Functional Conservation and Divergence of Five AP1/FUL-like Genes in Marigold (Tagetes erecta L.).

Members of AP1/FUL subfamily genes play an essential role in the regulation of floral meristem transition, floral organ identity, and fruit ripping. At present, there have been insufficient studies to explain the function of the AP1/FUL-like subfamily genes in Asteraceae. Here, we cloned two euAP1 clade genes TeAP1-1 and TeAP1-2, and three euFUL clade genes TeFUL1, TeFUL2, and TeFUL3 from marigold (Tagetes erecta L.). Expression profile analysis demonstrated that TeAP1-1 and TeAP1-2 were mainly expressed in receptacles, sepals, petals, and ovules. TeFUL1 and TeFUL3 were expressed in flower buds, stems, and leaves, as well as reproductive tissues, while TeFUL2 was mainly expressed in flower buds and vegetative tissues. Overexpression of TeAP1-2 or TeFUL2 in Arabidopsis resulted in early flowering, implying that these two genes might regulate the floral transition. Yeast two-hybrid analysis indicated that TeAP1/FUL proteins only interacted with TeSEP proteins to form heterodimers and that TeFUL2 could also form a homodimer. In general, TeAP1-1 and TeAP1-2 might play a conserved role in regulating sepal and petal identity, similar to the functions of MADS-box class A genes, while TeFUL genes might display divergent functions. This study provides a theoretical basis for the study of AP1/FUL-like genes in Asteraceae species.

Functional conservation and divergence of SEPALLATA-like genes in the development of two-type florets in marigold.

Marigold (Tagetes erecta), as one member of Asteraceae family, bears a typical capitulum with two morphologically distinct florets. The SEPALLATA genes are involved in regulating the floral meristem determinacy, organ identity, fruit maturation, seed formation, and plant architecture. Here, five SEP-like genes were cloned and identified from marigold. Sequence alignment and phylogenetic analysis demonstrated that TeSEP3-1, TeSEP3-2, and TeSEP3-3 proteins were grouped into SEP3 clade, and TeSEP1 and TeSEP4 proteins were clustered into SEP1/2/4 clade. Quantitative real-time PCR analysis revealed that TeSEP1 and TeSEP3-3 were broadly expressed in floral organs, and that TeSEP3-2 and TeSEP4 were mainly expressed in pappus and corollas, while TeSEP3-1 was mainly expressed in two inner whorls. Ectopic expression of TeSEP1, TeSEP3-2, TeSEP3-3, and TeSEP4 in arabidopsis and tobacco resulted in early flowering. However, overexpression of TeSEP3-1 in arabidopsis and tobacco caused no visible phenotypic changes. Notably, overexpression of TeSEP4 in tobacco decreased the number of petals and stamens. Overexpression of TeSEP1 in tobacco led to longer sepals and simpler inflorescence architecture. The comprehensive pairwise interaction analysis suggested that TeSEP proteins had a broad interaction with class A, C, D, E proteins to form dimers. The yeast three-hybrid analysis suggested that in ternary complexes, class B proteins interacted with TeSEP3 by forming heterodimer TePI-TeAP3-2. The regulatory network analysis of MADS-box genes in marigold further indicated that TeSEP proteins played a "glue" role in regulating floral organ development, implying functional conservation and divergence of MADS box genes in regulating two-type floret developments. This study provides an insight into the formation mechanism of floral organs of two-type florets, thus broadening our knowledge of the genetic basis of flower evolution.

Invasive species allelopathy decreases plant growth and soil microbial activity.

According to the 'novel weapons hypothesis', invasive success depends on harmful plant biochemicals, including allelopathic antimicrobial roots exudate that directly inhibit plant growth and soil microbial activity. However, the combination of direct and soil-mediated impacts of invasive plants via allelopathy remains poorly understood. Here, we addressed the allelopathic effects of an invasive plant species (Rhus typhina) on a cultivated plant (Tagetes erecta), soil properties and microbial communities. We grew T. erecta on soil samples at increasing concentrations of R. typhina root extracts and measured both plant growth and soil physiological profile with community-level physiological profiles (CLPP) using Biolog Eco-plates incubation. We found that R. typhina root extracts inhibit both plant growth and soil microbial activity. Plant height, Root length, soil organic carbon (SOC), total nitrogen (TN) and AWCD were significantly decreased with increasing root extract concentration, and plant above-ground biomass (AGB), below-ground biomass (BGB) and total biomass (TB) were significantly decreased at 10 mg·mL-1 of root extracts. In particular, root extracts significantly reduced the carbon source utilization of carbohydrates, carboxylic acids and polymers, but enhanced phenolic acid. Redundancy analysis shows that soil pH, TN, SOC and EC were the major driving factors of soil microbial activity. Our results indicate that strong allelopathic impact of root extracts on plant growth and soil microbial activity by mimicking roots exudate, providing novel insights into the role of plant-soil microbe interactions in mediating invasion success.

