堆肥提取液诱导草莓对黄萎病抗性及抑菌机理研究

为了明确菌糠堆肥提取液的生物防治效果,进一步探讨其抑菌防病机理,以便于有针对性地利用堆肥提取液达到防病、治病的效果。采用体内和体外2种试验方法,以草莓黄萎病菌为靶标病原菌,研究了堆肥提取液原液、高温灭菌液和过滤除菌液对大丽轮枝菌菌丝生长和分生孢子萌发的抑制作用,通过温室盆栽试验验证其对草莓黄萎病的防病促生效果,并测定根施堆肥提取液对草莓叶片内防御酶系的影响。研究表明,堆肥提取液对病原菌菌丝生长和分生孢子萌发均有显著的抑制作用,抑制率分别为92.43%和82.94%,经高温灭菌和过滤除菌后抑制效果显著降低。盆栽试验结果表明,预先用堆肥提取液灌根处理对草莓黄萎病的防治效果高达42.23%,且能诱导草莓叶片内防御酶活性显著增强,接病原菌后第6 d该处理下的POD和PPO活性分别比施清水对照提高了45.45%和39.47%,而MDA含量则下降了14.83%。说明微生物对病原菌的直接抑制作用以及诱导系统抗性是菌糠堆肥提取液发挥抑菌防病功效的主要因素。     

泰安市“香野”草莓采后主要病原菌的分离鉴定及精油抑菌效果评价

为明确山东省泰安市草莓采后主要致腐病原菌的种类及不同植物精油的抑菌效果,从腐败的"香野"草莓果实上分离、纯化优势菌株,进行形态学和分子生物学鉴定,并通过室内熏蒸毒力试验评价7种植物精油对上述病原菌的抑制效果。结果表明,泰安地区草莓分离得到3种病原菌,分别为灰葡萄孢菌Botrytis cinerea、链格孢菌Alternaria alternata和枝孢菌Cladosporium tenuissimum。7种植物精油对3种病原菌均表现出不同程度的抑制作用,百里香精油对灰葡萄菌和链格孢菌的室内毒力均最高,EC₅₀值分别为39.998和18.456 μL/L;柠檬草精油对枝孢菌的活性最高,EC₅₀值为30.523 μL/L。活体抑菌试验结果表明,百里香精油对草莓果实灰葡萄孢菌和链格孢菌的活体抑菌效果最高,防效分别为86.21%和89.29%;柠檬草精油对枝孢菌的防效最高,为75.86%。综合比较可以发现,百里香精油、玫瑰草精油、柠檬草精油及肉桂精油对草莓采后3种病原菌均具有较好的抑制效果。     

丁香精油及其与壳聚糖复合物对水果采后病原菌的抑制作用

研究了丁香精油以及丁香精油-壳聚糖复合物对几种水果采后腐烂的主要致病真菌灰霉菌、链格孢,青霉菌、浆孢菌的孢子萌发和菌丝生长的抑制效应,确定其最低抑菌浓度和最低杀菌浓度。结果表明,丁香精油对供试病原菌均有较强的抑制效果,10μL/mL丁香油对4种菌菌丝生长和孢子萌发的抑制率达到85%以上。丁香油-壳聚糖复合物溶液在10μL/mL时(含丁香油有效成分5μL/mL)对4种菌菌丝生长和孢子萌发的抑制率在80%以上,而5μL/mL丁香油对其菌丝生长和孢子萌发的抑制率大都在80%以下,复合物的抑菌效应比含有相同有效浓度的丁香精油抑菌效应有明显提高。     

瑞香狼毒根提取物对植物病原真菌的抑菌效果研究

用乙醇温浸法提取瑞香狼毒根的活性物质,对11种常见植物病害的病原菌,采用生长速率法进行抑菌活性测定。结果表明,乙醇提取液中存在抑菌活性物质,对油菜菌核病菌、辣椒疫病菌、番茄早疫病菌、草莓灰霉病菌的抑制效果较好,对其他几种病菌也表现出一定的抑制作用。     

