Phytostabilization of coal mine overburden waste, exploiting the phytoremedial efficacy of lemongrass under varying level of cow dung manure.

A pot study was performed to assess the phytoremedial potential of Cymbopogon citratus (D.C.) Staf. for reclamation of coal mine overburden dump wastes, emphasizing the outcome of amendment practices using cow dung manure (CM) and garden soil mixtures on the revegetation of over-burden wastes (OB). Wastes amendment with cow dung manure and garden soil resulted in a significant increase in soil health and nutrient status along with an increment in the phytoavailability of Zn and Cu which are usually considered as micronutrients, essential for plant growth. A significant increment in the total biomass of lemongrass by 38.6% under CM20 (OB: CM 80:20) was observed along with improved growth parameters under amended treatments as compared to OB (100% waste). Furthermore, the proportionate increases in the assimilative rate, water use efficiency, and chlorophyll fluorescence have been observed with the manure application rates. Lemongrass emerged out to be an efficient metal-tolerant herb species owing to its high metal-tolerance index (>100%). Additionally, lemongrass efficiently phytostablized Pb and Ni in the roots. Based on the strong plant performances, the present study highly encourages the cultivation of lemongrass in coal mining dumpsites for phytostabilization coupled with cow-dung manure application (20% w/w).

Gamma rays induced acquisition of structural modification in chitosan boosts photosynthetic machinery, enzymatic activities and essential oil production in citronella grass (Cymbopogon winterianus Jowitt).

Oligomers derived through irradiation of marine polysaccharides have generated a lot of interest of plant biologists as the application of these molecules has yielded positive results regarding various plant processes. To comprehend the previously established growth-promoting activity of irradiated chitosan (ICH) and to gain insight of the structure-property relationship, gamma rays induced structural changes were analyzed using techniques such as Fourier Transform Infrared (FT-IR) spectroscopy, Ultraviolet-visible (UV-Vis) spectroscopy, 13C-Nuclear Magnetic Resonance (NMR) spectroscopy and Scanning Electron Microscopy (SEM). Moreover, to study the bioactivity of ICH samples a pot experiment was conducted on citronella grass (Cymbopogon winterianus) to access its response to foliar application of various levels (40, 60, 80 and 100 mg L-1) of ICH in terms of growth, physiological attributes and essential oil (EO) production. The application of ICH at 80 mg L-1(ICH-80) resulted in the maximum values of most of the attributes studied. Due to this treatment, the maximum improvement in the content (29.58%) and yield (90.81%) of EO in Cymbopogon winterianus were achieved. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that ICH-80 also increased the content of citronellal (14.81%) and geraniol (18.15%) of the EO as compared to the control.

Biochar aided aromatic grass [Cymbopogon martini (Roxb.) Wats.] vegetation: A sustainable method for stabilization of highly acidic mine waste.

Dumping of acidic mine waste poses severe threats to the ecosystem due to high acidity, nutrient deficiency and mobility of toxic metals. The present study has been undertaken on phytoremediation by amending the acidic soil/mine waste with biochar (BC) and plantation of palmarosa (Cymbopogon martini (Roxb.) Wats. A greenhouse experiment in different combinations of biochar and acidic mine waste was conducted to assess the phytoremediation efficiency of palmarosa by BC amendments. Results indicate that the palmarosa tolerates multiple stresses effectively with a 54 % metal tolerance index (MTI) and capable of reducing acid production from the acidic mine waste alone. BC incorporation in the mine waste and soil treatments significantly enhanced the palmarosa biomass (1.11-3.3 times) and oil content by liming the acid, immobilization of metals and improving the soil quality. BC addition in highly acidic mine waste amplified the phytoremediation efficiency and mitigates abiotic oxidative stress on plants (MTI 84 % to >100 %). BC aided palmarosa plantation shifted the soil from high-risk assessment code (RAC) to low RAC for vegetation. Biochar amendments along with palmarosa plantation offer a sustainable technology for phytostabilization of highly acidic mine waste along with the production of industrially important essential oil.

