恶苗病菌对不同水稻品种过氧化物酶同工酶影响的初步研究

用垂直板状聚丙烯酰胺凝胶电泳方法,对抗、感水稻恶苗病不同类型的6个水稻品种的过氧化物酶同工酶进行了研究。提出了水稻芽期过氧化物酶同工酶基本谱型,模式酶带共7条。抗感程度不同的品种接种后过氧化物酶同工酶酶谱存在着明显差异,主要出现在C区谱带上。     

水稻抗瘟性与过氧化物酶同工酶的初步研究

本研究采用垂直板聚丙烯酰胺凝胶电泳的方法,测定了11个稻瘟菌小种接种的18个水稻品种(品系)的过氧化物酶同工酶。结果表明,受侵染植株与对照间的同工酶谱带数目及其相对迁移率(Rf)无明显差异、无新谱带出现。说明受侵染植株与对照间过氧化物酶同工酶的代谢途径没有变化;但过氧化物酶同工酶的活性与水稻抗瘟性有密切关系。接种7天后植株体内该酶的活性非亲和组合显著大于亲和组合。     

羊草发育过程中同工酶的研究

采用聚丙烯酰胺凝胶电泳法 ,对羊草不同物候期不同器官的酯酶和过氧化物酶同工酶的多态性研究结果表明 :羊草酯酶同工酶活性在地上与地下营养器官间存在明显的互补性 ;过氧化物酶活性与有性生殖器官的发育有一定的一致性。总的来看 ,过氧化物酶同工酶与羊草的生长发育的关系较酯酶密切 ,可以作为生长发育特性评价较好生理指标 ;酯酶的稳定性较强 ,标志性酶带较恒定 ,可以作为遗传鉴定的指标。     

木麻黄丛枝病过氧化物酶同工酶的初步研究

 利用聚丙烯酰胺凝胶电泳研究了木麻黄丛枝病健、病株以及各病级间过氧化物酶同工酶的变化.测定的结果,健株的过氧化物酶同工酶的活性比病株的要强;酶带数多2-6条.病级间过氧化物酶同工酶的变化与植株外部表现的症状相反,即病情越重,酶活性和带数则越小.因此植株的同工酶变化可看作植株内部的"生化症状",并可用作木麻黄丛枝病、健以及发病程度的简单而有效的鉴定方法.     

赖草发育过程中同工酶的研究

利用聚丙烯酰胺凝胶电泳技术 ,对赖草酯酶和过氧化物酶同工酶研究结果表明 :赖草不同发育期的酯酶和过氧化物酶同工酶酶谱及酶活性存在明显的器官间差异和多态性 ;其中过氧化物同工酶与赖草生长发育的关系比酯酶相对密切 ,同时稳定性也较强 ,可以作为赖草生长发育特性的生理指标和遗传鉴定指标     

枣疯病过氧化物酶及苯丙氨酸解氨酶的研究

采用分光光度计和不连续聚丙烯酰胺凝胶电泳,比较分析了不同枣树品种及株系接入病原植原体后,其过氧化物酶及同工酶和苯丙氨酸解氨酶的变化。结果表明:同一枣树品种,不同发病程度的株系间过氧化物酶活性和同工酶有一定差异,抗病品种苯丙氨酸解氨酶活性高于感病品种。这两项可作为研究枣树抗枣疯病机理的重要生理指标。     

澳洲大蠊二种同工酶谱及胆碱酯酶活性的研究

本文采用聚丙烯酰胺凝胶盘状电泳研究澳洲大蠊（ＰｅｒｉｐｌａｎｅｔａａｕｓｔｒａｌａｓｉａｅＦａｂ．）三个发育阶段酯酶同工酶、过氧化物酶同工酶谱的变化，并分别测定了发育三阶段和成虫头、胸、腹、脚胆碱酯酶活性。结果发现过氧化物酶同工酶与酯酶同工酶酶谱各有特征。从卵到二龄幼虫发育过程中表现最大活性的同工酶的酶带位置各不相同。胆碱酯酶（ＣＨＥ）活性在卵、一龄、二龄幼虫中以一龄幼虫活性最高，成虫中以头部活性最高、腹部活性最小     