壳低聚糖聚合度分析及室内抑菌活性研究

室内用壳聚糖氧化降解法得到了壳低聚糖 ,并采用HPLC方法分析了壳低聚糖的聚合度。结果显示 ,其聚合度分别在 1～12范围内 ,其中单糖占 5.79% ,2～5糖占 38.64% ,6～8糖占 15.29%。采用离体平皿法将获得的壳低聚糖对 17种常见植物病原菌进行抑菌活性测定 ,结果表明 ,壳低聚糖对其中 16种病原菌都有抑制作用 ,且随着浓度提高作用增强。壳低聚糖对土传病害真菌表现出较好的抑制作用 ,其中壳低聚糖对芦笋茎枯病、棉花枯萎病、棉花黄萎病 3种土传病害病原菌的EC₅₀分别为626.78、393.16、854.19μg/mL。     

链霉菌ZZSP-7的鉴定及其对草莓炭疽病的防效

为获得草莓炭疽病菌胶孢炭疽菌的优良拮抗菌,以草莓种植基地的土壤为拮抗菌来源,通过室内测定不同分离物对草莓炭疽病菌的抑菌活性,筛选抑菌率最高的菌株,在此基础上对所筛菌株进行分类鉴定,并评价其抑菌谱和防效。结果表明,从土壤中分离获得42株拮抗菌,筛选出5株对胶孢炭疽菌具有明显抑制作用的菌株。其中,菌株ZZSP-7的抑菌作用最强,5 d后的抑菌带宽达17.6 mm。经形态、生理生化及16S rDNA基因系统发育分析,确认菌株ZZSP-7为链霉菌Streptomyces sp.。菌株ZZSP-7抑菌谱广,对多种植物病原菌均具有良好的抑菌效果。盆栽试验结果表明,在盆栽中菌株ZZSP-7对“红颜”和“甜查理”两个品种草莓炭疽病菌的防效分别为78.64%和82.81%,具有进一步开发和利用的前景。     

香豆素对灰葡萄孢霉菌抑菌作用机理初探

为探究香豆素对灰葡萄孢霉菌Botrytis cinerea作用机理的影响，通过抑菌试验、酶活试验及电导率试验，分析香豆素对灰葡萄孢霉菌的抑菌活性，以及经香豆素处理后灰葡萄孢霉菌胞内外蛋白质含量、酶活性以及细胞膜透性的变化规律，揭示香豆素对灰葡萄孢霉菌的抑菌机理。结果表明:在PD液体培养基上香豆素对灰葡萄孢霉菌的EC₅₀值为101 mg/L；处理组胞内及胞外蛋白浓度均低于对照组蛋白浓度；香豆素浓度为101 mg/L时对灰葡萄孢霉菌三磷酸腺苷酶 (ATPase) 和过氧化氢酶 (CAT) 的抑制率分别为62.60%和76.5%，对纤维素酶 (CL)、多聚半乳糖醛酸酶 (PG) 和果胶酶 (pectinase) 的抑制率分别为57.63%、64.51%和61.13%；香豆素处理可显著增强灰葡萄孢霉菌的细胞膜透性，经香豆素处理48 h，灰葡萄孢霉菌的电导率为17568.79 μS/cm，为对照组电导率的1.9倍。可见，香豆素可以抑制灰葡萄孢霉菌的生长，使其呼吸代谢受阻，干扰灰葡萄孢霉菌细胞膜的渗透，抑制灰葡萄孢霉菌细胞壁酶的活性。该结果可为以香豆素为主的新型植物源农药开发以及灰霉病的防治提供理论支撑。     