An in situ study of growth of Lemongrass Cymbopogon flexuosus (Nees ex Steud.) W. Watson on varying concentration of Chromium (Cr+6) on soil and its bioaccumulation: Perspectives on phytoremediation potential and phytostabilisation of chromium toxicity.

Chromium (Cr) contamination in soil is a growing concern in sustainable agricultural production and food safety. Remediation of Cr from contaminated soils is a challenging task which may not only help in sustaining agriculture but also in minimizing adverse environmental impacts. Pot culture experiments were performed with the application of varied concentration of Cr+6 to assess the Chromium accumulation potential of Lemongrass and to study the impact of toxic concentration of Cr+6 on morphological, physiological and biochemical parameters of the plant. The results showed an increasing accumulation trend of Chromium with increasing Chromium concentrations in both root and shoot of 60 days old Lemongrass plants, while the protein and chlorophyll contents decreased. Similarly, accumulation of Cr increased the levels of proline and antioxidant enzymes indicating the enhanced damage control activity. The potentiality of the plant with the capacity to accumulate and stabilize Cr compound in Cr contaminated soil by phytoremediation process has been explored in the present investigation.

Proliferating effect of radiolytically depolymerized carrageenan on physiological attributes, plant water relation parameters, essential oil production and active constituents of Cymbopogon flexuosus Steud. under drought stress.

Carrageenan has been proved as potent growth promoting substance in its depolymerized form. However, relatively little is known about its role in counteracting the adverse effects of drought stress on plants. In a pot experiment, lemongrass (Cymbopogon flexuosus Steud.), grown under different water stress regimes [(100% field capacity (FC), 80% FC and 60% FC)], was sprayed with 40, 80 and 120 mg L-1 of gamma irradiated carrageenan (ICA). Foliar application of ICA mitigated the harmful effects of drought stress to various extents and improved the biochemical characteristics, quality attributes and active constituents (citral and geraniol) of lemongrass significantly. Among the applied treatments, ICA-80 mg L-1 proved the best in alleviating detrimental effects of drought. However, drought stress (80 and 60% FC), irrespective of the growth stages, had an adverse impact on most of the studied attributes. Generally, 60% FC proved more deleterious than 80% FC. At 80% FC, application of ICA-80 mg L-1 elevated the essential oil (EO) content by 18.9 and 25%, citral content by 7.33 and 8.19% and geraniol content by 9.2 and 8.9% at 90 and 120 days after planting (DAP), respectively, as compared to the deionized-water (DW) spray treatment (80% FC+ DW). Whereas, at 60% FC, foliar application of 80 mg L-1 ICA significantly augmented the EO content by 15.4 and 17.8% and active constituents viz. citral and geraniol, by 5.01 and 5.62% and by 6.06 and 5.61% at 90 and 120 DAP, respectively, as compared to the control (water-spray treatment).

In Vitro Mass Propagation of Cymbopogon citratus Stapf., a Medicinal Gramineae.

Cymbopogon citratus (D.C.) Stapf. is a medicinal plant source of lemon grass oils with multiple uses in the pharmaceutical and food industry. Conventional propagation in semisolid culture medium has become a fast tool for mass propagation of lemon grass, but the production cost must be lower. A solution could be the application of in vitro propagation methods based on liquid culture advantages and automation. This chapter provides two efficient protocols for in vitro propagation via organogenesis and somatic embryogenesis of this medicinal plant. Firstly, we report the production of shoots using a temporary immersion system (TIS). Secondly, a protocol for somatic embryogenesis using semisolid culture for callus formation and multiplication, and liquid culture in a rotatory shaker and conventional bioreactors for the maintenance of embryogenic culture, is described. Well-developed plants can be achieved from both protocols. Here we provide a fast and efficient technology for mass propagation of this medicinal plant taking the advantage of liquid culture and automation.

Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii.

Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha-1 and 15.11 Mg palmarosa ha-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha-1 respectively compared to reported 1749-3691 L ethanol ha-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass)-1. Additionally, lemongrass yielded 85.7 kg essential oil ha-1 and palmarosa yielded 67.0 kg ha-1 with an estimated value of USD $857 and $1005 ha-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.

Palmarosa [Cymbopogon martinii (Roxb.) Wats.] as a putative crop for phytoremediation, in tannery sludge polluted soil.

A field experiment using tannery sludge as a soil amendment material and palmarosa (Cymbopogon martinii) as a potential phytostabilizer was conducted to investigate their synergistic effect in relation to the improvement in soil quality/property. Three consecutive harvests of two cultivars of palmarosa-PRC-1 and Trishna, were examined to find out the influence of different tannery sludge doses on their herb, dry matter, essential oil yield and heavy metal accumulation. Soil fertility parameters (N, P, K, Organic carbon) were markedly affected by different doses of sludge. Enhanced soil nitrogen was positively correlated with herb yield (0.719*) and plant height (0.797*). The highest dose of tannery sludge (100 t ha(-1)) exhibited best performance than other treatments with respect to herb, dry matter and oil yield in all three harvests. Trishna was found to be superior to PRC-1 in relation to same studied traits. Quality of oil varied, but was insignificant statistically. Uptake of heavy metals followed same order (Cr>Ni>Pb>Cd) in roots and shoots. Translocation factor <1 for all trace elements and Bioconcentration factor >1 was observed in case of all heavy metals. Overall, tannery sludge enhanced the productivity of crop and metal accumulation occurred in roots with a meager translocation to shoots, hence it can be used as a phytostabiliser. The major advantage of taking palmarosa in metal polluted soil is that unlike food and agricultural crops, the product (essential oil) is extracted by hydro-distillation and there is no chance of oil contamination, thus is commercially acceptable.

Effect of Organic Manures on the Growth of Cymbopogon citratus and Chrysopogon zizanioides for the Phytoremediation of Chromite-Asbestos Mine Waste: A Pot Scale Experiment.

The abandoned chromite-asbestos mines are located in the Roro hills, West Singhbhum, Jharkhand, India, where mining operation ceased in 1983, and since then these mines are causing environmental pollution. The present study was planned to phytoremediate these metalloid and metal contaminated mine waste by using two aromatic grasses, Cymbopogon citratus and Chrysopogon zizanioides by applying different proportions of amendments (chicken manure, farmyard manure and garden soil). Mine waste has neutral pH, low electrical conductivity and organic carbon with higher concentration of total metals (Cr and Ni) as compared to soil. Application of manures resulted significant improvements of mine waste characteristics and plant growth, reduction in the availability of total extractable toxic metals (Cr, Ni) and increase in Mn, Zn and Cu concentration in the substrate. The maximum growth and biomass production for C. citratus and C. zizanioides were found in T-IV combination comprising of mine waste (90%), chicken manure (2.5%), farmyard manure (2.5%) and garden soil (5%). Addition of T-IV combination also resulted in low Cr and Ni accumulation in roots and reduction in translocation to shoots. Study indicates that C. citratus and C. zizanioides can be used for phytostabilization of abandoned chromite-asbestos mine waste with amendments.

Produtividade e qualidade do óleo essencial de capim-limão, Cymbopogon citratus, DC, submetido a diferentes lâminas de irrigaçã / Growth production and essential oil quality of lemongrass (Cymbopogon citratus) under different irrigation depths