澳洲大蠊二种同工酶谱及胆碱酯酶活性的研究

本文采用聚丙烯酰胺凝胶盘状电泳研究澳洲大蠊三个发育阶段酯酶同工酶，过氧化物酶同工酶谱的变化，并分别测定了发育三阶段和成虫头、胸、腹、脚胆碱脂酶活性。结果发现过化物酶同工酶与酯酶同工酶酶谱各有特征，从卵到二龄幼虫发育过程中表现最大活性的同工酶的酶带位置各不相同，胆碱酯酶活性在卵、一龄、二龄幼虫中以一龄幼虫活性最高，成虫中以头部活性最高，腹部活性最小。     

小麦品种对白粉病抗病性与过氧化物酶的关系

 不同抗白粉病小麦品种接种白粉菌后过氧化物酶均呈现两个酶活峰,峰Ⅰ出现在病菌分生孢子梗期,峰Ⅱ出现在分生孢子期。峰Ⅰ的相对酶活性与小麦品种的抗病性呈正相关。SDS-聚丙烯酰胺凝胶电泳扫描的结果显示峰Ⅰ中的高分子量(28,000道尔顿以上)酶带与植株的抗病性有密切关系。高抗品种MN 7213的同工酶谱多一条酶带,可能是抗性基因表达的结果。高感品种VilelaMar.的同工酶谱则在个别酶带上有所加强。     

丛枝菌根(AM)与桃树根癌病关系初探

通过对上海市奉贤区桃树果园调查发现,桃树丛枝菌根(AM)的形成与根癌病的发生表现出一定的相互抑制作用。根据不同时间、顺序对桃树苗木人工接种根癌土壤杆菌(Agrobactium tumefaciens)和摩西球囊霉(Glomus mosseae),结果表明桃树苗木形成AM后可以抑制根癌病的发生,反之苗木感染根癌病后也降低了AM真菌对根的侵染和在根内的扩展,对苗木同时接种Agrobactium tumefaciens和Glomus mossea时,病原菌要优先于AM真菌侵染寄主并形成病害。AM提高了苗木根系内与抗病性相关的过氧化物酶和多酚氧化酶活性。     

九种常用农药在桃树生长后期使用的安全性

为了评价桃生长后期使用农药的安全性，以桃早熟品种‘金陵黄露’为材料，分别在桃果收获前7和14 d，按最高推荐剂量及2倍最高推荐剂量混合施用9种农药，包括4种杀虫剂 (阿维菌素、氯虫苯甲酰胺、氯氟氰菊酯和吡虫啉) 和5种杀菌剂 (苯醚甲环唑、腈苯唑、嘧菌酯、甲基硫菌灵和多菌灵)，研究了桃果中的农药残留量变化及不同农药在桃枝、桃叶、果皮和果肉中的分布规律，以及套袋在桃生长后期阻控农药吸收中发挥的作用。结果表明:在桃收获前7 d，按2倍最高推荐剂量施用其中3种杀菌剂 (苯醚甲环唑、腈苯唑、嘧菌酯) 和4种杀虫剂 (阿维菌素、氯虫苯甲酰胺、氯氟氰菊酯、吡虫啉)，7种农药在桃全果中的残留量均低于中国国家农药残留限量标准(MRL)；而过量施用多菌灵和甲基硫菌灵，桃全果中多菌灵残留量显著高于MRL标准，且随着施药后时间的延长，增加了多菌灵由果皮或枝叶向果肉迁移的风险。套袋处理后，桃全果中多菌灵的残留量远低于中国MRL标准，同时显著减少了桃全果中其他8种农药的残留量。9种供试农药在桃树不同组织中的分布规律一致，由高到低依次为果皮>全果>桃叶≥果肉≥桃枝。本研究表明，不同农药品种在桃生长后期消解规律存在差异，其中多菌灵和甲基硫菌灵超量使用会增加多菌灵在桃果中残留超标的风险，而套袋处理可减少桃果中的农药残留。该结果对去除桃果中农药残留、降低膳食摄入风险有一定指导意义。     