腐霉菌对荧光假单胞菌株LT6代谢物的敏感性变异

为了探明不同靶标病原菌对生防菌荧光假单胞菌株LT6及其代谢物的敏感性差异，在1／5TSA平板上测定了荧光假单胞菌株LT6对69株腐霉菌的拮抗效果，在试验中观察到菌株LT6对不同种腐霉与同种腐霉不同菌株的拮抗效果存在明显差异，抑菌带最宽的为终极腐霉Pythium ultimum菌株，达7．5mm，对未知种腐霉菌株抑菌带宽最小，均小于3．0mm。腐霉菌株对由LT6产生的抗生素吩嗪-1-羧酸（PCA）的敏感性存在变异，被测的54株腐霉，当PCA浓度为7．0μg／mL时，敏感的为28株，高抗的为15株。用不同的培养液培养LT6所得的代谢物，在相同浓度下，对同一腐霉菌菌丝体生长的抑制效果不同，培养液1／5 TSB和NB明显强于KMB。综合所获结果可以看出，靶标病原菌对生防菌敏感性不一致；不同的培养基产生不同的代谢产物，对病原菌的抑制作用有明显差异。     

砖红镰刀菌菌株Pa2对草莓灰霉病的抑制作用

由灰葡萄孢菌Botrytis cinerea引起的草莓灰霉病是草莓栽培中最具破坏性的病害之一,严重降低食用以及经济价值。本研究以“红颜”草莓为试验材料,测定砖红镰刀菌Fusarium lateritium Pa2对草莓灰霉病菌的抑菌活性、防治效果以及草莓病程相关基因表达水平的影响。结果表明,菌株Pa2对草莓灰霉病菌具有显著的抑菌活性,其上清液可以破坏草莓灰霉病菌菌丝细胞膜,导致细胞内容物泄露。离体接种试验结果表明菌株Pa2对草莓叶片灰霉病、草莓果实灰霉病防治效果分别为79.13%、54.29%。经菌株Pa2上清液处理24h后草莓果实病程相关基因FaPR1、FaPR4、FaGR分别上升19.05、24.64、3.69倍。综上所述,砖红镰刀菌菌株Pa2是一种防治草莓灰霉病的新型生防菌资源。     

西瓜枯萎病生防菌的分离鉴定及其生防潜力研究

为筛选获得高效防治西瓜枯萎病菌的生防菌株,本研究以胶体几丁质为唯一碳源的培养基,从广东珠海红树林根际土分离的1000余株细菌中筛选到32株具有高几丁质酶活性菌株,采用平板对峙法进行复筛,最终获得10株综合效果好的菌株。温室结果表明,这10株菌株均具有促生及防病效果,其中菌株PL-29处理组相对于对照组防病效果最好,防治效果为63.11%,促生效果同样显著。经形态学、生理生化特征和16S rDNA系统发育分析,最终将菌株PL-29鉴定为黄三素链霉菌Streptomyces flavotricini。此外,抑菌谱试验结果表明,该菌株对辣椒疫霉Phytophthora capsici、灰葡萄孢Botrytis cinerea、立枯丝核菌Rhizoctonia solani等多种病原菌都具有拮抗能力。对菌株PL-29的抑菌作用进一步研究表明,菌株PL-29能抑制尖孢镰刀菌孢子的产生及萌发,从而抑制病原菌的生长。此外,还可以破坏尖孢镰刀菌质膜完整性,诱导ROS积累。综合上述结果表明,黄三素链霉菌S. flavotricini PL-29在防治西瓜枯萎病方面具有较高的潜在应用价值。     

