激发子物质处理富士苹果果实后抗轮纹病病菌侵染的研究

富士苹果果实经硝普钠(SNP)、茉莉酸甲酯(MeJA)、水杨酸(SA)和氯化钙处理后再接种轮纹病菌,各个处理均能不同程度地防止轮纹病菌的侵染和扩展,其中MeJA和SNP处理效果最明显,烂果率和烂果面积分别比对照减少26.7%、26.7%和41.6%、36.2%。另外,还对各处理果实的PAL、SOD、POD和PPO活性变化进行了分析,结果表明,接种轮纹病菌的72h内,4个处理的PAL和PPO活性均表现出先升后降的趋势,而SOD和POD活性变化除SA处理一直保持平稳波动上升外,其余3个处理也表现为先升后降趋势;各处理的PAL和POD峰值出现的时间均早于SOD和PPO。PAL、POD和PPO活性峰值和平均值均以MeJA处理最高,SOD活性峰值和平均值SNP处理最高。     

青香蕉和黄熟香蕉果皮感病过程中5种酶活性的变化

以同一品种的未后熟的青香蕉和已黄熟的香蕉为材料,测定了接种炭疽病菌5d内果皮PPO、POD、SOD、PAL和LOX活性的变化,探讨与香蕉抗病性相关的酶类。结果表明,不论接种与否,青香蕉果皮中的PPO、POD和SOD的活性明显低于黄熟香蕉,而PAL和LOX活性高于黄熟香蕉;接种对PPO、POD和LOX活性影响不大,但引起SOD和PAL活性下降。青香蕉果皮中较低的PPO、POD和SOD的活性有利于活性氧和酚类物质的积累而产生过敏性反应,较高的PAL和LOX活性则利于苯丙烷类代谢和脂质过氧化,有利于抗病物质的形成。PAL和LOX是香蕉抗病性形成的关键酶。     

高氧处理对冬枣货架期间膜脂过氧化和保护酶活性的影响

 研究了在- 1～ - 2℃条件下冬枣果实经流动的21% O₂ (空气对照) 、70% O₂ ( 30%N₂ ) 、100% O₂ 分别处理7 d和15 d, 在20℃货架期期间测定果实相对电导率、丙二醛(MDA) 含量以及保护酶系( SOD、CAT、POD) 活性的变化。结果表明, 高O₂ 处理可抑制冬枣货架期相对电导率的升高, 100%O₂ 处理效果好于70% O₂ 处理。70% O₂ 处理7 d对冬枣货架期期间的膜脂过氧化作用没有显著影响, 但诱导了SOD、CAT和POD活性的升高, 促进冬枣果实在货架期衰老。100% O₂ 处理能抑制冬枣果实货架期膜脂过氧化作用, 在货架期期间保持较稳定的SOD和CAT活性, 但对POD 活性的升高有促进作用。总体来看, 100% O₂ 处理15 d对减缓冬枣货架期的衰老代谢有较好效果。     

Effects of post-harvest salicylic acid treatment on fruit quality and anti-oxidant metabolism in pineapple during cold storage

Summary

Pineapple (Ananas comosus L. ‘Comte de Paris’) fruit at commercial maturity (180 fruit per treatment, three replicates) were immersed in 0, 1.0, 3.0, or 5.0 mM salicylic acid (SA) for 15 min, then stored at 10ºC and 90% relative humidity (RH) for 20 d. After 20 d in cold storage, they were moved to 20ºC for 2 d to simulate shelf-life. Physiological and biochemical responses were studied. The results showed that the 3.0 or 5.0 mM SA treatments lowered the internal browning (IB) index, while the 5.0 mM SA treatment decreased the soluble solids content (SSC), titratable acidity (TA), and soluble sugar content, but increased ascorbic acid (AsA) levels at the end of shelf-life. Furthermore, during cold storage, all SA treatments significantly decreased the rate of tissue respiration in pineapple fruit. SA at 5.0 mM significantly decreased the activities of peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL), but increased the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) compared with the non-SA treated (untreated) controls. Overall, these results indicate that post-harvest treatment with 5.0 mM SA delayed the occurrence of IB in pineapple, extended its shelf-life, and maintained fruit quality during cold storage.     