桃畸果病的发生及对桃果实生理生化指标的影响

近年来,在甘肃省兰州桃产区发现了一种由下心瘿螨(Eriophyes catacardiae Keifer)为害引起的桃果实病害,该病导致桃果实严重畸形。 2009-2010年对桃产区调查结果表明：下心瘿螨3月下旬到4月初出蛰为害,桃畸果平均发生率2009年为40.30%,2010年为73.65%,严重时高达86%。进一步的生理生化指标测试表明：被害桃果一些主要生理生化指标发生了明显的变化。受害果实的可溶性糖含量比对照下降了55.35%,可溶性蛋白质含量上升了66.16%,游离氨基酸含量上升了64.95%,游离脯氨酸含量上升了111.57%,过氧化氢酶活性增加了53.46%。     

山东烟台地区苹果园和桃园主要害虫及天敌昆虫发生动态

山东烟台地区是我国苹果和桃的重要产区.本研究利用性诱剂诱捕器和黄色粘虫板调查烟台地区果园中主要害虫和其他常见害虫及天敌昆虫的发生动态.结果 表明:山东烟台地区苹果园和桃园中主要害虫—梨小食心虫、桃小食心虫、小绿叶蝉在两个果园中的年发生总量存在一定差异,苹果园桃小食心虫年诱捕量为545.8头/诱捕器,显著高于桃园年诱捕量...     

啶虫脒在桃上的残留消解规律与膳食风险评估

啶虫脒在桃上的检出率高且未登记,缺少安全间隔期、用药间隔期等信息可能会导致盲目用药,增加残留风险。为明确桃果上啶虫脒的残留风险,本文通过消解试验以及模拟农户施药对其残留消解规律进行了分析,并于2015—2018年对中国9大主产区桃中的啶虫脒残留进行了调查与膳食摄入风险分析。结果表明:啶虫脒在桃果皮与果肉上的消解符合一级反应动力学方程,半衰期分别为3.92与3.14 d。模拟农户施药2次或3次后,距末次施药7、14和21 d,桃中啶虫脒的残留量均较低,且远低于其在核果上的最大残留限量 (MRL) 值;去皮食用能够明显降低其膳食摄入风险。9大桃主产区509份样品中啶虫脒的检出率在8%~38%之间,残留量在0.001~1.348 mg/kg之间,均未超过其在核果上的MRL标准。连续 4 年啶虫脒在桃上的急性膳食摄入风险占急性参考剂量 (ARfD) 的比值在1.520%~13.755%之间,慢性膳食摄入风险占每日允许摄入量 (ADI) 的比值在0.021%~0.086%之间,总体膳食风险的贡献较小。     

