不同愈伤时间对低温贮藏期间马铃薯块茎采后病害及品质的影响

以损伤和无伤马铃薯块茎为试材,研究了不同愈伤时间对低温贮藏期间块茎采后病害和品质的影响。结果表明,愈伤处理可明显减轻损伤和无伤接种马铃薯块茎贮藏期间的采后病害,愈伤时间越长,采后病害的发病率越低,愈伤14d后损伤和无伤接种马铃薯块茎干腐病发病率与不愈伤对照相比分别下降46.2%和55.0%,干腐病病情指数下降49.5%和42.9%,其它病害发病率下降80%和72%。愈伤处理明显降低了损伤接种块茎贮藏期间的失重率、绿化率、发芽率及芽长,愈伤14d后分别比不愈伤对照降低15.2%、48.3%、18.0%和46.2%。但对无伤接种块茎的品质影响不大。损伤块茎干腐病的发病率和病情指数以及其它病害的发病率、失重率均显著高于同期处理的无伤块茎,但绿化率、发芽率和芽长与无伤块茎相比无明显差异。由此表明,愈伤处理可明显减轻马铃薯块茎贮藏期间的采后病害并维持块茎品质。      

采后水杨酸处理对马铃薯块茎愈伤的促进及部分机理研究

本研究以"青薯168"马铃薯块茎为试材,研究4mmol/L水杨酸浸泡处理对马铃薯块茎愈伤效果的影响及部分机理。结果表明,4mmol/L水杨酸处理有效降低了损伤接种块茎的病情指数,减少了愈伤期间块茎的失重,处理块茎组愈伤第5d的失重率和病情指数分别比同期对照低44.27%和46.70%。水杨酸处理还明显促进了愈伤组织中H_2O_2的积累,提高了过氧化物酶的活性,SA处理后第3d,块茎H_2O_2含量和POD活性分别比同期对照高55.33%和6.91倍。此外,水杨酸处理有效促进了愈伤组织中木质素和软木脂的积累,处理后第14d,处理组愈伤组织木质素和软木脂积累的细胞层数均比同期对照增加了2层。由此表明,采后4mmol/L水杨酸浸泡处理可促进采后马铃薯块茎的愈伤,其对愈伤组织形成的促进作用是活性氧代谢和苯丙烷代谢增强的共同作用结果。     

低压静电场对采后马铃薯块茎愈伤效果的影响

为研究低压静电场处理对采后马铃薯块茎愈伤效果的影响,以“冀张薯12号”马铃薯块茎为试材,人工模拟机械损伤后,置于有低压静电场的常温[（20±2）℃]、相对湿度85%～90%、黑暗条件下愈伤,通过测定块茎愈伤期间的失重率、损伤伤口处硬度、褐变度、苯丙烷代谢关键酶活性和代谢产物含量的变化,以及分析低压静电场对过氧化物酶、多酚氧化酶活性和H2O2含量的影响来评价愈伤效果。结果表明,在愈伤期间低压静电场处理能够有效减少损伤块茎的重量损失,显著促进损伤部位褐变度值和硬度的增加,显著提高伤口处组织中苯丙氨酸解氨酶活性,促使总酚、类黄酮和木质素含量增加,此外,低压静电场处理增加了块茎伤口处的多酚氧化酶、过氧化物酶活性和H2O2含量,结果显示,低压静电场处理能够促进采后马铃薯块茎的愈伤。     

