zeatin-riboside and indoleacetic-acid

The photoperiod marks a varied set of behaviors in plants, including bulbing. Bulbing is controlled by inner signals, which can be stimulated or subdued by the ecological environment. It had been broadly stated that phytohormones control the plant development, and they are considered to play a significant part in the bulb formation. The past decade has witnessed significant progress in understanding and advancement about the photoperiodic initiation of bulbing in plants. A noticeable query is to what degree the mechanisms discovered in bulb crops are also shared by other species and what other qualities are also dependent on photoperiod. The FLOWERING LOCUS T (FT) protein has a role in flowering; however, the FT genes were afterward reported to play further functions in other biological developments (e.g., bulbing). This is predominantly applicable in photoperiodic regulation, where the FT genes seem to have experienced significant development at the practical level and play a novel part in the switch of bulb formation in Alliums. The neofunctionalization of FT homologs in the photoperiodic environments detects these proteins as a new class of primary signaling mechanisms that control the growth and organogenesis in these agronomic-related species. In the present review, we report the underlying mechanisms regulating the photoperiodic-mediated bulb enlargement in Allium species. Therefore, the present review aims to systematically review the published literature on the bulbing mechanism of Allium crops in response to photoperiod. We also provide evidence showing that the bulbing transitions are controlled by phytohormones signaling and FT-like paralogues that respond to independent environmental cues (photoperiod), and we also show that an autorelay mechanism involving FT modulates the expression of the bulbing-control gene. Although a large number of studies have been conducted, several limitations and research gaps have been identified that need to be addressed in future studies.

Topics: Abscisic Acid; Allium; Gene Expression Regulation, Plant; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Photoperiod; Plant Growth Regulators; Plant Roots

Adventitious root (AR) formation is a bottleneck for the mass propagation of apple rootstocks, and water stress severely restricts it. Different hormones and sugar signaling pathways in apple clones determine AR formation under water stress, but these are not entirely understood. To identify them, GL-3 stem cuttings were cultured on polyethylene glycol (PEG) treatment. The AR formation was dramatically decreased compared with the PEG-free control (CK) cuttings by increasing the endogenous contents of abscisic acid (ABA), zeatin riboside (ZR), and methyl jasmonate (JA-me) and reducing the indole-3-acetic acid (IAA) and gibberellic acid 3 (GA3) contents. We performed a transcriptomic analysis to identify the responses behind the phenotype. A total of 3204 differentially expressed genes (DEGs) were identified between CK and PEG, with 1702 upregulated and 1502 downregulated genes. Investigation revealed that approximately 312 DEGs were strongly enriched in hormone signaling, sugar metabolism, root development, and cell cycle-related pathways. Thus, they were selected for their possible involvement in adventitious rooting. However, the higher accumulation of ABA, ZR, and JA-me contents and the upregulation of their related genes, as well as the downregulation of sugar metabolism-related genes, lead to the inhibition of ARs. These results indicate that AR formation is a complicated biological process chiefly influenced by multiple hormonal signaling pathways and sugar metabolism. This is the first study to demonstrate how PEG inhibits AR formation in apple plants.

Topics: Abscisic Acid; Acetates; Cyclopentanes; Dehydration; Gene Expression Profiling; Gene Expression Regulation, Plant; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Malus; Oxylipins; Plant Proteins; Plant Roots; Polyethylene Glycols; Sequence Analysis, RNA

Efficient organogenesis induction in eggplant (Solanum melongena L.) is required for multiple in vitro culture applications. In this work, we aimed at developing a universal protocol for efficient in vitro regeneration of eggplant mainly based on the use of zeatin riboside (ZR). We evaluated the effect of seven combinations of ZR with indoleacetic acid (IAA) for organogenic regeneration in five genetically diverse S. melongena and one S. insanum L. accessions using two photoperiod conditions. In addition, the effect of six different concentrations of indolebutyric acid (IBA) in order to promote rooting was assessed to facilitate subsequent acclimatization of plants. The ploidy level of regenerated plants was studied.. In a first experiment with accessions MEL1 and MEL3, significant (p < 0.05) differences were observed for the four factors evaluated for organogenesis from cotyledon, hypocotyl and leaf explants, with the best results obtained (9 and 11 shoots for MEL1 and MEL3, respectively) using cotyledon tissue, 16 h light / 8 h dark photoperiod conditions, and medium E6 (2 mg/L of ZR and 0 mg/L of IAA). The best combination of conditions was tested in the other four accessions and confirmed its high regeneration efficiency per explant when using both cotyledon and hypocotyl tissues. The best rooting media was R2 (1 mg/L IBA). The analysis of ploidy level revealed that between 25 and 50% of the regenerated plantlets were tetraploid.. An efficient protocol for organogenesis of both cultivated and wild accessions of eggplant, based on the use of ZR, is proposed. The universal protocol developed may be useful for fostering in vitro culture applications in eggplant requiring regeneration of plants and, in addition, allows developing tetraploid plants without the need of antimitotic chemicals.

Topics: Cotyledon; Hypocotyl; In Vitro Techniques; Indoleacetic Acids; Isopentenyladenosine; Organogenesis, Plant; Plant Growth Regulators; Plant Leaves; Plant Shoots; Ploidies; Regeneration; Solanum melongena

In Brassica napus, pod number and pod density are critical factors to determine seed yield. Although the pod density is an essential yield trait, the regulation of yield formation in oil crops, as well as the genetic and molecular mechanisms, are poorly understood. In this study, we characterized a rapeseed high-density pod mutant (dpt247) from composite hybridization. To shed some light on the nature of this mutation, it was investigated morphologically, anatomically, physiologically, genetically and transcriptomically. The mutant plant showed noticeable phenotypic differences in comparison with the control plant, including reduced plant height and primary branch length, decreased number of primary branches, significantly increased number of pod on the main inflorescence, and more compact pod distribution. Besides, the mutant had higher levels of indole-3-acetic acid (IAA) and zeatin riboside (ZR) in the shoot apical meristem (SAM). The dense pod trait was controlled by two major recessive genes identified in the segregating genetic populations of GRE501 and dpt247. RNA sequencing indicated genes participated in auxin, cytokinin and WUS/CLV signalling pathway in dpt247 were more active in the mutant. These results provide important information for understanding the regulation of yield formation and high yield breeding in rapeseed.

