防治水果病害的生防酵母及生防制剂研究进展

水果在生长和贮藏过程中极易受到病原菌侵染而腐烂,从而造成巨大的经济损失。目前,田间病害防控及采后果实贮藏保鲜主要依靠化学制剂。化学制剂因其高效性及便利性在农业领域备受欢迎,但化学制剂的广泛使用对人体和环境都造成了很大的危害。因此,水果防腐需要寻求更安全、环保并高效的方法,其中生物防治是替代化学防治的有效措施之一。本文主要探究了生防酵母对于水果采后病害的生防效果及存在问题,并对国内外生防制剂的研究现状和前景进行了分析讨论,以期能为我国酵母生防制剂的商业化生产与应用提供有价值的参考。     

植物提取液对辣椒采后病原菌抑制及对根霉病抗性诱导作用

以‘湘研15号’辣椒为试材,分离、鉴定出4株辣椒采后病原菌,采用生长速率法测定丁香、肉桂、花椒等9种植物提取液对尖孢镰刀菌、黑色炭疽菌、红色炭疽菌、根霉菌的抑制效果,通过平板梯度稀释法测定植物提取液对上述4种供试病菌的最小抑菌浓度(minimum inhibitory concentration,MIC)和最小杀菌浓度(minimum bactericidal concentration,MBC);通过测定辣椒的病斑直径、发病率、总酚及类黄酮含量、苯丙氨酸解氨酶(phenylalanine ammonia lyase,PAL)、过氧化物酶(peroxldase,POD)、多酚氧化酶(polyphenol oxidase,PPO)活力,研究复合涂膜剂诱导辣椒对根霉病的抗性作用。结果显示,丁香、肉桂提取液对4种供试病原菌的抑菌率均为100%,对尖孢镰刀菌、黑色炭疽菌、红色炭疽菌和根霉菌的MIC均分别为1.25、2.50、2.50 mg/mL和5.00 mg/mL,MBC均分别为2.50、5.00、5.00 mg/mL和10.00 mg/mL。丁香、肉桂提取液复合涂膜剂能有效抑制辣椒的发病率和减小病斑直径,接种第8天时,与刺伤后接种根霉菌孢子组(CK2)相比,复合涂膜剂组发病率降低了6.67%(P0.05)、病斑直径减小了30.35%(P0.05);与刺伤后加无菌水组(CK1)和CK2组相比,复合涂膜剂处理辣椒的PAL活力分别提高了45.91%、24.54%(P0.05);POD活力分别提高了22.15%(P0.05)、12.54%(P0.05);PPO活力分别提高了80.00%、28.57%(P0.05);总酚含量分别提高了60.00%、43.74%(P0.05);类黄酮含量分别提高了82.05%、61.36%(P0.05)。结论:丁香、肉桂提取液复合涂膜剂能诱导辣椒对根霉病产生抗性,本研究可为开发高效、稳定、无毒无害辣椒防腐保鲜剂提供理论和技术支持。     

贵州水晶葡萄病原真菌分离鉴定及室内抑菌活性测试

[目的]确定引起贵州水晶葡萄采后贮藏病害的病原真菌种类及室内筛选用于该病害的主要防治杀菌剂。[方法]对病原菌进行分离纯化鉴定,通过科赫法则确定致病菌种类;筛选12种商品杀菌剂对炭疽病菌进行抑菌活性测定,筛选出有效药剂,为防治该病害提供一定的理论依据。[结果]从贵州省凯里市水晶葡萄采后贮藏病害分离鉴定出3株病原菌,为青霉菌(Penicillium sp.)、炭疽病菌(Clletotrichum gloeosporioides)和链格孢菌(Alternaria sp.),采用科赫法则,对3株病原真菌进行刺伤回接,发现3株均为水晶葡萄在贮藏过程中的主要致病菌。12种杀菌剂对水晶葡萄炭疽病菌进行室内抑菌活性测试结果表明:均具有较好的抑制活性,其中50%咯菌腈WP、50%苯菌灵WP、42%噻菌灵SC和43%戊唑醇SC对水晶葡萄炭疽病菌抑制活性最好,其EC50值分别为0.1024、0.1386、0.1624、0.1974 mg/L。[结论]凯里水晶葡萄采后病害病菌为青霉菌、炭疽病菌和链格孢菌;筛选出12种药剂针对水晶葡萄采后病害炭疽病菌的药剂,其中50%咯菌腈WP对炭疽病菌具有较好抑制效果,为水晶葡萄采后贮藏病害防治提供理论基础。     

Cover Image,Volume 99, Issue 13

The cover image is based on the Research Article Study of the physical and chemical changes during the maturation of three cocoa clones, EET8, CCN51, and ICS60 by Andrés F Cubillos Bojacá et al., DOI: 10.1002/jsfa.9882 . Cover image ©AGROSAVIA Images.

