Soil cadmium and lead affecting biochemical properties of Matricaria chamomilla L. at different growth stages in the greenhouse and field.

Heavy metals bioremediation by medicinal plants is an important research issue, which has yet to be investigated. Matricaria chamomilla accumulation of soil cadmium (Cd, 0, 10 and 40 mg/kg) and lead (Pb, 0, 60 and 180 mg/kg) affecting plant biochemical properties L. at different growth stages in the greenhouse and field was investigated. The 10-kg experimental pots (located in the greenhouse and field with 80% of field capacity moisture) were filled with the treated soils, and were planted with M. chamomilla L. seeds (three replicates). Plants were sampled to determine their biochemical properties including Cd and Pb contents, pigments, proline (Pro), leaf relative water (LRW), lipid peroxidation (LX), and superoxide dismutase (SOD, EC 1.15. 1.1), and catalase (CAT, EC 1.11.1.6) activities. Soil final concentration of Cd and Pb was also determined. Heavy metal stress significantly decreased plant pigment contents; however, it significantly increased plant PRO, LRW, LX and SOD, and not CAT. Heavy metal, growth stage, growth location, and their interactions significantly affected plant heavy metal concentrations. Interestingly, although significantly higher concentration of Cd was observed in plant aerial part under greenhouse conditions, plant roots had significantly higher concentrations of Cd under field conditions, and it was reverse for Pb. Increased concentration of Cd and Pb significantly enhanced plant Pro content and the highest one was resulted by Pb3 (913.46 mg/g fresh weight) significantly higher than other treatments including Cd3 (595.34 mg/g fresh weight). M. chamomilla is a suitable species for the bioremediation of soils polluted with Cd and Pb.

A general theory for target reproduction numbers with applications to ecology and epidemiology.

A general framework for threshold parameters in population dynamics is developed using the concept of target reproduction numbers. This framework identifies reproduction numbers and other threshold parameters in the literature in terms of their roles in population control. The framework is applied to the analysis of single and multiple control strategies in ecology and epidemiology, and this provides new biological insights.

The Role of Auxin in the Pattern Formation of the Asteraceae Flower Head (Capitulum).

Nature often creates complex structures by rearranging pre-existing units. One such example is the flower head (capitulum) in daisies, where a group of flowers (florets) and phyllaries (modified bracts) are arranged to superficially mimic a single flower. The capitulum is a key taxonomical innovation that defines the daisy family (Asteraceae), the largest flowering plant group. However, patterning mechanisms underlying its structure remain elusive. Here, we show that auxin, a plant hormone, provides a developmental patterning cue for the capitulum. During capitulum development, a temporal auxin gradient occurs, regulating the successive and centripetal formation of distinct florets and phyllaries. Disruption of the endogenous auxin gradient led to homeotic conversions of florets and phyllaries in the capitulum. Furthermore, auxin regulates floral meristem identity genes, such as Matricaria inodora RAY2 and M inodora LEAFY, which determine floret and phyllary identity. This study reveals the mechanism of capitulum patterning and highlights how common developmental tools, such as hormone gradients, have independently evolved in plants and animals.

Cloning and characterization of a farnesyl pyrophosphate synthase from Matricaria recutita L. and its upregulation by methyl jasmonate.

Matricaria recutita (L.), commonly known as chamomile, is one of the most valuable medicinal plants because it synthesizes a large number of pharmacologically active secondary metabolites known as α-bisabolol and chamazulene. Although the plant has been well characterized in terms of chemical constituents of essential oil as well as pharmacological properties, little is known about the genes responsible for biosynthesis of these compounds. In this study, we report a new full-length cDNA encoding farnesyl diphosphate synthase (FPS), a key enzyme in the pathway of biosynthesis of isoprenoids, from M. recutita. The cDNA of MrFPS comprises 1032 bp and encodes 343 amino acid residues with a calculated molecular mass of 39.4 kDa. The amino acid sequence homology and phylogenetic analysis indicated that MrFPS belongs to the plant FPS super-family and is closely related to FPS from the Asteraceae family. Expression of the MrFPS gene in Escherichia coli yielded FPS activity. Using real-time quantitative PCR, the expression pattern of the MrFPS gene was analyzed in different tissues of M. recutita as well as in response to methyl jasmonate. The expression analysis demonstrated that MrFPS expression varies in different tissues (with maximal expression in flowers and stems) and was significantly elevated in response to methyl jasmonate. This study will certainly enhance our understanding of the role of MrFPS in the biosynthesis and regulation of valuable secondary metabolites in M. recutita at a molecular level.

