Auxin conjugated to fluorescent dyes – a tool for the analysis of auxin transport pathways

Auxin is a small molecule involved in most processes related to plant growth and development. Its effect usually depends on the distribution in tissues and the formation of concentration gradients. Until now there has been no tool for the direct tracking of auxin transport at the cellular and tissue level; therefore the majority of studies have been based on various indirect methods. However, due to their various restrictions, relatively little is known about the relationship between various pathways of auxin transport and specific developmental processes. We present a new research tool: fluorescently labelled auxin in the form of a conjugate with two different fluorescent tracers, FITC and RITC, which allows direct observation of auxin transport in plant tissues. Chemical analysis and biological tests have shown that our conjugates have auxin‐like biological activity and transport; therefore they can be used in all experimental systems as an alternative to IAA. In addition, the conjugates are a universal tool that can be applied in studies of all plant groups and species. The conjugation procedure presented in this paper can be adapted to other fluorescent dyes, which are constantly being improved. In our opinion, the conjugates greatly expand the possibilities of research concerning the role of auxin and its transport in different developmental processes in plants.     

Potential of phenolic compounds from pomegranate (Punica granatum L.) by-product with significant antioxidant and therapeutic effects: A narrative review

The wealth of epidemiological evidence in the scientific world underscores the possibility that a plant-based diet can reduce the prevalence of common diseases such as diabetes, cardiovascular disease, cancer, and stroke. The therapeutic effects of plant sources are partly explained by phenolic secondary metabolites or polyphenolic compounds. Therefore, polyphenolic compounds, which are widely distributed in plants, are of great interest for the development of effective specific drugs with antioxidant and anti-inflammatory effects. Moreover, polyphenol compounds have no harmful effects due to their natural biocompatibility and safety. Numerous studies have highlighted the potential of some industrial food wastes from plant material processing, including apple peels and mashed potatoes, grape skins, tomato and carrot peels, pomegranate peels and seeds, and many others. These byproducts are considered low-cost sources of natural biological compounds, including antioxidants, which have beneficial effects on human health.The polyphenol complex of pomegranate peel (Punica granatum L.), which makes up half of the pomegranate fruit, has more pronounced antioxidant and anti-inflammatory properties than other parts. And the most important active components of pomegranate peel, which are found only in this plant, are punicalagin, followed by ellagic acid and gallic acid. It is known that these polyphenolic compounds of pomegranate peel have the most pronounced therapeutic effect. Several studies have shown the protective effect of ellagic acid, punicalagin, against oxidative stress damage caused by free radicals. The potential of pomegranate peel as an antioxidant and therapeutic component in various biological systems is high, according to scientific sources.However, despite extensive research in recent years, a review of sources has shown that there is insufficient evidence to support the therapeutic effects of polyphenolic compounds from pomegranate peels. The role of pomegranate peel polyphenolic compounds, including flavonoids, as antioxidants in various biological systems also requires further research. Of particular importance are the mechanisms by which antioxidants influence the cellular response against oxidative stress. The purpose of this review was to report our current knowledge of plant polyphenolic compounds and their classification, and to evaluate the potential of phenolic compounds from pomegranate peels with significant antioxidant and therapeutic effects.     

Application of hairy roots for phytoremediation: what makes them an interesting tool for this purpose?

In recent years, hairy roots (HRs) have been successfully used as research tools for screening the potentialities of different plant species to tolerate, accumulate, and/or remove environmental pollutants, such as PCBs, TNT, pharmaceuticals, textile dyes, phenolics, heavy metals, and radionuclides. This is in part due to several advantages of this plant model system and the fact that roots have evolved specific mechanisms to deal with pollutants because they are the first organs to have contact with them. In addition, by using HRs some metabolic pathways and enzymatic catalyzed reactions involved in pollutants detoxification can be elucidated as well as the mechanisms of uptake, transformation, conjugation, and compartmentation of pollutants in vacuoles and/or cell walls, which are important detoxification sites in plants. Plant roots also stimulate the degradation of contaminants by the release of root exudates and oxido-reductive enzymes, such as peroxidases (Px) and laccases, that are associated with the removal of some organic pollutants. HRs are also considered good alternatives as enzyme sources for remediation purposes. Furthermore, application of genetic engineering methods and development of microbe-assisted phytoremediation are feasible strategies to enhance plant capabilities to tolerate, accumulate, and/or metabolize pollutants and, hence, to create or find an appropriate plant system for environmental cleanup. The present review highlights current knowledge, recent progress, areas which need to be explored, and future perspectives related to the application and improvement of the efficiency of HRs for phytoremediation research.     