二氧化氯通过激活苯丙烷代谢加速马铃薯块茎的愈伤过程

二氧化氯（ClO2）是一种安全高效的消毒剂,广泛用于果蔬保鲜和疾病的防治,但ClO2处理对马铃薯采后块茎的愈伤效果尚不明确。本研究采用25 mg/L ClO2浸泡切半‘大西洋’马铃薯块茎10 min,然后于室温黑暗条件下愈伤0、3、5、7、14、21 d。测定损伤块茎在愈伤期间的质量损失率以及损伤接种硫色镰刀菌（Fusarium sulphureum）块茎的病情指数,观察伤口处聚酚软木脂和木质素的积累,测定伤口处苯丙烷代谢关键酶和过氧化物酶活力,以及苯丙烷代谢产物和H2O2的含量。结果表明,25 mg/L ClO2处理加速了聚酚软木酯和木质素的沉积,增加了愈伤期间损伤组织的细胞层厚度。此外,ClO2处理降低了损伤块茎的质量损失率以及损伤接种硫色镰刀菌（F. sulphureum）后块茎的病情指数,第14天时,处理块茎的质量损失率和病情指数分别低于对照20.8%和45.3%。另外,ClO2处理通过提高块茎伤口组织处苯丙氨酸解氨酶、肉桂酸-4-羟化酶与肉桂醇脱氢酶的活力,增加了5 种酚酸（肉桂酸、p-香豆酸、咖啡酸、阿魏酸和芥子酸）及3 种木质素单体（p-香豆醇、芥子醇和松柏醇）的含量;ClO2处理还显著促进了总酚、类黄酮和木质素的合成,提高了H2O2含量和过氧化物酶（peroxidase,POD）活力。综上所述,ClO2处理加速了愈伤期间马铃薯损伤块茎伤口处聚酚软木酯、木质素的沉积,降低了损伤块茎的质量损失率及病情指数,激活了苯丙烷代谢,提高了H2O2含量和POD活力。这些发现为ClO2处理加速马铃薯块茎的愈伤提供了理论依据。     

不同涂膜处理对马铃薯货架期品质的影响

以液体石蜡、植物油为涂膜材料,研究温度在15～20℃条件下各涂膜处理对马铃薯块茎呼吸强度、vc,还原糖、失重率、发芽率,腐烂率、多酚氧化酶(PPO)活性的影响.结果表明:两种涂膜处理可以明显抑制马铃薯块茎的呼吸强度,减少V<,c>含量的损失,降低还原糖含量,抑制PPO活性,降低块茎的失重率、发芽率、腐烂率,从而有效地延长块茎的货架期.     

低质量浓度T-2处理对马铃薯块茎苯丙烷代谢活性的诱导

由镰刀菌引起的干腐病是导致甘肃省马铃薯块茎贮藏期间的主要病害。以‘陇薯3号’马铃薯为试材,用1 μg/mL T-2处理马铃薯块茎切片,观察T-2处理对马铃薯块茎切片损伤接种硫色镰刀菌（Fusarium sulphureum）后,其对病斑直径的抑制效果,以及块茎切片苯丙烷代谢关键酶活性及产物积累的影响。结果表明,T-2处理有效降低了块茎切片损伤接种Fusarium sulphureum的病斑直径,提高了切片苯丙氨酸解氨酶和4-香豆酰-辅酶A连接酶的活性,促进了木质素、总酚、类黄酮及花青素的积累。由此表明,低质量浓度T-2处理可通过诱导马铃薯的苯丙烷代谢增强块茎对干腐病的抗性。     

微波处理对‘新大坪’马铃薯贮藏品质的影响

为了提升马铃薯贮藏品质,分别使用不同功率微波对马铃薯块茎进行处理,并将处理后的马铃薯保存在4℃的冰箱里,贮藏期间每10 d测量马铃薯的失重率、Vc含量、可溶性固形物含量、淀粉含量、褐变指数、多酚氧化酶活性、过氧化物酶活性。结果表明,微波处理能够有效提升马铃薯的贮藏品质,但微波处理不足(115 W/1 min)对马铃薯贮藏品质的提升效果不明显,微波处理过量(220 W/3 min)则会对马铃薯生理和品质造成损伤。实验中以微波功率220 W处理2 min的保鲜效果最佳,能够有效避免马铃薯块茎质量及Vc的损失,保持可溶性固形物含量和淀粉含量,减缓褐变指数的升高,抑制多酚氧化酶和过氧化物酶活性。该研究为马铃薯提供了微波处理提升贮藏品质的方法。     

香茅精油处理对马铃薯的抑芽作用研究

为探究出一种绿色安全的马铃薯抑芽方法,以“V7”马铃薯为试验材料,采用1.0 mL/kg(以马铃薯实际质量计)剂量的香茅精油处理马铃薯块茎,在常温下(25℃)贮藏20 d。每隔4 d取样观察马铃薯块茎发芽形态,并测定发芽率、发芽指数、糖代谢、蛋白质代谢相关指标。结果表明,香茅精油可有效抑制马铃薯块茎发芽,贮藏结束时,发芽率和发芽指数分别为15.00%和4.29%,而对照分别是100.00%和30.00%,达到显著差异水平(P<0.05)。贮藏期间,香茅精油处理可影响马铃薯呼吸强度,减缓淀粉、还原糖、总糖、可溶性蛋白质含量的下降,抑制了还原糖的积累,总蛋白含量变化较小,对果糖和葡萄糖的影响小,但加快了蔗糖的降解速度。结果表明,香茅精油有良好的抑芽效果,香茅精油对糖代谢的影响较大,而对蛋白质代谢的影响较小,但其具体的生理生化及分子机制还需进一步研究。     