Molecular cloning and characterization of the full-length Hsp90 gene from Matricaria recutita.

Heat shock protein 90 (Hsp90) is one of the most abundant and conserved chaperone proteins and plays important roles in plant growth and responses to environmental stimuli. However, little is known regarding the sequence and function of Hsp90s in Matricaria recutita. In the present study, we cloned the full-length cDNA sequence of the hsp90 gene from this species. Using rapid amplification of cDNA ends technologies with 2 degenerate primers that were designed based on the hsp90 gene sequence from other members of Asteraceae, we isolated and characterized an Hsp90 homolog gene from M. recutita (Mr-Hsp90). The full-length Mr-hsp90 cDNA sequence, containing 2097 base pairs, encodes a protein of 698 amino acids. Based on amino acid sequence identity, Mr-Hsp90 showed high similarity to other cloned Hsp90 proteins. The Mr-Hsp90 protein was closely clustered with the Lactuca sativa in a phylogenetic tree. These results indicate that the cloned sequence of Mr-Hsp90 is a member of the Hsp90 family, which is reported for the first time in M. recutita. Next, we conducted a salt stress experiment to determine the protein's function under salt stress conditions. Survival of chamomile seedlings subjected to heat-shock pretreatment was significantly increased compared with groups that had not undergone heat-shock pretreatment in a salt stress environment. This indicates that Mr-Hsp90 plays an important role in the salt resistance of chamomile seedlings.

Hexavalent chromium damages chamomile plants by alteration of antioxidants and its uptake is prevented by calcium.

Toxicity of low (3µM) and high (60 and 120µM) concentrations of hexavalent chromium/Cr(VI) in chamomile plants was studied. Fluorescence staining confirmed reduction of Cr(VI) to Cr(III). Cr was mainly accumulated in the roots with translocation factor <0.007. Notwithstanding this, both shoots and roots revealed increase in oxidative stress and depletion of glutathione, total thiols, ascorbic acid and activities of glutathione reductase and partially ascorbate peroxidase mainly at 120µM Cr. Though some protective mechanisms were detected (elevation of nitric oxide, enhancement of GPX activity and increase in phenols and lignin), this was not sufficient to counteract the oxidative damage. Consequently, soluble proteins, tissue water content and biomass production were considerably depleted. Surprising increase in some mineral nutrients in roots (Ca, Fe, Zn and Cu) was also detected. Subsequent experiment confirmed that exogenous calcium suppressed oxidative symptoms and Cr uptake but growth of chamomile seedlings was not improved. Alteration of naturally present reductants could be a reason for Cr(III) signal detected using specific fluorescence reagent: in vitro assay confirmed disappearance of ascorbic acid in equimolar mixture with dichromate (>96% at pH 4 and 7) while such response of glutathione was substantially less visible.

Manganese-induced oxidative stress in two ontogenetic stages of chamomile and amelioration by nitric oxide.

Impact of manganese (Mn(2+)) excess (100, 500 and 1000 µM over 7 days) on two ontogenetic stages (7-week-old plants and 7-day-old seedlings) of Matricaria chamomilla was compared. Mn excess depressed growth of seedlings (but not germination) and stimulated oxidative stress (ROS and lipid peroxidation) in both plants and seedlings. Growth inhibition could be evoked by higher Mn uptake and higher translocation factor in seedlings than in plants. Total thiols staining revealed elevation in almost all treatments. In 7-week-old plants, activity of peroxidases increased slightly and rather decreased under high Mn doses. Superoxide rather than hydrogen peroxide contributed to visualized ROS presence. Fluorescence of nitric oxide (NO) showed stimulation in plants but decrease in seedlings. Impact of exogenous nitric oxide donor (sodium nitroprusside/SNP) was therefore tested and results showed amelioration of 1000 µM Mn-induced oxidative stress in seedlings (decrease in H2O2 and increase in NO content while antioxidative enzyme activities were variably affected) concomitantly with depleted Mn accumulation. It is concluded that NO participates in tolerance to Mn excess but negative effects of the highest SNP dose were also observed. Extensive fluorescence microscopy is also explanatively discussed.

