Characterization of the host range and sensitivity to fungicides of Trichothecium spp. associated with fruit rot in the field and in storage

During 2017–2019, we observed Trichothecium spp. causing fruit rot in the field and in storage. This study was conducted to examine morphological differences of the species from different hosts, reveal the species’ potential host range, and evaluate the efficacy of five fungicides. Six strains of Trichothecium spp. isolated from nectarine, peach and walnut were selected. Although the colony morphology, mycelial growth rate and spore size differed among hosts, phylogenetic analysis based on the internal transcribed spacer and part of the 5ʹ end of the β-tubulin gene showed that all tested strains belonged to Trichothecium roseum. For its host range, 23 kinds of fruit were examined using T. roseum strain YT-1 as an inoculum; 10 kinds of fruit, including pear, apple, mango, Chinese chestnut, pepino melon, fig and durian, were susceptible to T. roseum, with minimum inoculation concentrations ranging from 10⁴ to 10⁵ spores/ml. The fungicides that most effectively inhibited the six isolates were fluazinam and fludioxonil, with EC₅₀ values of 0.07–0.1 and 0.01–0.04 μg/ml, respectively, followed by difenoconazole (0.81–2.96 μg/ml), boscalid (5.43–13.51 μg/ml) and azoxystrobin (9.18–27.25 μg/ml). Improvement of the shelf life of nectarines held in plastic trays was explored using allyl isothiocyanate (AITC) against T. roseum YT-1. The application of 10 μl/L AITC significantly suppressed disease symptoms. The findings provide useful information for future disease emergency management in the field and for food preservation.     

Introduction of New Promising Apple Genotypes: A Study of Quality Attributes of Apple in Crosses between Iranian Early Ripening and Exotic Late Ripening Apple Cultivars

Apple breeding is usually done to produce higher quality apples. We crossed two late ripening high quality apple cultivars (i.e., Golden Smoothie and Red Spur) as maternal parents with two Iranian domestic early ripening apple cultivars (i.e., Golab-e Kohanz and Shafi Abadi) as pollen parents in 2005 to breed new early ripening apple cultivars. We then measured qualitative and quantitative traits of 360 off spring during 2010 and 2011. Results of recorded traits on the 5th and 6th year of growth of the progeny showed that during two evaluation years, flowering and fruit ripening time, titrable acidity, SSC/acid ratio, and fruit weight had the highest coefficients of phenotypic variations. Progenies were classified in three groups: early, mid, and late ripening. Some of the selected progeny were better than their early ripening parental cultivars being earlier in the ripening, with larger fruit size and better texture and flavor. Genotypes A31, A32, I5, I23, and I57 were in the early ripening category, B11 and A34 were in the middle, and B77 and E21 were in the late ripening categories. These characteristics were considered to present an improvement.     

快速脱水抑制葡萄干制过程中膜脂过氧化及褐变

为探索脱水速度对无核白葡萄干制过程中膜脂过氧化作用及褐变的影响,以新疆无核白葡萄为试验材料,经过葡萄促干剂处理后,采用快速脱水和缓慢脱水2种处理,质量每减轻10%进行取样,测定脱水过程中果实干基含水率、干燥速率、褐变度、细胞膜透性、丙二醛(malonaldehyde,MDA)含量、脂氧合酶(lipoxygenase,LOX)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)活性以及总酚含量的变化。结果表明:与缓慢脱水相比,快速脱水处理显著(P0.05)降低了无核白葡萄褐变度的上升,减少MDA生成量以及膜透性的增加,抑制LOX活性的升高,保持较高的活性氧清除酶SOD、CAT及POD活性及较高的总酚含量,且使PPO活性保持在一个较低的水平。因此认为,快速脱水可以有效地抑制无核白葡萄的膜脂过氧化作用对细胞膜的破坏,保持细胞的完整性,且PPO活性较低,从而减少无核白葡萄脱水褐变的发生。研究结果为快速脱水在无核白葡萄干制中的应用提供参考。     

