Effect of Hormonization Treatment on Yield Quantity and Quality, Contents of Biologically Active Compounds, and Antioxidant Activity in 'Einset Seedless' Grapevine Fruits and Raisins.

In this study, we determined the effect of hormonization treatment on yield quantity and quality, content of biologically active compounds, and antioxidant activity in fruits and raisins of 'Einset Seedless' grapevine. Field studies were conducted in 2017 at Nobilis Vineyard (50°39' N; 21°34' E) in the Sandomierz Upland. Analytical studies were carried out in the Laboratory of the University of Life Sciences in Lublin. Hormonized fruits and raisins, which were dried at 40 °C in a food dryer for 7 days, were the experimental material. It was shown that the application of the hormonization treatment had a significant effect on yield size and quality. The hormonization treatment and the form of plant material analyzed had a significant effect on the content of biologically active compounds and the antioxidant activity in 'Einset Seedless' grapevine fruits and raisins. The concentration of applied gibberellic acid had a significant effect on the levels of acidity, content of anthocyanins, and antioxidant activity determined with the FRAP and DPPH methods. The application of the multivariate analysis technique showed that, in the fresh fruits and raisins, the level of biologically active compounds and antioxidant activity in the case of the 200 mg∙GA3∙L-1 concentration and in the control combination was similar but differed significantly in the case of the 300 mg∙GA3∙L-1 application.

Evaluation of serum IgE in peach-allergic patients with systemic reaction by using recombinant Pru p 7 (gibberellin-regulated protein)

BACKGROUND: Lipid transfer protein (LTP) is a major fruit allergen. It has, however, recently been revealed that the systemic reaction in peach-allergic patients is related not only to LTP (Pru p 3) but also to gibberellin-regulated protein (Pru p 7). We investigated recombinant Pru p 7 (rPru p 7) for its potential use in worldwide standardization for the diagnosis of peach allergy. METHODS: Natural Pru p 7 (nPru p 7) was purified from peach crude extract using a monoclonal antibody affinity column. Complementary DNA for Pru p 7 was cloned and expressed in Escherichia coli and Pichia pastoris. Serum immunoglobulin (Ig) E in peach-allergic patients was examined by enzyme-linked immunosorbent assay (ELISA) using nPru p 7 and rPru p 7 (E. coli product: erPru p 7 and P. pastoris product: prPru p 7). RESULTS: Peach-allergic patients (n = 27) were diagnosed and categorized into oral reaction (n=10) or systemic reaction (n = 17). The nPru p 7 positivity based on serum IgE levels was 52% in the systemic-reaction group and 0% in the oral-reaction group (P<0.05). In the systemic-reaction group, there was no significant difference in reactivity between nPru p 7 and prPru p 7, but the reactivity of erPru p 7 was significantly lower than those of nPru p 7 and prPru p 7 (P < 0.05). CONCLUSIONS: We found that prPru p 7 exhibited reactivity in ELISA comparable to that of nPru p 7 for the diagnosis of peach allergy with systemic reaction

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Evaluation of serum IgE in peach-allergic patients with systemic reaction by using recombinant Pru p 7 (gibberellin-regulated protein).

BACKGROUND: Lipid transfer protein (LTP) is a major fruit allergen. It has, however, recently been revealed that the systemic reaction in peach-allergic patients is related not only to LTP (Pru p 3) but also to gibberellin-regulated protein (Pru p 7). We investigated recombinant Pru p 7 (rPru p 7) for its potential use in worldwide standardization for the diagnosis of peach allergy. METHODS: Natural Pru p 7 (nPru p 7) was purified from peach crude extract using a monoclonal antibody affinity column. Complementary DNA for Pru p 7 was cloned and expressed in Escherichia coli and Pichia pastoris. Serum immunoglobulin (Ig) E in peach-allergic patients was examined by enzyme-linked immunosorbent assay (ELISA) using nPru p 7 and rPru p 7 (E. coli product: erPru p 7 and P. pastoris product: prPru p 7). RESULTS: Peach-allergic patients (n=27) were diagnosed and categorized into oral reaction (n=10) or systemic reaction (n=17). The nPru p 7 positivity based on serum IgE levels was 52% in the systemic-reaction group and 0% in the oral-reaction group (P<0.05). In the systemic-reaction group, there was no significant difference in reactivity between nPru p 7 and prPru p 7, but the reactivity of erPru p 7 was significantly lower than those of nPru p 7 and prPru p 7 (P<0.05). CONCLUSIONS: We found that prPru p 7 exhibited reactivity in ELISA comparable to that of nPru p 7 for the diagnosis of peach allergy with systemic reaction.