北京地区日光温室草莓灰霉病发生 动态监测和影响因素分析

 草莓灰霉病是由灰葡萄孢(Botrytis cinerea Pers.)引起的一种真菌病害,可造成草莓烂果,严重影响草莓产量和采后保存。为了探明日光温室草莓灰霉病的发生流行规律,在2013—2014年生长季和2014—2015年生长季,对北京地区草莓日光温室空气中灰葡萄孢分生孢子数量、草莓花瓣带菌率和灰霉病病果数进行了动态监测和调查,同时对日光温室中气象因子进行了系统监测和记录。结果表明,在草莓日光温室中,利用孢子捕捉器捕获的灰葡萄孢分生孢子数量在一天中主要集中在5:00-18:00,以11:00-14:00数量最大。在一天中每小时捕获的分生孢子数量与温度和光照强度呈极显著正相关(P≤0.01),与相对湿度呈极显著负相关(P≤0.01)。新增草莓灰霉病病果数与7 d前当天捕获的分生孢子数量呈极显著正相关(r=0.872,P≤0.01),与7 d前当天的新鲜花瓣带菌率亦呈极显著正相关(r=0.807,P≤0.01),这为利用捕获的分生孢子数量和新鲜花瓣的带菌率预测7 d后草莓灰霉病的发生情况提供了重要参考。本研究结果有助于了解日光温室中草莓灰霉病的发生规律和影响因素,为该病害的防控和预测测报提供了依据。     

天敌治虫和熊蜂授粉技术在大棚草莓上的应用

本文集成、应用大棚草莓天敌治虫、熊蜂授粉技术以减少化学农药使用量,降低农药残留,提高草莓品质。在大棚草莓上,以常规管理作为对照,采用草莓害虫天敌和熊蜂授粉相结合的模式防治大棚草莓害虫、提高果实品质。研究表明,采用多种天敌联合防治技术起到了很好的防治效果,且控制效果持续时间更长。其中对叶螨的防治效果达到74.29%;对粉虱的防治效果达到59.38%;对蚜虫的防治效果达到61.03%。熊蜂授粉技术与人工授粉对比,草莓形状、果色,平均单果重、果实维生素C含量、固形物含量以及固酸比都显著提高,畸形果率显著降低。以上结果表明,多种天敌防治技术对虫害的发生起到了很好的防治效果,优于传统化学防治方式,降低了农药残留;熊蜂授粉技术显著提升了草莓品质、品相及单果重量。     

Fruit Quality and Yield in Partially Defoliated Strawberry Plants in the Tropical Highlands

The partial loss or reduction of leaf area is a wide-spread occurrence in the plant life cycle, caused e.g. by herbivory, stress or pathogen attack. The objective of the study was to evaluate the effect of partial defoliation on fruit production and quality in strawberry (Fragaria ×ananassa Duch. cv. Chandler). Plants were grown in a greenhouse in Tunja, Colombia, in hydroponics with an aerated nutrient solution. As leaves emerged, one or two leaflets were removed from each compound leaf, to attain 38 % and 67 % reduction of leaf area. Control plants grew intact, without defoliation. Fruit yield and fruit quality characteristics were evaluated for each plant. The pH, total soluble solids, ratio of total soluble solids to fruit juice acidity, fruit yield, fruit mass and size, and the ratio of leaf area/fruit yield were reduced drastically in defoliated plants. Leaf area reduction in excess of 38 % adversely affected physical and chemical characteristics of strawberry fruit, which did not meet marketing criteria.     