Evolutionary responses of plants to anthropogenic pollutants

There is currently great concern over the possible adverse effects of atmospheric de position and other regionally distributed pollutants on plants and plant communitics. In Europe and North America there are major research efforts to determine whether such pollutants damage plants or affect ecosystem processes. A topic of growing concern is the possibility of genetic or evolutionary effects of pollutants. Past research has demonstrated that individuals, populations and varieties of a particular species can differ in their response to pollutants. Although such differences have been documented, the importance of evolutionary responses to regional, low level but chronic pollution remains to be established. The significance of regional chronic pollution is that effects on plants may no longer be limited to heavily industrialized or populated areas, but rather may also occur in virtually all natural ecosystems.     

Use of aged refuse-based bioreactor/biofilter for landfill leachate treatment

Sanitary landfilling is a proven way for disposal of municipal solid waste (MSW) in developed countries in general and in developing countries in particular, owing to its low immediate costs. On the other hand, landfilling is a matter of concern due to its generation of heavily polluted leachate. Landfill leachate becomes more refractory with time and is very difficult to treat using conventional biological processes. The aged refuse-based bioreactor/biofilter (ARB) has been shown to be a promising technology for the removal of various pollutants from landfill leachate and validates the principle of waste control by waste. Based on different environmental and operational factors, many researchers have reported remarkable pollutant removal efficiencies using ARB. This paper gives an overview of various types of ARBs used; their efficiencies; and certain factors like temperatures, loading rates, and aerobic/anaerobic conditions which affect the performance of ARBs in eliminating pollutants from leachate. Treating leachate by ARBs has been proved to be more cost-efficient, environment friendly, and simple to operate than other traditional biological techniques. Finally, future research and developments are also discussed.     

The potential for protein production from green plants

Data on protein yields show that forage crops, particularly alfalfa, produce several times more protein per acre than do seed crops. Amino acid analyses and estimations of biological values by enzymatic hydrolysis and feeding trials indicate that protein concentrates from green plants have high nutritive value. The protein concentrates from 10 plant species had a similar amino acid composition and biological value which indicates that good protein might be obtained from many plant species. It is suggested that the use of the fibrous residue as a feed for ruminants and the use of the protein concentrate as a high protein feed or base for processing into new protein foods may make it possible for the production of protein from green plants to compete with other sources of protein. This would markedly increase protein production per acre and allow the use of new plant species in our agriculture. The need for more research on protein production from different types of green plants and on ways to harvest, concentrate and process their proteins into edible forms is discussed.     

Plant acquisition of organic nitrogen in boreal forests

Research on plant nitrogen (N) uptake and metabolism has more or less exclusively concerned inorganic N, particularly nitrate. Nevertheless, recent as well as older studies indicate that plants may have access to organic N sources. Laboratory studies have shown that ectomycorrhizal and ericoid mycorrhizal plants can degrade polymeric N and absorb the resulting products. Recent studies have also shown that some non‐mycorrhizal plants are able to absorb amino acids. Moreover, amino acid transporters have been shown to be present in both plant roots and in mycorrhizal hyphae. Although both mycorrhizal and non‐mycorrhizal plants appear to have a capacity for absorbing a range of organic N compounds, is this capacity realized in the field? Several lines of evidence show that plants are outcompeted by microorganisms for organic N sources. Such studies, however, have not addressed the issue of spatial and temporal separation between plants and microorganisms. Moreover, competition studies have not been able to separate uptake by symbiotic and non‐symbiotic microorganisms. Qualitative assessment of organic N uptake by plants has been performed with dual‐labelled glycine in several studies. These studies arrive at different conclusions: some indicate that plants do not absorb this organic N source when competing with other organisms in soil, while others conclude that significant fractions of amino acid N are absorbed as intact amino acid. These variable results may reflect species differences in the ability to absorb glycine as well as differences in experimental conditions and analytical techniques. Although theoretical calculations indicate that organic N might add significant amounts of N to plant N uptake, direct quantitative assessment of the fraction of plant N derived from uptake by organic N sources is a challenge for future research.     

