近年新发现的一种病害,该病主要发生在玉米苗期,感病植株最先由种子根的一处、数处或根尖发生褐变,以后扩展成一段或整条根系,一条或数条可同时发生,继而侵染根间（中胚根）,造成根部发育不良,根毛减少,无次生根或少量几条次生根,初生根老化,皮层坏死,根系变黑褐色,并在第一节间形成坏死环状斑;地上部叶鞘褐色呈撕裂状,叶片发黄,边缘呈枯焦状,心叶卷曲,易折,以后叶片自下而上逐渐干枯;无次生根的产生死苗,有少量次生根的形成弱苗,危害严重的植株叶片出现火烧状枯死,心叶逐渐青枯萎蔫,茎基部发生腐烂,用手轻轻一提即可拔起。     

兰花白绢病识别与防治

<正>白绢病是兰花世界性病害之一。该病在春夏之交的梅雨季节,以及秋雨连绵时发生尤为严重,主要为害兰花的根部及茎基部分。初发病时,在兰叶基部接近土壤处出现水渍状黄色病斑,后迅速扩展至根部,随后叶片萎蔫、茎杆呈褐色腐烂,容易折断。严重时兰花假鳞茎也会被侵染,在病部产生白色绢丝状菌丝,呈辐射状延伸,并在根际土表蔓延。     

上海生科院揭示禾谷镰孢菌侵染玉米茎杆的新机制

正中国科学院上海生命科学研究院植物生理生态研究所唐威华研究组在玉米赤霉茎腐病研究中,采用激光显微切割技术获得正在玉米茎杆中侵染的禾谷镰孢菌深度表达谱,并通过表达谱动态分析,揭示禾谷镰孢菌在侵染玉米茎杆早期合成无磷膜脂应对玉米茎杆薄壁细胞胞外空间磷缺乏的致病新机制。丝状真菌禾谷镰孢菌能导致重要     

油菜素内酯提高玉米抗禾谷镰孢菌侵染的生理机制

为明确油菜素内酯(BR)增强玉米抗禾谷镰孢侵染的作用及机制,以玉米郑单958为试验材料,分设喷施BR和未喷施BR的处理,在玉米喷施BR 10 d后,接种禾谷镰孢菌,调查比较喷施BR后玉米感染禾谷镰孢菌的发病情况,确定油菜素内酯提高玉米抗禾谷镰孢侵染的确切作用,结果表明,在未喷施BR的自然生长条件下,在玉米上接种禾谷镰孢,发现茎秆表面有明显的病原菌沿接种针孔侵染扩散的痕迹,玉米茎剖面内髓组织黑褐色严重,几乎整个节间均已被病原菌侵染;但在喷施BR 10 d后再接种禾谷镰孢,玉米茎剖面内的髓组织被病原菌侵染面积明显减少,发病明显减轻,说明BR提高了玉米抗禾谷镰孢侵染的能力。用含BR的PDA培养基培养禾谷镰孢,与对照相比,禾谷镰孢发育未受到明显的影响。BR处理后,玉米叶片脯氨酸含量增加,Real-time PCR分析编码脯氨酸合成酶的基因Zm P5CS的表达量,发现其表达量确实受BR的诱导。同时BR处理后玉米叶片可溶性糖含量极显著增加,保护酶SOD和PAL活性显著增加,POD活性极显著增加。说明BR提高玉米自身抗逆性来提高抵抗禾谷镰孢侵染。油菜素内酯对禾谷镰孢的生长发育没有明显的影响;油菜素内酯提高玉米抗禾谷镰孢侵染的原因可能不是抑制禾谷镰孢的生长发育,而是通过提高玉米脯氨酸合成、保护酶活性、可溶性糖含量,从而提高玉米自身免疫能力。     

低温需防番茄疫霉根腐病

正连续半个多月受低温寡照天气影响,部分大棚番茄疫霉根腐病开始发生。该病一直是棚室蔬菜病害防治的难点,发病速度快,毁灭性强,必须加以重视。番茄疫霉根腐病发生初期于茎基部或根的上部产生褐斑,逐渐扩大后凹陷,严重时病斑绕茎基部或根都一周,地上部逐渐枯萎。纵剖茎基部或根部,导管变为深褐色,后根茎腐烂,不长新根,植株枯萎而死。该病属真菌性病害,发病与天气有     