Topics: Brassica napus; Cell Division; Chromosomes, Plant; Gene Expression Regulation, Plant; Genes, Plant; Genes, Recessive; Indoleacetic Acids; Isopentenyladenosine; Phenotype; Plant Shoots; Seeds; Sequence Analysis, RNA; Transcriptome

In this study, we investigated the changes in the distribution and regulation of endogenous hormones in Phyllostachys edulis 'Pachyloen' during bamboo shooting. Enzyme-linked immunosorbent assay was used to measure the mass fractions of indole-3-acetic acid (IAA), gibberellic acid (GA), zeatin riboside (ZR), and abscisic acid (ABA) in rhizomes, shoots, and maternal bamboo organs during shoot sprouting, shoot growth, and new-bamboo formation. Measurements were compared among bamboo parts and developmental periods. The overall mass fractions of IAA and ABA were significantly higher than those of ZR and GA, driven by differences among bamboo parts and developmental periods. The abundance of each endogenous hormone varied among bamboo parts and developmental periods. During bamboo shooting, ABA had the highest mass fraction in all bamboo parts sampled, followed by IAA, GA, and ZR. Among bamboo parts, rhizomes had more IAA, ZR, and GA than the other parts, but significantly less ABA. Winter shoots had higher ZR: IAA and GA: IAA ratios than rhizomes and maternal bamboo organs. During shoot growth, ABA was the most abundant hormone in rhizomes and maternal bamboo organs, followed by IAA, ZR, and GA. In contrast, IAA was the most abundant hormone in spring shoots, followed by ABA, ZR, and GA. Maternal bamboo organs had a significantly higher ZR: GA ratio, and significantly lower IAA: ABA, ZR: ABA, and GA: ABA ratios than rhizomes. Spring shoots had significantly higher IAA: ABA, ZR: ABA, and GA: ABA ratios than rhizomes and maternal bamboo organs; significantly higher ZR mass fractions, and ZR: GA and ZR: IAA ratios and significantly lower ABA mass fractions than rhizomes; and significantly higher GA: IAA ratio than maternal bamboo organs. During new-bamboo formation, ABA was the most abundant hormone in rhizomes, winter shoots, and maternal bamboo organs, followed by IAA, ZR, and GA. Maternal bamboo organs had significantly lower IAA mass fractions and significantly higher ABA mass fractions than rhizomes and new bamboo tissue. IAA and ABA abundances exhibited an inverse relationship in rhizomes and maternal bamboo organs. GA: ABA and GA: IAA ratios decreased gradually and other hormone ratios exhibited parabolic trends over the bamboo-shooting period, with the highest ratios observed in new bamboo tissues. Overall, the coordination or antagonism among endogenous hormones plays a key regulatory role in bamboo shoot growth. The formation of thick walls in P. edul

Topics: Abscisic Acid; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Plant Growth Regulators; Plant Shoots; Poaceae; Rhizome

Excessive tillage and soil compaction threaten the sustainable farmlands in the Huang-Huai-Hai Plains of China. Our study explores tillage practices to improve soil and root ecology and promote productivity in the winter wheat fields. We tested the impact of plowing, rotary, strip rotary tillage and strip rotary tillage with a two-year subsoiling interval (SRS) on wheat yield and root quality. SRS decreased soil bulk density compared with other treatments, resulting in lower soil penetration resistance. Root morphology and weight density decreased with the increased soil depth and was higher in SRS. Moreover, SRS increased the indoleacetic acid and trans zeatin riboside levels corresponding to greater TTC reduction activities, the total and active absorption root area. SRS increased the superoxide dismutase and catalase activities and soluble protein concentration and decreased the malondialdehyde concentration. The first two factors extracted using 11 root attributes in various soil layers through principal component analysis were selected as the integrated indicators for the minimum data set, and their integrated score was calculated to quantify the root quality. Our study suggests that SRS could significantly improve root morphology and enhance the root activity in subsoil layers, thus, delaying root senescence and increasing winter wheat yield.

Topics: Agriculture; Catalase; China; Crops, Agricultural; Farms; Humans; Indoleacetic Acids; Isopentenyladenosine; Malondialdehyde; Plant Growth Regulators; Plant Proteins; Plant Roots; Principal Component Analysis; Soil; Superoxide Dismutase; Triticum; Water

Topics: Abscisic Acid; Indoleacetic Acids; Isopentenyladenosine; Pinus; Plant Roots; Rejuvenation; Trees

Low light is a type of abiotic stress that seriously affects plant growth and production efficiency. We investigated the response mechanisms of summer maize to low light by measuring the changes in endogenous hormones in the grains and during grain filling in summer maize at different light intensities to provide a theoretical basis for the production and management of summer maize under light stress. We applied different light treatments in a field experiment as follows: S, shading from tassel stage (VT) to maturity stage (R6); CK, natural lighting in the field; and L, increasing light from VT to R6. The shading level was 60%, and the maximum illumination intensity of the increasing light treatment on cloudy days was 1600-1800 μmol m

Topics: Edible Grain; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Light; Plant Growth Regulators; Seasons; Zea mays