柠檬酸处理对两种马铃薯干腐病菌的抑制效果比较

研究了不同浓度柠檬酸处理对马铃薯干腐病菌Fusarium sulphureum和F.sambucinum的抑制效果。结果表明,柠檬酸对两种供试菌的菌落生长和孢子萌发具有明显的抑制作用,且抑制效果随浓度的提高而增强;2%柠檬酸处理二者菌落直径分别比同期对照下降了28.83%和21.59%,F.sulphureum的孢子萌发相比对照下降94.02%,完全抑制了F.sambucinum孢子的萌发;同时柠檬酸处理也显著降低了损伤接种块茎切片的病斑直径,其中以0.5%处理效果最好,分别比对照降低了59.01%和55.02%,更高浓度处理并没有增加抑制效果。由此表明,柠檬酸可通过直接抑菌和诱导抗性来减轻马铃薯干腐病的发生。      

马铃薯抑芽剂效果评价及残留风险研究

为了抑制马铃薯贮藏期间发芽,提高块茎的营养品质,以云南的丽薯6号为实验材料,分别配制不同浓度的氯苯胺灵和1-萘乙酸甲酯抑制剂,使用熏蒸法施药,避光进行储藏实验。每10天进行发芽率、芽长的测定,并进行残留量和风险分析。结果表明,常温(25℃±2℃)下储藏50 d,熏蒸质量浓度为40 mg/kg的氯苯胺灵和80 mg/kg的1-萘乙酸甲酯下抑芽效果最好,抑芽率分别为78.7%和88.6%,氯苯胺灵处理下的马铃薯的平均芽长要明显短于1-萘乙酸甲酯处理的平均芽长。随着储藏时间增加,氯苯胺灵和1-萘乙酸甲酯在马铃薯上逐渐降解,推荐浓度的氯苯胺灵和1-萘乙酸甲酯在马铃薯上施用50 d后残留量分别为(0.824～1.902)mg/kg和(0.085～0.924)mg/kg。风险评估结果表明,在马铃薯上施用抑制剂氯苯胺灵和1-萘乙酸甲酯的膳食风险均很低。     

Effects of nitric oxide on growth of Fusarium sulphureum and its virulence to potato tubers

The antifungal activity of nitric oxide (NO) on Fusarium sulphureum in vitro and curative or preventive efficacy against dry rot in potato tubers was studied. We report that NO released by sodium nitroprusside (SNP) aqueous solution strongly inhibited spore germination and mycelial growth of F. sulphureum in a concentration-dependent manner. When treated with SNP, the fungus, under scanning electron microscopy, appeared distorted with irregular hyphal growth. Transmission electron microscopy observations documented further ultrastructural alterations of hyphae treated with SNP, and these changes included abnormally contracted, distorted hyphal cell walls, large empty cavities in the cytoplasm and even malformed hyphae. Furthermore, SNP was effective at curing and preventing dry rot in potato tubers in vivo. These findings highlight NO as a promising natural fungicide that could partially substitute for the utilization of synthetic fungicides in potato tubers.     

壳聚糖处理对两种马铃薯干腐病菌的抑制效果比较

由镰刀菌(Fusarium)引起的干腐病是马铃薯块茎采后的重要病害。本文通过体外和体内实验测定了不同浓度壳聚糖处理对马铃薯干腐病菌的抑制效果。结果表明,体外条件下壳聚糖处理能够有效抑制F.sulphureum和F.sambucinum的孢子萌发,不同浓度壳聚糖处理后F.sulphureum的孢子萌发相比对照下降了92%,F.sambucinum的孢子萌发几乎完全被抑制。壳聚糖处理能够有效抑制F.sulphureum和F.sambucinum的菌落直径的扩展,其中以0.25%处理效果最好,比同期对照分别下降7.46%和8.9%,且对F.sambucinum的抑制效果较好。壳聚糖处理可显著降低F.sulphureum和F.sambucinum损伤接种马铃薯块茎切片的病斑直径,0.25%的壳聚糖处理者的病斑直径分别低于对照45.3%和34.5%,更高浓度处理并没有增加抑制效果。由此表明,壳聚糖可通过直接抑菌抑制马铃薯的干腐病。      

