H2S作为植物个体间交流的气体信号分子

植物遭受到昆虫取食、创伤及非生物胁迫时,会向环境中释放多种挥发性物质,直接或间接地帮助受胁迫植株抵抗伤害。同时,这些挥发性物质向附近的健康植株传递信息,以应对可能到来的侵害。硫化氢(H2S)作为细胞内气体信号分子提高植物对多种胁迫的抗性已有报道,本论文对H2S是否作为植物个体间传递信息的信号分子进行了研究。结果表明:40%PEG8000处理可以使谷子、白菜、番茄和拟南芥Col-0植株所在环境空气中H2S含量升高;谷子和拟南芥Col-0植株经PEG8000处理后,可以使邻近的非胁迫植株叶片的H2S含量升高和H2S响应基因表达变化,并诱导非胁迫植株气孔关闭;而拟南芥内源H2S产生酶基因LCD和DES1双基因突变体lcd/des1经PEG8000处理,不能引起空气中和邻近植物的H2S含量升高,不能诱导邻近植株气孔关闭。本论文表明,H2S可以作为植物个体间的信息传递分子;即受胁迫植物通过向周围环境中释放H2S,向邻近植株提供胁迫预警信息,可能对种群的生存有重要意义。     

Nanoparticles as smart treatment-delivery systems in plants: assessment of different techniques of microscopy for their visualization in plant tissues

BacKGROUND AND AIMS: The great potential of using nanodevices as delivery systems to specific targets in living organisms was first explored for medical uses. In plants, the same principles can be applied for a broad range of uses, in particular to tackle infections. Nanoparticles tagged to agrochemicals or other substances could reduce the damage to other plant tissues and the amount of chemicals released into the environment. To explore the benefits of applying nanotechnology to agriculture, the first stage is to work out the correct penetration and transport of the nanoparticles into plants. This research is aimed (a) to put forward a number of tools for the detection and analysis of core-shell magnetic nanoparticles introduced into plants and (b) to assess the use of such magnetic nanoparticles for their concentration in selected plant tissues by magnetic field gradients. METHODS: Cucurbita pepo plants were cultivated in vitro and treated with carbon-coated Fe nanoparticles. Different microscopy techniques were used for the detection and analysis of these magnetic nanoparticles, ranging from conventional light microscopy to confocal and electron microscopy. KEY RESULTS: Penetration and translocation of magnetic nanoparticles in whole living plants and into plant cells were determined. The magnetic character allowed nanoparticles to be positioned in the desired plant tissue by applying a magnetic field gradient there; also the graphitic shell made good visualization possible using different microscopy techniques. CONCLUSIONS: The results open a wide range of possibilities for using magnetic nanoparticles in general plant research and agronomy. The nanoparticles can be charged with different substances, introduced within the plants and, if necessary, concentrated into localized areas by using magnets. Also simple or more complex microscopical techniques can be used in localization studies.     

The physiological activity of volatile substances of plants in air and water media

Physiological effects of volatile substances released by the overground as well as by the underground organs of higher plants were studied. The activity of the volatile substances was tested both when these substances were allowed to act directly in the air and when they were dissolved in water in the form of solutions. Plants which do not contain essential oils or which are not rich in them as well as those abounding in essential oils and other volatiles were used in the experiments. The physiological activity of the volatile substances was tested on rye seedlings. The overground as well as underground mature organs of the tested plants were found to release volatile substances causing, when acting directly, in the majority of cases an inhibition of the growth in length and of the formation of dry matter in rye seedlings. A pronounced inhibition of the growth of rye seedlings was brought about especially by the volatile substances of “aromatic” plants such as common dill, wild thyme, yarrow milfoil, garden thyme, marjoram, etc. The volatile substances released by the organs of “non-aromatic” plants like sugar-beet, common sunflower, quackgrass, etc., were found to bring about a significant inhibition of the growth of rye seedlings, too. The volatile substances released by the plant organs were found to be altogether absorbable in water and physiologically active also in the form of water solutions. With the exception of volatile substances from hemp and quackgrass leaves, which brought about a mild stimulation of the dry matter formation in rye seedlings, inhibitory effects of these solutions were found to prevail in all cases. Most effective were the solutions of the volatiles from some of the “aromatic plants”. An assay for olefines in the atmosphere of the experimental vessels demonstrated that in almost all cases ethylene is being released by the plant organs.     