Effects of co-exposure to imidacloprid and gibberellic acid on redox status, kidney variables and histopathology in adult rats.

Data on the individual nephrotoxic effects of imidacloprid (IMI) and gibberellic acid (GA3) are scarce. Moreover, there is a lack of information about their combined effects on the renal tissue. Our study investigated the effects of IMI and GA3 separately or together on rats kidney. IMI (64 mg/kg bw) was given for 3 weeks by gavage either individually or in combination with GA3 (200 mg/L) via drinking water. IMI associated or no with GA3 increased the levels of kidney malondialdehyde, advanced oxidation protein products, protein carbonyls and metallothionein, plasma creatinine, urea, blood urea nitrogen and lactate dehydrogenase activity. A decline of kidney uric acid level and antioxidant status was also observed. All these changes were supported by histopathological observations. Our results highlighted the role of IMI and/or GA3-induced nephrotoxicity. Co-exposure to IMI and GA3 exhibited synergism in biochemical kidney variables and histopathology and antagonism in physical and morphological parameters.

γ-Polyglutamic acid/chitosan nanoparticles for the plant growth regulator gibberellic acid: Characterization and evaluation of biological activity.

The growth regulator gibberellic acid (GA3) has several uses in the field, improving germination, plant development, productivity, and the quality of food. This work describes the development of a nanocarrier system for GA3, based on the poly(γ-glutamic acid) (γ-PGA) and chitosan (CS) polymers, Nanoparticles without GA3 (nano-γPGA/CS-GA3) showed colloidal characteristics, with an average size of 117±9nm, PDI of 0.43±0.07, and zeta potential of -29±0.5mV. The encapsulated nanoparticles (nano-γPGA/CS-GA3) presented an average size of 134±9nm, PDI of 0.35±0.05, zeta potential of 27.9±0.5mV, and 61% encapsulation. The images of nanoparticles observed by Transmission and scanning electron microscopy (TEM and SEM) showed a spherical shape of the nanoparticles. The system showed sustained release, with 58% release after 48h. Evaluation of thermal properties using DSC and TGA analyses indicated that there was an interaction between the CS and γ-PGA polymers. In tests using Phaseolus vulgaris seeds, nano-γPGA/CS-GA3 showed high biological activity, enhancing the rate of germination in the first day (50-70%) when compared with free GA3 (10-16%). Encapsulated GA3 was also more efficient than the free hormone in the increase of leaf area and the induction of root development (including the formation of lateral roots). These effects were not observed when seeds were treated with nano-γPGA/CS without GA3. The results demonstrated the considerable potential of nano-γPGA/CS-GA3 for use in agriculture.

Gibberellin derivative GA-13315 sensitizes multidrug-resistant cancer cells by antagonizing ABCB1 while agonizes ABCC1.

PURPOSE: GA-13315 is a gibberellin derivative that reveals antitumor and antineoplastic effects both in vitro and in vivo. In the present study, the chemosensitizing effects of GA-13315 in multidrug-resistant cell lines were examined and the underlying mechanisms were investigated. METHODS: Cytotoxicity and chemosensitizing effects of GA-13315 were determined by MTT assay. Function of ABC transporter was analyzed by measuring intracellular drug accumulation of doxorubicin and rhodamine 123 and by determining the ATPase activity of ABC transporter. Expression levels of apoptosis regulators were analyzed using real-time quantitative PCR and Western blot. RESULTS: GA-13315 selectively killed MCF-7/adr cells that overexpress P-glycoprotein (ABCB1) over the parent MCF-7 cells. In combination with conventional chemotherapeutic agents, GA-13315 at sub-toxic concentrations reversed the multidrug resistance mediated by ABCB1 but exacerbated the resistance conferred by multidrug resistance-associated protein 1 (ABCC1). GA-13315 increased intracellular accumulation of doxorubicin and rhodamine 123 in MCF-7/adr cells and in ABCB1-transfected HEK293 cells but facilitated drug flush-out from cells that overexpress ABCC1. GA-13315 inhibited the ATPase activity of ABCB1 while stimulated that of ABCC1. Moreover, the downregulated expression of Bax in MCF-7/adr cells was restored by GA-13315 markedly. CONCLUSION: These data suggest that GA-13315 sensitizes multidrug-resistant cells at least partially by impeding the efflux function of ABCB1. The upregulation of Bax by GA-13315 may also contribute to the sensitizing action. The opposite effects of GA-13315 on different ATP-binding cassette transporters and their implications in overcoming drug resistance require further investigation.