草莓中吡虫啉和氟硅唑残留的膳食暴露风险

为明确吡虫啉和氟硅唑在草莓上施用后可能产生的膳食暴露风险,进行了规范的田间残留试验及对不同人群的膳食风险评估。结果表明:保护地栽培条件下,吡虫啉、氟硅唑在草莓上的消解速率符合一级动力学方程,半衰期分别为6.3 d和9.9~11.5 d。10%吡虫啉可湿性粉剂(WP)分别按有效成分37.5和56.25 g/hm2剂量于草莓果实为成熟个体一半大小时开始施药,共施2~3次,每次间隔7 d,于末次施药后3、5、7、10 d时分别采样测定,草莓中吡虫啉的残留量在0.022~0.16 mg/kg之间;400 g/L的氟硅唑乳油(EC)分别按有效成分45和67.5 g/hm2剂量于草莓果实为成熟个体一半大小时开始施药,共施2~3次,每次间隔7 d,于末次施药后3、5、7、10 d时分别采样测定,氟硅唑在草莓中的残留量为0.079~0.30 mg/kg。基于此残留试验数据、各类食物的日平均膳食摄入量及每日允许摄入量(ADI),计算得到中国各类人群中吡虫啉和氟硅唑暴露的风险商(RQ)。结果表明:草莓中吡虫啉和氟硅唑的急性风险商(ARQ)分别为其急性参考剂量(ARfD)的0.18%~1.0%和10%~37.7%,不存在不可接受的急性膳食暴露风险;草莓中吡虫啉和氟硅唑的慢性风险商(CRQ)分别为其ADI值的18.6%~85.3%和68.3%~316.4%,其中氟硅唑对2~4岁幼童的暴露风险超过100%,存在明显风险,但草莓中的氟硅唑对其全膳食暴露风险的贡献率不超过3.2%,并非其主要风险源;两种农药对其他暴露人群均不存在明显膳食风险。中国尚未制定草莓中吡虫啉和氟硅唑的最大残留限量(MRL)值,本研究推荐的吡虫啉和氟硅唑的MRL值对消费者长期慢性暴露风险的保护水平(CPLc)分别为18~109倍和2~13倍,短期急性暴露风险的保护水平(CPLa)分别为121~725倍及6~36倍,对消费者的保护水平均较高。建议:草莓中吡虫啉和氟硅唑的MRL值均可定为0.5 mg/kg,安全间隔期可分别为3 d和5 d;但对于2~4岁幼童,应充分关注氟硅唑对其的慢性膳食暴露风险。     

Pathogenic and Nonpathogenic Lifestyles in Colletotrichum acutatum from Strawberry and Other Plants

ABSTRACT Anthracnose is one of the major fungal diseases of strawberry occurring worldwide. In Israel, the disease is caused primarily by the species Colletotrichum acutatum. The pathogen causes black spot on fruit, root necrosis, and crown rot resulting in mortality of transplants in the field. The host range and specificity of C. acutatum from strawberry was examined on pepper, eggplant, tomato, bean, and strawberry under greenhouse conditions. The fungus was recovered from all plant species over a 3-month period but caused disease symptoms only on strawberry. Epiphytic and endophytic (colonization) fungal growth in the different plant species was confirmed by reisolation from leaf tissues and by polymerase chain reaction (PCR)-specific primer amplification. C. acutatum was also isolated from healthy looking, asymptomatic plants of the weed genera Vicia and Conyza. Isolates that were recovered from the weeds caused disease symptoms on strawberry and were positively identified as C. acutatum by PCR. The habitation of a large number of plant species, including weeds, by C. acutatum suggests that, although it causes disease only on strawberry and anemone in Israel, this fungus can persist on many other plant species. Therefore, plants that are not considered hosts of C. acutatum may serve as a potential inoculum source for strawberry infection and permit survival of the pathogen between seasons.     

Influence of Colletotrichum simmondsii R. G. Shives & Y. P. Tan infection on selected primary and secondary metabolites in strawberry (Fragaria x ananassa Duch.) fruit and runners

The effect of Colletotrichum simmondsii infection on the contents of sugars, organic acids, and individual phenolic compounds was investigated in strawberry cultivar ‘Clery’. Primary metabolites were determined with the use of HPLC and secondary metabolites further confirmed with HPLC-MS. Colletotrichum simmondsii caused a decrease in sucrose and an increase in fructose and glucose in strawberry fruit. A significant decrease in the content of malic and citric acids was recorded in infected fruit. 12 forms of ellagic acid, nine flavanols and eight flavonols were identified in strawberry runners and nine forms of ellagic acid, six flavanols, seven flavonols and four anthocyanins in strawberry fruit. Significant differences in individual phenolic compounds in strawberry fruit were detected at the beginning of the infection compared to non-infected fruit. Specifically, ellagic acids significantly increased, flavonols generally decreased, and flavanols and anthocyanins increased with the progression of infection. Similarly, some forms of ellagic acid increased and others decreased in infected runners, procyanidins generally decreased and flavonols, increased but the differences were much less prominent.     