Carotenoid metabolite and transcriptome dynamics underlying flower color in marigold (Tagetes erecta L.).

Marigold (Tagetes erecta L.) is an important ornamental plant with a wide variety of flower colors. Despite its economic value, few biochemical and molecular studies have explored the generation of flower color in this species. To study the mechanism underlying marigold petal color, we performed a metabolite analysis and de novo cDNA sequencing on the inbred line 'V-01' and its petal color mutant 'V-01M' at four flower developmental stages. A total of 49,217 unigenes were identified from 24 cDNA libraries. Based on our metabolites and transcriptomic analyses, we present an overview of carotenoid biosynthesis, degradation, and accumulation in marigold flowers. The carotenoid content of the yellow mutant 'V-01M' was higher than that of the orange inbred line 'V-01', and the abundances of the yellow compounds lutein, neoxanthin, violaxanthin, zeaxanthin, and antheraxanthin were significantly higher in the mutant. During flower development, the carotenoid biosynthesis genes were upregulated in both 'V-01' and 'V-01M', with no significant differences between the two lines. By contrast, the carotenoid degradation genes were dramatically downregulated in the yellow mutant 'V-01M'. We therefore speculate that the carotenoid degradation genes are the key factors regulating the carotenoid content of marigold flowers. Our research provides a large amount of transcriptomic data and insights into the marigold color metabolome.

Identification, characterization and functional analysis of AGAMOUS subfamily genes associated with floral organs and seed development in Marigold (Tagetes erecta).

BACKGROUND: AGAMOUS (AG) subfamily genes regulate the floral organs initiation and development, fruit and seed development. At present, there has been insufficient study of the function of AG subfamily genes in Asteraceae. Marigold (Tagetes erecta) belongs to Asteraceae family whose unique inflorescence structure makes it an important research target for understanding floral organ development in plants. RESULTS: Four AG subfamily genes of marigold were isolated and phylogenetically grouped into class C (TeAG1 and TeAG2) and class D (TeAGL11-1 and TeAGL11-2) genes. Expression profile analysis demonstrated that these four genes were highly expressed in reproductive organs of marigold. Subcellular localization analysis suggested that all these four proteins were located in the nucleus. Protein-protein interactions analysis indicated that class C proteins had a wider interaction manner than class D proteins. Function analysis of ectopic expression in Arabidopsis thaliana revealed that TeAG1 displayed a C function specifying the stamen identity and carpel identity, and that TeAGL11-1 exhibited a D function regulating seed development and petal development. In addition, overexpression of both TeAG1 and TeAGL11-1 leaded to curling rosette leaf and early flowering in Arabidopsis thaliana. CONCLUSIONS: This study provides an insight into molecular mechanism of AG subfamily genes in Asteraceae species and technical support for improvement of several floral traits.

Influence of Harvest Date and Postharvest Treatment on Carotenoid and Flavonoid Composition in French Marigold Flowers.

The aim of this study was to characterize carotenoids and flavonoids present in French marigold flowers (Tagetes patula "Durango Red") as well as to assess the effects of harvest dates and postharvest treatments on these compounds. Carotenoids and flavonoids were quantified using their respective standards or semiquantified using relevant related standards. Lutein and its derivatives largely dominated the flower carotenoids, while the flavonoids were diverse with patuletin leading the list. Of the different postharvest treatments, ensilage leads to the highest content of carotenoids (from 5.0 to 7.8 g kg-1 dw) and flavonoids (from 19 to 50 g kg-1 dw). The composition of individual flavonoids was greatly influenced by different postharvest treatments, while the influence of harvest dates was secondary. Ensilage and drying induced separate metabolic pathways leading to degradation of high-molecular glycosidic compounds, converting the compounds either to their aglycones or into the intermediate flavonoid glycosides. We conclude that according to the intended industrial application, different postharvest techniques can be employed to acquire desired flavonoids on a large scale.