     

Regulation of the levels of health promoting compounds: lupeol,mangiferin and phenolic acids in the pulp and peel of mango fruit: a review

There is a demand for feasible methodologies that can increase/maintain the levels of health-promoting phytochemicals in horticultural produce, due to strong evidence that these compounds can reduce risk of chronic diseases. Mango (Mangifera indica L.), ranks fifth among the most cultivated fruit crops in the world, is naturally rich in phytochemicals such as lupeol, mangiferin and phenolic acids (e.g. gallic acid, chlorogenic acid and vanillic acid). Yet, there is still much scope for up-regulating the levels of these compounds in mango fruit through manipulation of different preharvest and postharvest practices that affect their biosynthesis and degradation. The process of ripening, harvest maturity, physical and chemical elicitor treatments such as low temperature stress, methyl jasmonate (MeJA), salicylic acid (SA) and nitric oxide (NO) and the availability of enzyme cofactors (Mg²⁺, Mn²⁺ and Fe²⁺) required in terpenoid biosynthesis were identified as potential determinants of the concentration of health-promoting compounds in mango fruit. The effectiveness of these preharvest and postharvest approaches in regulating the levels of lupeol, mangiferin and phenolic acids in the pulp and peel of mango fruit will be discussed. In general spray application of 0.2% iron(II) sulphate (FeSO₄) 30 days before harvest, harvest at sprung stage, storage of mature green fruit at 5 °C for 12 days prior to ripening, fumigation of mature green fruit with 10⁻⁵ mol L⁻¹ and/or 10⁻⁴ mol L⁻¹ MeJA for 24 h or 20 and/or 40 µL L⁻¹ NO for 2 h upregulate the levels of lupeol, mangiferin and phenolic acids in pulp and peel of ripe mango fruit. © 2019 Society of Chemical Industry     

Experimental performance comparison and trade-off among air-based precooling methods for postharvest apples by comprehensive multiscale thermodynamic analyses

Air-based precooling methods including room cooling and forced-air cooling were traditionally used for postharvest horticultural products. In this study, disturbed-air cooling with different layouts was proposed for the trade-off between room cooling with long cooling time and forced-air cooling with high energy consumption. Lab-scale experiments with 30 bins of postharvest apples were conducted using the aforementioned methods to measure the temperature history. Multiscale thermodynamic analyses from energy, entropy, exergy, and entransy perspectives were then performed. The time evolution of transient quantities and overall comparison of the trade-off performances were further discussed. The ventilation power and transformed heat became more significant respectively for the total energy consumption and heat load during the precooling processes. The rates of entropy generation, exergy destruction, and entransy dissipation reduced in consistent with the tendency of heat rejection from all bins. The major part of these losses was resulted by the ventilation for convective heat transfer between cold air and apples and became more significant during later stage of precooling processes. The middle-parallel disturbed-air cooling achieved the best trade-off between the lowest energy consumption for room cooling and the lowest maximum seven-eighths cooling time for forced-air cooling by respectively reaching 81.68% and 28.82% of the optimization potential. The best trade-off between the lowest thermodynamic loss for room cooling and the lowest heat transfer ability loss for forced-air cooling was also achieved by this method with around 55% to 62% optimization of the coefficients of performance, around 83% optimization of the entropy generation ratio, around 58% to 62% optimization of the exergy destruction ratio, and around 36% optimization of the entransy dissipation ratio.     

1-MCP对鸡枞菌采后生理及贮藏品质的影响

为探讨1-甲基环丙烯(1-methylcyclopropene,1-MCP)对鸡纵菌采后生理及贮藏品质的影响,在室温(25±2)℃条件下分别采用0.5、1.0、1.5μL/L的1-MCP对鸡纵菌进行熏蒸处理,处理后的鸡枞菌在(4±1)℃条件下贮藏。结果表明:1-MCP处理可明显改善鸡纵菌的贮藏效果,降低呼吸强度,提高可溶性糖含量和过氧化氢酶的活性,延缓可溶性蛋白的降解,抑制丙二醛含量的积累和多酚氧化酶的活性;1-MCP处理可较好地调控鸡纵菌贮藏期间的生理代谢,改善贮藏品质,延缓采后衰老进程。处理鸡枞菌的适宜1-MCP含量为1.0μL/L,此条件下处理的鸡枞菌于(4±1)℃贮藏12 d后无明显褐变与开伞现象,保鲜度为0.51。因此,1-MCP处理可延长鸡枞菌的保鲜期,提高商品价值。