化学药剂诱导植物抗病性研究进展

诱导抗病性(Induced resistance)是指利用生物或物理、化学因子处理植物,改变植物对病原的反应,从而使其获得局部或系统的抗性.本文综述了近年来水杨酸、寡糖、聚糖及BTH等几种主要化学诱导剂在诱导植物抗病性中的应用.     

植物的诱导抗病性研究进展

诱导抗病性就是利用物理的、化学的以及生物的方法预先处理植株,改变植物对病害的反应,使原来感病反应产生局部或系统的抗性。在此,着重从植株诱导处理后发生的一系列生理变化、植物体内多种抗病防卫反应间的相互关系等方面对植物诱导抗病性作了概括性介绍。许多研究表明,植株经诱导物诱导后,体内产生PR蛋白,其过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶、几丁酶活性都大大增加,侵染点周围迅速木质化;在植物的诱导抗病进程中有两套基因先后起作用,即抗病基因和防卫反应基因,抗病基因产物与病菌无毒基因产物有识别作用,从而诱导防卫反应基因表达。     

植物诱导抗病性的常规鉴定 ——相关酶活性变化与其的关系

概述了诱导植物抗病性的过程、相关酶以及几种主要相关酶活性变化与诱导植物抗病性的关系。为早期鉴别植物抗性提供了理论和方法。     

植物诱导抗病性及其机理的研究现状

植物诱导抗病性是国际上重要的农业研究领域,被认为是植物保护的新途径和新技术,其防病原理主要是诱发植物本身潜在的抗病机能.综述了植物诱导抗病性的概念及其特点,并从诱导植株的相关酶的活性变化、新蛋白的合成、细胞壁的保护反应以及植物抗毒素等方面综述了植物诱导抗病机理的研究进展.同时对诱导抗病性的应用前景作了展望,并提出了目前研究中存在的问题及今后的研究方向.     

植物激发子及其信号传导之研究进展

植物诱导抗病性是当前科学研究的热点,是研究病源物和植物互作关系的关键。植物激发子在植物诱导抗病性中发挥着重要的作用,它是一类能诱导寄主植物产生防卫反应的特殊化合物,在与受体分子结合后,通过一定的信号传导途径激发植物产生防卫反应。综述了近年来激发子在植物诱导抗病性中的研究进展,包括激发子的种类,受体类型以及激发子引起的信号传导,并对激发子研究存在的问题及应用前景进行了展望。     

植物系统获得抗病性及其在控制农作物病害中的应用前景

本文从系统获得抗病性的特征、商品化抗病诱导剂及获得抗病性在未来农作物病害防治中的应用前景等方面对植物诱导抗病性进行了阐述。     

利用植物系统获得抗病性控制农作物病害

<正>植物系统获得抗病性是植物抵抗病原物侵染的一种主要特性,即指植物经过弱毒性或另一个病原物的接种或一些化学物质诱导,经过7d左右后被接种的植物产生新的、广谱的系统抗性,从而对病原物再次侵染以及其它病菌的侵染均具有很强的抗性,该抗性水平可扩展到整个植株,故称为系统获得抗     

植物的化学诱导表达系统

利用植物内源性化学诱导启动子或其它生物的化学诱导响应元件都可以在植物中构建化学诱导表达系统.化学诱导表达系统可以分为去抑制、失活、激活三种,三种方式的原理相似,需要两个转录单位组成,第一个转录单位由一个组成型启动子(如CaMV 35S)转录一个对化学诱导剂敏感的转录因子,第二个转录单位含有多个能结合转录因子的位点与一个基本植物启动子(如截短的CaMV 35S)组成的嵌合型启动子调控目的基因的表达.构建双元调控系统可以克服单元系统的不足.文章叙述了一些已构建的化学诱导系统的特征和局限性,阐明了理想化学诱导表达系统的要求和理想化学诱导剂的条件.指出化学诱导系统的应用是很有前途的.     

热带水果采后炭疽病生物防治研究进展

总结了动物源活性物质、植物源活性物质和有益微生物及其产生的活性物质对热带水果炭疽病的生物防治研究概况,归纳出这些物质的生防机制主要包括拮抗、竞争定殖作用和诱导植物产生抗病性等。得出了防治热带水果炭疽病的最有效方法是综合生物、物理和化学等多种方法,并为热带水果采后炭疽病的生防产品的开发提供新的研究思路。     

植物的化学诱导表达系统

利用植物内源性化学诱导启动子或其它生物的化学诱导响应元件都可以在植物中构建化学诱导表达系统。化学诱导表达系统可以分为去抑制、失活、激活三种，三种方式的原理相似，需要两个转录单位组成，第一个转录单位由一个组成型启动子(如CaMV 35S)转录一个对化学诱导剂敏感的转录因子，第二个转录单位含有多个能结合转录因子的位点与一个基本植物启动子(如截短的CaMV 35S)组成的嵌合型启动子调控目的基因的表达。构建双元调控系统可以克服单元系统的不足。文章叙述了一些已构建的化学诱导系统的特征和局限性，阐明了理想化学诱导表达系统的要求和理想化学诱导剂的条件。指出化学诱导系统的应用是很有前途的。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.