四种植物粗提物对小麦纹枯病病菌抑菌作用

采用抑菌圈法、生长速率法测定了4种植物不同部位乙醇提取液对小麦纹枯病菌（Rhizoctonia cerealis）的抑菌活性．结果表明：凤尾兰植物提取液对小麦纹枯病菌有很好的抑菌效果,采用抑菌圈法抑制率达10。30％;用生长速率法,在有效浓度为6mg／ml抑制率达100％,其抑制率随浓度的增加而增加。凤尾兰植物提取液属粗提物,效果低于井冈霉素,而其他植物提取液均无明显的抑菌效果．     

小麦纹枯病发生因素分析及治理对策

系统分析了辉县市小麦纹枯病逐年加重和发生流行的因素,并结合当地实际情况提出了当地小麦纹枯病综合治理对策.     

三种寄生性种子植物丙酮提取物对植物病原真菌的抑菌活性研究

应用生长速率法测定了桑寄生（Loranthus parasiticus）、菟丝子（Cuscuta chinenssis）和无根藤（Cassytha fuliformis）三种寄生性种子植物的丙酮提取物对立枯丝核茵（Rhizoctonia solani）、茄链格孢茵（Ahernaria solani）、腐皮镰刀茵（Fusarium solani）、玉米大斑凸脐蠕孢茵（Exserohilum turcicum）和香蕉炭疽菌（Gloeosporium musarum）的抑菌活性。结果显示三种植物都表现出一定的抑茵活性,其中桑寄生对所有供试菌种的抑菌活率茵均在50％以上;其次是无根藤,除对香蕉炭疽茵效果较差外,对其余4种病原菌的抑茵率均在40％以上;菟丝子则对立枯丝核茵、茄链格孢菌和香蕉炭疽菌表现出较好抑茵活性,其抑菌率在30％以上。     

河南省小麦纹枯病防治关键时间和关键技术研究

研究了小麦纹枯病防治关键时间和关键技术。防治关键时期一是冬前防治以拌种为主控制入侵，二是春季药剂防治为关键控制扩展，同时搞好肥水管理。河南省小麦纹枯病在返青-拔节气温上升到20～25℃时防治效果较好，时间为3月10日～4月20日。拌种以三唑酮较好，喷雾以井冈霉素和三唑酮为主，适时喷雾能有效控制小麦纹枯病的流行和发展，此外还应利用抗耐品种和加强农业防治等措施。     

小麦纹枯病不同接种方法的比较

为了使鉴定方法简单、科学、可靠,选用了3种接种纹枯病的方法.即沟带接种法、土表接种法、牙签嵌入接种法,比较了不同抗性水平品种、不同接种方法之间发病率、病情指数的差异.结果表明:不同接种方法之间、不同品种之间发病率、病情指数存在显著差异.沟带接种法简单、粗放,受环境的影响较大,可以用于大量材料的初选.牙签嵌入接种法的发病率最高,平均发病率在90%以上,重复之间差异不显著,接种容易成功,重复性好,但试验鉴定要求细致、繁琐,工作量大.土表接菌法最为简单、方便,通过适当控制试验条件,可以获得满意的接种效果.在实际研究过程中,可根据自身条件和试验要求选择合适的接种方式.SW038、WH06-7、Niavt14和CI12633等材料在三种接种方法下都表现抗病,可作抗病亲本在小麦育种中利用.     

浅谈植物源农药

植物源农药作为生物农药的重要组成部分,成为目前各国研究的热点,通过植物源农药的特点、研究和开发途径、开发和使用时应注意的问题等几个方面作了综述,展望开发应用前景.     

浅谈植物源农物

植物源农药作为生物农药的重要组成部分，成为目前各国研究的热点，通过植物源农药的特点、研究和开发途径、开发和使用时应注意的问题等几个方面作了综述，展望开发应用前景．     

植物生长调节剂浸种对小麦幼苗抗旱性的影响

利用植物生长调节剂浸小麦种子可提高其幼苗的抗旱性.在干旱条件下,用植物生长调节剂浸种小麦后,其幼苗叶片含水量下降缓慢,相对电导率升幅小,游离脯氨酸含量增加少,叶绿素降解慢,SOD酶活性明显增强.利用麦丰、五号(自配)浸种的效果最好.用多效唑、化控二号浸种的效果优于用惠满丰、缩节安浸种的效果.     

