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Plant Parts (plant + part)
Kinds of Plant Parts Selected AbstractsFood mechanical properties in three sympatric species of Hapalemur in Ranomafana National Park, MadagascarAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Nayuta Yamashita Abstract We investigated mechanical dietary properties of sympatric bamboo lemurs, Hapalemur g. griseus, H. aureus, and H. (Prolemur) simus, in Ranomafana National Park, Madagascar. Each lemur species relies on bamboo, though previous behavioral observations found that they specialize on different parts of a common resource (Tan: Int J Primatol 20 1999 547,566; Tan: PhD dissertation 2000 State University of New York, Stony Brook). On the basis of these earlier behavioral ecology studies, we hypothesized that specialization on bamboo is related to differences in mechanical properties of specific parts. We quantified mechanical properties of individual plant parts from the diets of the bamboo lemur species using a portable tester. The diets of the Hapalemur spp. exhibited high levels of mechanical heterogeneity. The lemurs, however, could be segregated based on the most challenging (i.e., mechanically demanding) foods. Giant bamboo culm pith was the toughest and stiffest food eaten, and its sole lemur consumer, H. simus, had the most challenging diet. However, the mechanical dietary properties of H. simus and H. aureus overlapped considerably. In the cases where lemur species converged on the same bamboo part, the size of the part eaten increased with body size. Plant parts that were harvested orally but not necessarily masticated were the most demanding, indicating that food preparation may place significant loads on the masticatory apparatus. Finally, we describe how mechanical properties can influence feeding behavior. The elaborate procurement processes of H. simus feeding on culm pith and H. griseus and H. aureus feeding on young leaf bases are related to the toughnesses of protective coverings and the lemurs' exploitation of mechanical vulnerabilities in these plants. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Flowers Are an important food for small apes in southern SumatraAMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2009Susan Lappan Abstract Flowers are included in the diets of many primates, but are not generally regarded as making an important contribution to primate energy budgets. However, observations of a number of lemur, platyrrhine, and cercopithecine populations suggest that some flower species may function as key primate fallback foods in periods of low abundance of preferred foods (generally ripe fruits), and that flowers may be preferred foods in some cases. I report heavy reliance on flowers during some study months for a siamang (Symphalangus syndactylus) population in southern Sumatra. Siamangs at Way Canguk spent 12% of feeding time eating flowers from October 2000 to August 2002, and in 1 month flower-feeding time exceeded 40% of total feeding time. The overall availabilities of fig and nonfig fruits, flowers, and new leaves in the study area were not significant predictors of the proportion of time that siamangs spent consuming any plant part. However, flower-feeding time was highest in months when nonfig fruit-feeding time was lowest, and a switch from heavy reliance on fruit to substantial flower consumption was associated with a shift in activity patterns toward reduced energy expenditure, which is consistent with the interpretation that flowers may function as a fallback food for Way Canguk siamangs. Hydnocarpus gracilis, a plant from which siamangs only consume flowers, was the third-most-commonly consumed plant at Way Canguk (after Ficus spp. and Dracontomelon dao), and flowers from this plant were available in most months. It is possible that relatively high local availability of these important siamang plant foods is one factor promoting high siamang density in the study area. Am. J. Primatol. 