华盛顿脐橙果实采后油胞病害与酶活性的相关性

以华盛顿脐橙果实为试验材料,研究采后果皮油胞病害的发生状况及病变过程中果皮POD(过氧化物酶)、PPO(多酚氧化酶)、PAL(苯丙氨酸解氨酶)等相关酶活性的变化,以探索柑橘果皮油胞的病变生理。研究结果表明,果皮油胞病害发生率随贮藏时间的增加而上升;伤果的发病率显著增加,发病时间早;低温降低了贮藏后期果皮油胞病变率。损伤处理显著提高了果皮PPO、POD和PAL酶活性,而低温则抑制了这些酶活性。在整个常温贮藏过程中,正常果和损伤果的油胞病害发生率与这3种酶活性都呈显著和极显著正相关。说明果皮POD、PPO和PAL的高活性是果皮油胞病变的重要生理因素。     

Benzothiadiazole- or methyl jasmonate-induced resistance to Colletotrichum musae in harvested banana fruit is related to elevated defense enzyme activities

Summary

The ability of benzothiadiazole (BTH) or methyl jasmonate (MeJA) to induce disease resistance in harvested banana fruits was investigated in relation to the activities of several defense-related enzymes. Harvested banana fruit were sprayed with BTH or MeJA solution before being stored at 22°C. Disease development and the activities of six defense-related enzymes were monitored during storage. Compared with untreated fruits, BTH or MeJA treatment significantly reduced the severity of disease in non-inoculated bananas, and lesion diameters and the incidence of disease in bananas inoculated with Colletotrichum musae. The activities of the defense-related enzymes peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), β1,3-glucanase, and chitinase were all enhanced in BTH- and in MeJA-treated banana fruit whether inoculated with the pathogen or not. The results suggest that post-harvest decay in bananas can be controlled by BTH or MeJA, and involves activation of the disease defense system. In non-inoculated bananas, MeJA and BTH had similar effects on the three defense enzymes (CAT, PPO and PAL), but different effects on the three PR proteins (POD, β1,3-glucanase and chitinase). In inoculated bananas, MeJA and BTH had similar effects on all six enzymes.     

钾、钙、硼、硅对茄子抗黄萎病效果的影响

以茄子黄萎病为研究对象,采用田间施用钾（K）、钙（Ca）、硼（B）、硅（Si）的方法,探讨4种元素对接种黄萎病菌后茄子幼苗的发病率、植株生长状况及防御酶活性的影响。结果表明,与对照相比,施用4种元素的各处理均降低了茄子黄萎病的发病率和病情指数,低浓度的K、Ca、B、Si促进了茄子幼苗株高、茎粗、根长、全株鲜质量、根系活力及POD、PPO、PAL活性,而后随着浓度增大,促进作用减弱。其中以B 50 mg·L^-1处理抗病性最好,其发病率比对照低46.66个百分点,各生长指标显著高于对照,根系活力比对照提高286 %;POD、PPO、PAL活性分别比对照提高20 %、78 %、87 %。说明B对诱导茄子黄萎病抗性有显著效果,可应用到生产。     

钾营养对菜薹（菜心）炭疽病发生和植株防御酶活性的影响

通过接种炭疽病菌,测定了不同钾营养水平下菜薹的抗病品种和感病品种的病情指数、苯丙氨酸解氨酶（PAL）、多酚氧化酶（PPO）和过氧化物酶（POD）活性。结果表明,不同钾营养水平处理的菜薹炭疽病发病程度均比对照轻,病情指数明显下降,钾营养处理明显增加了菜薹对炭疽病的抗性水平。随着钾营养处理水平的提高,抗病品种的PAL活性、PPO活性都呈上升趋势,而钾营养处理的POD活性则低于对照|感病品种的PAL活性、PPO活性、POD活性都呈先上升后下降趋势,酶活性在中K处理时达到最高。     

苯并噻二唑处理提高采后沙糖橘对指状青霉菌的抗性

对沙糖橘(Citrus reticulata Blancdo‘Shiyueju’)果实进行苯并噻二唑(S-methyl benzo thiadiazole-7-carbothioate,BTH)渗透处理后接种指状青霉菌孢子,12h后即可明显诱导果皮中抗病相关蛋白CR-CT1和CR-BG3基因表达并在贮藏期间维持较高水平;不同浓度BTH处理果实的发病率和病斑面积均比对照低,其中以0.025g·L-1BTH处理的效果最好;BTH处理提高了果皮几丁质酶(CT)、β–1,3–葡聚糖酶(GUN)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、过氧化物酶(POD)活性和H2O2含量,表明BTH诱导的沙糖橘果实抗病性与果实CR-CT1和CR-BG3基因的表达增强,CT、GUN、PAL、PPO和POD等相关酶活性和H2O2含量提高密切相关。     