花生白绢病的发生特点与综合防治技术

<正>花生白绢病是一种土传真菌性病害,在我国多数花生产区均有发生,以南方地区发生较多,近几年山东胶东地区有发生加重的趋势。现将该病的发生特点与综合防治技术介绍给大家。1.发病症状该病多发生在花生成株期,主要侵染花生茎基部,也可为害果柄和荚果。茎基部染病,病斑初为暗褐色波纹状,后逐渐下凹呈软腐状,病斑表面长出白色绢状菌丝。高湿条件下,菌丝扩展覆盖病株下部茎秆及周围土壤,并形成油菜籽状的菌核,初为白色,后变为暗褐色。发病初期叶片枯黄,严重时茎基部呈纤维状,整株枯死。受害果柄和荚果呈湿腐状腐烂,长出     

Intercropping Maize with Climbing Beans, Cowpeas and Velvet Beans

When one of the crops is a legume, intercropping has potential to reduce fertilizer nitrogen (N) needs and increase food quality. Total dry matter (DM) and grain yields of different plant populations of intercropped maize ( Zea mays L.) and climbing beans ( Phaseolus vulgaris L.), cowpeas ( Vigna unguiculata [L.] Walp.), or velvet beans ( Mucuna pruriens [L.] DC. var utilis [Wight] Bruck.) were compared in two experiments. Maize populations were 40,400 and 50,500 plants ha⁻¹ in combination with climbing bean populations of 0, 20,200, 40,400 and 80,800 plants ha⁻¹ in Experiment 1. In the second experiment, climbing beans, cowpeas and velvet beans at 215,200 plants ha⁻¹ were intercropped with maize at 64,600 plants ha⁻¹. Climbing beans contributed up to 5% to total DM yields in the first experiment. In the second experiment legume contributions to total DM were 20% for climbing beans, 12% for cowpeas and 8% for velvet beans. Increasing populations of maize and climbing beans increased grain and DM yields. Dry matter yield of maize was lowered by intercropping. However, DM yields of the intercrop were not different to maize sole cropped. Maize/cowpeas produced more total DM than maize/climbing beans. Cowpeas increased the total yield of crude protein by over 15% without lowering total DM yield of the intercrop compared to maize alone and are promising as a legume for intercropping with maize. Climbing beans show little promise as a possible legume for intercropping with maize.     

玉米、花生根间菌丝桥对氮传递的研究

应用五室分隔法研究了玉米和花生根间菌丝桥对氮的传递作用。 研究表明： 供体接种菌根 ， 对花生、 玉米的生长均有明显的促进作用， 且对玉米的促进作用明显大于对花生的促 进 作用。 此外， 无论是以玉米为供体， 还是以花生为供体， 接种后， 均能在玉米和花 生根间形成菌丝桥， 形成的菌丝桥能传递氮， 且传递方向是双向     

盐胁迫下AM真菌对玉米生长及耐盐生理指标的影响

在自然盐渍土壤上和人工模拟盐胁迫条件下, 采用盆栽方法研究了长期(86天)和短期(1周)盐胁迫条件下丛枝菌根真菌对玉米植株生长和耐盐生理指标的影响。 结果表明： 在自然盐渍土壤和人工模拟长期盐胁迫条件下, 菌根真菌显著提高了玉米的相对产量; 在短期盐胁迫条件下, 接种菌根真菌处理的玉米叶片细胞质膜透性低于不接种     

设施条件接种丛枝菌根真菌对紫色土上玉米/大豆生长及氮素利用的影响

为了阐明紫色土上接种丛枝菌根真菌（arbuscular mycorrhizal fungus,AMF）和不同间作方式对提高间作玉米（Zea mays L.）、大豆（Glycine max L.）的氮素利用和减少土壤氮残留的贡献。本试验在设施盆栽条件下,采用根系分隔模拟装置研究玉米/大豆间作体系中根系不分隔、尼龙网分隔、塑料膜分隔3种方式和不同AMF处理[不接种AMF（NM）、接种Glomus mosseae（GM）]对玉米、大豆植株生长、氮素累积与利用的影响。研究结果表明：接种GM不同程度提高了间作玉米和大豆根系菌根侵染率、株高、植株生物量及氮含量,而显著降低了玉米和大豆种植土壤的碱解氮含量。其中,GM-根系不分隔处理玉米、大豆的菌根侵染率最高。无论是否接种AMF,大豆生物量和植株氮含量均以根系分隔处理显著高于不分隔处理,而玉米生物量和植株氮含量却刚好相反。此外,GM处理条件下,玉米、大豆根际土壤碱解氮含量均以尼龙网分隔和不分隔处理显著低于塑料膜分隔处理。在所有复合处理中,以GM-根系不分隔处理对玉米生长及氮素累积的促进作用最好;GM-尼龙网分隔处理对大豆生长及氮素累积的促进效果最佳,并更能显著降低玉米、大豆根际土壤的碱解氮残留,可望减轻土壤氮流失而降低氮素流失对地表水体的污染风险。     