Exogenously applied calcium alleviates cadmium toxicity in Matricaria chamomilla L. plants.

Cadmium (Cd) toxicity in plants leads to serious disturbances of physiological processes, such as inhibition of chlorophyll synthesis, oxidative injury to the plant cells and water and nutrient uptake. Response of Matricaria chamomilla L. to calcium chloride (CaCl(2)) enrichment in growth medium for reducing Cd toxicity were studied in this study. Hydroponically cultured seedlings were treated with 0, 0.1, 1, and 5 mM CaCl(2), under 0, 120, and 180 µM CdCl(2) conditions, respectively. The study included measurements pertaining to physiological attributes such as growth parameters, Cd concentration and translocation, oxidative stress, and accumulation of phenolics. Addition of CaCl(2) to growth media decreased the Cd concentration, activity of antioxidant enzymes, and reactive oxygen species accumulation in the plants treated with different CdCl(2), but increased the growth parameters. Malondialdehyde and total phenolics in shoots and roots were not much affected when plants were treated only with different CaCl(2) levels, but it showed a rapid increase when the plants were exposed to 120 and 180 CdCl(2) levels. CaCl(2) amendment also ameliorated the CdCl(2)-induced stress by reducing oxidative injury. The beneficial effects of CaCl(2) in ameliorating CdCl(2) toxicity can be attributed to the Ca-induced reduction of Cd concentration, by reducing the cell-surface negativity and competing for Cd(2+) ion influx, activity enhancement of antioxidant enzymes, and biomass accumulation.

Integrated management of wild chamomile (Matricaria chamomilla L.) populations by tillage.

Nowadays, environmental, health and economic concerns encourage reviewing our weed management in agriculture. Integrated pest management is one key element in the development of weed management strategies less dependent from herbicides. To reach this goal, impact of different methods of tillage (Combinations of stubble cultivator and moldboard plow) on biology and dynamic of wild chamomile populations was studied in experimental plots of experimental farm of Gembloux Agro-Bio Tech. In summer 2012, wild chamomile densities were significantly lower in plots tilled with a moldboard plow. The use of a stubble cultivator did not significantly affect M. chamomilla density. In addition, we found higher wheat yields in plowed plots, indicating that the decrease in M. chamomilla densities reduces competition for wheat. These results show well long run impact of plowing and his effect on densities of wild chamomile and the seedbank.

Modulation of copper uptake and toxicity by abiotic stresses in Matricaria chamomilla plants.

The impact of salinity (S) or nitrogen deficiency (-N) on copper (Cu) uptake and changes to metabolism were studied in the combined treatments after 7 days of exposure. S suppressed growth, water content, soluble proteins, and reducing sugars more negatively than -N. ROS (hydrogen peroxide and superoxide) were differentially but relatively slightly affected while peroxidase activities were strongly elevated mainly in Cu+NaCl variant. Total soluble phenols and individual phenolic acids (free and cell wall-bound fraction) were accumulated the most in Cu-N while, among free amino acids, proline sharply increased in Cu+NaCl; this suggests a compensatory mechanism between the syntheses of antioxidants aimed to maintain antioxidative protection because numerous root phenolic acids were even depressed by S. Salinity also suppressed accumulation of coumarin herniarin, but its glucosidic precursors ((Z)- and (E)-2-ß-D-glucopyranosyloxy-4-methoxycinnamic acids) increased. Activities of selected phenolic enzymes were rather suppressed by S after a given exposure period while lignin content increased, suggesting different time dynamics if S and -N variants are compared. Selected mineral nutrients (K, Fe, and partially Mg) were more reduced by S than by -N. Shoot and root Cu amounts were depressed by -N but elevated by S. Significance and possible role of observed metabolic changes in relation to Cu accumulation are discussed.