Evaluating the use of plant hormones and biostimulators in forage pastures to enhance shoot dry biomass production by perennial ryegrass (Lolium perenne L.).

Fertilisation of established perennial ryegrass forage pastures with nitrogen (N)-based fertilisers is currently the most common practice used on farms to increase pasture forage biomass yield. However, over-fertilisation can lead to undesired environmental impacts, including nitrate leaching into waterways and increased gaseous emissions of ammonia and nitrous oxide to the atmosphere. Additionally, there is growing interest from pastoral farmers to adopt methods for increasing pasture dry matter yield which use 'natural', environmentally safe plant growth stimulators, together with N-based fertilisers. Such plant growth stimulators include plant hormones and plant growth promotive microorganisms such as bacteria and fungi ('biostimulators', which may produce plant growth-inducing hormones), as well as extracts of seaweed (marine algae). This review presents examples and discusses current uses of plant hormones and biostimulators, applied alone or together with N-based fertilisers, to enhance shoot dry matter yield of forage pasture species, with an emphasis on perennial ryegrass.

Investigation of neurotoxic and immunotoxic effects of some plant growth regulators at subacute and subchronic applications on rats.

The present study was aimed to investigate the effects of subacute and subchronic treatment of some plant growth regulators (PGRs), such as abscisic acid (ABA) and gibberellic acid (GA3), on neurological and immunological biomarkers in various tissues of rats. The activities of acetylcholinesterase (AChE) and butrylcholinesterase (BChE) were selected as biomarkers for neurotoxic biomarkers. Adenosine deaminase (ADA) and myeloperoxidase (MPO) were measured as indicators for immunotoxic investigation purpose. Wistar albino rats were orally administered with 25 and 50 ppm of PGRs ad libitum for 25-50 days continuously with drinking water. The treatment of PGRs caused different effects on the activities of enzymes. Results showed that the administrations of ABA and GA3 increased AChE and BChE activities in some tissues of rats treated with both the dosages and periods of ABA and GA3. With regard to the immunotoxic effects, ADA activity fluctuated, while MPO activity increased after subacute and subchronic exposure of treated rat tissues to both dosages when compared with the controls. The observations presented led us to conclude that the administrations of PGRs at subacute and subchronic exposure increased AChE, BChE, and MPO activities, while fluctuating the ADA activity in various tissues of rats. This may reflect the potential role of these parameters as useful biomarkers for toxicity of PGRs.

Inclusion complex of GA-13316 with ß-cyclodextrin: preparation, characterization, molecular modeling, and in vitro evaluation.

The inclusion complex of GA-13316 with ß-cyclodextrin (ß-CD) is one of a unique series of gibberellin derivatives possessed of potential anticancer activities. The complex with ß-CD was characterized by means of UV, XRD, DSC, TG, (1)H, and 2D NMR spectroscopy. In addition, we investigated the main aspects of the interaction between GA-13316 and ß-CD using both experimental and molecular modeling approaches. The complex still maintained its anticancer activity, as shown by in vitro cell survival assay on the human colon carcinoma cell line (HCT116) and the human lung cancer cell line (H460). The results showed that the use of ß-CD could be obviously improved the water solubility and stability of GA-13316, implying that the inclusion complex could be a promising future therapeutic agent.

Quantifying the impact of exogenous abscisic acid and gibberellins on pre-maturity α-amylase formation in developing wheat grains.