Stay-green, a key trait of wheat, can not only increase the yield of wheat but also its resistance to heat stress during active photosynthesis. Cytokinins are the most potent general coordinator between the stay-green trait and senescence. The objectives of the present study were to identify and assess the effects of cytokinins on the photosynthetic organ and heat resistance in wheat. Two winter wheat cultivars, Wennong 6 (a stay-green cultivar) and Jimai 20 (a control cultivar), were subjected to heat stress treatment from 1 to 5 days after anthesis (DAA). The two cultivars were sprayed daily with 10 mg L-1 of 6-benzylaminopurine (6-BA) between 1 and 3 DAA under ambient and elevated temperature conditions. We found that the heat stress significantly decreased the number of kernels per spike and the grain yield (P < 0.05). Heat stress also decreased the zeatin riboside (ZR) content, but increased the gibberellin (GA3), indole-3-acetic acid (IAA), and abscisic acid (ABA) contents at 3 to 15 DAA. Application of 6-BA significantly (P < 0.05) increased the grain-filling rate, endosperm cell division rate, endosperm cell number, and 1,000-grain weight under heated condition. 6-BA application increased ZR and IAA contents at 3 to 28 DAA, but decreased GA3 and ABA contents. The contents of ZR, ABA, and IAA in kernels were positively and significantly correlated with the grain-filling rate (P < 0.05), whereas GA3 was counter-productive at 3 to 15 DAA. These results suggest that the decrease in grain yield under heat stress was due to a lower ZR content and a higher GA3 content compared to that at elevated temperature during the early development of the kernels, which resulted in less kernel number and lower grain-filling rate. The results also provide essential information for further utilization of the cytokinin substances in the cultivation of heat-resistant wheat.

Topics: Abscisic Acid; Benzyl Compounds; Cytokinins; Gibberellins; Hot Temperature; Indoleacetic Acids; Isopentenyladenosine; Plant Growth Regulators; Purines; Triticum

The cytokinin 6-benzylaminopurine (6-BAP) influences the embryogenic capacity of the tissues of Picea balfouriana during long subculture (after 3 months). Tissues that proliferate in 3.6 and 5 µM 6-BAP exhibit the highest and lowest embryogenic capacity, respectively, generating 113 ± 6 and 23 ± 3 mature embryos per 100 mg of tissue. In this study, a comparative transcriptomic and proteomic approach was applied to characterize the genes and proteins that are differentially expressed among tissues under the influence of different levels of 6-BAP. A total of 51 375 unigenes and 2617 proteins were obtained after quality filtering. There were 2770 transcripts for proteins found among these unigenes. Gene ontology (GO) analysis of the differentially expressed unigenes and proteins showed that they were involved in cell and binding activity and were enriched in ribosome and glutathione metabolism pathways. Ribosomal proteins, glutathione S-transferase proteins, germin-like proteins and calmodulin-independent protein kinases were up-regulated in the embryogenic tissues with the highest embryogenic ability (treated with 3.6 µM 6-BAP), which was validated via quantitative real-time polymerase chain reaction (qRT-PCR) analysis, and these proteins might serve as molecular markers of embryogenic ability. Data are available via Sequence Read Archive (SRA) and ProteomeXchange with identifier SRP042246 and PXD001022, respectively.

Topics: Benzyl Compounds; Gene Expression Profiling; Indoleacetic Acids; Isopentenyladenosine; Kinetin; Molecular Sequence Annotation; Picea; Plant Somatic Embryogenesis Techniques; Proteome; Purines; Sequence Analysis, RNA; Transcriptome

The effect of salinity on brown seeds/black seeds ratio, seed weight, endogenous hormone concentrations, and germination of brown and black seeds in the euhalophyte Suaeda salsa was investigated. The brown seeds/black seeds ratio, seed weight of brown and black seeds and the content of protein increased at a concentration of 500 mM NaCl compared to low salt conditions (1 mM NaCl). The germination percentage and germination index of brown seeds from plants cultured in 500 mM NaCl were higher than those cultured in 1 mM NaCl, but it was not true for black seeds. The concentrations of IAA (indole-3-acetic acid), ZR (free zeatin riboside) and ABA (abscisic acid) in brown seeds were much greater than those in black seeds, but there were no differences in the level of GAs (gibberellic acid including GA1 and GA3) regardless of the degree of salinity. Salinity during plant culture increased the concentration of GAs, but salinity had no effect on the concentrations of the other three endogenous hormones in brown seeds. Salinity had no effect on the concentration of IAA but increased the concentrations of the other three endogenous hormones in black seeds. Accumulation of endogenous hormones at different concentrations of NaCl during plant growth may be related to seed development and to salt tolerance of brown and black S. salsa seeds. These characteristics may help the species to ensure seedling establishment and population succession in variable saline environments.

Topics: Chenopodiaceae; Indoleacetic Acids; Isopentenyladenosine; Salinity; Salt Tolerance; Seeds; Sodium Chloride

A pot experiment was conducted to analyze the effects of Funneliformis mosseae on endogenous hormones and photosynthesis in leaves of Sorghum haipense grown in soil contaminated with Cs. The results showed that Cs stress profoundly promoted abscisic acid (ABA) synthesis and decreased indoleacetic acid (IAA), gibberellin (GA), and zeatin riboside (ZR) contents in Sorghum haipense leaves, which led to significant increases in ABA/IAA and ABA/GA ratio. However, F. mosseae inoculation reduced the IAA, GA and ZR decreasing amplitudes and the ABA increasing range, which would maintain the ratio of ABA/IAA, ABA/GA and ABA/(IAA+GA+ ZR). Radionuclide cesium pollution significantly reduced the photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr), which caused the plant photosynthetic efficiency to be lower than control. F. mosseae could alleviate the negative effect caused by cesium pollution on plant photosynthetic efficiency. It is suggested that to improve the efficiency of photosynthesis and anabolin, enhance plant tolerance and improve bioremediation efficiency, arbuscular mycorrhizal fungi (AMF) such as F. mosseae could be introduced into the field of phytoremediation in radionuclide contaminated soils.