Accumulation of tetracoumaroyl spermine in Matricaria chamomilla during floral development and nitrogen deficiency.

The new natural polyamine conjugate 1N,5N,10N,14N-tetracoumaroyl spermine (tetracoumaroyl spermine) recently isolated from chamomile (Matricaria chamomilla L.) flower heads is applicable for the treatment of several human disorders such as depression and anxiety. High variability in the level of tetracoumaroyl spermine is found in commercial tisanes. Accumulation of tetracoumaroyl spermine was tested during floral development, and nitrogen deficiency was chosen as its putative limiting environmental factor. It was observed that tetracoumaroyl spermine is present mainly in tubular flowers, reaching its maximal content during the 3rd phase of flowering when the corollae of tubular flowers start to open. The later observed decrease could result from a release of pollen that also contains a considerable amount of tetracoumaroyl spermine. It is likely that tetracoumaroyl spermine plays an important role in pollen development, and so, despite overall N-deficiency in the plants, tetracoumaroyl spermine is accumulated at the same or even higher rate than in the flowers of the N-sufficient control.

Fast quality assessment of German chamomile (Matricaria chamomilla L.) by headspace solid-phase microextraction: influence of flower development stage.

For an adequate quality evaluation of aromatic plants grown under different conditions, a rapid, simple and sensitive method for the analysis of volatile constituents is indispensable. The main objective of the present study was to compare fast screening of German chamomile (Matricaria chamomilla L.) by means of headspace solid-phase microextraction (HS-SPME) with conventional isolation of the essential oil (steam distillation-solvent extraction (SDSE)) for the differentiation of chamomile essential oil constituents. Flowers were harvested at two distinct development stages: stage I, when ligulate flowers start to develop and tubular flowers are still closed, and stage II, when tubular flowers are partially to completely opened. Dried chamomile flowers at two development stages were extracted by means of both SDSE and HS-SPME, followed by GC-MS analysis. Among 30 compounds detected, (E)-beta-farnesene (49%), artemisia ketone (10%) and germacrene D (9%) were the predominant volatile components in the HS-SPME-extract, while alpha-bisabolol oxide A (42%), chamazulene (21%) and (Z)-spiroether (8%) were the main essential oil constituents among the 13 compounds obtained by SDSE. After statistical analysis of the data, both techniques enabled the same conclusion: (E)-beta-farnesene was the only compound which showed significant differences between the two flower development stages. These results suggest that HS-SPME-GC-MS can be used as a sensitive technique for the rapid screening and quality assessment of M. chamomilla.

Evaluation of immunomodulatory effect of three herbal plants growing in Egypt.

A group of medicinal plant including Silene (Silene nocturna), Black seed (Nigella sativa) and Chamomile (Matricaria chamomilla) growing in Egypt were examined for their immunomodulatory effect in Balb/c mice. Treatment (intraperitoneal injection) with five doses of methanolic extract for each plant was found to enhance the total white blood cells count (up to 1.2 × 10(4) cells/mm(3)). Bone marrow cellularity also increased significantly (P < 0.01) after the administration of the extract of each of three test plants. Furthermore, spleen weight of the treated groups was significantly increased (P < 0.01). Two groups of mice were immunosuppressed with cyclophosphamide, the one which pretreated with the plants extracts significantly (P < 0.01) restored their resistance against lethal infection with the predominately granulocyte-dependant Candida albicans. These results confirm the immunomodulatory activity of Silene, Black seed, and Chamomile extracts and may have therapeutical implications in prophylactic treatment of opportunistic infections and as supportive treatment in oncogenic cases.

