Zinc Nutrition and its Activated Roles on Growth, Inflorescences Attributes and Some Physiological Parameters of Tagetes erecta L. Plants.

BACKGROUND AND OBJECTIVE: There are scarcity scientific reports on the response of medicinal plants to zinc nutrition, despite its remarkable role in growth, cell division, photosynthesis and tryptophan formation, which is involved auxin (IAA) synthesis. Therefore, further studies are required to understand the effects of zinc on one of these important plants, marigold plant. MATERIALS AND METHODS: For this, a greenhouse experiment was conducted to evaluate the promoting impacts of zinc-nutrition (0, 50, 75, 100 mg L-1) on marigold growth, plant height, branch number, herb and root fresh mass (FM), herb and root dry mass (DM), flowering attributes, inflorescence number/plant (IN), inflorescence diameter (ID), inflorescence (IW) weight (fresh and dry), days to first bud emergence, leaf relative water content (RWC) as well as some physiological responses, pigments, total carbohydrate, N, P, K, Zn contents of marigold plants. RESULTS: The results indicated that zinc-fertilizer at 100 mg L-1 was the superior treatment in improving the previous parameters relative to the other levels and control. Supplying Zn significantly enhanced growth parameters, flower attributes, RWC as well as nutrient contents of marigold leaves. Chlorophyll, carotenoids content and carbohydrates (%) were enhanced due to suppling Zn. Zn treatments raised the contents of N, P, K and Zn in leaves relative to unfertilized ones. A comparison of the usage treatments showed that the higher dose of Zn was better than the lower one or control but insignificant differences were observed between this treatment and the intermediate one (75 mg L-1) for some studies parameters. CONCLUSION: The obtained results suggest that exogenous application of Zn could be essentially for the nutrition program of marigold plants to provide plants by the optimum dose of Zn-fertilizer for improving the growth and, quantity and quality of inflorescence parameters.

Arbuscular mycorrhizal fungi enhance the copper tolerance of Tagetes patula through the sorption and barrier mechanisms of intraradical hyphae.

Arbuscular mycorrhizal fungi (AMF) are widespread soil fungi that can form endosymbiotic structures with the root systems of most plants and can improve the tolerance of host plants to heavy metals. In the present study, we investigated the effects of AMF (Glomus coronatum) inoculation on the tolerance of Tagetes patula L. to Cu. Almost all of the non-mycorrhizal plants exposed to 100 µM Cu died after 3 d, whereas phytotoxicity was only observed in mycorrhizal plants that were exposed to Cu concentrations greater than 100 µM. Analysing the dynamic accumulation of Cu indicated that, after 7 d of Cu exposure, less Cu was absorbed or accumulated by mycorrhizal plants than by control plants, and significantly less Cu was translocated to the shoots. Meanwhile, analysing the root morphology, the integrity of the root plasma membranes, the photosynthesis rate, and the content of essential elements of plants growing in cultures with 50 µM Cu revealed that AMF inoculation markedly alleviated the toxic effects of Cu stress on root system activity, photosynthesis rate, and mineral nutrient accumulation. In addition, to understand the Cu allocation, an energy spectrum analysis of Cu content at the transverse section of root tips was conducted and subsequently provided direct evidence that intraradical hyphae at the root endodermis could selectively immobilise large amounts of Cu. Indeed, the sorption and barrier mechanisms of AMF hyphae reduce Cu toxicity in the roots of T. patula and eventually enhance the plants' Cu tolerance.

The response of marigold (Tagetes erecta Linn.) to ozone: impacts on plant growth and leaf physiology.