Devido às poucas informações sobre as práticas de cultivo do capim-limão (Cymbopogon citratus, DC.) objetivou-se avaliar o efeito de lâminas de irrigação sobre: a produção de biomassa, o rendimento e composição do óleo essencial. O experimento foi instalado em ambiente protegido para possibilitar o controle das lâminas de irrigação e avaliar a viabilidade para situações em que as condições climáticas normais sejam inadequadas. O delineamento experimental foi em blocos inteiramente casualizados com cinco tratamentos e três repetições. Os dados foram submetidos à análise de variância pelo tese F e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Na etapa um, os tratamentos consistiram da aplicação de lâminas referentes a 50%, 75%, 100%, 125% da evapotranspiração da cultura (ETc), irrigando duas vezes por semana e de 100% da evapotranspiração da cultura (ETc), irrigando uma vez por semana, sendo denominados de T1, T2, T3, T4 e T5, respectivamente. Na etapa dois, os tratamentos consistiram da aplicação de lâminas referentes a 50%, 75%, 100%, 125% da ETc irrigando uma vez por semana e de 100% da ETc, irrigando a cada 14 dias, sendo denominados de T6, T7, T8, T9 e T10 respectivamente. O corte do capim-limão foi realizado após 60 dias do início dos tratamentos. Avaliou-se a altura de plantas, o número de perfilhos por touceira, a massa seca da parte aérea, o rendimento e a composição do óleo essencial. O T5, caracterizado por estresse hídrico e intervalo de irrigação moderado, foi o que apresentou a maior produção de matéria seca, maior produtividade do capim-limão e maior estimativa da produtividade de óleo essencial e maior concentração de citral, na primeira etapa. Na etapa dois, o T6, correspondente ao estresse hídrico crescente e acentuado, foi o que apresentou maior estimativa da produtividade de óleo essencial. De acordo com os resultados observados, não foi possível definir a melhor lâmina, porém, concluiu-se que uma única irrigação semanal, para as condições estudadas neste experimento promoveu o melhor resultado.

The aim of this work was to evaluate the effect of different irrigation depths on biomass production, yield and composition of lemongrass (Cymbopogon citratus)essential oil, because of poor information on cultivation practices. The experiment was set up in a protected environment to control irrigation and also to evaluate situations in which the normal climatic conditions are inadequate. A complete randomized block design was incorporated with five treatments and three replications, and averages were compared using the Tukey's test at 5% probability. In phase one, the treatments consisted of irrigation depths relating to 50%, 75%, 100%, 125% of crop evapotranspiration (ETc), irrigating twice a week, and irrigating only once a week for a sample supplied with 100% of the crop evapotranspiration (ETc); these were labeled T1, T2, T3, T4 and T5, respectively. In phase two, the treatments consisted of depths of 50%, 75%, 100%, 125% of the ETc, irrigating once a week, and another with 100% of the ETc, irrigating every 14 days, which were denominated T6, T7, T8, T9 and T10, respectively. Harvest of the lemon grass was done after 60 days of treatment. Plant height, number of tillers per plant, dry mass of the shoots, yield and composition of essential oil were evaluated. Treatment T5, characterized by water stress and a moderate irrigation interval, presented the highest dry matter production, lemongrass productivity, estimate of essential oil productivity and concentration of citral in the first phase. In phase two of this work, T6,characterized by a sharp increaseof water stress, presented the greatest estimate of essential oil productivity. According to the results observed, we could not define an optimal irrigation depth; however, we concluded that a single irrigation per week for the conditions of this experiment provided the best result.

Controle de plantas invasoras em cultivo orgânico e convencional de capim-limão (Cymbopogon citratus (DC) Stapf. ) / Weed control in organic and conventional crops of lemongrass

O cultivo orgânico é preconizado para o capim-limão (Cymbopogon citratus (DC) Stapf.) como planta medicinal promissora ao desenvolvimento de fármacos no Brasil. Objetivou-se avaliar técnicas de controle de plantas invasoras sobre componentes de produção de capim limão em cultivos orgânico e convencional. Dois experimentos foram instalados sob delineamento inteiramente casualizado, com quatro repetições, em esquema fatorial 2x2x3, considerando-se duas áreas (orgânico e convencional) e os tratamentos combinando cobertura morta (presente e ausente) e técnicas de controle de plantas invasoras (capina manual, roçada e nenhuma). Altura, perfilhamento, teor e rendimento total de óleo essencial de capim-limão no cultivo orgânico foram superiores ao convencional, mas a produtividade de biomassa aérea seca não diferiu entre ambos. A capina, com ou sem cobertura morta, favoreceu o rendimento de óleo no cultivo orgânico.