植物源农药

本文概述了植物源农药特点、应用研究现状及展望。     

花椒等4种植物对植物病原菌孢子萌发的抑制作用

采用孢子萌发法,测定了蓖麻、狗尾草、花椒和茴香提取物对玉米黑粉病菌Ustilago magdis、棉花红粉病菌Trichothecium roseum、葡萄霜霉病菌Plasmopara viticola和棉花红腐病菌Fusarium spp.的抑菌作用.结果表明:狗尾草、花椒、茴香和蓖麻提取物对4种植物病菌孢子的萌发均具有一定的抑制作用,且随着浓度的升高,抑制率增加.4种植物提取物浓度为200 mg/mL时,对棉花红腐病菌孢子萌发的抑制作用最强,抑制率分别达到91.7%、91.8%、93.7%和89.7%;浓度为100 mg/mL时,抑制率均超过65.0%;浓度为50 mg/mL时抑制作用相对较弱,但仍和对照有显著差异.     

汉麻不同器官提取物对植物病原菌的抑制作用

采用溶剂浸提法,对汉麻植株的花、叶、茎和根4种不同器官分别进行平行提取,采用菌丝生长速率法,测定汉麻粗提物对大豆疫霉病菌(Phytophthora sojae)、小麦赤霉病菌(Fusarium graminearum)和玉米小斑病菌(Bipolaris maydis)3种植物病原菌的抑制活性.结果表明:汉麻的不同器官粗提物对3种植物病原菌均具有一定的抑菌活性,其中汉麻花的乙醇提取物对小麦赤霉病菌的抑制活性最佳,抑制率可达50％.     

热带植物花卉的抗氧化性研究

为了筛选具有抗氧化性的热带花卉，对海南师范大学校园中的12种花卉的鲜花和干花的水提取物、50％乙醇提取物和70％丙酮提取物进行清除DPPH的实验．结果表明：紫薇、干凤凰花、干洋金凤、大叶龙船花卉和干小叶龙船花卉的抗氧化效果最好．     

四种植物提取物对菜粉蝶产卵行为的影响

室内测定了几种植物的丙酮提取物对菜粉蝶成虫产卵行为的影响,筛选具有忌避活性的植物种类.结果表明：紫茉莉花提取物对菜粉蝶的产卵忌避作用最好,72 h的产卵忌避率可达68%;凌霄叶提取物次之,72 h的产卵忌避率为59%;紫茉莉叶、艾蒿叶和丁香叶72 h的平均产卵忌避率分别为59.7%、57%和50.7%.同时,紫菜莉花和叶及凌霄叶对菜粉蝶选择产卵部位还有一定干扰作用,叶正面与叶背面卵数之比与对照相比显著提高.     

Antibacterial potency of methanol extracts of lower plants

Antibacterial potency of methanol extracts of three green lower plants, Pneumatopteris afra, Platycerium bifurcatum and Nephrolepsis bisserata was determined using agar dilution method on clinical strains of Escherichia coli, Staphylococcus aureus, Klebsiella spp. and Salmomelia typhi. Antibacterial activities were observed at concentrations of 12.5, 25.0, 50.0 and 100.0 μg/ml. Their minimum inhibitory concentrations ranged from 12.5~100 μg/ml. Extracts of P. afra and P. bifurcatum were most active. Antibacterial activities observed with N. bisserata were less pronounced with no detectable activity at extract con-centrations of 12.5 and 25.0 μg/ml. E. coli, together with S. aureus appeared to be the most susceptible of the test bacteria while Klebsiella spp. was least sensitive. The significance of our findings is discussed.     