Topics: Abscisic Acid; Cesium; Gibberellins; Glomeromycota; Indoleacetic Acids; Isopentenyladenosine; Mycorrhizae; Photosynthesis; Plant Growth Regulators; Plant Leaves; Soil Microbiology; Soil Pollutants; Sorghum

In order to investigate the influence of different barnyardgrass species on rice yield and physiological characteristics of rice, two rice cultivars, Liangyoupeijiu (an indica hybrid cultivar) and Nanjing 9108 (a japonica cultivar) , were employed to co-culture with four barnyardgrass species during the period from transplanting to maturity under alternate wetting and moderate drying ir- rigation condition. The treatments were separately designed as follow: weed free ( control) , rice with Echinochloa crusgalli var. mitis (T1), rice with E. crusgalli (T2), rice with E. crusgali var. zelayensis (T3) and rice with E. colonum (T4). The results showed that T1, T2, T3 and T4 treatments reduced the Liangyoupeijiu yield by 13.8%, 10.6%, 23.8% and 0.5%, but the corresponding yield loss of Nanjing 9108 could reach up to 45.5%, 36.9%, 60.7% and 15.1%, respectively. The results above showed that T1, T2 and T3 treatments all significantly reduced grain yield, and T4 treatment only reduced grain yield for Nanjing 9108 but not for Liangyoupeijiu. All treatments elevated malondialehyde contents of rice leaf, but the activities of peroxidase, catalase, superoxide dimutase, dry matter accumulation in maturity stage, root oxidation activities and contents of indole-3-acetic acid as well as zeatin + zeatin riboside in roots during rice grain filling stage were all decreased. The influence degree of four barnyardgrass against physiological indices of rice had the order of T3 > T1 >T2 > T4. It showed that the reductions in enzyme activities of antioxidant system, root oxidation activities, contents of indole-3-acetic acid, zeatin + zeatin riboside during grain filling stage and accumulation of dry matter in maturity as well as increase in contents of malondialehyde of rice during grain filling stage might be important reasons for grain yield reduction when grew with barnyardgrass.

Topics: Agricultural Irrigation; Desiccation; Echinochloa; Indoleacetic Acids; Isopentenyladenosine; Oryza; Plant Leaves; Plant Roots; Seeds; Wettability

Papaya fruits (Carica papaya L. cv 'Sui you 2') harvested with < 5% yellow surface at the blossom end were fumigated with 60 microL/L of nitric oxide for 3 h and then stored at 20 degrees C with 85% relative humility for 20 days. The effects of nitric oxide treatment on ethylene production rate, the activities of cell wall softening related enzymes including polygalacturonase, pectin methyl esterase, pectate lyase and cellulase and the levels of hormones including indole acetic acid, abscisic acid, gibberellin and zeatin riboside were examined. The results showed that papaya fruits treated with nitric oxide had a significantly lower rate of ethylene production and a lesser loss of firmness during storage. A decrease in polygalacturonase, pectin methyl esterase, pectate lyase and cellulase activities was observed in nitric oxide treated fruit. In addition, the contents of indole acetic acid, abscisic acid and zeatin riboside were reduced in nitric oxide treated fruit, but no significant reduction in the level of gibberellin was found. These results indicate that nitric oxide treatment can effectively delay the softening and ripening of papaya fruit, likely via the regulation of cell wall softening related enzymes and certain hormones.

Topics: Abscisic Acid; Carboxylic Ester Hydrolases; Carica; Cell Wall; Cellulase; Ethylenes; Food Storage; Free Radical Scavengers; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Nitric Oxide; Plant Growth Regulators; Polygalacturonase; Polysaccharide-Lyases

Fermentation broth and biomass from three strains of Botryodiplodia theobromae were characterized by high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) method, in order to quantify different phytohormones and to identify amino acid conjugates of jasmonic acid (JA) present in fermentation broths. A liquid-liquid extraction with ethyl acetate was used as sample preparation. The separation was carried out on a C18 reversed-phase HPLC column followed by analysis via ESI-MS/MS. The multiple reaction monitoring mode was used for quantitative measurement. For the first time, indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and JA were identified and quantified in the ethyl acetate extracts from the biomass, after the separation of mycelium from supernatant. The fermentation broths showed significantly higher levels of JA in relation to the other phytohormones. This is the first report of the presence of gibberellic acid, abscisic acid, salicylic acid and the cytokinins zeatin, and zeatin riboside in fermentation broths of Botryodiplodia sp. The presence of JA-serine and JA-threonine conjugates in fermentation broth was confirmed using HPLC-ESI tandem mass spectrometry in negative ionization mode, while the occurrence of JA-glycine and JA-isoleucine conjugates was evidenced with the same technique but with positive ionization. The results demonstrated that the used HPLC-ESI-MS/MS method was effective for analysing phytohormones in fermentation samples.

Topics: Abscisic Acid; Ascomycota; Chromatography, High Pressure Liquid; Cyclopentanes; Fermentation; Gibberellins; Indoleacetic Acids; Indoles; Isopentenyladenosine; Oxylipins; Plant Growth Regulators; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Zeatin

Organogenesis in peach (Prunus persica L. Batsch) and peach rootstocks (P. persica × Prunus dulcis) has been achieved and the action of the regeneration medium on 7 phytohormones, zeatin (Z), zeatin riboside (ZR), indole-3-acetic acid (IAA), abscisic acid (ABA), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), and jasmonic acid (JA), has been studied using High performance liquid chromatography - mass spectrometry (HPLC-MS/MS). Three scion peach cultivars, 'UFO-3', 'Flariba' and 'Alice Bigi', and the peach × almond rootstocks 'Garnem' and 'GF677' were cultured in two different media, Murashige and Skoog supplemented with plant growth regulators (PGRs) (regeneration medium) and without PGRs (control medium), in order to study the effects of the media and/or genotypes in the endogenous hormones content and their role in organogenesis. The highest regeneration rate was obtained with the peach × almond rootstocks and showed a lower content of Z, IAA, ABA, ACC and JA. Only Z, ZR and IAA were affected by the action of the culture media. This study shows which hormones are external PGRs-dependent and what is the weight of the genotype and hormones in peach organogenesis that provide an avenue to manipulate in vitro organogenesis in peach.