Progressively increasing ozone (O3) concentrations pose a potential threat to the value of marigold (Tagetes erecta Linn.), a plant widely used in urban landscaping. The response of marigold to elevated O3 has been reported earlier, but the mechanisms underlying the O3 effect have not been clearly elucidated. In the present study, we exposed marigold "Moonsong Deep Orange" plants to elevated O3, including ambient non-filtered air (NF) plus 60 ppb (NF+60) and 120 ppb (NF+120) O3, to assess visible injury and the possible physiological consequences of this pollutant. Yellow lesions appeared after 4 days under NF+120 treatment and 12 days under NF+60 treatment, with 85.6% and 36.8% of the leaves being injured at harvest time, respectively. Compared with NF, NF+60 inhibited leaf photosynthesis, stem-diameter growth, and biomass production significantly, while the parameters were decreased more by NF+120. Although the stomatal conductance decreased under elevated O3 exposure, the O3 flux into leaves increased by 28.0-104.8% under NF+60 treatment and 57.5-145.6% under NF+120 treatment. The total ascorbic acid (ASA) content increased due to elevated O3 exposure, while the reduced ASA content did not, resulting in a decreased ratio of reduced to total ASA. A lower level of jasmonic acid (JA) was observed under elevated O3 exposure. In conclusion, the impacts of elevated O3 on marigold plants may be ascribed to increased O3 flux into leaves and reduced protective capacity of leaves to convert oxidized to reduced ASA and synthesize endogenous JA.

Irrigational impact of untreated and treated brewery-distillery effluent on seed germination of marigold (Tagetes erecta L.).

Current study presents the effect of irrigation with different concentrations (20, 40, 60, 80 and 100%) of untreated and treated brewery-distillery effluent on germination behaviour of marigold (Tagetes erecta L. var. Pusa Basanti). The 100% untreated effluent showed acidic pH (4.80) and higher values of BOD (1500.00 mg l(-1)), COD (4000.00 mg l(-1)), chloride (1742.20 mg l(-1)), TSS (900.00 mg l(-1)) as compared to that of treated effluent. Tagetes seeds were exposed to different concentrations of effluent and the results revealed maximum values of germination parameters viz., percent germination, peak value, germination value, germination index, speed of germination and vigour index at 20% untreated and 60% treated effluent concentrations, whereas the values for negative germination parameters viz., delay index, germination period and percent inhibition were minimum at 20% untreated and 60% treated effluent concentrations.

Transcriptomic Analysis of Differentially Expressed Genes during Flower Organ Development in Genetic Male Sterile and Male Fertile Tagetes erecta by Digital Gene-Expression Profiling.

Tagetes erecta is an important commercial plant of Asteraceae family. The male sterile (MS) and male fertile (MF) two-type lines of T. erecta have been utilized in F1 hybrid production for many years, but no report has been made to identify the genes that specify its male sterility that is caused by homeotic conversion of floral organs. In this study, transcriptome assembly and digital gene expression profiling were performed to generate expression profiles of MS and MF plants. A cDNA library was generated from an equal mixture of RNA isolated from MS and MF flower buds (1 mm and 4 mm in diameter). Totally, 87,473,431 clean tags were obtained and assembled into 128,937 transcripts among which 65,857 unigenes were identified with an average length of 1,188 bp. About 52% of unigenes (34,176) were annotated in Nr, Nt, Pfam, KOG/COG, Swiss-Prot, KO (KEGG Ortholog database) and/or GO. Taking the above transcriptome as reference, 125 differentially expressed genes were detected in both developmental stages of MS and MF flower buds. MADS-box genes were presumed to be highly related to male sterility in T. erecta based on histological and cytological observations. Twelve MADS-box genes showed significantly different expression levels in flower buds 4 mm in diameter, whereas only one gene expressed significantly different in flower buds 1 mm in diameter between MS and MF plants. This is the first transcriptome analysis in T. erecta and will provide a valuable resource for future genomic studies, especially in flower organ development and/or differentiation.

An efficient plant regeneration and Agrobacterium-mediated genetic transformation of Tagetes erecta.