杧果采前喷施茉莉酸甲酯对其抗病性和采后品质的影响

 以‘台农1号’杧果（Mangifera indica L.‘Tainong 1’）为试材,研究了采前喷施茉莉酸甲酯（MeJA）处理对杧果抗病性和采后品质的影响及其相关机理。结果表明,与对照果实相比,50 μmol · L^-1 MeJA采前处理显著降低了采收时的病果率和贮藏期的病情指数,抑制了接种炭疽病菌果实的病斑直径;有利于杧果贮藏品质的保持,提高了果肉中维生素C含量,延缓了可溶性糖含量的升高和可滴定酸含量的降低;同时,采前MeJA处理可以提高杧果果皮中苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）、多酚氧化酶（PPO）和β–1,3–葡聚糖酶（GLU）等防御酶的活性,提高贮藏早期的过氧化氢（H₂O₂）水平,抑制贮藏后期H₂O₂和MDA含量的积累。这些结果表明,采前MeJA处理提高杧果抗病性和保持果实品质与激活杧果的防御系统及降低膜脂过氧化程度有关。     

Variations in contents of browning substrates and activities of some related enzymes during litchi fruit development

Pericarp browning is a major factor to limit storage and transportation of postharvest litchi fruit. Experiments were conducted firstly to determine variations in contents of browning substrate (−)-epicatechin in pericarp tissues of litchi fruit during development. Changes in the activities of polyphenoloxidase (PPO), peroxidase (POD) and phenylalanine ammonialyase (PAL) in association with the synthesis or oxidation of (−)-epicatechin were also examined. (−)-Epicatechin content tended to decrease during fruit development. PAL activity had a high level at the initial stage of fruit development, then decreased rapidly, and finally increased slightly, which was in agreement with the variation in (−)-epicatechin content. The higher contents of total phenolics and (−)-epicatechin of fruit of ‘Nuomici’ than ‘Feizixiao’ were also related to the higher PAL activity. PPO had a similar change to PAL in activity, but POD activity slowly decreased at the early fruit development and then increased markedly. It is suggested that (−)-epicatechin content might be largely regulated by PAL activity. This study could help to understand the variations in the content of the browning substrate and the activities of some substrate-related enzymes of litchi fruit during development and then control better pericarp browning of harvested litchi fruit by the application of appropriate preharvest treatments.     

草酸对冷藏期间桃果实抗氧化系统和PPO活性的影响

 桃( Prunus persica L. ) 栽培品种‘八月脆’果实采后经5 mmol·L ^{- 1}草酸溶液浸泡10 min后在低温条件下贮藏, 与对照相比, 果实的CAT和PPO活性提高, SOD和POD活性在贮藏10 d后较高; 还原型抗坏血酸(AsA) 含量下降减缓; 超氧阴离子(O₂· ) 生成速率随贮藏增加, 过氧化氢(H₂O₂ ) 含量先升后降, 但经草酸处理后O₂ ·生成速率和H₂O₂ 含量分别在5 d和5、10 d时显著低于对照。说明草酸处理通过提高果实抗氧化防御系统的能力和PPO活性来延缓果实成熟和增强果实抗病能力。     

Pre- and post-harvest salicylic acid treatments alleviate internal browning and maintain quality of winter pineapple fruit

The post-harvest internal browning (IB) and quality in pineapple (Ananas comosus L. ‘Comte de Paris’) fruit were studied in relation to pre-harvest salicylic acid (SA) spray (PSS) or/and post-harvest salicylic acid immersion (PSI) treatments at 10 °C for up to 20 days plus 2 days at 20 °C (shelf-life). In addition, the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) were measured during cold storage. The results showed that all SA treatments significantly reduced IB incidence and intensity. Furthermore, SA did not affect soluble solids content (SSC), titratable acidity (TA) and total phenolics (TP) content, but delayed the decline of ascorbic acid (AsA) content. At the same time, SA significantly inhibited PPO and PAL activities. The study indicated the beneficial effect of SA by pre-harvest spray and/or post-harvest immersion on pineapple fruit quality and resistance to IB, and PSS + PSI treatment showed the best effect.     

外源水杨酸对黄瓜叶片几种酶活性和抗氧化物质含量的影响

 采用不同浓度的水杨酸(SA) 对营养液培养的黄瓜( Cucumis sativus L. ) 进行处理, 结果表明, 不同浓度的SA 均明显提高了黄瓜叶片中过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶的活性, 其中以SA 200μmol·L^-1处理的效果最为显著。SA 100μmol·L^-1的处理显著抑制了IAA 氧化酶和抗坏血酸氧化酶的活性, 而SA 200 和400μmol·L^-1的处理则有促进作用。SA 100μmol·L^-1的处理显著增加了黄瓜叶片中还原型抗坏血酸、还原型谷胱甘肽和氧化型谷胱甘肽的含量。     

GA3对杨梅叶片木质素水平及其相关酶活性和成花的影响

 ‘荸荠种’杨梅小年树花芽孕育初期, 苯丙氨酸解氨酶(PAL) 活性首先达到高峰; 之后多酚氧化酶(PPO) 活性出现高峰。花芽孕育盛期过氧化物酶(POD) 活性达到高峰, 且与木质素积累到最大值相一致。花芽发端期间, POD活性和木质素水平均降低。GA₃处理降低了花芽孕育期间PAL、PPO 和POD 的活性, 导致木质素合成滞缓, 抑制花芽发端和降低成花率。     