Topics: Abscisic Acid; Amino Acids, Cyclic; Cyclopentanes; Cytokinins; Indoleacetic Acids; Isopentenyladenosine; Organogenesis; Oxylipins; Plant Growth Regulators; Prunus; Salicylic Acid; Zeatin

A method for the simultaneous determination of indole-3-acetic acid, N6-(2-isopentenyl) adenosine, N6-(2-isopentenyl) adenine, trans-zeatin riboside, zeatin, strigolactone, abscisic acid, salicylic acid, gibberellin A3 and jasmonic acid in five different parts of main branch, lateral branch, primary leaf, secondary leaf and stem of Sargasum fusiforme (Hary.) Seichell was established by high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-TQMS). The samples were extracted with methanol/water/formic acid (15 : 4 :1, v/v/v) (containing 0.5% 2, 6-di-tert-butyl-4-methylphenol, BHT) after vacuum freeze-drying. The separation was performed on a Hypersil Gold C18 column by using methanol and water as mobile phases with gradient elution. The analytes were detected by tandem mass spectrometry in selected reaction monitoring (SRM) mode. The electrospray ionization (ESI) source was used for the quantitative analysis in the positive mode or negative mode. Under the optimized conditions, the correlation coefficients (r) of the ten phytohormones were from 0. 9989 to 1. 0000 in the linear ranges. The detection limits of the ten phytohormones were 0. 001 2-4. 651 2 μ/L. The average recoveries were 72. 24% -91. 31% with the relative standard deviations not more than 6. 59%. In the five parts of fresh Sargasum fusiforme (Hary.) Seichell samples, the contents of the ten phytohormones were from not detected to 4 041. 431 ng/g. This method has good sensitivity, precision, recovery, and can be used to simultaneously determine the phytohormones.

Topics: Abscisic Acid; Chromatography, High Pressure Liquid; Cyclopentanes; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Oxylipins; Plant Growth Regulators; Reproducibility of Results; Sargassum; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

The grazing tolerance mechanism of ryegrass was investigated by examining the effects of roots on leaves under frequent defoliation. The study consisted of four treatments: (1) with root breaking and cytokinin spraying, (2) root breaking without cytokinin spraying, (3) cytokinin spraying with no root breaking, and (4) no root breaking and no cytokinin spraying. Results showed that root breaking or frequent defoliation inhibited the ryegrass regrowth, which resulted in low biomass of the newly grown leaves and roots, as well as low soluble carbohydrate content and xylem sap quantity in the roots. Spraying with exogenous cytokinin promoted the increase in newly grown leaf biomass, but decreased root biomass, root soluble carbohydrate content, and root xylem sap quantity. Determination of gibberellic acid, indole-3-acetic acid, abscisic acid, and zeatin riboside (ZR) in roots, newly grown leaves, and stubbles showed that cytokinin is a key factor in ryegrass regrowth under frequent defoliation. Root breaking and frequent defoliation both decreased the ZR content in roots and in newly grown leaves, whereas spraying with exogenous cytokinin increased the ZR content in roots and in newly grown leaves. Therefore, cytokinin enhances the above ground productivity at the cost of root growth under frequent defoliation.

Topics: Abscisic Acid; Adaptation, Physiological; Biomass; Carbohydrate Metabolism; Cytokinins; Gibberellins; Herbivory; Indoleacetic Acids; Isopentenyladenosine; Lolium; Plant Growth Regulators; Plant Leaves; Plant Roots; Plant Shoots; Signal Transduction; Xylem

Pseudomonas fluorescens 6-8, a rhizosphere isolate previously shown to enhance root elongation of canola ( Brassica napus L.), was characterized for its ability to produce indole-3-acetic acid and cytokinins in pure culture and in the rhizosphere of canola under gnotobiotic conditions in comparison with the cytokinin-producing strain P. fluorescens G20-18 and its mutant CNT2. Strain 6-8 produced isopentenyl adenosine, zeatin riboside, and dihydroxyzeatin riboside at levels similar to those of G20-18, but only very low concentrations of indole-3-acetic acid. In a gnotobiotic assay canola inoculated with 6-8 and G20-18 had higher concentrations of isopentenyl adenosine and zeatin riboside in the rhizosphere and greater root length than the noninoculated control. The ability of strain 6-8 to colonize canola roots was assessed following transformation with the green fluorescent protein and inoculation onto canola seed in a gnotobiotic assay. Higher populations of strain 6-8 were observed on the proximal region of the root closest to the seed than on the mid and distal portions 9 days after seed inoculation. The ability of P. fluorescens 6-8 to produce cytokinins, colonize the roots of canola seedlings, and enhance root elongation may contribute to its ability to survive in the rhizosphere and may benefit seedling growth.