71:624,635, 2009. © 2009 Wiley-Liss, Inc. [source] Organoarsenic compounds in plants and soil on top of an ore veinAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2002Anita Geiszinger Abstract Plants and soil collected above an ore vein in Gasen (Austria) were investigated for total arsenic concentrations by inductively coupled plasma mass spectrometry (ICP-MS). Total arsenic concentrations in all samples were higher than those usually found at non-contaminated sites. The arsenic concentration in the soil ranged from ,700 to ,4000,mg kg,1 dry mass. Arsenic concentrations in plant samples ranged from ,0.5 to 6,mg kg,1 dry mass and varied with plant species and plant part. Examination of plant and soil extracts by high-performance liquid chromatography,ICP-MS revealed that only small amounts of arsenic (<1%) could be extracted from the soil and the main part of the extractable arsenic from soil was inorganic arsenic, dominated by arsenate. Trimethylarsine oxide and arsenobetaine were also detected as minor compounds in soil. The extracts of the plants (Trifolium pratense, Dactylis glomerata, and Plantago lanceolata) contained arsenate, arsenite, methylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, the tetramethylarsonium ion, arsenobetaine, and arsenocholine (2.5,12% extraction efficiency). The arsenic compounds and their concentrations differed with plant species. The extracts of D. glomerata and P. lanceolata contained mainly inorganic arsenic compounds typical of most other plants. T. pratense, on the other hand, contained mainly organic arsenicals and the major compound was methylarsonic acid. Copyright © 2002 John Wiley & Sons, Ltd. [source] Pomegranate flower: a unique traditional antidiabetic medicine with dual PPAR-,/-, activator propertiesDIABETES OBESITY & METABOLISM, Issue 1 2008Yuhao Li PPARs are transcription factors belonging to the superfamily of nuclear receptors. PPAR-, is involved in the regulation of fatty acid (FA) uptake and oxidation, inflammation and vascular function, while PPAR-, participates in FA uptake and storage, glucose homeostasis and inflammation. The PPARs are thus major regulators of lipid and glucose metabolism. Synthetic PPAR-, or PPAR-, agonists have been widely used in the treatment of dyslipidaemia, hyperglycaemia and their complications. However, they are associated with an incidence of adverse events. Given the favourable metabolic effects of both PPAR-, and PPAR-, activators, as well as their potential to modulate vascular disease, combined PPAR-,/-, activation has recently emerged as a promising concept, leading to the development of mixed PPAR-,/-, activators. However, some major side effects associated with the synthetic dual activators have been reported. It is unclear whether this is a specific effect of the particular synthetic compounds or a class effect. To date, a medication that may combine the beneficial metabolic effects of PPAR-, and PPAR-, activation with fewer undesirable side effects has not been successfully developed. Pomegranate plant parts are used traditionally for the treatment of various disorders. However, only pomegranate flower has been prescribed in Unani and Ayurvedic medicines for the treatment of diabetes. This review provides a new understanding of the dual PPAR-,/-, activator properties of pomegranate flower in the potential treatment of diabetes and its associated complications. [source] Elevated dominance of extrafloral nectary-bearing plants is associated with increased abundances of an invasive ant and reduced native ant richnessDIVERSITY AND DISTRIBUTIONS, Issue 5 2009Amy M. Savage Abstract Aim, Invasive ants can have substantial and detrimental effects on co-occurring community members, especially other ants. However, the ecological factors that promote both their population growth and their negative influences remain elusive. Opportunistic associations between invasive ants and extrafloral nectary (EFN)-bearing plants are common and may fuel population expansion and subsequent impacts of invasive ants on native communities. We examined three predictions of this hypothesis, compared ant assemblages between invaded and uninvaded sites and assessed the extent of this species in Samoa. Location, The Samoan Archipelago (six islands and 35 sites). Methods, We surveyed abundances of the invasive ant Anoplolepis gracilipes, other ant species and EFN-bearing plants. Results,Anoplolepis gracilipes was significantly more widely distributed in 2006 than in 1962, suggesting that the invasion of A. gracilipes in Samoa has progressed. Furthermore, (non- A. gracilipes) ant assemblages differed significantly between invaded and uninvaded sites. Anoplolepis gracilipes workers were found more frequently at nectaries than other plant parts, suggesting that nectar resources were important to this species. There was a strong, positive relationship between the dominance of EFN-bearing plants in the community and A. gracilipes abundance on plants, a relationship that co-occurring ants did not display. High abundances of A. gracilipes at sites dominated by EFN-bearing plants were associated with low