砀山酥梨不同发育时期套袋对石细胞发育的影响

 以不同发育时期套袋处理的砀山酥梨为试材, 研究了果实石细胞团的密度、大小、含量、几种相关酶的活性变化及果实品质等。结果表明, 套袋后果实可滴定酸含量显著高于对照, 而可溶性固形物、可溶性总糖含量、单果质量及果实内石细胞含量等均低于对照; 果实内石细胞团的分布密度在幼果期较高,随着果实发育膨大密度渐低, 接近成熟前两个月左右趋于稳定, 石细胞团的纵径、横径是随着果实发育先增大后减小, 而后又稍有增大, 果实石细胞含量也是先增加后减少, 在盛花后49 d达到最大值。不同时期套袋的果实内苯丙氨酸解氨酶、过氧化物酶及多酚氧化酶的活性均低于对照, 其活性变化是在果实发育初期较高, 盛花后63～77 d处于低水平, 且缓慢下降, 这与果实内石细胞最终含量成正相关。     

热水及加钙处理对冬枣果实货架期间衰老相关生理的影响

 用50～55℃热水处理冬枣6～8 min能显著抑制货架期间其相对电导率、丙二醛含量、褐变指数的上升以及硬度下降, 抑制多酚氧化酶、外切和内切多聚半乳糖醛酸酶活性上升, 延长货架期。热水中加入1% CaCl₂ 可进一步提高处理效果, 但对多酚氧化酶和褐变指数影响不大。     

诱抗处理对甜瓜叶片酚类物质代谢的影响

以甜瓜抗白粉病品种‘银帝’和感白粉病品种‘卡拉克赛’为材料,研究诱导抗性处理对其叶片酚类物质代谢的影响及其与抗病性的关系。结果表明：苯丙噻重氮（BTH）和水杨酸（SA）处理以及接种白粉菌均可显著诱导甜瓜叶片苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）、多酚氧化酶（PPO）活性和绿原酸、总酚、类黄酮含量升高,但纳米硅（SiO2）诱导无效。经诱导和接菌后,甜瓜抗病品种叶片PAL、POD、PPO活性和总酚、绿原酸、类黄酮含量高于感病品种。BTH和SA诱导甜瓜抗病性增强的原因之一是提高了叶片次生代谢相关酶的活性,增加了叶组织次生代谢物质的含量。     

香蕉枯萎病菌4号生理小种毒素解毒剂的筛选及对香蕉防御酶活性的影响

从15种候选解毒剂中筛选出对香蕉枯萎病菌(Fusarium oxysporum f.sp.cubense)4号生理小种(简称Foc 4)毒素解毒效果最好的2种解毒剂——硫酸锌和井冈霉素。在2 g.L-1浓度下,硫酸锌和井冈霉素对Foc 4毒素的钝化率分别为76.67%和71.33%,而在5 g.L-1浓度下,它们的钝化率分别为90.33%和80.00%。探索了毒素—硫酸锌和毒素—井冈霉素处理体系在2 g.L-1和5 g.L-1浓度下对香蕉苗5种防御酶(PAL、POD、PPO、SOD和CAT)活性的影响。结果表明,在这个处理体系中,香蕉苗PAL和PPO酶活高峰出现的时间(PAL 36 h、PPO 36 h和48 h)较毒素单独处理(PAL 48 h、PPO 60 h)早;SOD和CAT酶活高峰出现的时间与对照基本一致;而POD酶活高峰出现的时间较复杂。总体上,这个处理体系的酶活高于毒素单独处理和无菌水对照。"毒素—硫酸锌处理体系"在PAL、SOD整体酶活上高于"毒素—井冈霉素处理体系",而后者在其他3种酶活上普遍高于前者。     

蝴蝶兰外植体褐变发生与总酚含量、PPO、POD和PAL的关系

 蝴蝶兰外植体在褐变发生前期PPO和POD活力皆升高, 褐变发生后酶活力下降。同工酶谱分析发现, 培养0 d的蝴蝶兰外植体PPO没有酶带出现, 而POD有1条弱带。离体培养2 d POD出现3条酶带, 第4天有新酶带Ⅰ发生, 随后消失, 其余3条带, 随培养天数的延长, 酶带活性渐弱。PPO同工酶谱在培养2 d出现3条酶带, 迁移率为0128的酶带Ⅲ在培养4 d活性较强, 随后3条酶带减弱。总酚含量和PAL活力随外植体褐变增强而逐渐增加, 两者呈现极显著正相关。