Topics: Animals; Brassica napus; Cytokinins; Germ-Free Life; Indoleacetic Acids; Isopentenyladenosine; Plant Growth Regulators; Plant Roots; Pseudomonas fluorescens; Rhizosphere; Seedlings; Seeds; Symbiosis

The physiological and anatomical attributes of haustoria tissues in hemi-parasitic Santalum album L. seedlings, growing on the potential host, Kuhnia rosmarnifolia Vent., were investigated before and after attachment to the host. Quantization of endogenous levels of indole-3-acetic acid (IAA), zeatin (Z), zeatin riboside (ZR), GA-like substances (GAs) and abscisic acid (ABA) was performed by HPLC. Histological preparations were used to characterize structural differences between pre- and post-attachment haustoria. The contents of GAs and ABA were higher in attached haustoria, with 3.61 and 3.50μgg(-1) fresh weight, respectively, and three times higher than in non-attached haustoria. Cytokinins, Z, ZR and IAA levels were also high, and their contents in attached haustoria increased 2.04-, 2.17-, and 2.82-fold more, respectively, than in non-attached haustoria. A high auxin-to-cytokinin ratio contributed to haustorial development of S. album. A numerous amount of starch in parenchyma cells around the meristematic region above the haustorial gland and the endophyte tissue of the post-attachment haustoria were reported in a Santalaceae member for the first time. Many lysosomes were present and large-scale digestion of host cells occurred at the interface between the parasite and host. The haustorial penetration in S. album into the host stele was suggested to be a function of mechanical force and enzymatic activity. Analysis of the endogenous hormone levels and the structural characters in S. album haustoria indicated that the haustoria were able to synthesize phytohormones, which appeared to be necessary for cell division and differentiation during haustorial development. These results suggest that endogenous hormones are involved in the haustorial development of S. album and in water and nutrient transport in the host-parasite association.

Topics: Abscisic Acid; Asteraceae; Gibberellins; Host-Pathogen Interactions; Indoleacetic Acids; Isopentenyladenosine; Mycorrhizae; Plant Growth Regulators; Plant Roots; Santalum; Seedlings; Zeatin

Pinus radiata D. Don is one of the most abundant species in the north of Spain. Knowledge of drought response mechanisms is essential to guarantee plantation survival under reduced water supply as predicted in the future. Tolerance mechanisms are being studied in breeding programs, because information on such mechanisms can be used for genotype selection. In this paper, we analyze the changes of leaf water potential, hydraulic conductance (K(leaf)), stomatal conductance and phytohormones under drought in P. radiata breeds (O1, O2, O3, O4, O5 and O6) from different climatology areas, hypothesizing that they could show variable drought tolerance. As a primary signal, drought decreased cytokinin (zeatin and zeatin riboside-Z + ZR) levels in needles parallel to K(leaf) and gas exchange. When Z + ZR decreased by 65%, indole-3-acetic acid (IAA) and abscisic acid (ABA) accumulation started as a second signal and increments were higher for IAA than for ABA. When plants decreased by 80%, Z + ZR and K(leaf) doubled their ABA and IAA levels, the photosystem II yield decreased and the electrolyte leakage increased. At the end of the drought period, less tolerant breeds increased IAA over 10-fold compared with controls. External damage also induced jasmonic acid accumulation in all breeds except in O5 (P. radiata var. radiata × var. cedrosensis), which accumulated salicylic acid as a defense mechanism. After rewatering, only the most tolerant plants recovered their K(leaf,) perhaps due to an IAA decrease and 1-aminocyclopropane-1-carboxylic acid maintenance. From all phytohormones, IAA was the most representative 'water deficit signal' in P. radiata.

Topics: Abscisic Acid; Adaptation, Physiological; Amino Acids, Cyclic; Breeding; Climate; Cyclopentanes; Droughts; Electrolytes; Genotype; Indoleacetic Acids; Isopentenyladenosine; Oxylipins; Photosynthesis; Photosystem II Protein Complex; Pinus; Plant Growth Regulators; Plant Leaves; Plant Stomata; Salicylic Acid; Signal Transduction; Spain; Stress, Physiological; Water; Zeatin

A variety of insect species induce galls on host plants. Several studies have implicated phytohormones in insect-induced gall formation. However, it has not been determined whether insects can synthesize phytohormones. It has also never been established that phytohormones function in gall tissues. Liquid chromatography and tandem mass spectrometry (LC/MS/MS) were used to analyse concentrations of endogenous cytokinins and the active auxin IAA in the gall-inducing sawfly (Pontania sp.) and its host plant, Salix japonica. Feeding experiments demonstrated the ability of sawfly larvae to synthesize IAA from tryptophan. Gene expression analysis was used to characterize hormonal signalling in galls. Sawfly larvae contain high concentrations of IAA and t-zeatin, and produce IAA from tryptophan. The glands of adult sawflies, the contents of which are injected into leaves upon oviposition and are involved in the initial stages of gall formation, contain an extraordinarily high concentration of t-zeatin riboside. Transcript levels of some auxin- and cytokinin-responsive genes are significantly higher in gall tissue than in leaves. The abnormally high concentration of t-zeatin riboside in the glands strongly suggests that the sawfly can synthesize cytokinins as well as IAA. Gene expression profiles indicate high levels of auxin and cytokinin activities in growing galls.

Topics: Animal Structures; Animals; Cell Division; Cyclin D; Gene Expression Regulation, Plant; Genes, Plant; Hymenoptera; Indoleacetic Acids; Isopentenyladenosine; Larva; Oviposition; Plant Growth Regulators; Plant Leaves; Plant Tumors; Plant Vascular Bundle; RNA, Messenger; Salix; Seasons; Signal Transduction; Tryptophan; Zeatin

The characterization of yield trait mutants is important for understanding the regulation of grain yield formation in staple food crops. Meh0239 is a yield trait-related mutant identified from a mutant library of the common wheat cultivar Wangshuibai created by ethylmethyl sulfide (EMS) treatment of dry seeds. To shed some light on the nature of this mutation, it was investigated morphologically, physiologically, anatomically and genetically. The mutant plant showed obvious phenotypic differences in comparison with the wild type, starting at the seedling stage, including reduced plant height, wider and shorter leaves, shortened spikes, spikelets and grains and a more compact spikelet distribution. Also, seeds produced in the mutant germinated more slowly. Meh0239 contained a significantly higher level of abscisic acid (ABA) but lower levels of indole-3-acetic acid (IAA), methyl jasmonate (MeJA) and zeatin riboside (ZR) in flag leaves. Cells of all types in the leaf epidermis appeared shorter along the axial direction. The bulliform cells and long cells on the adaxial leaf surface were abnormal in shape. A genetic analysis using two F₂ segregating populations indicated that a single recessive mutation in wheat chromosome 7DS, about 3.1cM distal from Xwmc506, caused these variations. Because of the pleiotropic nature of this gene and its relation with yield trait formation, we named it Yt1 for yield trait related 1.