Natural Polyphenols: Biological Activity,Pharmacological Potential,Means of Metabolic Engineering (Review)

This review examines the main features of natural phytoalexines of flavonoid and stilbenoid natures, which are secondary metabolism products in numerous plants widely used as biologically active substances in the medicine, pharmacology, and agricultural plants protection. We considered the role of flavonoids and stilbenes in phytoimmune and antistress responses in plants, bactericide antifungul, and antiviral effects towards microorganisms, and the wide medical application for a number of mammalian pathologies. The main achievements in the metabolic engineering of flavonoids in microbial biotechnologies are discussed.     

Plants used as natural dye sources in Turkey

This study was carried out in the regions where handcrafts such as carpet and rug weaving are common in Turkey. In the regions where natural dyes are used, 123 plant species belonging to 50 families were identified as sources of natural dyes. In natural dye production, different parts of the plant or the whole aboveground plant is used. Ten different colors are gained from the plants. Sometimes the same color can be obtained from different plants. By mixing different plants, it is possible to produce various colors. We also identified more than 12 natural and more than eight chemical assistant substances (mordant) that are used in the regions to bind dye to fibers, to maintain the strongness and brightness of the colors, and to obtain various colors     

Plants as sources of natural and recombinant anti-cancer agents

Herbal remedies were the first medicines used by humans due to the many pharmacologically active secondary metabolites produced by plants. Some of these metabolites inhibit cell division and can therefore be used for the treatment of cancer, e.g. the mitostatic drug paclitaxel (Taxol). The ability of plants to produce medicines targeting cancer has expanded due to the advent of genetic engineering, particularly in recent years because of the development of gene editing systems such as the CRISPR/Cas9 platform. These technologies allow the introduction of genetic modifications that facilitate the accumulation of native pharmaceutically-active substances, and even the production heterologous recombinant proteins, including human antibodies, lectins and vaccine candidates. Here we discuss the anti-cancer agents that are produced by plants naturally or following genetic modification, and the potential of these products to supply modern healthcare systems. Special emphasis will be put on proteinaceous anti-cancer agents, which can exhibit an improved selectivity and reduced side effects compared to small molecule-based drugs.     

The concentration of xylem sap constituents in root exudate, and in sap from intact, transpiring castor bean plants (Ricinus communis L.)

Root exudates were sampled from detopped root systems of castor bean (Ricinus communis). Different volume flux rates were imposed by changing the pneumatic pressure around the root system using a Passioura-type pressure chamber. The concentrations of cations, anions, amino acids, organic acids and abscisic acid decreased hyperbolically when flux rates increased from pure root exudation up to values typical for transpiring plants. Concentrations at low and high fluxes differed by up to 40 times (phosphate) and the ratio of substances changed by factors of up to 10. During the subsequent reduction of flux produced by lowering the pneumatic pressure in the root pressure chamber, the concentrations and ratios of substances deviated (at a given flux rate) from those found when flux was increased. The flux dependence of exudate composition cannot therefore be explained by a simple dilution mechanism. Xylem sap samples from intact, transpiring plants were collected using a Passioura-type root pressure chamber. The concentrations of the xylem sap changed diurnally. Substances could be separated into three groups: (1) calcium, magnesium and amino acid concentrations correlated well with the values expected from their concentration-flux relationships, whereas (2) the concentrations of sulphate and phosphate deviated from the expected relationships during the light phase, and (3) nitrate and potassium concentrations in intact plants varied in completely the opposite manner from those in isolated root systems. Abscisic acid concentrations in the root exudate were dependent on the extent of water use and showed strong diurnal variations in the xylem sap of intact plants even in droughtstressed plants. Calculations using root exudates overestimated export from the root system in intact plants, with the largest deviation found for proton flux (a factor of 10). We conclude that root exudate studies cannot be used as the sole basis for estimating fluxes of substances in the xylem of intact plants. Consequences for studying and modelling xylem transport in whole plants are discussed.     