Tagetes erecta, L. an asteraceous plant of industrial and medicinal value, contains important compounds like pyrethrins, thiophenes and lutein, possessing immense potential for insecticidal, nematicidal and nutraceutical activities. Considering the importance and demand for these natural compounds, genetic manipulation of this crop for better productivity of secondary metabolites holds great significance. A rapid and reproducible direct regeneration and genetic transformation system is the prerequisite for genetic manipulation of any crop. This paper elucidates the establishment of an efficient direct regeneration and transformation protocol of T. erecta using Agrobacterium tumefaciens. Investigation of the effects of different types of explants (Hypocotyls, cotyledonary leaves, rachis and leaf sections) and different BAP and GA3 combinations on the regeneration frequency of T. erecta suggested that the best regeneration frequency (66 %) with an average of 5.08 ± 0.09 shoot buds/explant was observed from hypocotyl explants cultured on media containing 1.5 mg/l BAP and 5 mg/l GA3. The transformation protocol was established using A. tumefaciens strain LBA4404, containing the binary vector pBI121, along with the gusA reporter gene with intron under the transcriptional control of the Cauliflower Mosaic Virus (CaMV) 35S promoter and the neomycin phosphotransferase II (nptII) gene as a kanamycin-resistant plant-selectable marker. Various parameters like optimization of kanamycin concentration (200 mg/l) for selection, standardization of cocultivation time (45 min) and acetosyringone concentration (150 µM) for obtaining higher transformation frequency were established using hypocotyl explants. The selected putative transgenic shoots were subsequently rooted on the Murashige and Skoog medium and transferred to the green house successfully. The plants were characterised by analysing the gus expression, amplification of 600 bp npt II fragment and Southern blot hybridization using the PCR-amplified gusA fragment as probe. The standardised protocol established during the study will open new vistas for genetic manipulation and introduction of desired genes for genetic improvement of T. erecta.

Comparison of endogenous cytokinins and cytokinin oxidase/dehydrogenase activity in germinating and thermoinhibited Tagetes minuta achenes.

Tagetes minuta L. achenes are thermoinhibited at temperatures above 35°C and have accelerated radicle emergence (germination) when subsequently transferred to an optimal temperature (25°C). Endogenous cytokinins and cytokinin oxidase/dehydrogenase (CKX) activity were compared in normally germinating (25°C) and thermoinhibited (72h at 36°C then transferred to 25°C) T. minuta achenes. Following imbibition, endogenous cytokinin concentrations changed in normally germinating T. minuta achenes, with a gradual decrease in dihydrozeatin-type (DHZ) cytokinins, a large increase in cis-zeatin-type (cZ) cytokinins, a smaller increase in N6-(2-isopentenyl)adenine-type (iP) cytokinins and a peak of trans-zeatin-type (tZ) cytokinins at 13 h. These changes in the isoprenoid cytokinin profile were similar in the thermoinhibited achenes imbibed at 36°C, despite the thermal block preventing radicle emergence. The exception was the iP-type cytokinins that only increased when transferred to 25°C. Profiles of the physiologically active free bases showed an increase in tZ prior to radical emergence in both normally germinating (13 h) and thermoinhibited achenes. A large transient peak in aromatic cytokinins [N6-benzyladenine-type (BA)] occurred during early seedling establishment in normally germinating achenes (40 h) while a transient maximum in BA-type cytokinins was found prior to radicle emergence in the thermoinhibited achenes (24 h). The CKX activity was enhanced in normally germinating achenes as the cytokinin concentration increased following imbibition. In thermoinhibited achenes, an elevated temperature negatively affected the CKX activity that only increased when the achenes were transferred to 25°C, corresponding to an increase in iP-type cytokinins. However, the favored cytokinin deactivation pathway in T. minuta appears to be 9-glycosylation, as 9-glucosides accounted for over 50% of the total cytokinin pool in both normal and thermoinhibited achenes.

[Drought-resistance evaluation of marigold cultivars based on multiple statistics analysis].