吡唑醚菌酯和戊唑醇在桃中的残留与膳食风险评估

为评估桃中吡唑醚菌酯和戊唑醇残留的膳食风险，开展了8个典型地域的规范残留试验，研究了收获期2种农药残留物在桃中的最终残留。利用高效液相色谱-三重四极杆串联质谱仪 (HPLC-MS/MS)，通过改进，建立了吡唑醚菌酯和戊唑醇在桃中残留的分析方法。结果表明:在0.01~4.0 mg/L质量浓度范围内，吡唑醚菌酯和戊唑醇的进样浓度与峰面积之间具有良好线性关系(R2≥0.9906)。添加水平为0.01~4.0 mg/kg时，桃中吡唑醚菌酯的回收率范围为88%~92%，相对标准偏差 (RSD) 为5.6%~18.7%，戊唑醇的回收率范围为96%~106%，RSD为0.8%~13.2%。吡唑醚菌酯和戊唑醇在桃全果中的半衰期分别为7.9~13.9 d和5.4~8.9 d；在桃全果中的残留中值 (STMR) 分别为0.037和0.053 mg/kg，最高残留值 (HR) 分别为0.16和0.24 mg/kg。距末次施药后28 d，桃中吡唑醚菌酯和戊唑醇残留量对风险商 (RQ) 的贡献率 (RQc) 分别为0.02%和0.03%，说明通过桃摄入的吡唑醚菌酯和戊唑醇对我国一般人群产生的长期膳食暴露风险较低。对于短期膳食暴露风险，吡唑醚菌酯和戊唑醇的国家估算短期摄入量 (NESTI) 分别占急性参考剂量 (ARfD) 的0.4%和2%，对于1~6岁儿童分别占2%和4%，短期膳食暴露风险亦处于可接受水平。基于本次规范残留试验结果，总体上可认为，严格按照良好农业操作规范和标签推荐的方式施用，吡唑醚菌酯和戊唑醇在桃树上使用的长期和短期膳食暴露风险均是可接受的。     

Effect of hot water treatment on peach volatile emission and Monilinia fructicola development

The effect of hot water treatment (HWT) to control peach brown rot was investigated. Peaches were dipped in water at 60°C for 60 s and artificially inoculated with Monilinia fructicola conidia. HWT failed to control brown rot if applied before inoculation and microscopic observations revealed a stimulatory effect on germ tube elongation of M. fructicola conidia placed immediately after HWT on the fruit surface, compared to the control. The influence of fruit volatile emission due to HWT was performed on the pathogen conidia exposed to the headspace surrounding peaches. The results showed an increase of M. fructicola conidial germination ranging from 33 to 64% for cultivars Lucie Tardibelle and Red Haven heat‐treated peaches, respectively, compared to the control. The volatile blend emitted from heat‐treated fruit was analysed by solid‐phase microextraction/gas chromatography‐mass spectrometry (SPME/GC‐MS) and proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). Fifty compounds were detected by SPME/GC‐MS in volatile blends of cv. Lucie Tardibelle peaches and significant differences in volatile emission were observed among heated and control fruit. Using PTR‐ToF‐MS analysis, acetaldehyde and ethanol were detected at levels 15‐ and 28‐fold higher in heated fruit compared to unheated ones, respectively. In vitro assays confirmed the stimulatory effect (60 and 15%) of acetaldehyde (0·6 μL L^?1) and ethanol (0·2 μL L^?1) on M. fructicola conidial germination and mycelial growth, respectively. The results showed that volatile organic compounds (VOCs) emitted from heat‐treated peaches could stimulate M. fructicola conidial germination, increasing brown rot incidence in treated peaches when the inoculation occurs immediately after HWT.     

High inoculum of Monilinia fructicola is a threat to peach production in the tropics due to fruit susceptibility at all development stages

Brown rot is the main disease of stone fruits in Brazil, but the susceptibility of peaches to brown rot at different stages of development in the field has not been studied under subtropical conditions. This information is relevant to guide the management of the disease. The objective of this research was to determine the influence of inoculating peaches with Monilinia fructicola at different stages of development on the infection and progress of brown rot at postharvest. Two experiments were carried out: one ex vivo with two cultivars and the other in the field for two seasons. Peaches were inoculated at different sizes for both experiments. In the field, peaches were bagged to avoid natural infection, and M. fructicola inoculum was monitored. The ex vivo incidence of the disease was lower at pit hardening than at other fruit stages for both cultivars. The incidence of brown rot for peaches attached to the trees increased with fruit ripening. Conversely, the time for symptom expression was reduced according to peach diameter. Peaches inoculated with a diameter smaller than 2 cm showed a lower incidence of brown rot and longer periods for disease expression than fruit inoculated near harvest. In conclusion, in areas with high inoculum in the orchard, a common condition in the subtropics, the grower must prevent infection at all stages of fruit development, thus avoiding losses during marketing.     