Antiviral activities of extracts from Hong Kong seaweeds

We extracted six Hong Kong brown seaweed species with hot water for their antiviral properties. The cytotoxicity and antiviral activity of these extracts were tested by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] method, cytopathic effect reduction assay, and plaque reduction assay. The antiviral effect was further determined by flow cytometric analysis. The results showed that most of these extracts inhibited the propagation of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) standard strains with very low cytotoxicity to the host cells. The extracts ofHydroclathrus clathratus and Lobophora variegata showed more potential anti-HSV activities than the extracts of the other four seaweeds. They also had moderate anti-respiratory syncytial virus (RSV) activities but could not inhibit influenza A virus. Hydroclathrus clathratus was further extracted by diluted acid and alkali and the antiviral effects of the extracts were also detected. The result showed that the hot water extract contained the main carbohydrate components that exhibited the antiviral activities against various strains of HSV, including the acyclovir-resistant strain. HI-3, a compound fractionated from this hot water extract, showed a dose-dependent anti-HSV activity in flow cytometric analysis and plaque reduction assay.     

Anti-allergic effects of ethanol extracts from brown seaweeds

Ethanol extracts of brown seaweeds from Pakistan and China were isolated and compared for their antiallergenic activities.They included Sargassum tennerimum (ST) and Sargassum cervicorne (SC) from Pakistan,and Sargassum graminifolium turn (SG),Sargassum thunbergii (STH),and Laminariajaponica (LJ) from China.The ethanol extracts of these brown seaweeds were optimized at 85% (v/v) ethanol for the maximum yield of phlorotannin,an inhibitor against hyaluronidase.Total phlorotannins contained in the crude extracts were measured as 1.71% (SG),0.74% (STH),0.97% (LJ),3.30% (SC),and 5.06% (ST).The 50% inhibitory concentrations (IC50) of Pakistani SC and ST were 109.5 and 21 μg/ml,respectively,lower than those of Chinese SG,STH,and LJ (134,269,and 148 μg/ml,respectively).An antiallergic drug,disodium cromoglycate (DSCG),had an IC50=39 μg/ml,and a natural inhibitor of hyaluronidase,catechin,had an IC50=20 μg/ml.The IC50 of ST extract was found similar to that of catechin (21 vs 20 μg/ml) and lower than that of DSCG (21 vs 39 μg/ml).This suggests that ST is a potent inhibitor of hyaluronidase,indicating a promising future development of natural antiallergic medicines or functional foods.     

龙葵水提物对2种常见致病菌的抑制作用研究

利用平板菌落计数法筛选菌体密度为104 cfu/mL的菌液并涂布平板,将用龙葵提取液浸泡过的药敏纸片分别贴到含大肠杆菌和金黄葡萄球菌的平板上,培养后测抑菌圈直径并对其进行差异显著性检验.结果表明:龙葵水提物对2种致病菌均有抑制作用,当质量浓度分别大于或等于250mg/mL和125mg/mL时,大肠杆菌和金黄葡萄球菌对龙葵水提物表现敏感.同一质量浓度下,龙葵水提物对金黄葡萄球菌的抑制效果更好,不同质量浓度龙葵水提物产生的抑菌圈直径之间差异显著.     

野草香地上器官水浸液的自毒作用

以风干野草香茎、叶、花序为供体,种子为受体,研究了野草香地上部器官水浸液的自毒作用.采用A×B=3×5二因素完全随机试验设计,室内生物测定法,测定了受体的发芽势、发芽指数、发芽率、成苗率、胚轴长度、胚根长度6项指标,并计算化感效应指数和化感综合效应(SE).结果表明:A因素(野草香的地上器官叶、花序、茎)3个水平的SE值分别为-0.52、-0.64、-0.61,表现出叶>花序>茎的自毒作用强弱顺序;B因素(供体水浸液的浓度)5个水平的SE值分别为0、-0.18、-0.78、-0.99、-1.00,说明随供体水浸液浓度的升高自毒作用增强;受体6项指标的SE值分别为-0.53、-0.58、-0.58、-0.59、-0.54、-0.73,表明供体对受体6项指标的自毒作用强弱顺序为胚根长度>成苗率>发芽指数=发芽率>胚轴长度>发芽势.