Organic farming is recommended for lemongrass as a promising medicinal plant for drug development in Brazil. The purpose of this paper was to evaluate the effect of the techniques to control weed on the plant height, tillering, biomass productivity, content and yield of the essential oil of lemon grass in organic and conventional crops. Two experiments were set in a completely randomized design with four replications, at a 2x2x3 factorial scheme, considering two areas (organic and conventional) and treatments combining mulching (present and absent) and weed control techniques (hoeing, skimming and none). Plant height, tillering, content and yield of the essential oil of lemongrass were better in the organic crop, but the biomass productivity did not differ between both areas. The biomass production was better in the conventional crop as to weed control, with or without mulching, and for organic crop under hoeing or skimming with mulching. Hoeing or skimming with no mulching improved the oil content in organic crops. Hoeing or skimming with mulching was better than any other weed control technique with no mulching, and hoeing was better than skimming, justifying its recommendation as a technique for this crop system.

Grazing-induced effects on soil properties modify plant competitive interactions in semi-natural mountain grasslands.

Plant-soil feedbacks are widely recognized as playing a significant role in structuring plant communities through their effects on plant-plant interactions. However, the question of whether plant-soil feedbacks can be indirectly driven by other ecological agents, such as large herbivores, which are known to strongly modify plant community structure and soil properties, remains poorly explored. We tested in a glasshouse experiment how changes in soil properties resulting from long-term sheep grazing affect competitive interactions (intra- and inter-specific) of two graminoid species: Nardus stricta, which is typically abundant under high sheep grazing pressure in British mountain grasslands; and Eriophorum vaginatum, whose abundance is typically diminished under grazing. Both species were grown in monocultures and mixtures at different densities in soils taken from adjacent grazed and ungrazed mountain grassland in the Yorkshire Dales, northern England. Nardus stricta performed better (shoot and root biomass) when grown in grazing-conditioned soil, independent of whether or not it grew under inter-specific competition. Eriophorum vaginatum also grew better when planted in soil from the grazed site, but this occurred only when it did not experience inter-specific competition with N. stricta. This indicates that plant-soil feedback for E. vaginatum is dependent on the presence of an inter-specific competitor. A yield density model showed that indirect effects of grazing increased the intensity of intra-specific competition in both species in comparison with ungrazed-conditioned soil. However, indirect effects of grazing on the intensity of inter-specific competition were species-specific favouring N. stricta. We explain these asymmetric grazing-induced effects on competition on the basis of traits of the superior competitor and grazing effects on soil nutrients. Finally, we discuss the relevance of our findings for plant community dynamics in grazed, semi-natural grasslands.

Floral structure of Cardiopteris (Cardiopteridaceae) with special emphasis on the gynoecium: systematic and evolutionary implications.

Cardiopteris, a small herbaceous genus, had long been placed in its own family, Cardiopteridaceae. However, the family was recently broadly circumscribed to include more genera in Aquifoliales. To better understand the morphological relationships of the genus and the family, I studied the floral anatomy and development of Cardiopteris using C. quinqueloba. As has been previously described, flowers are 5-merous with a unilocular gynoecium. I confirmed that the gynoecium is bicarpellate, possessing two dissimilar styles. An analysis of the development, structure, and vasculature of the gynoecium showed that it is pseudomonomerous, consisting of one fertile adaxial carpel and one solid sterile abaxial carpel. The adaxial carpel forms a thin style with a capitate stigma, whereas the abaxial carpel has a thick style, which develops into a freshy fruit appendage. Comparisons with flowers of other genera (Citronella, Gonocaryum, and Leptaulus) of Cardiopteridaceae as well as the other families (Aquifoliaceae, Helwingiaceae, Phyllonomaceae, and Stemonuraceae) of Aquifoliales showed that the pseudomonomerous gynoecium is very likely a synapomorphy to support the sister-group relationship between Cardiopteridaceae and Stemonuraceae. Moreover, contrary to all previous descriptions, Cardiopteris flowers were found to have an annular nectariferous disk at the base of the gynoecium.