利用OWRK法预测桃叶表面润湿性能的研究

对桃叶表面润湿性能的预测方法进行了研究。应用OWRK法对不同生长期桃叶的近轴面、远轴面的表面自由能及其分量进行了测定。无论近轴叶面还是远轴叶面,随着桃叶生长期的增长,均表现出表面自由能减小,润湿性能变差,极性分量所占比例下降,色散分量所占比例上升等特性。这些变化与前人对于桃叶表皮蜡的蜡质含量、组份含量变化的研究成果相一致。说明用OWRK法测定桃叶表面自由能及其分量所得结果可靠,可以较好地描述桃叶表面的润湿性能和能量特征。     

绿盲蝽为害对不同空间位置桃叶生理指标的影响

为明确绿盲蝽为害不同时期桃树的应激反应发生发展过程,采用生化测定方法分析了桃树上、中、下部不同受害程度叶片内的可溶性糖、蛋白质、游离氨基酸含量以及防御性酶活性的变化。结果表明,绿盲蝽为害后,随着时间的延长,受轻度为害的桃树叶片内可溶性糖含量由28.61 mg/g减少至19.21 mg/g,蛋白质含量由1.29 mg/g先增加至2.01 mg/g,后减少至1.66 mg/g,游离氨基酸含量由0.49 mg/g增加至0.72 mg/g;而受重度为害的叶片内可溶性糖和蛋白质的含量均先减少后增加,游离氨基酸含量则先增加后减少。防御性酶活性随绿盲蝽为害程度的加重也发生了不同程度的变化,随着时间的延长,受轻度为害的叶片内超氧化物歧化酶活性降低,过氧化物酶和过氧化氢酶活性有所升高;而受重度为害的叶片内超氧化物歧化酶活性先降低后升高,过氧化物酶活性升高,过氧化氢酶活性降低。说明不同位置桃树叶片对绿盲蝽的为害胁迫产生了应激反应,通过调整其体内各种防御性物质的含量,对绿盲蝽为害产生诱导抗性,且与为害程度有一定的相关性。     

Signals induced by exogenous nitric oxide and their role in controlling brown rot disease caused by <Emphasis Type="Italic">Monilinia fructicola</Emphasis> in postharvest peach fruit

Recent evidence suggests that nitric oxide (NO) signaling plays an important role in plant–pathogen interactions and that aconitase is a major target of NO. In the present study on the signaling role of NO in the elicitation of defense responses in peach fruit against Monilinia fructicola and subsequent effect on brown rot disease, 15 μM NO solution induced disease resistance in harvested peaches. As a potentiated elicitor, NO induced high levels of endogenous NO and superoxide (O₂ ^?), hydrogen peroxide (H₂O₂), and NADPH oxidase and Ca²⁺-ATPase activity in the fruit. Aconitase activity in peach fruit was inhibited by NO. Activity of partially purified aconitase was inhibited in vitro by sodium nitroprusside (SNP) and H₂O₂; however, the inhibition could be relieved by carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (cPTIO) or catalase (CAT), indicating that the defense response and signals induced by NO transduction depend on aconitase and conditions leading to elevated levels of NO; otherwise, H₂O₂ would inactivate aconitase directly in fruit. Treatment with NO resulted in salicylic acid (SA) accumulating during storage. Higher levels of jasmonic acid (JA) were detected in NO-treated fruit 48 h after the treatment. But after NO was removed, the level of SA and JA were lower than in the control. The results suggest that exogenous NO enhances resistance of harvested peach fruit against the fungus by inducing signals such as endogenous NO, reactive oxygen species (ROS), SA and JA and by inhibiting aconitase activity.