Mechanisms for flowering plants to benefit arthropod natural enemies of insect pests： Prospects for enhanced use in agriculture

Reduction of noncrop habitats, intensive use of pesticides and high levels of disturbance associated with intensive crop production simplify the farming landscape and bring about a sharp decline of biodiversity. This, in turn, weakens the biological control ecosystem service provided by arthropod natural enemies. Strategic use of flowering plants to enhance plant biodiversity in a well-targeted manner can provide natural enemies with food sources and shelter to improve biological control and reduce dependence on chemical pesticides. This article reviews the nutritional value of various types of plant-derived food for natural enemies, possible adverse effects on pest management, and the practical application of flowering plants in orchards, vegetables and field crops, agricultural systems where most research has taken place. Prospects for more effective use of flowering plants to maximize biological control of insect pests in agroecosystem are good but depend up on selection of optimal plant species based on information on the ecological mechanisms by which natural enemies are selectively favored over pest species.     

植物组蛋白变体生物学功能

组蛋白变体是重要的表观遗传调控因子,能够在染色质特定位置替换常规组蛋白,维持染色质结构进而保证转录激活或抑制的顺利进行.目前,组蛋白变体的调控功能已成为植物学研究领域的一个热点.近年来,随着植物组蛋白变体生物学功能研究的不断深入,发现组蛋白变体能够在植物生长发育和环境应答调控等多个生物学过程中发挥重要作用.该文简要介绍...     

链霉菌的功能及其在农业上的应用

链霉菌是自然界中大量存在的一类微生物,具有多种多样的功能,其基内菌丝多核有间隔,气生菌丝上附着孢子链,从孢子萌发到孢子释放完成整个生命周期。链霉菌以菌丝体的形式定殖于多种植物体的根、茎、叶等部位而发挥功能,能分泌多种具有促进植物生长与生物防治功能的代谢物。对近几年链霉菌在提升植物营养吸收、促进植物生长、增强植物应对逆境能力、改善土壤结构、恢复污染水体等方面的研究进行了综述,并对今后链霉菌的研究方向和应用前景进行了展望。     

Recent developments in microbial biotransformation and biodegradation of dioxins

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), commonly known as dioxins (PCDD/Fs), are toxic environmental pollutants formed from various sources. Elimination of these pollutants from the environment is a difficult task due to their persistent and ubiquitous nature. Removal of dioxins by biological degradation (biodegradation) is considered a feasible method as an alternative to other expensive physicochemical approaches. Biodegradation of dioxins has been extensively studied in several microorganisms, and details concerning biodiversity, biodegradation, biochemistry and molecular biology of this process have accumulated during the last three decades. There are several microbial mechanisms responsible for biodegradation of dioxins, including oxidative degradation by dioxygenase-containing aerobic bacteria, bacterial and fungal cytochrome P-450, fungal lignolytic enzymes, reductive dechlorination by anaerobic bacteria, and direct ether ring cleavage by fungi containing etherase-like enzymes. Many attempts have been made to bioremediate PCDD/Fs using this basic knowledge of microbial dioxin degradation. This review emphasizes the present knowledge and recent advancements in the microbial biotransformation, biodegradation and bioremediation of dioxins.     