To study the role of abscisic acid (ABA) and gibberellins (GA) in pre-maturity α-amylase (PMA) formation in developing wheat grain, two glasshouse experiments were conducted under controlled conditions in the highly PMA-susceptible genotype Rialto. The first, determined the relative efficacy of applying hormone solutions by injection into the peduncle compared to direct application to the intact grain. The second, examined the effects of each hormone, applied by either method, at mid-grain development on PMA in mature grains. In the first experiment, tritiated ABA ((3)H-ABA) and gibberellic acid ((3)H-GA3) were diluted with unlabelled ABA (100 µM) and GA3 (50 µM), respectively, and applied at mid-grain development using both methods. Spikes were harvested after 24, 48 and 72 h from application, and hormone taken up by grains was determined. After 72 h, the uptake per grain in terms of hormones applied was approximately 13% for ABA and 8% for GA3 when applied onto the grains, and approximately 17% for ABA and 5% for GA3 when applied by injection. In the second experiment, applied ABA reduced, whereas applied GA3 increased α-amylase activity. This confirmed that exogenously applied ABA and GA were absorbed in sufficient amounts to alter grain metabolism and impact on PMA.

Optimization of factors influencing in vitro flowering of gherkin (Cucumis anguria L.).

This study investigated the factors influencing in vitro flowering of gherkin (Cucumis anguria L.). Multiple shoots were efficiently regenerated from cotyledonary node and axillary bud explants of C. anguria within 15 days on MSB5 medium containing 3% sucrose and supplemented with 1.5 mg l-1 6-benzyladinine (BA). The elongated shoots were excised and transferred to MSB5 medium containing 4% sucrose supplemented with 0.5 mg l(-1) gibberellic acid (GA(3)) and 1.0 mg l(-1) indole-3-butyric acid (IBA) induced maximum number of flowers (9.5 flowers/plant) and root induction (16.5 roots/plant). Factors that influence the in vitro flowering were optimizing pH, photoperiod and temperature. In vitro flowering was significantly early and higher number of flowers produced at pH (5.8), photoperiod (12/12 h) and room temperature (28 °C). In vitro developed flowers were less viable (80 ± 1.0%) compared to control plants (90 ± 2.0%). Our in vitro flower induction procedures provide an extremely effective method for further research on flowering regulation mechanisms in C. anguria. These plantlets were successfully transferred to the soil where they grew well for 3 to 5 weeks with 90% survivability. Plants grew normally and produced flowers with viable pollen and fertile seeds.

Effect of exogenous gibberellin on reserve accumulation during the seed filling stage of oilseed rape.

Exogenous gibberellins (GAs) are widely applied to increase crop yields, with knowledge about the physiological functioning and biochemistry mechanisms of these phytohormones improving; however, information remains limited about the effect of GAs on seed filling. In this study, the siliques (containing the seeds) of oilseed rape (Brassica napus L.) were treated with GA3 at 3 stages of seed filling. We confirmed that GA3 regulates the deposition of storage reserves in developing seeds. The percentage of crude fat in the seeds increased during the early stage, but remained stable during the middle and late stages. In comparison, the percentage of total protein decreased during the early and middle stages, but significantly increased during the late stage. In addition, Q-PCR was employed to analyze the expression level of related genes in response to GA3. It was found that the expression of WRI and ABI3 transcription factors corresponded to crude fat content and total protein content, respectively. The expression of storage reserve related genes DGAT, MCAT, SUC2, and GPT was consistent with crude fat content, whereas the expression of Napin corresponded to total protein content. The results of this study indicate that exogenous GA3 has a different effect on storage reserve deposition in seed during different stages of seed filling, and the effect might be achieved via changing the expression of related genes.

Overexpression of the gibberellin 2-oxidase gene from Torenia fournieri induces dwarf phenotypes in the liliaceous monocotyledon Tricyrtis sp.