Alleviation of salt stress in lemongrass by salicylic acid.

Soil salinity is one of the key factors adversely affecting the growth, yield, and quality of crops. A pot study was conducted to find out whether exogenous application of salicylic acid could ameliorate the adverse effect of salinity in lemongrass (Cymbopogon flexuosus Steud. Wats.). Two Cymbopogon varieties, Krishna and Neema, were used in the study. Three salinity levels, viz, 50, 100, and 150 mM of NaCl, were applied to 30-day-old plants. Salicylic acid (SA) was applied as foliar spray at 10(-5) M concentration. Totally, six SA-sprays were carried out at 10-day intervals, following the first spray at 30 days after sowing. The growth parameters were progressively reduced with the increase in salinity level; however, growth inhibition was significantly reduced by the foliar application of SA. With the increase in salt stress, a gradual decrease in the activities of carbonic anhydrase and nitrate reductase was observed in both the varieties. SA-treatment not only ameliorated the adverse effects of NaCl but also showed a significant improvement in the activities of these enzymes compared with the untreated stressed-plants. The plants supplemented with NaCl exhibited a significant increase in electrolyte leakage, proline content, and phosphoenol pyruvate carboxylase activity. Content and yield of essential oil was also significantly decreased in plants that received salinity levels; however, SA overcame the unfavorable effects of salinity stress to a considerable extent. Lemongrass variety Krishna was found to be more adapted to salt stress than Neema, as indicated by the overall performance of the two varieties under salt conditions.

Organic and conventional fertilisation procedures on the nitrate, antioxidants and pesticide content in parts of vegetables.

Different parts of plant foods are generally discarded by consumers such as peel, stalk and leaves, which could however possess a nutritional value. However, few studies have analysed the composition of these marginal foods. The phenolic compound, flavonoid, polyamine, nitrate and pesticide contents of parts of vegetables that are usually discarded--but which were cultivated according to conventional and non-conventional procedures--were analysed to provide suggestions on how to improve the consumption of these parts and to reduce the production of urban solid waste. Few, but significant, differences between the two manuring procedures were observed. Higher nitrate content and the presence of organochlorine pesticides were found in conventional cultivated papaya peel, lemon balm leaves, jack fruit pulp, and beet stalk and peel. Discarded parts of plant foods such as stalk, leaves and peels can be used as a source of antioxidant compounds, such as phenolic compounds.

Phytostabilisation potential of lemon grass (Cymbopogon flexuosus (Nees ex Stend) Wats) on iron ore tailings.

The present pot culture study was carried out for the potential phytostabilisation of iron ore tailings using lemon grass (Cymbopogon flexuosus) a drought tolerant, perennial, aromatic grass. Experiments have been conducted by varying the composition of garden soil (control) with iron ore tailings. The various parameters, viz. growth of plants, number of tillers, biomass and oil content of lemon grass are evaluated. The studies have indicated that growth parameters of lemon grass in 1:1 composition of garden soil and iron ore tailings are significantly more (-5% increase) compared to plants grown in control soil. However, the oil content of lemon grass in both the cases more or less remained same. The results also infer that at higher proportion of tailings the yield of biomass decreases. The studies indicate that lemongrass with its fibrous root system is proved to be an efficient soil binder by preventing soil erosion.