The impact of different operating conditions on membrane fouling and EPS production

The main goal of this research was to investigate how different factors influence membrane fouling. The impact of the different concentrations of activated sludge and the amount of extracellular polymer substances (EPS) were monitored. Two pilot plants with submerged membrane modules (hollow fiber and flat sheet) were operated and the raw wastewater was used.Humic substances were identified as the major components of EPS in the activated sludge (more than 34%) in both pilot plants. As the basic constituent in permeate, humic substances were identified as the most dominant components in the effluent (61%) in both pilot plants. Conversely, proteins were mostly analyzed in permeate and supernatant below the detection limit. The total amount of EPS [mg g⁻¹ (VSS)] was similar for concentrations of activated sludge 6, 10 and 14 g L⁻¹. Carbohydrates were identified as the component of EPS which tends most to clog membranes.     

Forage selection by Royle's pika (Ochotona roylei) in the western Himalaya,India

Forage selection decisions of herbivores are often complex and dynamic; they are modulated by multiple cues, such as quality, accessibility and abundance of forage plants. To advance the understanding of plant–herbivore interactions, we explored foraging behavior of the alpine lagomorph Royle's pika (Ochotona roylei) in Kedarnath Wildlife Sanctuary, India. Pika bite counts on food plants were recorded through focal sampling in three permanently marked plots. Food plant abundance was recorded by traditional quadrat procedures; forage selection was estimated with Jacob's selection index. Multiple food-choice experiments were conducted to determine whether forage selection criteria would change with variation in food plant composition. We also analyzed leaf morphology and nutrient content in both major food plants and abundantly available non-food plants. Linear regression models were used to test competing hypotheses in order to identify factors governing forage selection. Royle's pika fed primarily on 17 plant species and each forage selection decision was positively modulated by leaf area and negatively modulated by contents of avoided substances (neutral detergent fiber, acid detergent fiber, acid detergent lignin and tannin) in food plants. Furthermore, significance of the interaction term “leaf size × avoided substance” indicates that plants with large leaves were selected only when they had low avoided substance content. The forage selection criteria did not differ between field and laboratory experiments. The parameter estimates of best fit models indicate that the influence of leaf size or amount of avoided substance on pika forage selection was modulated by the magnitude of predation risk.     

Principles of classification of medicinal plants as hyperaccumulators or excluders

Strategies of plants, known as metallophytes, in response to metal excess are explored. Specific features of medicinal plants related to metal exposition are discussed. Different parameters used for metallophyte classification are discussed. Bioaccumulation and translocation factors are characterized. Chamomile (Matricaria recutita L.), one of the most important medicinal plants, is presented as a case history. Based on actual knowledge of plant response to metal excess and published data related to chamomile, it has been concluded that this plant species is Cd hyper/accumulator. Thus, chamomile can manifest high potential for cleaning-up (phytoremediation) of the soils contaminated with cadmium. However, it should be stressed that cultivation of this medicinal plant under natural conditions for pharmaceutical use should be carefully supervised.     

Utilisation of blue-green algae as biofertilisers

Biologically active compounds may be liberated from blue-green algae growing on the surface of moist soils. Such compounds may also be released as exudates from algae grown in liquid culture.This report describes inoculation of soils in pots, containing radish or tomato plants, with algal suspensions or exudates, which resulted in increased growth rates of both plants and increased their overall yield. Autoclaved exudates were generally as effective as fresh exudates. Interaction of effects between the various active substances depends on the algal species and method by which the soils are amended.     

Natural Plant Chemicals Acting as Oviposition Deterrents on Cabbage Butterflies (Pieris btassicae (L.), P. rapae (L.) and P. napi (L.))