Influencia de los bioplaguicidas en los parámetros de calidad de Calendula officinalis L y Matricaria recutita L / Biopesticides influence on the quality parameters of Calendula officinalis L and Matricaria recutita L

INTRODUCCIÓN: Calendula officinalis L y Matricaria recutita L son dos especies medicinales de gran importancia económica y social en Cuba, su cultivo con frecuencia anual se ha visto afectado por la aparición de plagas y enfermedades, con el deterioro del rendimiento de masa vegetal y en su calidad. OBJETIVOS: determinar la influencia de los bioplaguicidas en los parámetros de calidad de Calendula officinalis L y Matricaria recutita L MÉTODOS: las drogas vegetales, fueron sometidas a tratamiento con bioplaguicidas de origen botánico: (Melia azederach L y Nicotiana tabacum L) y de origen biológico: (los hongos Beauveria bassiana, Verticillun lecanii y Trichoderma viridis, con la bacteria Bacillus thuringiensis), teniendo en cuenta los bajos costos y métodos sencillos de obtención de sus extractos sin causar prejuicios al medio. Los parámetros de calidad realizados a las inflorescencias en ambas drogas vegetales después de secadas a 38 ºC y trituradas fueron: humedad, cenizas totales, sustancias solubles, aceite esencial y flavonoides totales. RESULTADOS: se comprobó que las aplicaciones por nebulización de los bioplaguicidas no evidenciaron influencia en las cenizas totales, actuaron en la superficie de los capítulos florales por la propiedad repelente o veneno contacto que poseen los bioplaguicidas empleados; se observó aumento en los flavonoides totales y en las sustancias solubles en etanol 70 por ciento en el caso de C officinalis, mientras M recutita mostró favorecidos los porcentajes de sustancias solubles en agua y aceite esencial con respecto a los testigos. CONCLUSIONES: se controló el umbral económico de infestación en estos cultivos y se favoreció la calidad de las drogas obtenidas

INTRODUCTION: Calendula officinalis L and Matricaria recutita L are two medicinal species of a great economic and social significance in Cuba, its growing with yearly frequency has been affected by appearance of plagues and diseases deteriorating the plant mass performance and its quality. OBJECTIVES: to determine the biopesticides influence on quality parameters of Calendula officinalis L and Matricaria recutita L. METHODS: the plant drugs underwent a botanical origin biopesticides treatment: (Melia azederach L and Nicotiana tabacum L) and of biological origin: (the mushrooms Beauveria bassiana, Verticillun lecanii and Trichoderma viridis with the bacteria Bacillus thuringiensis), taking into account the low costs and single methods to obtain its extracts without damage the environment. The quality parameters performed to inflorescence in both plant drugs after its drying at 38 ºC and grinding were: humidity, total ashes, soluble substances, essential oil and total flavonoids. RESULTS: it was proved that applications by biopesticides nebulization have not influence on total ashes, working in surface of floral inflorescence due to repellent property or poison-contact present in biopesticides used noting an increase in total flavonoids and in soluble substances in 70 percent ethanol in the case of C officinalis whereas M recutita showed as favored the percentages of soluble substances in water and in essential oil as regards the controls. CONCLUSIONS: in these cultures the infestation economic threshold favoring the quality of drugs obtained

Salicylic acid alleviates NaCl-induced changes in the metabolism of Matricaria chamomilla plants.

Influence of 100 mM NaCl and 50 microM salicylic acid (SA) and their combination on the metabolism of chamomile (Matricaria chamomilla) during 7 days was studied. NaCl reduced growth and selected physiological parameters and SA in combined treatment (NaCl + SA) reversed majority of these symptoms. Application of SA reduced NaCl-induced increase of Na+ in the rosettes, but not in the roots. Accumulation of total amino acids was stimulated in NaCl-treated roots, especially due to exceptional increase of proline (4.4-fold). Among phenolic acids, accumulation of protocatechuic acid was the most enhanced in NaCl-exposed leaf rosettes (ca. 3-fold) while chlorogenic and caffeic acids in the roots (2.4- and 2.8-fold, respectively). Total soluble phenols increased after NaCl and SA treatments, but root lignin content was not affected. Activity of phenylalanine ammonia-lyase and shikimate dehydrogenase increased in response to NaCl, but cinnamyl alcohol dehydrogenase was not affected and polyphenol oxidase decreased. Stress parameters were elevated by NaCl treatment (superoxide radical and malondialdehyde content, activities of catalase, ascorbate- and guaiacol-peroxidase) and substantially prevented by SA, while accumulation of hydrogen peroxide decreased. Overall, SA showed strong beneficial properties against NaCl-induced negative symptoms. Protective effect of SA was the most visible at the level of guaiacol-peroxidase and through amelioration of stress parameters and mineral nutrient contents.