Gibberellins (GAs) are the plant hormones that control many aspects of plant growth and development, including stem elongation. Genes encoding enzymes related to the GA biosynthetic and metabolic pathway have been isolated and characterized in many plant species. Gibberellin 2-oxidase (GA2ox) catalyzes bioactive GAs or their immediate precursors to inactive forms; therefore, playing a direct role in determining the levels of bioactive GAs. In the present study, we produced transgenic plants of the liliaceous monocotyledon Tricyrtis sp. overexpressing the GA2ox gene from the linderniaceous dicotyledon Torenia fournieri (TfGA2ox2). All six transgenic plants exhibited dwarf phenotypes, and they could be classified into two classes according to the degree of dwarfism: three plants were moderately dwarf and three were severely dwarf. All of the transgenic plants had small or no flowers, and smaller, rounder and darker green leaves. Quantitative real-time reverse transcription-polymerase chain reaction (PCR) analysis showed that the TfGA2ox2 expression level generally correlated with the degree of dwarfism. The endogenous levels of bioactive GAs, GA1 and GA4, largely decreased in transgenic plants as shown by liquid chromatography-mass spectrometry (LC-MS) analysis, and the level also correlated with the degree of dwarfism. Exogenous treatment of transgenic plants with gibberellic acid (GA3) resulted in an increased shoot length, indicating that the GA signaling pathway might normally function in transgenic plants. Thus, morphological changes in transgenic plants may result from a decrease in the endogenous levels of bioactive GAs. Finally, a possibility of molecular breeding for plant form alteration in liliaceous ornamental plants by genetically engineering the GA metabolic pathway is discussed.

Systemic insecticide and gibberellin reduced cone damage and increased flowering in a spruce seed orchard.

Insects feeding in conifer cones are difficult to control with nonsystemic insecticides. Newly developed systemic insecticides that can be injected into tree trunks may be a possible way of reducing both insect damage and negative side-effects to the surrounding environment, compared with conventional spraying. Several insecticides that could be injected into tree stems were tested on Picea abies (L.) Karst. In one experiment, insecticides (bifenthrin, deltamethrin, abamectin, and imidacloprid) were injected during flowering; in a second experiment two of these insecticides (abamectin and imidacloprid) were injected 1 yr before the expected flowering. In the second experiment insecticide treatment was also combined with treatments with the flower stimulating hormone, gibberellin (GA(4/7)). The only insecticide that reduced damage was abamectin, both after injection during flowering and after injection 1 yr before the expected flowering. Injections with GA(4/7) increased flowering and were as efficient as the conventional application method of drilling but abamectin was not effective in combination with the drilling method. There was no negative effect of the insecticide injections on seed quality. The injections were ineffective against the seed chalcid Megastigmus strobilobius (Ratzeburg), which was found to have an unexpected, negative effect on seed quality. Our results suggest that it may be possible to reduce damage from certain insect species, and to increase flowering by injecting abamectin and GA(4/7) in the year before a cone crop.

Inclusion complex of GA-13315 with cyclodextrins: preparation, characterization, inclusion mode and properties.

GA-13315 (13-chlorine-3,15-dioxy-gibberllic acid methyl ester) was semi-synthesized by GA3 (gibberellic acid) as a potential anticancer drug. To pursue its promising application, cyclodextrin was used for forming complexes to overcome its drawbacks such as poor water solubility and stability. So, GA-13315/CD complexes were prepared with native ß-cyclodextrin and its derivatives (hydroxypropyl-ß-cyclodextrin (HPßCD)) and their inclusion complexation behavior, characterization and binding ability in both solution and the solid state was studied by means of UV, XRD, DSC, SEM, (1)H and 2D NMR spectroscopy. Furthermore, preliminary in vitro cytotoxicity assay showed that the complexes still maintain antitumor activities, compared with GA-13315 or adriamycin (ADM, positive control) as the positive control. The results showed that the water solubility and stability of GA-13315 were obviously improved in the inclusion complex with cyclodextrins, suggesting the inclusion complexes as promising future therapeutic agents.