俄罗斯欧洲花楸观赏性研究

俄罗斯欧洲花楸是世界著名观赏树种之一,与我国本地野生品种百花山花楸相比在观赏性上有着非常明显的优势。研究结果表明:俄罗斯花楸在侧枝数量、总花量、结果量、坐果率方面都要优于本地的野生花楸,在城市绿化方面的优势非常明显。     

不同促成栽培草莓果实品质及采后生理的研究

以不同促成栽培草莓果实为试材,在温度为(5±1)℃以及相对湿度(80±1.5)%避光条件下贮藏,研究了各品种果实品质和果实采后贮藏期间生理变化,为引进新品种和草莓果实贮藏保鲜提供理论依据.结果表明."甜查理"综合品质相对较好;试验证明在低温条件下贮藏,果实在前3d比较稳定,6d后果实腐烂指数显著增加,而且果实硬度越低,腐烂指数越大;果实呼吸速率第3d后明显增强,贮藏过程中,维生素C含量与超氧化物体歧化酶活性总体呈先上升后下降的变化趋势,丙二醛含量以及超氧阴离子代谢速率与腐烂指数呈正相关变化.这证明了果实腐烂与果实硬度的相关性,说明了果实腐烂与超氧阴离子以及丙二醛的积累有关,揭示了维生素C可能参与了果实衰老过程中自由基的清除.     

黑穗醋栗果实生长发育过程中抗坏血酸含量 及相关酶活性的变化

【目的】 研究不同品种不同生长时期黑穗醋栗果实内抗坏血酸（AsA）含量及其合成代谢过程中相关酶活性的变化,以明确果实生长发育过程中AsA含量与代谢合成相关酶之间的关系,为全面揭示黑穗醋栗果实AsA积累规律提供理论依据。【方法】 以3个不同黑穗醋栗品种（‘亚德’‘布劳德’和‘黑丰’）为试材,测定果实在幼果期、膨大期、半转色期、转色期和成熟期时还原型抗坏血酸（AsA）、氧化型抗坏血酸（DHA）、还原型谷胱甘肽（GSH）和氧化型谷胱甘肽（GSSG）含量以及AsA合成与代谢相关酶活性。【结果】 不同品种黑穗醋栗果实大小、AsA含量以及AsA相关代谢物水平存在明显的多样性。其中‘亚德’单果重最大,为1.97 g。果实生长发育过程中,总抗坏血酸（T-AsA）和AsA含量在3个品种中变化趋势一致,均在幼果期含量最高,其中‘亚德’幼果期果实中AsA含量最高,为83.17 μmol·g ^-1 FW,随着果实的生长迅速下降,在成熟期降至21.28 μmol·g ^-1 FW;3个品种果实中GSH和T-GSH含量随着果实发育呈升高趋势,但不同品种升高时期或增加幅度不同;GSSG含量在不同品种间存在较大差异,成熟果中‘黑丰’含量最低,为0.008 μmol·g ^-1 FW,仅为‘亚德’的10.2%。AsA-GSH循环再生代谢中,脱氢抗坏血酸还原酶（DHAR）和单脱氢抗坏血酸还原酶（MDHAR）活性在果实膨大期达到最高,成熟期降至最低,其中‘布劳德’果实中DHAR和MDHAR活性略高于‘亚德’和‘黑丰’;谷胱甘肽还原酶（GR）活性在幼果期最高,‘亚德’幼果期果实中GR活性最高（0.06 μmol·min ^-1·g ^-1 FW）,之后随着果实的生长发育不断下降,抗坏血酸过氧化物酶（APX）活性变化与之相似;L-半乳糖途径的关键酶L-半乳糖-1,4-内酯脱氢酶（GalLDH）活性随着果实生长发育的变化趋势与AsA含量变化相一致,且‘亚德’果实中GalLDH活性在幼果期和成熟期均高于其他两个品种。通过相关性分析发现,GalLDH与T-AsA、AsA、DHA、DHAR和MDHAR呈现极显著正相关关系,相关系数可达0.91以上,即果实中GalLDH活性越高,果实中AsA含量也越高;DHAR和MDHAR与T-AsA、AsA间也存在极显著正相关关系,而APX与T-GSH、GSH间相关性较强。【结论】 黑穗醋栗幼果期果实中AsA含量最高,且品种间差异显著;GalLDH、MDHAR和DHAR可能是黑穗醋栗果实中AsA合成代谢的关键酶,黑穗醋栗果实中AsA含量积累主要取决于GalLDH活性,说明合成途径起着更关键的作用,而AsA-GSH循环再生途径相关酶对AsA合成也有一定的贡献,黑穗醋栗高AsA含量的积累是由合成途径与循环途径共同作用的结果。     