脉冲电场对啤酒大麦萌发性质的影响

在啤酒麦芽制备过程中引入脉冲电场(PEF)技术,对浸渍后的大麦种子进行不同电场强度的处理,以了解PEF对大麦萌发性质的影响。结果表明,PEF处理有利于提高大麦萌发活力和相关理化性质。大麦籽粒经电场强度1.5、3.0、4.5、6.0、7.5 kV/cm处理后,萌发大麦的芽长、根长、根数、鲜重、干重、发芽势、发芽率、简化活力指数、还原糖含量、β-葡聚糖酶活力、α-淀粉酶活力、β-淀粉酶活力、可溶性蛋白质和氨基态氮含量等指标与对照组比较均有明显提高,发芽势、根长、β-葡聚糖酶活力、α-淀粉酶活力和β-淀粉酶活力提高的幅度分别为38.96%、43.33%、21.46%、26.48%和23.57%。对14项指标进行主成分分析的结果表明,当电场强度为6.0 kV/cm时,脉冲电场对大麦萌发的促进效果最好。     

A study of weight loss of stored yam (Dioscorea cayenensis) as affected by the ventilation of the storage locations

Investigation of the effect of ventilation on the storage losses of yam (Dioscorea cayenensis L) was carried out. The tubers were stored in three ventilation locations (1.4%, 3.8% and exposed ventilation) in two storage environments. It was found that the higher the ventilation level, the greater the weight loss. Exposed tubers that were subjected to direct heating and cooling of the sun and rain, respectively, rotted away; the high temperature involved preventing the sprouting of the tubers. Tubers in the 1.4% and 3.8% ventilation levels outside took a longer time to sprout than those stored inside.     

Effect of curing and pre-storage dip treatments on the control of storage mould of kola nuts

 The effect of curing kola nuts at 30  °C was evaluated at the Cocoa Research Institute of Nigeria, Ibadan, to determine the effect of curing time and delay between inoculation and initiation of curing on storage rot. For nuts inoculated 24 h prior to curing, 48–72 h curing at 30  °C gave optimal disease control. The incidence of rot was higher when the treatment was delayed for 48 h after inoculation. When artificially wounded and inoculated kola nuts were dipped in a solution of 1.0 g l^–1 of sodium bicarbonate for 2 mins, disease development was significantly reduced compared to the 0.5% sodium hypochorite treatment. Sodium metabisulphite also reduced disease development but the level of disease control achieved was not significantly different from that of the water-dipped controls. The in vivo results were consistent with the in vitro results. Received: 15 April 1998     

Effect of curing and pre-storage dip treatments on the control of storage mould of kola nuts

 The effect of curing kola nuts at 30  °C was evaluated at the Cocoa Research Institute of Nigeria, Ibadan, to determine the effect of curing time and delay between inoculation and initiation of curing on storage rot. For nuts inoculated 24 h prior to curing, 48–72 h curing at 30  °C gave optimal disease control. The incidence of rot was higher when the treatment was delayed for 48 h after inoculation. When artificially wounded and inoculated kola nuts were dipped in a solution of 1.0 g l^–1 of sodium bicarbonate for 2 mins, disease development was significantly reduced compared to the 0.5% sodium hypochorite treatment. Sodium metabisulphite also reduced disease development but the level of disease control achieved was not significantly different from that of the water-dipped controls. The in vivo results were consistent with the in vitro results.     

不同生长期花生芽中主要营养成分变化

对发芽至不同时期的花生芽中营养成分含量的变化进行了研究。结果表明,发芽后花生籽仁中的主要营养成分及其含量发生了不同程度的变化:生长5d的花生芽中蛋白质、游离氨基酸和VC含量分别为48.75%干重（DW）、0.59%DW和21.53mg·100g-1鲜重（FW）,显著高于未发芽时的含量（p<0.05）,其中VC含量与发芽时间显著正相关（p<0.05）;脂肪含量为27.25%DW,显著低于未发芽时的含量（p<0.05）;脂肪酸组成中亚油酸、亚麻酸所占比例较未发芽时降低,油酸比例增加;氨基酸组成中总必需氨基酸含量略有降低,但是总必需氨基酸与总氨基酸的比值基本没变;单糖组成中半乳糖醛酸含量、葡萄糖含量和阿拉伯糖含量显著增加（p<0.05）。