Calagem e adubação fosfatada favorecem o crescimento do capim-limão, Cymbopogon citratus (DC) Stapf / Liming and phosphate fertilization promote lemongrass, Cymbopogon citratus (DC) Stapf. growth

O capim-limão, Cymbopogon citratus (DC) Stapf., é uma planta utilizada para fins medicinais e aromáticos, porém pouco se conhece sobre as exigências nutricionais. O objetivo do presente trabalho foi avaliar os efeitos da elevação do pH do solo e da adubação com fósforo (P) na disponibilidade de nutrientes e no crescimento inicial do capim-limão. O experimento foi conduzido em Lages, SC, de abril a dezembro de 2008, em casa de vegetação. Foi utilizado um esquema fatorial, incluindo quatro níveis de pH (4,1; 5,5; 6,0 e 6,5) e três doses de P (0, 50 e 100 mg kg-1 de solo), com quatro repetições (correspondendo a um vaso com duas plantas). A correção do pH aumentou o Ca e Mg e diminuiu o Al, Mn, Fe, Cu e Zn no solo. A aplicação de 100 mg kg-1 de P elevou em mais de 250% a concentração deste nutriente no solo, independente do pH. A aplicação de P e, principalmente, a elevação do pH do solo incrementaram todos os atributos avaliados nas plantas de capim limão (massa seca da parte aérea e do sistema radicular, número de folhas e altura de plantas), sendo que a interação entre pH e dose de P somente foi significativa para o número de folhas. O maior crescimento das plantas ocorreu no tratamento com pH 6,5, associado à adição de 100 mg kg-1 de P.

Lemongrass, Cymbopogon citratus (DC) Stapf., is a plant with medicinal and aromatic uses. However, little is known about its nutrition requirements. This work was carried out to investigate the effects of pH and phosphorus levels on nutrients availability and the initial growth of lemongrass. The experiment was carried out in Lages (SC, Brazil) from April tol December 2008, in greenhouse conditions. The experiment followed a factorial design, with four levels of pH (4.1, 5.5, 6.0, and 6.5), three doses of phosphorus (0, 50, and 100 mg kg-1 of soil), and four replicates (each replicate corresponding to a pot with two plants). The correction of pH increased Ca and Mg, and reduced Al, Mn, Fe, Cu, and Zn in the soil. The addition of 100 mg kg-1 P increased by more than 250% the P in the soil, irrespective of pH. The addition of P and the correction of pH, specially the last one, increased all growth attributes of lemongrass (dry matter of shoot and root parts, number of leaves, and plant height), with a significant interaction between pH and the dose of P only for the number of leaves. The highest plant growth was achieved by correcting the soil pH to 6.5, with the addition of 100 mg kg-1 P.

Crescimento, produção de fitomassa e teor de óleo essencial de folhas de capim citronela (Cymbopogon nardus (L. ) Rendle) em cultivo consorciado com algodoeiro colorido no semiárido mineiro / Growth, phytomass yield and essential oil content of leaves of citronella grass [Cymbopogon nardus (L. ) Rendle] intercropping with colored cotton

Avaliou-se o crescimento, a produção e o teor do óleo essencial de dois cortes de capim citronela em cultivo consorciado com algodoeiro colorido no semiárido. Para isso foram utilizados dois sistemas de consórcios (tratamentos): algodão colorido consorciado com capim citronela 3x1 e algodão colorido consorciado com capim citronela 1x1. A variedade de algodão colorido utilizada foi a BRS Rubi e as mudas de capim citronela foram produzidas no Horto de Plantas Medicinais da Unimontes. O delineamento experimental utilizado foi em blocos casualizados com dois tratamentos e 16 repetições. O experimento foi mantido em regime de sequeiro e foi avaliado a altura das plantas de capim citronela. Foram realizadas duas colheitas das folhas de capim citronela, sendo a primeira no momento da colheita da fibra do algodão e a segunda na rebrota do capim, seis meses após. Todas as plantas da parcela foram colhidas e as folhas frescas foram pesadas, no campo, com o auxílio de balança digital. Amostras das folhas colhidas foram retiradas e levadas para secagem em estufa com circulação forçada de ar a 35ºC até atingirem massa constante. Foi verificada a massa seca e posteriormente realizada a extração do óleo essencial pelo método de hidrodestilação em aparelho modificado de Clevenger. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste Skott-Knott (p<0,05). A altura das plantas não diferiu entre os tratamentos nas colheitas. Para a produção de massa fresca e seca houve diferença entre os tratamentos apenas na segunda colheita. Neste caso, as plantas cultivadas em consórcio 1x1 produziram mais do que as do consórcio 3x1. O teor de óleo essencial de capim citronela não variou entre os dois sistemas de consórcio, tanto no primeiro como no segundo corte.