In several growers' reports Solatium lycopersicum, Sambucus nigra. Thymus vulgaris, Salvia officinalis, Artemisia absinthium, A. abrotanum , and Allium cepa are said to decrease the oviposition of Pieris brassicae, P. rapae and P. napi. In the present study the butterflies were fed with honey automats and reared throughout the year in artificial light in an insec-tarium. In a dual-choice chamber with a slow throughflow of air two equally sized cabbage leaves were placed on opposite sides. Significantly fewer eggs were layed on the cabbage leaf on which extracts of the mentioned plants had been applied. Ten butterflies were used in each experiment. The chemoreceptors and the chemicals involved are not identified but the inhibitory substances are surely secondary plant substances. Acceptance or rejection of secondary plant metabolics determines the complicated food relationships between plants and insects. The use of secondary plant substances for ecological control of insect pests is proposed.     

Gibberellin-like Substances Obtained from Chilled Plants of Dianthus barbatus L. by an Agar Diffusion Technique

Plants of Dianthus barbatus with a cold requirement for floweringwere subjected to chilling treatments at 5 °C. An agar diffusiontechnique was used to collect gibberellin-like substances fromshoot tips excised from these plants and from plants that hadbeen kept in the glasshouse at a minimum temperature of 14 °C.Shoot tips from chilled plants gave markedly higher yields ofgibberellin-like substances. The effect of chilling was no longerso apparent if plants were returned to the higher temperaturesof the glasshouse for 1 week before the shoot tips were excised. The proportion of plants that flowered as a result of the differentchilling treatments varied widely but this variation was notassociated with any obvious differences in the yields of gibberellin-likesubstances. Application of gibberellins to plants grown at aminimum temperature of 14 °C did not promote flowering.     

果实(种子)化学防御与食果实动物的适应对策

种子植物在果实(种子)成熟后需要防御食果实动物捕食种子,同时要传播种子至适宜萌发的生境。很多植物依赖食果实动物传播种子,称动物传播植物。果实(种子)化学防御是抵御种子捕食者的重要手段。果实(种子)中次生物质包括各种生物碱、生氰糖苷、萜类和酚类等,种类繁多;次生物质的含量随果实成熟过程而变化。次生物质可以抵御动物的捕食,其毒性对种子传播者和种子捕食者没有选择性,即具泛毒性。果肉中的次生物质也可以起到轻泻剂的作用,缩短种子在动物消化道的滞留时间,以影响传播效率。果实(种子)次生物质的产生不受植物环境条件的影响,其产生与果实质量有关。在温带地区,通常SS型果实次生物质含量低,而FL型果实含量高。食果实动物可通过调整捕食行为、摄取环境中特殊物质和获得丰富营养等3个方面适应次生物质。果实(种子)中次生物质的研究对动植物相互作用、协同进化理论具有重要的意义。     

The properties of a biologically formed manganese oxide,its availability to oats and its solution by root washings

Summary Manganese oxide, produced byCorynebacterium sp. in liquid medium was found to be amorphous, probably hydrated and was readily reduced by neutral quinol. Preparations of the oxide had values of n in the formula MnO_n which ranged from 1.76 to 1.88. The oxide was completely available to oats grown in sand culture but only slightly available in a manganese deficient soil. Plants grown under sterile conditions on agar slopes were able to obtain manganese from manganese oxide, indicating that the roots and not associated micro-organisms, were responsible for the solution process. Root washings of oat plants contained substances which dissolved manganese oxides and the activity of these substances increased with increasing acidity. The possible importance of these substances in making soil manganese available to plants is discussed.     