A review of dietary stilbenes: sources and bioavailability

Stilbenes are a class of phenolic metabolites found in various edible plants, such as grapevine, berries and peanuts. Their bioactivitiy and their potential benefits for human health have been the subject of several studies. Among all identified stilbenes, resveratrol has been particularly studied and results from literature showed that it presents several biological activities, including antioxidant, anti-inflammatory and antiproliferative effects. Likewise, some researches focused on other stilbenes and highlighted similar biological activity for those compounds. However, stilbenes present a high diversity in their phenolic structures (various chemical substituents and polymerization) which is a determining factor of their absorption and metabolism rates. Consequently, this could affect the effectiveness of stilbenes in vivo. In this context, an evaluation of the bioavailability and metabolism of stilbenes is necessary to move forward with pharmacological and clinical studies. Hence, this review aims to present recently obtained data and results concerning stilbenes sources and bioavailability, as a contribution to the valorization of the role of dietary stilbenes in the human diet.     

Biological control of arthropod pests using banker plant systems: Past progress and future directions

The goal of banker plant systems is to sustain a reproducing population of natural enemies within a crop that will provide long-term pest suppression. The most common banker plant system consists of cereal plants infested with Rhopalosiphum padi L. as a host for the parasitoid Aphidius colemani L. Aphidius colemani continually reproduce and emerge from the banker plants to suppress aphid pests such as Aphis gossypii Glover and Myzus persicae Sulzer. Banker plant systems have been investigated to support 19 natural enemy species targeting 11 pest species. Research has been conducted in the greenhouse and field on ornamental and food crops. Despite this there is little consensus of an optimal banker plant system for even the most frequently targeted pests. Optimizing banker plant systems requires future research on how banker plants, crop species, and alternative hosts interact to affect natural enemy preference, dispersal, and abundance. In addition, research on the logistics of creating, maintaining, and implementing banker plant systems is essential. An advantage of banker plant systems over augmentative biological control is preventative control without repeated, expensive releases of natural enemies. Further, banker plants conserve a particular natural enemy or potentially the ‘right diversity’ of natural enemies with specific alternative resources. This may be an advantage compared to conserving natural enemy diversity per se with other conservation biological control tactics. Demonstrated grower interest in banker plant systems provides an opportunity for researchers to improve biological control efficacy, economics, and implementation to reduce pesticide use and its associated risks.     

The relationships of vascular plants

Recent phylogenetic research indicates that vascular plants evolved from bryophyte-like ancestors and that this involved extensive modifications to the life cycle. These conclusions are supported by a range of systematic data, including gene sequences, as well as evidence from comparative morphology and the fossil record. Within vascular plants, there is compelling evidence for two major clades, which have been termed lycophytes (clubmosses) and euphyllophytes (seed plants, ferns, horsetails). The implications of recent phylogenetic work are discussed with reference to life cycle evolution and the interpretation of stratigraphic inconsistencies in the early fossil record of land plants. Life cycles are shown to have passed through an isomorphic phase in the early stages of vascular plant evolution. Thus, the gametophyte generation of all living vascular plants is the product of massive morphological reduction. Phylogenetic research corroborates earlier suggestions of a major representational bias in the early fossil record. Mega-fossils document a sequence of appearance of groups that is at odds with that predicted by cladogram topology. It is argued here that the pattern of appearance and diversification of plant megafossils owes more to changing geological conditions than to rapid biological diversification.     

Biosorption of oxybenzene using biosorbent prepared by raw wastes of Zea mays and comparative study by using commercially available activated carbon

Organic pollutants present in waste water have undesirable effect on the environment. Industry activities are the key sources of organic pollutants. Prime pollutants released from various sources react instantly with the environment and become derived (secondary) pollutants, which stay for an elongated time. The present research work has been carried out using biosorbent prepared from various Zea mays wastes for elimination of oxybenzene. Different parameters viz contact time, initial concentration; adsorbent dose, temperature and pH were optimized for the biosorption of oxybenzene on to the biosorbent samples. BCS (Baby corn silk) showed higher percentage of biosorption at optimum contact time of 3 h, pH between 5 and 6 and temperature at 25 °C. Analysis of equilibrium biosorption data in terms of several isotherm models revealed that Langmuir isotherm and Freundlich isotherm indicates better agreement with the experimental data. The kinetics of oxybenzene biosorption on to the biosorbents was described with the pseudo-first-order model. Thermodynamic parameters indicated that biosorption onto biosorbent was feasible in nature, spontaneous, and endothermic for some biosorbents, but on contrary not feasible, exothermic and non spontaneous for other biosorbents. The result of this study showed that the biosorbent derived from Zea mays can be used as a prospective biosorbent for oxybenzene in wastewater and also can be an alternative for the commercially activated carbon.     