Topics: Abscisic Acid; Acetates; Cyclopentanes; Gene Expression Regulation, Plant; Genes, Plant; Genes, Recessive; Germination; Indoleacetic Acids; Isopentenyladenosine; Mutation; Oxylipins; Phenotype; Plant Leaves; Plants, Genetically Modified; Seeds; Triticum

We investigated endogenous plant hormones and needle growth in Pinus tabulaeformis plants grown in open-top chambers and exposed to ambient or elevated concentrations of carbon dioxide (CO(2)) and/or ozone (O(3)). Exposure to elevated CO(2) for 100 days significantly increased the change in fresh needle weight, indole-3-acetic acid (IAA), isopentenyl-adenosine (iPA), and dihydrozeatin riboside (DHZR) content. Abscisic acid (ABA) content decreased, and no effect was observed on zeatin riboside (ZR) content or changes in needle dry weight. The ratios of IAA/ABA and total cytokinins (CKs)/ABA [Formula: see text] were increased. Elevated O(3) significantly decreased IAA and ZR, and decreased the ratios of IAA/ABA and CKs/ABA. Ozone treatment increased ABA content but did not change iPA or DHZR content or change fresh or dry needle weights. The combination treatment significantly increased ABA content and the IAA/ABA ratio but decreased the total CKs/ABA ratio and had no effect on CKs or IAA content or change in fresh and dry needle weights. The results indicate that elevated CO(2) ameliorated the effects of elevated O(3) on tree growth.

Topics: Abscisic Acid; Carbon Dioxide; Indoleacetic Acids; Isopentenyladenosine; Ozone; Pinus; Plant Growth Regulators; Plant Leaves; Trees

Through analysis of variation and function of 5 main endogenous hormones in the formation of microtuber of Dioscorea opposite in vitro to explore the physiological and biochemical mechanism of microtuber development.. When microtubers were induced on MS + 6-BA 1.5 mg x L(-1) + NAA 1.5 mg x L(-1) + sucrose 5% medium, the endogenous hormones were isolated during different formation stages of microtubers, then purified and detected with enzyme-linked immunosorbent assays (ELISA).. The results showed that GA3 slightly decreased in initial period, rose suddenly 20 days later, and than decreased. IAA showed a dropping tendency in the total course, ABA and ZR increased in a long period, dropped at last. JA continuously rose and never dropped, GA3 and ABA and the ratio of GA3 and JA varied obviously.. IAA, ABA, JA , ZR and GA3 play an important role in controlling formation of microtubers in D. opposite in vitro.

Topics: Abscisic Acid; Cyclopentanes; Dioscorea; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Oxylipins; Plant Growth Regulators; Plant Tubers

This study reports the effects of thidiazuron (TDZ) on the endogenous levels of indoleacetic acid (IAA), zeatin, zeatin riboside ([9R]Z), isopentenyladenine and isopentenyladenosine ([9R]iP) as well as structural changes in the apical meristem of Dendrobium Second Love shoots during flower induction and initial development in vitro. The results revealed that the presence of 1.8microM TDZ had a profound effect on the endogenous cytokinins (CKs) and IAA levels of the explants, when compared to those grown on a TDZ-free medium. A significant increase in CKs (especially [9R]iP and [9R]Z) and IAA in the first samples (taken at day 5) grown on TDZ-enriched medium was associated with flower induction, while a second increase in the level of these hormones after 25d of culture was related to flower development. The histological changes detected in the shoot apical meristem of explants grown in the presence of 1.8microM TDZ during 30d of culture are also described. Based on these findings, it is suggested that both auxin and CKs seem to be involved with the floral transition of Dendrobium Second Love in vitro. However, a possible direct effect of TDZ on flower formation is not discarded.

Topics: Adenosine; Cytokinins; Dendrobium; Flowers; Indoleacetic Acids; Isopentenyladenosine; Phenylurea Compounds; Plant Shoots; Thiadiazoles; Zeatin

Embryogenic tissue of hybrid larch (Larix x marschlinsii Coaz) was multiplied on Medium M (modified MSG medium supplemented with the plant growth regulators (PGRs) 2,4-dichlorophenoxyacetic acid (2,4-D; 9 microM) and N-6-benzyladenine (2.25 microM)). After 1 week, cultures were transferred to either MSG lacking PGRs (Medium C-) or MSG lacking PGRs but supplemented with 1% activated charcoal (Medium C+). Embryos were sampled after 1 week on Medium M, C- or C+. Embryos were analyzed by ELISA for abscisic acid (ABA), abscisic acid-glucose ester, 2,4-D, indole-3-acetic acid (IAA), indole-3-aspartate (IAAsp), zeatin (Z), zeatin riboside (ZR), isopentenyladenine (iP) and isopentenyladenosine (iPA). Transfer of embryos to Medium C+ reduced the embryo concentrations of 2,4-D and iPA, but resulted in elevated concentrations of IAA, IAAsp, ABA, Z, ZR and iP. Charcoal reduced 2,4-D concentrations of embryos by an order of magnitude greater than PGR-free medium alone. Charcoal affected embryo concentrations of five of the eight PGRs quantified. Use of either C+ or C- medium as part of the maturation protocols also affected germination and plantlet establishment of the embryos. A 1-week treatment on Medium C+ positively influenced plantlet establishment and generally reduced variability during both germination and plantlet establishment.