Parasitoids diversity in organic Sweet Pepper (Capsicum annuum) associated with Basil (Ocimum basilicum) and Marigold (Tagetes erecta ) / Diversidade de parasitoides em Pimentão Orgânico (Capsicum annuum) associado com Manjericão (Ocimum basilicum ) e Cravo Amarelo (Tagetes erecta)

Abstract The sweet pepper (Capsicum annuum L.) is one of the most important crops in Brazilian farming. Many insect are related to this crop, compromising the quantity and quality of the fruit, representing a production problem. Vegetable diversification is one of the main elements that can be managed for suppressing undesirable insect populations in organic production, once that supports the presence of natural enemies. The basil Ocimum basilicum L. and the marigold Tagetes erecta L. are attractive and nutritious plants for parasitoids, being important candidates for diversified crops. This study evaluated the parasitoids attracted by the association of basil and marigold to organic sweet pepper crop. The experiment comprised three treatments: a) sweet pepper monoculture; b) sweet pepper and basil intercropping; c) sweet pepper and marigold intercropping. Hymenopteran parasitoids were collected over 14 weeks. 268 individuals from 12 families and 41 taxa were collected. Sweet pepper monoculture, sweet pepper-basil intercropping, and sweet pepper-marigold intercropping hosted 40, 98, and 130 individuals and richness of 24, 24, and 23, respectively. Furthermore, the insects of greater abundance in the basil and marigold were different to those collected in the monoculture. The number of parasitoids increased in the associations of sweet pepper with basil and marigold, providing advantages in the use of vegetable diversification for the organic pepper crops management.

Resumo O pimentão (Capsicum annuum L.) é um dos vegetais mais importantes dentre os cultivados no Brasil. Muitos insetos pragas estão relacionados a esta cultura, comprometendo a quantidade e a qualidade do pimentão, tornando-se um grande problema para a produção. A diversificação vegetal é um dos principais componentes a serem manejados para suprimir as populações de pragas na produção orgânica, devido ao apoio a inimigos naturais das pragas. O manjericão ( Ocimum basilicum L.) e cravo amarelo (Tagetes erecta L.) são plantas atrativas e nutritivas para parasitoides, importantes candidatas em cultivos diversificados. Este trabalho avaliou os parasitoides atraídos pela associação de manjericão e cravo amarelo em cultivo de pimentão orgânico. O experimento foi composto por três tratamentos: a) monocultura de pimentão; B) pimentão consorciado com manjericão; C) pimentão consorciado com cravo amarelo. Foram coletadas amostras de parasitoides himenópteros durante 14 semanas. Os espécimes foram identificados até o menor nível de taxonomia possível. Foram coletados 268 indivíduos ao longo de 12 famílias e 41 táxons. Os tratamentos de monocultura, pimentão consorciado com manjericão e pimentão consorciado com cravo amarelo resultaram em 40, 98 e 130 indivíduos e riqueza de espécies de 24, 24 e 23, respectivamente. Além disso, os insetos de maior abundância coletados no manjericão e cravo amarelo, foram diferentes daqueles coletados na monocultura. Houve um aumento na abundância de parasitoides nas associações de pimentão com manjericão e cravo amarelo, proporcionando vantagens no uso da diversificação vegetal, podendo ser usada no manejo do pimentão orgânico.

Soil lead pollution modifies the structure of arbuscular mycorrhizal fungal communities.