Zinc seed priming improves salt resistance in maize

Salt stress is a major yield‐limiting factor in crops by reducing nutrient uptake and plant growth. Under salt stress, decreased water and nutrient uptake results in nutrient imbalance in plants. In addition, at high pH in saline conditions, solubility of minerals is also reduced leading to low availability of certain nutrients. Perspectives to overcome these limitations by Zn seed priming were studied with maize plants exposed to NaCl as salt stress. Maize seeds were primed for 24 hr in deionized water and 4 mm ZnSO₄·7H₂O solution (ZnP) and subsequently air‐dried at room temperature before further use. The DTZ (diphenylthiocarbazone) staining method was used for showing Zn²⁺ localization in the seeds. Zn²⁺ and other nutrient concentrations in unprimed, water and ZnP seeds and maize plants were analysed by inductively coupled plasma mass spectroscopy (ICP‐MS). Maize plants (cv. Sun star L.) were grown for 3 weeks in complete nutrient solution with or without salt stress (100 mm NaCl) under glasshouse conditions. Seed Zn²⁺ contents were increased after ZnP treatment by 600%. In maize seeds, most of the primed Zn²⁺ accumulated in the outer tissues (particularly, aleurone layer) of maize seed. Zn priming decreased the injurious effects of salt stress on plant growth. Under salt stress conditions, biomass production of plants from ZnP treatments was 25% higher compared to water priming treatment. Zn seed priming also improved mineral nutrient status of plants grown in both control and salt stress conditions. Plants from ZnP treatments also showed higher accumulation of Na⁺ in the shoots. This offers perspectives for using Zn seed priming for improving early seedling development and plant nutrient status of maize under salt stress conditions.     

Development of a gene-based marker correlated to reduced aflatoxin accumulation in maize

Aflatoxins are carcinogenic and toxic metabolites produced by the fungus Aspergillus flavus during infection of maize (Zea mays L.) and other seed oil crops. Climatic conditions in the southeastern United States favor A. flavus infection and aflatoxin contamination in maize, making it a major issue for farmers in the region. One of the most promising avenues to combat aflatoxin contamination is the development of resistant maize lines. However, this has proven difficult due to a lack of reliable markers for resistance. Previous studies have identified candidate genes that were differentially expressed in response to A. flavus infection. One gene, encoding a chloroplast precursor, was found to contain multiple polymorphisms that were used to design a marker designated Mississippi Marker 1 (MpM1). The marker differentiates between the “resistance” and “susceptible” forms of the allele. This marker was used to screen three populations of F_2:3 mapping families, where it was found to map to chromosome 4 and was associated with a significant effect for resistance to aflatoxin accumulation in the Mp313E × B73 mapping population. Furthermore, the marker MpM1 identified a previously unknown quantitative trait loci for resistance to aflatoxin accumulation on maize chromosome 4. MpM1 is the first gene-based marker developed specifically for resistance to aflatoxin accumulation in maize and can now be integrated into existing marker assisted selection programs aimed at incorporating resistance into elite maize breeding lines.     

抗全蚀病、根腐病的转PgPGIP1基因小麦的获得与鉴定

全蚀病和根腐病是小麦(Triticum aestivum)重要的土传真菌病害。PgPGIP1是人参(Panax ginseng)的一种多聚半乳糖醛酸酶抑制蛋白,可以抑制部分病原真菌分泌的多聚半乳糖醛酸酶的活性。本研究人工合成了PgPGIP1基因,并构建PgPGIP1基因的单子叶植物表达载体pA25-PgPGIP1,通过基因枪介导法将其转入小麦品种扬麦18中。对转PgPGIP1基因的T₀至T₄代植株进行PCR、RT-PCR和Q-RT-PCR分析,并对其全蚀病和根腐病抗性进行鉴定。结果表明,PgPGIP1基因能够在4个转基因小麦株系中遗传、转录与表达。与未转基因的小麦扬麦18相比,4个转基因小麦株系对全蚀病与根腐病的抗性明显提高,说明PgPGIP1表达增强了转基因小麦对全蚀病与根腐病的抗性。     