Topics: Abscisic Acid; Adenine; Adenosine; Charcoal; Indoleacetic Acids; Isopentenyladenosine; Larix; Plant Growth Regulators; Seeds; Trees; Zeatin

One of the proposed mechanisms by which rhizobacteria enhance plant growth is through the production of plant growth regulators. Five plant growth promoting rhizobacterial (PGPR) strains produced the cytokinin dihydrozeatin riboside (DHZR) in pure culture. Cytokinin production by Pseudomonas fluorescens G20-18, a rifampicin-resistant mutant (RIF), and two TnphoA-derived mutants (CNT1, CNT2), with reduced capacity to synthesize cytokinins, was further characterized in pure culture using immunoassay and thin layer chromatography. G20-18 produced higher amounts of three cytokinins, isopentenyl adenosine (IPA), trans-zeatin ribose (ZR), and DHZR than the three mutants during stationary phase. IPA was the major metabolite produced, but the proportion of ZR and DHZR accumulated by CNT1 and CNT2 increased with time. No differences were observed between strain G20-18 and the mutants in the amounts of indole acetic acid synthesized, nor were gibberellins detected in supernatants of any of the strains. Addition of 10(-5) M adenine increased cytokinin production in 96- and 168-h cultures of strain G20-18 by approximately 67%. G20-18 and the mutants CNT1 and CNT2 may be useful for determination of the role of cytokinin production in plant growth promotion by PGPR.

Topics: Adenine; Adenosine; Burkholderia; Cytokinins; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Lactuca; Plant Roots; Pseudomonas

Lodging-resistant rice (Oryza sativa) cultivars usually show slow grain filling when nitrogen is applied in large amounts. This study investigated the possibility that a hormonal change may mediate the effect of water deficit that enhances whole plant senescence and speeds up grain filling. Two rice cultivars showing high lodging resistance and slow grain filling were field grown and applied with either normal or high amount nitrogen (HN) at heading. Well-watered and water-stressed (WS) treatments were imposed 9 days post anthesis to maturity. Results showed that WS increased partitioning of fixed (14)CO(2) into grains, accelerated the grain filling rate but shortened the grain filling period, whereas the HN did the opposite way. Cytokinin (zeatin + zeatin riboside) and indole-3-acetic acid contents in the grains transiently increased at early filling stage and WS treatments hastened their declines at the late grain filling stage. Gibberellins (GAs; GA(1) + GA(4)) in the grains were also high at early grain filling but HN enhanced, whereas WS substantially reduced, its accumulation. Opposite to GAs, abscisic acid (ABA) in the grains was low at early grain filling but WS remarkably enhanced its accumulation. The peak values of ABA were significantly correlated with the maximum grain filling rates (r = 0.92**, P < 0.01) and the partitioning of fixed (14)C into grains (r = 0.95**, P < 0.01). Exogenously applied ABA on pot-grown HN rice showed similar results as those by WS. Results suggest that an altered hormonal balance in rice grains by water stress during grain filling, especially a decrease in GAs and an increase in ABA, enhances the remobilization of prestored carbon to the grains and accelerates the grain filling rate.

Topics: Abscisic Acid; Adenosine; Biological Transport, Active; Carbon Radioisotopes; Cellular Senescence; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Nitrogen; Oryza; Osmotic Pressure; Plant Leaves; Seeds; Tissue Distribution; Water; Zeatin

Transgenic tobacco lines simultaneously expressing the Agrobacterium iaaM, iaaH and ipt genes, obtained by crossing lines expressing ipt with lines expressing iaaM and iaaH, were used to study in planta interactions between auxin and cytokinins. All phenotypic traits of the respective parental lines characteristic of cytokinin and auxin overproduction were present in the cross. Indole-3-acetic acid (IAA) and combined zeatin riboside (ZR) and zeatin riboside-5'-monophosphate (ZRMP) contents were analysed by mass spectrometry in young, developing leaves from the cross, the parental lines and the wild type. Unexpectedly, hormone levels in the cross were very similar to wild-type levels. Thus IAA levels in the cross were much lower throughout vegetative development than in the parental IAA overproducing line, although expression of the bacterial IAA biosynthesis genes was not reduced. The results suggest that effects on apical dominance, adventitious root formation, leaf morphology and other traits commonly +/- associated with IAA and cytokinin overproduction, and observed in the iaa E ipt cross, cannot be explained solely by analysis of auxin and cytokinin contents in individual organs. As traits associated with both hormones are expressed in close spatial and temporal proximity, it is likely that cellular resolution of hormone contents is essential to explain physiological responses to auxins and cytokinins.

Topics: Adenosine; Alkyl and Aryl Transferases; Bacterial Proteins; Crosses, Genetic; Cytokinins; Indoleacetic Acids; Isopentenyladenosine; Nicotiana; Phenotype; Plant Leaves; Plants, Genetically Modified; Plants, Toxic; Rhizobium

To study the plant hormones produced by 5 species of endophytic fungi isolated from medicinal plants and to illustrate the mechanism on endophytic fungi stimulating the growth of plants.. Extracting plant hormones from mycelia and its culture solution with organic solvent, and detecting them by HPLC.. One or more plant hormones [GA3 (Gibberellin), IAA (Indoleacetic acid), ABA (Abscisic acid), Z (Zeatin), ZR (Zeatin riboside)] were detected from the mycelia and its culture solution.. The plant hormones produced by the endophytic fungi are important materials that may be used to reveal the mechanism of endophytic fungi stimulating the growth of medicinal plants (Orchidacea).

Topics: Abscisic Acid; Adenosine; Fungi; Gibberellins; Indoleacetic Acids; Isopentenyladenosine; Orchidaceae; Plant Growth Regulators; Plants, Medicinal; Zeatin