植物生长调节剂的研究及应用进展

植物生长调节剂是合成植物激素,其可以调节植物的代谢和生理功能,并且已广泛用于农业、林业和其他领域。而植物生长调节剂本身存在的毒副作用所引起的安全问题也不容忽视,在使用调节剂时应保证其安全性和有效性。文章概述了植物生长调节剂的种类、作用功效、国内外植物生长剂的研究和应用情况及在使用中存在的问题,分析了调节剂药效的影响因素,就植物生长调节剂的进一步应用提出了建议,进行了展望,并对其应用于生态修复领域的可行性进行了分析。植物生长调节剂在使用时应注意:(1)适时适量;(2)多种药型谨慎搭配,科学调控植物生长剂的使用;(3)植物生长调节剂不能随意与农药搭配以避免不良反应的发生。     

Ethylene and vegetative development

The past decade has witnessed a tremendous increase in our understanding of the role of ethylene in plant development. Genes encoding enzymes of the ethylene biosynthesis pathway have been isolated, allowing the manipulation of endogenous ethylene levels in intact plants. In parallel, a collection of ethylene mutants was obtained by using a simple response assay. This resulted in the identification of several genes involved in ethylene signal transduction. The data obtained using these new tools have allowed long-standing hypotheses to be tested, while gaining novel insight into the function of ethylene in development. Recent molecular evidence supported the existence of an intense hormonal cross-talk during plant growth. Numerous processes are controlled by ethylene in a close interaction with auxin, and often it was impossible to differentiate between auxin and ethylene effects. Molecular-genetic tools are now allowing the dissection of these interactions. Ethylene does not seem essential for many developmental processes. Nevertheless, it is of crucial importance for survival in most species as it occupies a key position in the developmental response mechanisms of plants under mechanical stress.     

Statistical evaluation of field and laboratory investigations into applied growth regulator effects: An editorial comment

Statistical aspects of a field and laboratory investigation involving the use of plant growth regulators are described. The design and recording of a field trial on carrots are discussed, with special reference to those points where compromise is necessary between the ideal statistical arrangement and the constraints involved in a practical field trial. The results of the field trial were analysed in detail to examine the assumptions underlying the statistical methods used, and these assumptions were shown to be satisfied.The laboratory investigation included a comparison of different methods of taking samples for sugar determinations. The standard method of bulking samples from different roots was as satisfactory in practice as the more laborious method of sampling individual roots. There was more variation between samples than between different determinations on the same sample.The consequences of these results are discussed, not only in terms of this trial but also for what might be expected in other trials with plant growth regulators. The advantages of close collaboration between plant physiologist and statistician are emphasised. Editorial note: This paper has been prepared to assist potential contributors working on applied aspects of plant growth regulators. This has been inspired by the fact that a number of submitted papers dealing with growth regulator field experimentation have been unacceptable, not because of the basic rationale, but because the experimental design has not been sound enough to support the conclusions reached.     

Plant hormones and plant growth regulators in plant tissue culture

Summary This is a short review of the classical and new, natural and synthetic plant hormones and growth regulators (phytohormones) and highlights some of their uses in plant tissue culture. Plant hormones rarely act alone, and for most processes— at least those that are observed at the organ level—many of these regulators have interacted in order to produce the final effect. The following substances are discussed: (a) Classical plant hormones (auxins, cytokinins, gibberellins, abscisic acid, ethylene and growth regulatory substances with similar biological effects. New, naturally occurring substances in these categories are still being discovered. At the same time, novel structurally related compounds are constantly being synthesized. There are also many new but chemically unrelated compounds with similar hormone-like activity being produced. A better knowledge of the uptake, transport, metabolism, and mode of action of phytohormones and the appearance of chemicals that inhibit synthesis, transport, and action of the native plant hormones has increased our knowledge of the role of these hormones in growth and development. (b) More recently discovered natural growth substances that have phytohormonal-like regulatory roles (polyamines, oligosaccharins, salicylates, jasmonates, sterols, brassinosteroids, dehydrodiconiferyl alcohol glucosides, turgorins, systemin, unrelated natural stimulators and inhibitors), as well as myoinositol. Many of these growth active substances have not yet been examined in relation to growth and organized developmentin vitro.     

Microarray and proteomic analysis of brassinosteroid- and gibberellin-regulated gene and protein expression in rice

Brassinosteroid (BR) and gibberellin (GA) are two groups of plant growth regulators essential for normal plant growth and development. To gain insight into the molecular mechanism by which BR and GA regulate the growth and development of plants, especially the monocot plant rice, it is necessary to identify and analyze more genes and proteins that are regulated by them. With the availability of draft sequences of two major types, japonica and indica rice, it has become possible to analyze expression changes of genes and proteins at genome scale. In this review, we summarize rice functional genomic research by using microarray and proteomic approaches and our recent research results focusing on the comparison of cDNA microarray and proteomic analyses of BR- and GA-regulated gene and protein expression in rice. We believe our findings have important implications for understanding the mechanism by which BR and GA regulate the growth and development of rice.     