ToMV-Resistant transgenic tomato as a material for the first field experiment of genetically engineered plants in Japan

Summary An F₁ hybrid betweenLycopersicon esculentum andL. peruvianum was transformed using a Ti-plasmid binary vector with a coat protein gene cDNA of an attenuated tomato mosaic virus (ToMV) strain L₁₁A which was expressible by the 35S promoter of cauliflower mosaic virus (CaMV). A transgenic plant which expressed the most resistance to ToMV was chosen as a material to be tested in a nonisolated greenhouse and in the field. This transgenic tomato plant was propagated by cutting. In the first test using an isolated greenhouse and in the second test conducted in an nonisolated greenhouse, no major morphologic and physiologic differences were found between the transgenic plants and the nontransgenic control plants. Also, there was no evidence that the transgenic plants produced any new hazardous substances. Both the transgenic and the nontransgenic plants were self-sterile, and crossing of the cultivated species with pollen of these plants produced few seeds. These features of the transgenic plants satisfied the requirements for a small scale field test. The field test of the transgenic plants are in progress. Presented in the Session-in-Depth “Field Test Requirements and Performance of Transgenic Plants” at the 1991 World Congress on Cell and Tissue Culture, Anaheim, California, June 16–20, 1991.     

Antimicrobial activity of vascular plants

Numerous surveys have demonstrated the wide occurrence of active antimicrobial substances in higher plants. The array of compounds with unique structures which plants produce has served as a stimulus to continued search for useful antibiotics. Reports referred to in the table indicate that active substances have been found in plants from 157 families.     

Plants as human adornment in India

Plants have served for human adornment in India for millennia. Their use as ornaments and cosmetics is not only ancient but survives to the present time. In addition to decoration, adornment is often regarded as having amuletic powers or is used as social diacritical marks. Over 165 plant species used for human adornment in India have been identified from the literature and by personal observations. This study points out the importance of plants as human adornment both to aboriginal groups and modern urban and rural Indians. The widespread employment of vegetal materials for adornment indicates that in India they have traditionally been more important for this use than have mineral or animal substances.     

Inhibition of Candida rugosa lipase by berberine and structurally related alkaloids, evaluated by high-performance liquid chromatography.

It is known that certain microorganisms produce extracellular lipase to better colonize the skin and mucosal surfaces. Since different extracts from medicinal plants have anti-lipase activity (Shimura et al., Biosci. Biotechnol. Biochem., 56: 1478-1479, 1992), we examined the effects of selected natural substances on Candida rugosa lipase. In the presence of the compounds under examination, the enzyme was incubated with beta-naphthyl laurate, and beta-naphthol, produced by the enzymatic reaction, was extracted with ethyl acetate and analyzed by reversed phase HPLC, using a C-18 column. Thus, the inhibitory activity was calculated by a proper formula based on the variations of the area under the chromatographic peak of beta-naphthol. The method was validated by analyzing substances with known anti-lipase activity such as saturated fatty acids (C10-16) and tetracycline. Berberine and a number of structurally related alkaloids such as chelidonine, chelerythrine, and sanguinarine appeared active. This property of berberine and sanguinarine is of interest because they are used in pathological conditions in which microbial lipases could play a pathogenic role.     

Alcohol dehydrogenase expression as a biomarker of denitrification activity in activated sludge using methanol and glycerol as electron donors

Carbon sources such as methanol and glycerol are used for enhancing denitrification at wastewater treatment plants, which are required to meet increasingly stringent effluent nitrogen limits. Consequently, dosing strategies for these compounds could benefit from the development and application of molecular activity biomarkers to infer and distinguish between methanol- or glycerol-based denitrification in activated sludge. In this study, the applicability of genes coding for methanol dehydrogenase (mdh2 and mxaF) and glycerol dehydrogenase (dhaD) as potential biomarkers of denitrification activity using these specific substrates was explored and confirmed using a two-pronged approach. First, during short-term spikes of activated sludge biomass with glycerol, the ability of dhaD mRNA concentrations to closely track nitrate depletion profiles was demonstrated. Second, a high-degree of correlation of the mRNA concentrations of mdh2, mxaF and dhaD with methanol- and glycerol-based denitrification kinetics during long-term bioreactor operation using these substrates was also shown. Based on these results, expression of mdh2, mxaF and dhaD genes are promising biomarkers of in situ denitrification activity on methanol and glycerol, respectively, in mixed-culture engineered wastewater treatment processes.