Salicylic acid-induced changes to growth and phenolic metabolism in Matricaria chamomilla plants.

The influence of salicylic acid (SA) doses of 50 and 250 microM, for a period of up to 7 days, on selected physiological aspects and the phenolic metabolism of Matricaria chamomilla plants was studied. SA exhibited both growth-promoting (50 microM) and growth-inhibiting (250 microM) properties, the latter being correlated with decrease of chlorophylls, water content and soluble proteins. In terms of phenolic metabolism, it seems that the higher SA dose has a toxic effect, based on the sharp increase in phenylalanine ammonia-lyase (PAL) activity (24 h after application), which is followed by an increase in total soluble phenolics, lignin accumulation and the majority of the 11 detected phenolic acids. Guaiacol-peroxidase activity was elevated throughout the experiment in 250 microM SA-treated plants. In turn, some responses can be explained by mechanisms associated with oxidative stress tolerance; these mitigate acute SA stress (which is indicated by an increase in malondialdehyde content). However, PAL activity decreased with prolonged exposure to SA, indicating its inhibition. Accumulation of coumarin-related compounds (umbelliferone and herniarin) was not affected by SA treatments, while (Z)- and (E)-2-beta-D: -glucopyranosyloxy-4-methoxycinnamic acids increased in the 250 microM SA-treated rosettes. Free SA content in the rosettes increased significantly only in the 250 microM SA treatment, with levels tending to decrease towards the end of the experiment and the opposite trend was observed in the roots.

Sistema de policultivos en plantas medicinales: aloe vera, Calendula officinalis, Matricaria recutita, Plantago lanceolata y Plantago major / System of polycultures in medicinal plants: aloe vera, Calendula officinalis, Matricaria recutita, Plantago lanceolata and Plantago major

Fundamentos: existe una tendencia creciente por los agricultores a desarrollar las producciones agrícolas mediante sistemas de policultivos. Objetivos: demostrar las ventajas del sistema de policultivo sobre el monocultivo basados en el incremento del rendimiento de masa vegetal de las especies que lo integran. Métodos: en la Estación Experimental de Plantas Medicinales Dr Juan Tomás Roig se investigó sobre suelo ferralítico rojo hidratado (ferralsols), en una plantación establecida de Aloe vera (L.) N. L. Burm. cultivo perenne y principal, el intercalamiento de varias especies: Calendula officinalis L., Matricaria recutita L., Plantago lanceolata L. y Plantago major L.; cultivos de períodos vegetativos cortos para aprovechar el espacio entre surcos que requiere esta planta; se determinó el rendimiento de masa vegetal fresca en cada una de las especies de esta compleja asociación y se compararon con los de sus respectivos cultivos únicos o monocultivos. Los valores obtenidos se analizaron mediante análisis de varianza, además se calculó el incremento productivo a partir del cual se determinó el uso equivalente de la tierra. Resultados: de forma general, se encontró en todas las especies componentes del policultivo (cultivo permanente y plantas intercaladas) ventajas sobre el monocultivo en cuanto a sus rendimientos, sin afectación de los principios activos, así como el aumento de la eficiencia productiva de los suelos. Conclusiones: se demostró en las especies estudiadas la superioridad que ofrece el sistema de siembra por policultivo.