Advances in upstream players of cytokinin phosphorelay: receptors and histidine phosphotransfer proteins

Cytokinins are a class of plant hormones that have been linked to numerous growth and developmental aspects in plants. The cytokinin signal is perceived by sensor histidine kinase receptors and transmitted via histidine phosphotransfer proteins (HPts) to downstream response regulators. Since their discovery, cytokinin receptors have been a focus of interest for many researchers. Ongoing research on these transmembrane receptors has greatly broadened our knowledge in terms of cytokinin–receptor interaction, receptor specificity, receptor cellular localization, and receptor functions in cytokinin related growth and developmental processes. This review focuses on the recent advances on the cytokinin receptors and HPt proteins in Arabidopsis.     

Phytochrome coordinates Arabidopsis shoot and root development

The phytochrome family of photoreceptors are potent regulators of plant development, affecting a broad range of responses throughout the plant life cycle, including hypocotyl elongation, leaf expansion and apical dominance. The plant hormone auxin has previously been linked to these phytochrome-mediated responses; however, these studies have not identified the molecular mechanisms that underpin such extensive phytochrome and auxin cross-talk. In this paper, we show that phytochrome regulates the emergence of lateral roots, at least partly by manipulating auxin distribution within the seedling. Thus, shoot-localized phytochrome is able to act over long distances, through manipulation of auxin, to regulate root development. This work reveals an important role for phytochrome as a coordinator of shoot and root development, and provides insights into how phytochrome is able to exert such a powerful effect on growth and development. This new link between phytochrome and auxin may go some way to explain the extensive overlap in responses mediated by these two developmental regulators.     

A matter of size: developmental control of organ size in plants

The intrinsic size of plant organs is determined by developmental signals, yet the molecular and genetic mechanisms that control organ size are largely unknown. Ongoing functional analysis of Arabidopsis genes is defining important regulators involved in these mechanisms. Key features of this control are the coordinated activation of growth and cell division by growth regulators and the maintenance of meristematic competence by the ANT gene, which acts as an organ-size checkpoint. Alterations of genome size by polyploidization and endoreduplication can reset this checkpoint by ploidy-dependent, epigenetically regulated differential gene expression. In addition, the regulation of polarized growth and phytohormone signaling also affect final organ size. These findings reveal unique aspects of plant organ-size control that are distinct from animal organ-size control.     

A critical review on natural compounds interacting with the plant plasma membrane H+-ATPase and their potential as biologicals in agriculture

The plant plasma membrane (PM) H⁺-ATPase is an essential enzyme controlling plant growth and development. It is an important factor in response to abiotic and biotic stresses and is subject to tight regulation. We are in demand for new sustainable natural growth regulators and as a key enzyme for regulation of transport into the plant cell the PM H⁺-ATPase is a potential target for these. In this review, we have evaluated the known non-protein natural compounds with regulatory effects on the PM H⁺-ATPase, focusing on their mechanism of action and their potential as biologicals/growth regulators in plant production of future sustainable agriculture.     

Interactions between plant hormones and thiol-related heavy metal chelators

Upon toxic metal stress numerous defence mechanisms have been induced, including the synthesis of metal-binding ligands and plant hormones or plant growth regulators in plants. As several elements in the promoter region of the heavy metal-responsive genes can be activated by plant hormones and growth regulators, understanding and revealing possible and special relationships between these regulator compounds and the metal chelator phytochelatins, which are in the first line of heavy metal defence mechanism is of great important. Phytochelatins are synthetized from glutathione and have a structure of [(γ-Glu-Cys)_n]-Gly, where n is the number of repetition of the (γ-Glu-Cys) units. Evidences for the role of PCs in heavy metal tolerance are very strong; however, little information is available on how plant growth regulators influence the phytochelatin synthesis at molecular or even gene expression level. In the present review we provide an overview of the role and synthesis of phytochelatins in metal-tolerance mechanism from a new point of view, i.e. their relation to the plant growth regulator molecules, with special regard also on those cases, when close direct relationship exists because of the partly overlapped synthesis pathways of plant growth regulators and glutathione/phytochelatins.     

Mix of trinexapac-ethyl and nitrogen application to reduce upland rice plant height and increase yield

Plant Growth Regulation - Techniques to increase grain production such as nitrogen fertilization and plant growth regulators are essential to enable and enhance rice yield. Therefore, our goal was...     