The impact of lead (Pb) pollution on native communities of arbuscular mycorrhizal fungi (AMF) was assessed in soil samples from the surroundings of an abandoned Pb smelting factory. To consider the influence of host identity, bulk soil surrounding plant roots soil samples of predominant plant species (Sorghum halepense, Bidens pilosa, and Tagetes minuta) growing in Pb-polluted soils and in an uncontaminated site were selected. Molecular diversity was assessed by sequencing the 18S rDNA region with primers specific to AMF (AMV4.5NF/AMDGR) using Illumina MiSeq. A total of 115 virtual taxa (VT) of AMF were identified in this survey. Plant species did not affect AMF diversity patterns. However, soil Pb content was negatively correlated with VT richness per sample. Paraglomeraceae and Glomeraceae were the predominant families while Acaulosporaceae, Ambisporaceae, Archaeosporaceae, Claroideoglomeraceae, Diversisporaceae, and Gigasporaceae were less abundant. Acaulosporaceae and Glomeraceae were negatively affected by soil Pb, but Paraglomeraceae relative abundance increased under increasing soil Pb content. Overall, 26 indicator taxa were identified; four of them were previously reported in Pb-polluted soils (VT060; VT222; VT004; VT380); and five corresponded to cultured spores of Scutellospora castaneae (VT041), Diversispora spp. and Tricispora nevadensis (VT060), Diversispora epigaea (VT061), Glomus proliferum (VT099), and Gl. indicum (VT222). Even though AMF were present in Pb-polluted soils, community structure was strongly altered via the differential responses of taxonomic groups of AMF to Pb pollution. These taxon-specific differences in tolerance to soil Pb content should be considered for future phytoremediation strategies based on the selection and utilization of native Glomeromycota.

Soil amendments for cadmium phytostabilization by five marigold cultivars.

In recent years, ornamental plants have come under investigation as phytoremediation agents. In addition to reducing contaminant concentrations in soil, such plants support local economies by serving social (e.g., religious) and decorative purposes. Greenhouse studies investigated the phytostabilization potential of soil cadmium (Cd) by five cultivars of marigold (Tagetes erecta), a common ornamental flower in Asia. The effects of organic (cattle manure and pig manure) and inorganic (leonardite and Osmocote®) amendments in supporting plant growth and enhancing Cd uptake were also examined. Marigold cultivars Babuda and Sunshine grown in soil supplemented with pig manure produced the greatest biomass and experienced greatest Cd accumulation and flower production. In all treatments, plant parts accumulated Cd in the following order: root > shoot ≈ flower. Furthermore, Babuda and Sunshine cultivars had a high phytostabilization potential as evidenced by translocation factors < 1 and bioconcentration factors > 1 for roots. It is proposed that Babuda and Sunshine marigold cultivars be applied toward Cd phytostabilization while enhancing local economies as an ornamental species.

Parasitoids diversity in organic Sweet Pepper (Capsicum annuum) associated with Basil (Ocimum basilicum) and Marigold (Tagetes erecta ).

The sweet pepper (Capsicum annuum L.) is one of the most important crops in Brazilian farming. Many insect are related to this crop, compromising the quantity and quality of the fruit, representing a production problem. Vegetable diversification is one of the main elements that can be managed for suppressing undesirable insect populations in organic production, once that supports the presence of natural enemies. The basil Ocimum basilicum L. and the marigold Tagetes erecta L. are attractive and nutritious plants for parasitoids, being important candidates for diversified crops. This study evaluated the parasitoids attracted by the association of basil and marigold to organic sweet pepper crop. The experiment comprised three treatments: a) sweet pepper monoculture; b) sweet pepper and basil intercropping; c) sweet pepper and marigold intercropping. Hymenopteran parasitoids were collected over 14 weeks. 268 individuals from 12 families and 41 taxa were collected. Sweet pepper monoculture, sweet pepper-basil intercropping, and sweet pepper-marigold intercropping hosted 40, 98, and 130 individuals and richness of 24, 24, and 23, respectively. Furthermore, the insects of greater abundance in the basil and marigold were different to those collected in the monoculture. The number of parasitoids increased in the associations of sweet pepper with basil and marigold, providing advantages in the use of vegetable diversification for the organic pepper crops management.

Stability lies in flowers: Plant diversification mediating shifts in arthropod food webs.