Cálcio e fitorreguladores no desenvolvimento e estado nutricional de Mentha spicata x suaveolens cultivada em solução nutritiva / Calcium and plant growth regulators on the development and nutritional status of Mentha spicata x suaveolens cultivated in nutrient solution

O trabalho teve como objetivo estudar o desenvolvimento e o estado nutricional de Mentha spicata x suaveolens cultivada em diferentes níveis de Calcio em solução nutritiva com aplicação de fitorreguladores. O experimento constou de esquema fatorial (4x4) sendo quatro níveis de Ca2+ na solução nutritiva (160, 120, 80 e 40 mg L-1) e três aplicações foliares, com intervalos de 15 dias, de ácido naftaleno acético (NAA), ácido giberélico (GA3), benzinaladenina (BA) e água destilada como testemunha. As plantas foram coletadas 60 dias após a transferência para a solução e avaliadas as variáveis, matéria fresca e seca, área foliar e número de folhas; volume, comprimento e superfície radiculares e teores de Ca, K, Mg, N e P das folhas. As variáveis foram submetidas à análise de variância e as médias comparadas pelo teste Tukey. Não foram encontradas diferenças entre os níveis de Ca para a produção de biomassa. A auxina não influenciou a matéria seca das plantas, embora tenha aumentado os teores foliares de Ca; a citocinina acarretou diminuição da matéria seca total e a giberelina aumento da matéria seca do caule. A variação de Ca2+ não influenciou os teores foliares de N, P, K e Mg. Houve resposta para aplicação de Ca2+, com teores foliares atingindo o máximo de 15,73 mg kg-1 na dose de 137,81 mg L-1 pela análise de regressão

This study aimed to verify the development and the nutritional status of Mentha spicata x suaveolens cultivated under different Ca2+ levels in nutrient solution with application of plant growth regulators. The experiment was in factorial design (4X4) with four Ca2+ levels in the nutrient solution (160, 120, 80 and 40 mg L-1) and three leaf applications, at 15-day intervals, of naphthalene acetic acid (NAA), gibberellic acid (GA3), benzyladenine (BA) and distilled water as control. Plants were harvested at 60 days after transferring to the nutrient solution and the following variables were evaluated fresh and dried matter, leaf area, number of leaves, volume, length and surface of roots, and leaf content of Ca, K, Mg, N and P. The variables were subjected to analysis of variance and means compared by Tukey's test. There were no differences between Ca levels for biomass production. The auxin did not influence the dry matter of plants although it increased the leaf content of Ca2+, the cytokinin reduced total dry matter and the gibberellin increased the stem dry matter. The change in Ca2+ did not influence the leaf content of N, P, K and Mg. There was response for the application of Ca2+, reaching the maximum of 15.73 mg L-1 leaf content at the level of 137.81 mg L-1, according to regression analysis

Low levels of gibberellic acid control the biosynthesis of ajmalicine in Catharanthus roseus cell suspension cultures.

In periwinkle cell suspensions, amounts of gibberellic acid ranging from 10 ( - 10) M to 10 ( - 7) M significantly antagonized, in a dose-dependant manner, the stimulation of ajmalicine biosynthesis by cytokinins (CKs). This inhibitory effect was strictly correlated with the abolition of the expression of two genes encoding enzymes of the monoterpenoid indole alkaloid (MIA) biosynthetic pathway and was normally upregulated after CK treatments. Moreover, low concentrations of the gibberellin biosynthesis inhibitor paclobutrazol could reverse the inhibitory effects of low auxin levels on ajmalicine accumulation in the cells. On the other hand, gibberellic acid could not affect the expression of two type-A response regulators considered to be CK primary response genes in periwinkle cells. The antagonistic effects of gibberellins and cytokinins on MIA biosynthesis and their possible impact on elements of the signal transduction are discussed.

Phytohormones and their metabolites during long shoot development in Douglas-fir following cone induction by gibberellin injection.

Changes in plant hormones and metabolites in long-shoot stems of interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) during cone induction by gibberellic acid (GA) treatment were analyzed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode. A mixture of GA(4) and GA(7), including small amounts of GA(3) and GA(1), was stem-injected into each tree in amounts of 0, 4, 40 or 400 mg. One week after injection, concentrations of GA(4), GA(7) and GA(3) were elevated in all GA-treated samples. The ratio of GA(4) to GA(7) decreased significantly at Week 3. Absolute concentrations of all gibberellins declined sharply at Week 3 after GA application. After 5 weeks, GA(1) and GA(4) were below detection limits in all samples, and GA(7) and GA(3) were found only in the samples from trees treated with 40 or 400 mg of GA. Endogenous indole-3-acetic acid (IAA) concentrations increased following GA injection, and peaked at Week 2 or Week 3 in the trees treated with 40 or 400 mg GA, respectively. Injection of 400 mg of GA brought about a twofold increase in IAA concentration compared with control values. Injection of 40 and 400 mg of GA caused significant increases in stem dry mass in Week 5. Seed orchard data revealed that injection of either 40 or 400 mg GA enhanced female cone formation, whereas male cone formation was enhanced only by 400 mg GA. Slight decreases in concentrations of abscisic acid (ABA) and isopentenyl adenosine were observed after GA application. No significant changes were detected in the concentrations of ABA metabolites except for a slight decrease in the concentration of 7'-hydroxy ABA. The concentration of ABA declined during the growing season and the concentration of ABA glucose ester increased correspondingly.