A method for drought tolerance screening in sunflower

One difficulty in obtaining drought-tolerant varieties is the unequivocal evaluation of plant response to soil-water deficits. A method is proposed that allows reproducible soil-water deficit treatments to be applied to different sunflower genotypes. Maize ( Zea mays L.) plants were sown in the same pots as but earlier than some sunflower plants in order to rapidly deplete the soil water. This method was compared to a standard method in which plants under evaluation are used to dry out the soil. The method was reproducible in the evaluation of drought tolerance of four sunflower inbred lines. Advantages of the proposed method are that: (i) it allows the desired soil water content to be reached quickly; (ii) the resulting soil water content in the pot is uniform and (iii) the rate of decrease in soil water content is independent of the genotype being evaluated. Data indicate that maize plants had no effect on the growth of sunflower genotypes.     

The Effect of Plastic Mulch and Greenhouse-Raised Seedlings on Yield of Maize

The yield of maize ( Zea mays L.) can be increased appreciably if canopy closure is brought forward. In France and Germany, the use of plastic mulch has boosted dry matter yields of silage maize by approximately 4 t/ha. In Germany, the grain yield of maize plants grown from greenhouse-raised seedlings was 2.4 t/ha more than that of plants grown conventionally. The present study aimed to review and quantify the effect of the use of plastic mulch and greenhouse-raised seedlings on yield of maize. In field trials the effect of a photo-degradable transparent plastic mulch on the yield of two hybrids: Clipper (early-maturing) and Dea (late-maturing) was tested. In two of these trials the effect of using seedlings raised in the greenhouse up to the five-leaf stage was also tested. Crops with plastic mulch required 10 % fewer growing degree days from planting to silking than the unmulched crops, and this number was more constant between years and sites. On average, plastic mulch increased whole plant dry matter content from 29 % to 33 %, and the dry matter of the ear from 45 % to 52 %. In Dea , dry matter yields of the whole plant and of the ear rose by 2.6 and 2.1 t/ha respectively. In Clipper the yield increases were half as large. The regression of whole plant dry matter yield on the sum of global radiation from silking to harvest was similar for mulched and unmulched crops. This suggests that the yield increases obtained with the plastic mulch were largely attributable to advancement of canopy establishment. The whole-plant dry matter yield of plants initially raised in the greenhouse was similar to that of maize sown in situ, but the ear dry matter yield was 2.4 t/ha higher.     

Performance of Clipped Maize

To study the effect of leaf clipping on maize ( Zea mays L.) performance, nine different treatments were tested on an open-pollinated genotype of maize. In the spring grown maize, grain yield/plant was increased up to 38% for plants with their upper half leaves cut. Root weight/plant and modified flowering were also increased. Cutting the whole plant decreased grain yield and caused death of about 50% of plants. Meanwhile, leaf clipping decreased several agronomic traits in the fall grown maize. The results of modified flowering lead to the speculation that genes could change their location on the chromosome and/or material dose when plants be under stressed conditions.

Zusammenfassung

Untersuchungen an entblätterten Mais-pflanzen Um den Einfluß einer Blattentfernung an Mais ( Zea mays L.) bezüglich der Leistung zu unter-suchen, wurden neun unterschiedliche Be-handlungen an offen abblühenden Genotypen von Mais vorgenommen. Im Frühjahr ange-bauter Mais zeigte eine Erhöhung des Kornertrages um 38% bei Pflanzen, an denen die obere Hälfte der Blätter entfernt worden war. Das Wurzelgewicht der Pflanze wurde erhöht und die Blüte modifiziert. Die Entfernung aller Blätter veränderte merit nur den Kornertrag, sondern verursachte auch das Absterben von 50% der Pflanzen. Die Blattentfernung min-derte zahlreiche pflanzenbauliche Eigenschaf-ten bei im Herbst angebauten Maispflanzen. Die Modifikation der Blüte läßt vermuten, daß unter Streßbedingungen Gene ihre Lokation an den Chromosomen oder ihre quantitative Wirkung verändern.