Foundations: there is an increasing trend on the part of the agriculturists to develop productions by polyculture systems. Objectives: to show the advantages of the polyculture system over the monoculture based on the increase of the yield of plant mass of the species included. Methods: in an established plantation of Aloe vera (L.) N. L. Burm., perennial and main culture, with hydrated red ferriferous soil (ferralsols), at Dr Juan Tomás Roig Experimental Station of Medicinal Plants, it was investigated the intercropping of various species: Calendula officinalis L., Matricaria recutita L., Plantago lanceolata L. and Plantago major L.; cultures of short vegetative periods used to avail the space between furrows required by this plant. The yielding of fresh plant mass was also determined in each of the species of this complex association and they were compared with those of their respective unique cultures or monocultures. The values obtained were analyzed by variance analysis. The productive growth from which the equivalent use of the soil was determined was calculated, too. Results: generally, in all the species composing the polyculture (permanent culture and intercropped plants) there were advantages over the monoculture as regards their yieldings without affecting the active principles. An increase of the productive efficiency of the soils was also observed. Conclusions: the superiority of the polyculture system was proved in the studied species.

Oxidative status of Matricaria chamomilla plants related to cadmium and copper uptake.

Cadmium (Cd) and copper (Cu) uptake by the plants of Matricaria chamomilla and relation to activities of guaiacol peroxidase (GPX, EC 1.11.1.7), catalase (CAT, EC 1.11.1.6) and glutathione reductase (GR, EC 1.6.4.2) up to 7 days of exposure to 3, 60 and 120 microM Cd or Cu was studied. Cd content in rosettes was ca. 10-fold higher in comparison to Cu while Cu was preferentially accumulated in the roots. In line with this observation, increase of CAT and GPX activity was similar in rosettes of Cd and Cu-treated plants, indicating non-redox active properties of Cd and low Cu accumulation. In the roots, Cu showed strong pro-oxidant effect, as judged from extreme stimulation of CAT and GPX, followed by increase of hydrogen peroxide and malondialdehyde. However, GPX seemed to be more important for alleviation of oxidative stress (ca. 93-250-fold higher activity in 120 microM Cu-treated roots). Cd had substantially lower influences and stimulated GR activity more than Cu. Activities of hydrogen peroxide-scavenging enzymes in relation to its accumulation are also discussed.

Dynamics of phenolic acids and lignin accumulation in metal-treated Matricaria chamomilla roots.

Phenylalanine ammonia-lyase (PAL) activity, 11 phenolic acids and lignin accumulation in Matricaria chamomilla roots exposed to low (3 microM) and high (60 and 120 microM) levels of cadmium (Cd) or copper (Cu) for 7 days were investigated. Five derivatives of cinnamic acid (chlorogenic, p-coumaric, caffeic, ferulic and sinapic acids) and six derivatives of benzoic acid (protocatechuic, vanillic, syringic, p-hydroxybenzoic, salicylic acids and protocatechuic aldehyde) were detected. Accumulation of glycoside-bound phenolics (revealed by acid hydrolysis) was enhanced mainly towards the end of the experiment, being more expressive in Cu-treated roots. Interestingly, chlorogenic acid was extremely elevated by the highest Cu dose (21-fold higher than control) suggesting its involvement in antioxidative protection. All compounds, with the exception of chlorogenic acid, were detected in the cell wall bound fraction, but only benzoic acids were found in the ester-bound fraction (revealed by alkaline hydrolysis). Soluble phenolics were present in substantially higher amounts in Cu-treated roots and more Cu was retained there in comparison to Cd. Cu strongly elevated PAL activity (by 5.4- and 12.1-fold in 60 and 120 microM treatment, respectively) and lignin content (by 71 and 148%, respectively) after one day of treatment, indicating formation of a barrier against metal entrance. Cd had slighter effects, supporting its non-redox active properties. Taken together, different forms of phenolic metabolites play an important role in chamomile tolerance to metal excess and participate in active antioxidative protection.

A new method for calculating net reproductive rate from graph reduction with applications to the control of invasive species.

Matrix models are widely used for demographic analysis of age and stage structured biological populations. Dynamic properties of the model can be summarized by the net reproductive rate R (0). In this paper, we introduce a new method to calculate and analyze the net reproductive rate directly from the life cycle graph of the matrix. We show, with examples, how our method of analysis of R (0) can be used in the design of strategies for controlling invasive species.