Arthropod community composition in agricultural landscapes is dependent on habitat characteristics, such as plant composition, landscape homogeneity and the presence of key resources, which are usually absent in monocultures. Manipulating agroecosystems through the insertion of in-field floral resources is a useful technique to reduce the deleterious effects of habitat simplification. Food web analysis can clarify how the community reacts to the presence of floral resources which favour ecosystem services such as biological control of pest species. Here, we reported quantitative and qualitative alterations in arthropod food web complexity due to the presence of floral resources from the Mexican marigold (Tagetes erecta L.) in a field scale lettuce community network. The presence of marigold flowers in the field successfully increased richness, body size, and the numerical and biomass abundance of natural enemies in the lettuce arthropod community, which affected the number of links, vulnerability, generality, omnivory rate and food chain length in the community, which are key factors for the stability of relationships between species. Our results reinforce the notion that diversification through insertion of floral resources may assist in preventing pest outbreaks in agroecosystems. This community approach to arthropod interactions in agricultural landscapes can be used in the future to predict the effect of different management practices in the food web to contribute with a more sustainable management of arthropod pest species.

Acclimatization study of Tagetes lucida L. in Egypt and the chemical characterization of its essential oils.

Seeds of Tagetes lucida were imported to Egypt from Canada and propagated under greenhouse conditions in peat moss media. Soil was sandy in texture and the irrigation system was dripping irrigation. The growth parameters were determined at five successive plant ages, fresh and dry weights of herb were determined at three successive plant ages. The yield of aerial parts after 175 days, was about 7.5 Mg/ha. The essential oil (EO) was extracted by hydro-distillation for three hours with a yield of about 0.5% (w/v). The EO of each sample was subjected to gas-chromatography/mass spectrometry analyses to study the chemical composition. The main component of the EO was identified as methyl chavicol which matched over 90% of the whole composition. Chlorophyll a and carotenes increased with increasing plant age in both sites and seasons. Flavonoids decreased with the development of plant age, while the opposite was true with coumarines content.

Characterization and Functional Analysis of Five MADS-Box B Class Genes Related to Floral Organ Identification in Tagetes erecta.

According to the floral organ development ABC model, B class genes specify petal and stamen identification. In order to study the function of B class genes in flower development of Tagetes erecta, five MADS-box B class genes were identified and their expression and putative functions were studied. Sequence comparisons and phylogenetic analyses indicated that there were one PI-like gene-TePI, two euAP3-like genes-TeAP3-1 and TeAP3-2, and two TM6-like genes-TeTM6-1 and TeTM6-2 in T. erecta. Strong expression levels of these genes were detected in stamens of the disk florets, but little or no expression was detected in bracts, receptacles or vegetative organs. Yeast hybrid experiments of the B class proteins showed that TePI protein could form a homodimer and heterodimers with all the other four B class proteins TeAP3-1, TeAP3-2, TeTM6-1 and TeTM6-2. No homodimer or interaction was observed between the euAP3 and TM6 clade members. Over-expression of five B class genes of T. erecta in Nicotiana rotundifolia showed that only the transgenic plants of 35S::TePI showed altered floral morphology compared with the non-transgenic line. This study could contribute to the understanding of the function of B class genes in flower development of T. erecta, and provide a theoretical basis for further research to change floral organ structures and create new materials for plant breeding.

Uptake and translocation of benzo[a]pyrene (B[a]P) in two ornamental plants and dissipation in soil.

Pot experiments were conducted to evaluate the phytoremediation of B[a]P contaminated soil using two ornamental plants (Tagetes patula and Mirabilis jalapa). The results showed that the dry biomass of two plants was increased at low B[a]P contaminated soil and then inhibited with increasing B[a]P concentrations. It exhibited a significantly positive linear relationship between B[a]P absorption in roots, stems, leaves and shoots of the tested plants and the concentration of B[a]P in soils (P<0.01). Meanwhile, the contents of B[a]P in different tissues of the plants increased with growing time. After planting T. patula and M. jalapa, plant-promoted biodegradation of B[a]P was account for 79.5-99.8% and 71.1-99.9%, respectively, whereas the amount of B[a]P dissipation enhancement was only 0.2-20.5% and 0.1-28.9%, respectively. Moreover, low bioaccumulation factor (BF) and translocation factor (TF) values indicated that T. patula and M. jalapa took up B[a]P from contaminated soil and transferred them to the aerial parts with low efficiency. The B[a]P removal rates in rhizosphere soils at different growing stages of T. patula and M. jalapa were 2.7-26.8% and 0.4%-33.9%, respectively, higher than those of non-rhizopshere soils. Therefore, the presence of T. patula and M. jalapa roots was effective in promoting the phytoremediation of B[a]P contaminated soils.