主要果树果实品质遗传改良与提升实践

全面总结分析国内外果树果实品质改良现状、中国果树品质改良与发达国家的差距与成因,在此基础上系统阐述柑橘、苹果、梨、桃及葡萄等主要果树果实品质遗传改良的目标、技术途径与成果、品质性状遗传倾向、芽变机理,并举例阐述柑橘原生质体融合与无核品种创制、功能型苹果及其育种技术体系创建、早熟核果类果树品种和无核葡萄胚培育种、野生樱桃李资源品种化及转基因缩短童期新技术等方面取得的突破性进展。最后针对中国果实品质改良提出几条建议：进一步加强野生果树资源评价及亲本利用研究,努力拓宽栽培品种的遗传基础,协同提升果实品质;进一步开展细胞工程等生物技术以及芽变机理和性状遗传变异规律研究,建立生物技术与常规技术结合、杂交育种与芽变选种优势互补的果树果实品质高效改良技术体系;进一步加强新品系的国际品种区域栽培试验及国际品种权申请与保护,培育国际性的果树“大品种”。     

橙汁果酒绮丽酵母的筛选及耐受性

为获得适合橙汁果酒发酵的菌种,从橙汁发酵醪液中纯化出酵母菌,采用杜氏管法、CO2失重法及感官评定法进行筛选。通过形态观察和生理生化试验对菌株进行鉴定,并对菌株进行耐受性研究。结果表明：从发酵醪液中分离出4株酵母菌,经过初筛及复筛得到一株发酵能力强、还原糖利用率高、果酒风味柔和等优良特征的酵母菌,编号为 FJ-20,鉴定为酵母属的绮丽酵母。该菌株对酸的耐受能力为 pH2．5,对酒精的耐受能力为10％vol,对氯化钠耐受能力为11％,对蔗糖的耐受能力为35％。该菌株发酵能力强、还原糖利用率高、果酒风味柔和,发酵产香浓郁,适合作为橙汁低纯果酒的酿造酵母。     

增施钾肥对无花果贮藏品质的影响

为了提高无花果果实品质与耐贮性,以无花果品种布兰瑞克为试材,进行果实生长发育期追施钾肥对果实品质与贮藏性能影响的研究。结果表明适量增施钾肥能提高无花果采收时可溶性固形物含量和维生素C含量,降低果实可滴定酸含量;减缓冷藏期间果实可滴定酸含量的下降,抑制果实可溶性固形物含量的上升和维生素C的损失,较好地保持了果实的品质,提高了果实的耐贮性。无花果每年每株2次追施1.0 kg氯化钾时,果实贮藏效果最佳。西北林学院学报22卷第6期黄鹏增施钾肥对无花果贮藏品质的影响     

桔小实蝇在龙眼果实上产卵成功率测定试验

桔小实蝇（Bactrocera dorsalis)是为害水量的害虫，龙眼（Dimocarpus longan Lour.)被认为是其寄主之一，但经过对桔小实绳在龙眼果实上产卵成功率的测试试验，证明此虫只可在受了伤的果实的伤口处成功产卵，而不在健全的龙眼果实上成功产卵。