Reproducibility of dwarf pea shoot growth stimulation by homeopathic potencies of gibberellic acid.

OBJECTIVES: Investigation of the conditions for reproducibility of dwarf pea shoot growth stimulation through homeopathic potencies of gibberellic acid. METHODS: 4 batches of pea seed (Pisum sativum L. cv. Früher Zwerg; harvests from 1997, 1998, 1999, and 2000) were tested regarding their reaction to gibberellic acid 17x and 18x (compared to unsuccussed and succussed water (1x) as controls) in 8 independent randomized and blinded experiments. Pea seed was immersed for 24h in watery solutions of homeopathic potencies or controls, and cultivated under controlled laboratory conditions. Pea shoot length was measured after 14 days. Two systematic negative control experiments assessed the stability of the experimental set-up. RESULTS: The systematic negative control experiments yielded no significant effects and confirmed the stability of the experimental set-up. 2 out of 4 seed batches reacted to the homeopathic treatment (p<0.05). Seed batch 1997 showed a reproducible reaction to gibberellic acid 17x (shoot length stimulation of +11.2%, p=0.007), and seed batch 1998 showed a significant varying response (increase/decrease). Seed batch 1997 differed from the other 3 batches by an increased glucose and fructose content, and reduced 1000kernel weight. Meta-analysis with data of earlier experiments is in accordance with the results of the present experimental series. CONCLUSIONS: We identified 'seed quality' as a possible trigger factor for successful reproducibility in homeopathic basic research. Premature harvesting as a possible key factor for responsiveness of dwarf peas to homeopathic potencies of gibberellic acid is our current working hypothesis to be tested in future experiments.

Evalution of toxicity of abcisic acid and gibberellic acid in rats: 50 days drinking water study.

In the present study, the influence of subchronic effects of two plant growth regulators (PGRs) [Abcisic acid (ABA) and Gibberellic acid (GA3)] on antioxidant defense systems [reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation level (malondialdehyde = MDA) in various tissues of the rat were investigated during treatment as a drinking water model. 75 ppm of ABA and GA3 in drinking water were continuously administered orally to rats (Sprague-Dawley albino) ad libitum for 50 days. The PGRs treatments caused different effects on the antioxidant defense systems and MDA content of dosed rats compared to controls. The lipid peroxidation end product MDA significantly increased in the lungs, heart and kidney of rats treated with GA3 without significant change in the spleen. ABA caused also a significant increase in MDA content in the spleen, lungs, heart and kidney. The GSH levels were significantly depleted in the spleen, lungs and stomach of rats treated with ABA without any change in the tissues of rats treated with GA3 except the kidney where it increased. Antioxidant enzyme activities such as SOD significantly increased in the lungs and stomach and decreased in the spleen and heart tissues of rats treated with GA3. Meanwhile, SOD significantly decreased in the spleen, heart and kidney and increased in the lungs of rats treated with ABA. While CAT activity significantly decreased in the lungs of rats treated with GA3, a significant increase occurred in the heart of rats treated with both PGRs. On the other hand, the ancillary enzyme GR activity in the tissues were either significantly depleted or not changed with PGRs treatment. The drug metabolizing enzyme GST activity significantly decreased in the lungs of rats treated with ABA but increased in the stomach of rats treated with both PGRs. As a conclusion, the rats resisted oxidative stress via the antioxidant mechanism. But the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat's tissues. This data, along with changes, suggests that PGRs produced substantial systemic organ toxicity in the spleen, lungs, stomach, heart and kidney during a 50-day period of subchronic exposure.