[Effects of different perlite additions on physical and chemical properties of sewage sludge compost and growth of Tagetes patula].

In order to resolve the problem of poor permeability of sewage sludge compost (SSC) which was used as the substitution of peat, perlite was used to regulate the permeability of the sewage. The pure SSC was used as control. The proportions of perlite in the mixtures with SSC were 20%, 40%, 60%, 80% and 100% (V/V), respectively. The effects of different perlite ratios on the physical and chemical properties and the growth of Tagetes patula were studied. The bulk density, water holding porosity and water holding porosity to aeration porosity decreased, but the total porosity and aeration porosity increased with the increasing addition of perlite to the SSC. For the chemical properties, the pH increased, and the EC and nutrient contents decreased with the increasing addition of perlite to the SSC. The aboveground biomass and flowers of T. patula were the highest in the 60% perlite treatment, and the lowest in the pure SSC treatment. The root morphology and activity were the best in the 40%, 60% and 80% perlite treatments. Aeration was the strongest factor to impact the maximum root length and average root diameter. Perlite promoted the growth of T. patula mainly through impacting the physical properties of the SSC. The addition of 60% perlite to the SSC could significantly improve the poor aeration and decrease the high salinity greatly in the SSC and regulate the growth of the root and aboveground of T. patula.

Influence of heavy metal rich tannery sludge on soil enzymes vis-à-vis growth of Tagetes minuta, an essential oil bearing crop.

Tannery sludge is available in plenty and is hazardous to environment as well as plant and animal life. It is very important to manage the tannery sludge in an environmentally sound manner. The aim of this study was to assess the physico-chemical, microbial and biochemical properties of soil treated with different levels of sludge. In this study, Tagetes minuta an essential oil bearing crop was grown in two different textured soils treated with different levels of tannery sludge. Application of tannery sludge (TS) increased the growth and oil yield of plant and also the activity of urease and soil microbial biomass nitrogen (SMBN) when applied in 50:50 combinations of soil:sludge. The crop performed well in coarse soil with a soil:sludge ratio of 50:50. High concentration of tannery sludge exhibited inhibitory effect on SMBN and urease activity. Acid/alkaline phosphatase, dehydrogenase and soil microbial biomass carbon (SMBC) increased as the sludge concentration increased in soil. This may be due to high organic matter present in tannery sludge. Roots accumulated more metal than the shoot. No detectable amount of metal was found in oil of T.minuta. To test the relation between 20 characters principal component analysis (PCA) was performed. PCA analysis indicates that cation exchange capacity (CEC), SMBC, dehydrogenase, acid and alkaline phosphatases were grouped in group 1. SMBN, urease and cis-ocimene content in oil were in group 2 whereas biomasss, chlorophyll a, limonene, Z and E-tagetone were in group 3. PC-I contributes 54% of total variance and PC-II contributes 38% of the total variance. The results concluded that T.minuta can mitigate metal toxicity by root absorption. Microbial activity and biomass of plant was higher in coarse soil with TS than fine soil with TS.

Callus culture development of two varieties of Tagetes erecta and carotenoid production

Background The properties of natural pigments, such as antioxidants, functional, medical, and nutraceutical, have demonstrated the advantages of these natural compounds over synthetic ones. Some products are accepted only when they are pigmented with natural, food-quality colorants: for example poultry products (manly marigold flower extracts). Carotenoids such as β-carotene, β-criptoxanthin and lutein are very attractive as natural food colorants due to their antioxidant and pro-vitamin activities which provide additional value to the target products. Marigold (Tagetes erecta) is an Asteraceous ornamental plant native to Mexico, and it is also important as a carotenoid source for industrial and medicinal purposes but nowadays its production is destined mainly for ornamental purposes. Results Friable callus of T. erecta yellow flower (YF) and white flower (WF) varieties was induced from leaf explants on Murashige and Skoog (MS) medium supplemented with 9.0 µM 4-dichlorophenoxyacetic acid (2,4-D) and 8.8 µM benzyladenine (BA). Calluses developed from both varieties were different in pigmentation. Extract characterization from callus cultures was carried out by high-performance liquid chromatography (HPLC). This analytical process detected several carotenoids; the main pigments in extracts from YF callus were lutein and zeaxanthin, whereas in the extracts of the WF callus the main pigments were lutein, zeaxanthin, β-cryptoxanthin and β-carotene. Callus cultures of T. erecta accumulated pigments even after several rounds of subculture. Conclusions WF callus appeared to be a suitable candidate as a source of different carotenoids, and tested varieties could represent an alternative for further studies about in vitro pigment production.