草莓温室施用百菌清对施药及采收人员的暴露水平与风险评估

采用手动背负式喷雾器,在草莓温室中均匀施用75%百菌清可湿性粉剂,通过贴片法分析了施药者及果实采收者的人体暴露量,研究了草莓温室施用百菌清对操作人员的职业暴露风险。结果表明:在草莓温室中施用百菌清,对施药者人体暴露的施药液量为19.2~46.6 mL/h,平均为30.2 mL/h,主要暴露部位为小腿;采收果实时,施药后第1天采收者人体暴露的施药液量为3.8 mL/h,第7天时为0.027 mL/h,主要暴露部位均为手部。在本研究暴露条件下,施药者的安全限值(MOS)为0.258,表明该暴露环境对施药者存在风险;施药后1~7 d,采收者的MOS值均1,表明该暴露环境对采收者人体暴露为安全。研究表明,在草莓温室中施用百菌清,对田间操作人员存在职业暴露风险,因此应注意加强防护措施,或缩短暴露时间;采收时,对采收者无职业暴露风险,但应对主要暴露部位手部加强防护。     

Yield losses of asymptomatic strawberry plants infected with <Emphasis Type="Italic">Strawberry mild yellow edge virus</Emphasis>

After successive vegetative propagation cycles, strawberry (Fragaria × ananassa Duch.) plants often accumulate multiple virus species that result in viral symptoms and losses in yield and quality. However, strawberry plants infected by a single virus species usually remain asymptomatic with unknown effects on fruit production and quality. In this context, the effect of Strawberry mild yellow edge virus (SMYEV) on fruit production was studied in strawberry plants, cultivar Camarosa, over two years. Asymptomatic SMYEV-infected plants showed a significant reduction in total and marketable fruit number and weight compared with healthy plants. These reductions ranged between 28% and 63%, depending on the parameter measured and the production cycle. Fluctuations in SMYEV concentration in the plants was detected throughout the crop cycle, suggesting that samples for virus diagnosis should be taken when the plant has the highest virus concentration; in this study, this occurred at the end of the crop cycle. These results show that analyzing symptomless strawberry plants should be part of a virus disease management plant and an important component to control the quantitative and qualitative impacts of SMYEV on strawberry yield.     

草莓灰霉病研究进展

草莓灰霉病是草莓上最重要的病害之一,在温室和露地栽培中均普遍发生,草莓生长期和采后果实均可被侵染,造成严重的经济损失。本文结合作者近年来对草莓灰霉病的有关研究,就草莓灰霉病的症状和危害,病原菌的种类,分生孢子萌发的最适温湿度,病原菌的抗药性,影响草莓灰霉病发生的因素包括品种抗感性、不同器官的带菌量和空气中的孢子量及环境条件,草莓灰霉病综合防治等方面的国内外研究进展进行综述,以期为从事相关研究的科研人员和生产技术人员提供参考与帮助。     

Selective Isolation of Bacterial Antagonists of Botrytis cinerea

Most potential fungal antagonists have been identified only after exhaustive non-selective screening. Bacteria antagonistic to Botrytis cinerea were selected using a simple method based on techniques developed for trace enrichment studies, where a crude cell wall preparation from B. cinerea was used as a selective substrate and bacteria were isolated based on growth on cell wall agar media. Most of the 52 bacterial isolates that were obtained from the surface of organically grown strawberry fruit and could grow on B. cinerea wall media in culture showed some ability to inhibit the growth of the fungus. Potato dextrose agar seeded with B. cinerea spores (104ml–1) were challenged with each of these bacterial isolates at concentrations of 109 and 106 colony forming units ml–1. Eleven of the 52 isolates initially recovered, subsequently demonstrated strong antagonism in vitro and were selected for additional screening tests on strawberry fruit. All 11 isolates reduced grey mold rot incidence on fruit in storage. Three of the best isolates were tested in limited field trials, and also reduced grey mold rot on fruit under field conditions.