Magnesium transporters and their role in Al tolerance in plants

Magnesium (Mg) is an essential macronutrient for plant growth, which has diverse biological functions. However, little is known about the transport system of this nutrient in plants. In the genome of plants such as rice and Arabidopsis, there are homologues of bacterial Mg transporters (CorA) and some of them have been functionally characterized, but the physiological role of these transporters are poorly understood. On the other hand, Mg is able to alleviate Al toxicity in a number of plant species, but the mechanisms underlying this alleviation are not well understood. Recently, this alleviation has been associated with a Mg transporter in rice. In this paper, we present our opinions on Mg transporters, which are required for uptake, translocation, distribution and storage in plants. Possible mechanisms for Mg-mediated alleviation of Al toxicity are also discussed.     

Ellagitannin geraniin: a review of the natural sources,biosynthesis, pharmacokinetics and biological effects

The discovery of the ellagitannin geraniin was made exactly 40 years ago. It is a secondary metabolite found in plants and is categorised as a hydrolysable tannin under the huge family of polyphenolic compounds. At present, the occurrence of geraniin has been verified in at least 71 plant species, many of which are used in traditional medicine. Hence, like other polyphenols, geraniin has also received widespread interest as a research focus to unearth its beneficial biological effects and therapeutic values apart from understanding its chemical properties, biosynthesis and interaction with the body system. Indeed, it has been demonstrated that geraniin possesses antioxidant, antimicrobial, anticancer, cytoprotective, immune-modulatory, analgesic properties besides exerting promising therapeutic effects on hypertension, cardiovascular disease and metabolic dysregulation. The objective of this review is to summarise the current knowledge about the basic chemistry, natural sources, isolation techniques, biosynthesis, pharmacokinetics and pharmacodynamics of geraniin. With reference to this information, the clinical significance, obstacles and future perspectives in geraniin research will also be scrutinised.     

稳定同位素技术在植物水分利用研究中的应用

近20a稳定同位素技术在植物生态学研究中的应用得到了长足发展,使得对植物与水分关系也有了更深一步的了解。介绍稳定同位素性碳、氢、氧同位素在研究植物水分关系中的应用及进展,以期能为国内植物水分利用研究提供参考。由于植物根系从土壤中吸收水分时并不发生同位素分馏,对木质部水分同位素分析有助于对植物利用水分来源,生态系统中植物对水分的竞争和利用策略的研究,更好地了解生态系统结构与功能。稳定碳同位素作为植物水分利用效率的一个间接指标,在不同水分梯度环境中,及植物不同代谢产物与水分关系中有着广泛的应用。同位素在土壤-植被-大气连续体水分中的应用,有助于了解生态系统的水分平衡。随着稳定同位素方法的使用,植物与水分关系的研究将取得更大的进展。     

Plant biodiversity: phytochemicals and health

Biodiversity may be defined as the variability occuring among living organisms and affecting all species of animals and plants, their genetics and their environment. Biological diversity of plants also relies on the chemical diversity deriving from their specialized metabolites which possess a wide range of different chemical structures as a result of plant evolution. They are responsible for the plant ecological properties and are required for the plant-environment interactions. In addition, many of them display important pharmacological properties. In the recent years, the growing interest in using plant metabolites to treat diseases in humans and animals and the high request of health products originating from natural sources rather than synthetic has revived the research on plant biodiversity to identify new bioactive molecules. Based on our studies on the chemical and biological characterization of rare or less studied plant species, the present paper aims to describe a selection of botanical species with phytopharmaceutical importance in order to highlight the chemical polymorphism deriving from their biodiversity along with its implications on bioactivity.