The research was performed to evaluate the growth, production and essential oil content of the two harvests of citronella grass in intercropped with colored cotton in semiarid.For this, was used two system consortium (treatments): colored cotton intercropped with citronella grass 3X1 and colored cotton intercropped with citronella grass 1X1. The variety of colored cotton used was BRS Rubi and the citronella grass seedlings were produced in the Medicinal Plants Garden of Unimontes. The experimental design used was randomized blocks with two treatments and 16 repetitions. The experiment was maintained under rainfed conditions. Was evaluated plant height of citronella grass. Citronella grass leaves were harvested twice: the first was made at harvest of cotton fiber and the second in the grass regrowth, six months later. All plants in the plot were harvested and the fresh leaves were weighed, in the field, with the aid of a digital balance. Samples from leaves harvested were collected and taken for drying in an oven with forced air at 35ºC until reaching constant weight. Dry mass was verified and the performed the extraction of essential oil by hydrodestilation in Clevenger modified apparatus. Data were subjected to analysis of variance and means compared by Skott-Knott test (p<0.05). The plants height did not differ between treatments in harvests. For the production of fresh and dry mass was significant difference between treatments only in the second harvest. In this case the plants cultivated in the consortium 1x1 produced more than in the consortium 3x1. The essential oil content of citronella grass did not vary between the two systems consortium, in the first and the second harvest.

Growth inhibition and morphological alterations of Trichophyton rubrum induced by essential oil from Cymbopogon winterianus Jowitt ex Bor

Trichophyton rubrum is one of the most common fungi causer of dermatophytosis, mycosis that affect humans and animals around the world. Researches aiming new products with antifungal activity become necessary to overcome difficulties on treatment of these infections. Accordingly, this study aimed to investigate the antifungal activity of essential oil from Cymbopogon winterianus against the dermatophyte T. rubrum. The antifungal screening was performed by solid medium diffusion method with 16 T. rubrum strains, minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined using the microdilution method. The effects on mycelial dry weight and morphology were also observed. Screening showed essential oil in natura inhibited all the tested strains, with inhibition zones between 24-28 mm diameter. MIC50 and MIC90 values of the essential oil were 312 µg/mL for nearly all the essayed strains (93.75 percent) while the MFC50 and MFC90 values were about eight times higher than MIC for all tested strains. All tested essential oil concentrations managed to inhibit strongly the mycelium development. Main morphological changes on the fungal strains observed under light microscopy, which were provided by the essential oil include loss of conidiation, alterations concerning form and pigmentation of hyphae. In the oil presence, colonies showed folds, cream color and slightly darker than the control, pigment production was absent on the reverse and with evident folds. It is concluded that C. winterianus essential oil showed activity against T. rubrum. Therefore, it could be known as potential antifungal compound especially for protection against dermatophytosis.

Influence of salt stress on essential oil yield and composition of lemon grass (Cymbopogon schoenanthus L. Spreng. ssp. Laniger (Hook) Maire et Weil).

Cymbopogon is an aromatic plant valued for its citrus scent aroma. In this article, the effect of saline irrigation water on yield and quality of Cymbopogon schoenanthus L. was evaluated. Compounds of essential oils were identified by gas chromatography-mass spectrometry and/or (13)C-NMR spectroscopy. Results showed that the growth of the aerial part was not affected at a concentration of 50 mmol NaCl. Under salt stress, the content of major chemical compounds was affected differently by the treatment level.