The effect of phosphate bio-fertilizer (Barvar-2) on the growth of marigold.

The present study was conducted to study the individual and combined effect of bio-fertilizer (Barvar-2) and chemical phosphate fertilizer on the floral quality of marigold (Tagetes erecta L.). A factorial experiment was carried out which consisted of two factors: i) inoculation of seed, root and seed + root with bio-fertilizer (Barvar-2) and control; application of chemical phosphorus at 100 mg I(-1), 200 mg l(-1), 300 mg l(-1) and 400 mg l(-1) levels. In this study, flowering time, display life, fresh and dry weight of flower, available soil phosphorus, shoot phosphorus and carotenoid content were evaluated. Results showed that the combined effect of bio- and chemical fertilizer was insignificant (p < 1 and 5%) for most of the characteristics studied except for shoot phosphorus and carotenoid content in petals. The lowest time to flowering (64.67 days) was obtained in seeds and transplant roots inoculation to bio-fertilizer x 400 mg I(-1) P. Maximum display life (25.35), fresh weight (16.20 g), carotenoid content (3.903 mg g(-1) d. wt.) and concentration of P in shoots (0.352%) were observed in transplant roots inoculation to bio-fertilizer x 400 mg I(-1) P.

The potential of gibberellic acid 3 (GA3) and Tween-80 induced phytoremediation of co-contamination of Cd and Benzo[a]pyrene (B[a]P) using Tagetes patula.

The present study was conducted to investigate the effectiveness of GA(3) and Tween-80 on enhancing the phytoremediation of Cd-B[a]P co-contaminated soils. Results showed that the addition of GA(3) and GA(3)-Tween-80 enhanced Tagetes patula growth by 14%-32% and 23%-55%, respectively, relative to the control group. However, under independent GA(3)-treated soils, Cd and B[a]P concentrations in the shoots of the plants decreased by 15%-33% and 15%-53%, respectively, compared with CK. By contrast, the shoot concentration and accumulation of Cd under GA(3)-Tween-80 treatment increased by 0.01-0.46 and 1.33-1.55 times, respectively, whereas those of B[a]P increased from 0.57 to 0.82, and 1.33 to 1.55 times, respectively, compared with those of the control. Optimal result for Cd phytoextraction was obtained under combined 5 mmol Tween-80 kg(-1) and 1 mmol GA(3) kg(-1) treatment, and the maximum removal rate of B[a]P was obtained after the application of 5 mmol Tween-80 kg(-1) and 5 mmol GA(3) kg(-1).

Nitric oxide and hydrogen peroxide alleviate drought stress in marigold explants and promote its adventitious root development.

Drought stress is one of the most important environmental factors that regulates plant growth and development. In this study, we examined the effects of nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) on adventitious rooting in marigold (Tagetes erecta L.) under drought stress. The results showed that the promoting effect of NO or H(2)O(2) on rooting under drought stress was dose-dependent, with a maximal biological response at 10 µM NO donor sodium nitroprusside (SNP) or 600 µM H(2)O(2). Results also indicated that endogenous NO and H(2)O(2) may play crucial roles in rooting under drought conditions, and H(2)O(2) may be involved in rooting promoted by NO under drought stress. NO or H(2)O(2) treatment attenuated the destruction of mesophyll cells ultrastructure by drought stress. Similarly, NO or H(2)O(2) increased leaf chlorophyll content, chlorophyll fluorescence parameters (Fv/Fm, ΦPS II and qP), and hypocotyls soluble carbohydrate and protein content, while decreasing starch content. Results suggest that the protection of mesophyll cells ultrastructure by NO or H(2)O(2) under drought conditions improves the photosynthetic performance of leaves and alleviates the negative effects of drought on carbohydrate and nitrogen accumulation in explants, thereby adventitious rooting being promoted.