Plant growth regulators and virus infection: A critical review

Virus infection can severely inhibit plant growth and distort development. This article reviews changes in plant growth regulator metabolism caused by infection. In general, virus infection decreases auxin and gibberellin concentrations and increases abscisic acid concentration. Ethylene production is stimulated in necrotic or chlorotic reactions to infection, but not where the virus spreads systemically without necrosis. While these broad trends are true for most host-virus combinations studied, several situations are recorded where the virus had other effects on growth substance concentration. Cytokinin changes do not show any common pattern: both increases and decreases after infection have been reported.The extent to which virus-induced changes in growth substance concentration could be responsible for observed alterations in host growth and development is discussed. While changes in abscisic acid, gibberellin and ethylene production seem potentially important, the experimental evidence does not provide conclusive proof for control of growth by these changes.The numerous investigations of effects of exogenous regulators on virus multiplication and pathogenesis are reviewed. Different regulators, or the same regulator applied at different times or concentrations, had very diverse effects, and in some cases did significantly alter virus multiplication and pathogenesis. However, such studies seem to have yielded disappointingly little understanding of the biochemistry of the host-virus interaction, and the possible involvement of growth substances in this.Possible uses of plant growth regulators in chemotherapy of virus disease, and their possible involvement in natural or induced resistance mechanisms are discussed.     

Involvement of Plant Hormones and Plant Growth Regulators on in vitro Somatic Embryogenesis

In spite of the importance attained by somatic embryogenesis and of the many studies that have been conducted on this developmental process, there are still many aspects that are not fully understood. Among those features, the involvement of plant hormones and plant growth regulators on deTermining the conversion of somatic onto embryogenic tissues, and on allowing progression and maturation of somatic embryos, are far away from being completely comprehended. Part of these difficulties relies on the frequent appearance of contradictory results when studying the effect of a particular stimulus over a specific stage in somatic embryogenesis. Recent progress achieved on understanding the interaction between exogenously added plant growth regulators over the concentration of endogenous hormones, together with the involvement of sensitivity of the tissues to particular hormone groups, might help clarifying the occurrence of divergent patterns in somatic embryogenesis, and in tissue culture in general. The aspects described above, emphasizing on the effect of the concentration of plant hormones and of the addition of plant growth regulators during the different phases of somatic embryogenesis, will be reviewed in this paper. Citations will be limited to review articles as much as possible and to individual articles only in those cases in which very specific or recent information is presented.     

三种植物生长调节剂对降香黄檀种子发芽的影响

采用三种植物生长调节剂GA3、IBA和6-BA不同浓度按正交设计方法,搭配处理组合,对降香黄檀种子进行处理,通过对种子发芽率、发芽势和发芽指数指标的测定,研究不同浓度的植物生长调节剂对珍贵用材树种降香黄檀种子萌发的影响。结果表明:3种植物生长调节剂浸种对降香黄檀种子萌发以6-BA的促进效果较好,GA3次之,而IBA对降香黄檀种子的发芽促进作用不明显,以处理组合6-BA50mg/L6h为最优,显著提高种子的萌发率。     

Pre-procambial cells are niches for pluripotent and totipotent stem-like cells for organogenesis and somatic embryogenesis in the peach palm: a histological study

The direct induction of adventitious buds and somatic embryos from explants is a morphogenetic process that is under the influence of exogenous plant growth regulators and its interactions with endogenous phytohormones. We performed an in vitro histological analysis in peach palm (Bactris gasipaes Kunth) shoot apexes and determined that the positioning of competent cells and their interaction with neighboring cells, under the influence of combinations of exogenously applied growth regulators (NAA/BAP and NAA/TDZ), allows the pre-procambial cells (PPCs) to act in different morphogenic pathways to establish niche competent cells. It is likely that there has been a habituation phenomenon during the regeneration and development of the microplants. This includes promoting the tillering of primary or secondary buds due to culturing in the absence of NAA/BAP or NAA/TDZ after a period in the presence of these growth regulators. Histological analyses determined that the adventitious roots were derived from the dedifferentiation of the parenchymal cells located in the basal region of the adventitious buds, with the establishment of rooting pole, due to an auxin gradient. Furthermore, histological and histochemical analyses allowed us to characterize how the PPCs provide niches for multipotent, pluripotent and totipotent stem-like cells for vascular differentiation, organogenesis and somatic embryogenesis in the peach palm. The histological and histochemical analyses also allowed us to detect the unicellular or multicellular origin of somatic embryogenesis. Therefore, our results indicate that the use of growth regulators in microplants can lead to habituation and to different morphogenic pathways leading to potential niche establishment, depending on the positioning of the competent cells and their interaction with neighboring cells. KEY MESSAGE: Our results indicate that the use of growth regulators in microplants can lead to habituation and to different morphogenic pathways leading to potential niche establishment, depending on the positioning of the competent cells and their interaction with neighboring cells.