By the methods of principal component analysis, subordinate function, and cluster analysis, a comprehensive evaluation was conducted on the drought-resistance of 16 physiological indices of nine marigold cultivars. Under drought stress, the 16 physiological indices had different responses, among which, free proline (Pro), H2O2, and ascorbate peroxidase (APX) showed the greatest sensitivity. There existed significant correlations in the drought-resistance coefficients of parts of the physiological indices. Four principal factors presented 88.6% of the information of the 16 indices, and the cultivars 'Janie' and 'Gate gold', 'Bonanzn', 'Janie', and 'Chokdee' had the strongest drought-resistance for the 4 principal factors, respectively. The comprehensive evaluation value of the drought-resistance of the 9 cultivars was in the order of 'Janie' > 'Gate gold' > 'Bonanza' > 'Chokdee' > 'Giant' > 'Great hero' > 'Little hero' > 'Durango' > 'Discovery'. The 9 cultivars could be clustered into 3 groups, and 'Gate gold', 'Janie', 'Bonanza' and 'Chokdee' belonged to the drought-resistance group.

The effect of flavonoids on transduction mechanisms in lipopolysaccharide-treated human gingival fibroblasts.

Periodontal disease comprises a group of infections that lead to inflammation of the gingival and destruction of periodontal tissues and is accompanied by the loss of the alveolar bone with eventual exfoliation of the teeth. Porphyromonas gingivalis is a Gram-negative bacteria obtained from the periodontal pocket of patients with aggressive and chronic periodontitis. This bacteria presents in the external membrane lipopolysaccharide (LPS). Flavonoids are molecules obtained from plants and possess anti-inflammatory properties. Herein we characterize the effect of the flavonoids quercetin, genistein, luteolin, and quercetagetin on LPS-activated transduction mechanism regulation in human gingival fibroblasts (HGF). In this study, we investigated the role of the previously mentioned flavonoids on mitogen-activated protein kinase (MAPK) activation induced by LPS obtained from P. gingivalis. Our results showed that LPS treatment induces activation of extracellular signal related kinase 1/2 (ERK1/2), p38, and c-jun-NH(2)-terminal kinase (JNK). All flavonoids demonstrated an inhibitory effect on MAPK activation, interleukin, 1beta, and cyclooxygenase-2 (COX-2) expression, IL-1beta and prostaglandin E2 (PGE2) synthesis. The most active flavonoid was quercetagetin. Finally we found that the treatment with quercetagetin had no effect on cellular viability or in genetic material integrity.

Factors contributing to the regulation of thermoinhibition in Tagetes minuta L.

Thermoinhibition in Tagetes minuta achenes is tightly and rapidly regulated with regard to its imposition and release, with both processes occurring within 2-3h. Germination at high temperatures is almost exclusively regulated by the embryo, while the pericarp appears to play only a minor role. Thermoinhibition in T. minuta could not be alleviated by any single plant growth regulator application, but a combination of treatments that both reduced ABA levels and increased ethylene levels were able to restore germination at supraoptimal temperatures. This suggests a role for both ethylene and ABA in the imposition of thermoinhibition in this species.

Monitoring the effects of atmospheric ethylene near polyethylene manufacturing plants with two sensitive plant species.

Data of a multi-year (1977-1983) biomonitoring programme with marigold and petunia around polyethylene manufacturing plants was analysed to assess plant responses to atmospheric ethylene and to determine the area at risk for the phytotoxic effects of this pollutant. In both species, flower formation and growth were severely reduced close to the emission sources and plant performance improved with increasing distance. Plants exposed near the border of the research area had more flowers than the unexposed control while their growth was normal. Measurements of ethylene concentrations at a border site revealed that the growing season mean was 61.5 g m(-3) in 1982 and 15.6 g m(-3) in 1983. In terms of number of flowers, petunia was more sensitive than marigold and adverse effects were observed within ca. 400 m distance from the sources for marigold and within ca. 460 m for petunia. The area at risk (ca. 870 m) for ethylene-induced growth reduction was also limited to the industrial zone. Plants were more sensitive to ethylene in terms of growth reduction than in terms of inhibition of flowering. In the Netherlands, maximum permissible levels of ethylene are currently based on information from laboratory and greenhouse studies. Our results indicate that these levels are rather conservative in protecting field-grown plants against ethylene-induced injury near polyethylene manufacturing plants.