species richness of native plant-visiting ant species. Anoplolepis gracilipes did not display any significant relationships with the diversity of other non-native ants. Main conclusions, Together, these data suggest that EFN-bearing plants may promote negative impacts of A. gracilipes on co-occurring ants across broad spatial scales. This study underscores the potential importance of positive interactions in the dynamics of species invasions. Furthermore, they suggest that conservation managers may benefit from explicit considerations of potential positive interactions in predicting the identities of problematic invaders or the outcomes of species invasions. [source] A comparison of the host-searching efficiency of two larval parasitoids of Plutella xylostellaECOLOGICAL ENTOMOLOGY, Issue 1 2002Xin-Geng Wang Summary 1. A host specialist parasitoid is thought to have greater efficiency in locating hosts or greater ability to overcome host defence than a generalist species. This leads to the prediction that a specialist should locate and parasitise more hosts than a generalist in a given arena. The work reported here tested these predictions by comparing the host-searching behaviour of Diadegma semiclausum (a specialist) and Cotesia plutellae (an oligophagous species), two parasitoids of larval Plutella xylostella. 2. Both parasitoids employed antennal search and ovipositor search when seeking hosts but D. semiclausum also seemed to use visual perception in the immediate vicinity of hosts. 3. Larvae of P. xylostella avoided detection by parasitoids by moving away from damaged plant parts after short feeding bouts. When they encountered parasitoids, the larvae wriggled vigorously as they retreated and often hung from silk threads after dropping from a plant. 4. These two parasitoids differed in their responses to host defences. Diadegma semiclausum displayed a wide-area search around feeding damage and waited near the silk thread for a suspended host to climb up to the leaf, then attacked it again. Cotesia plutellae displayed an area-restricted search and usually pursued the host down the silk thread onto the ground. 5. Diadegma semiclausum showed a relatively fixed behavioural pattern leading to oviposition but C. plutellae exhibited a more plastic behavioural pattern. 6. The time spent by the two parasitoids on different plants increased with increasing host density, but the time spent either on all plants or a single plant by D. semiclausum was longer than that of C. plutellae. Diadegma semiclausum visited individual plants more frequently than C. plutellae before it left the patch, and stung hosts at more than twice the rate of C. plutellae. 7. The results indicated that the host-location strategies employed by D. semiclausum were adapted better to the host's defensive behaviour, and thus it was more effective at detecting and parasitising the host than was C. plutellae. [source] Uptake and translocation of p,p,-dichlorodiphenyldichloroethylene supplied in hydroponics solution to CucurbitaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2007Martin P. N. Gent Abstract Field studies show shoots of zucchini (Cucurbita pepo L.) accumulate various hydrophobic contaminants from soil, although many other plants do not, including cucumber (Cucumis sativus L.). To investigate the mechanism for this uptake, we presented p,p,-dichlorodiphenyldichloroethylene (DDE) to these two species in hydroponics solution. A mixture of DDE bound to TenaxÔ beads stirred with a solution of water passing through a reservoir provided a flowing solution containing DDE at approximately 2 ,g/L for many weeks duration. Approximately 90% of the DDE supplied in solution was adsorbed on the roots of both cucumber and zucchini. Less than 10% of the sorbed DDE was released subsequently when clean solution flowed past these contaminated roots for 9 d. The shoots of both species accumulated DDE, but the fraction that moved from the roots to the shoot in zucchini, ranging from 6 to 27% in various trials, was 10-fold greater than that in cucumber, 0.7 to 2%. The gradient in DDE concentration in zucchini tissues was in the order root > stem > petiole > leaf blade, indicating the movement was through the xylem in the transpiration stream. Some DDE in leaf blades might have been absorbed from the air, because the concentration in this tissue varied less with time, position in trough, or species, than did DDE in stems and petioles. The remarkable ability of zucchini to translocate DDE could not be attributed to differences in tissue composition, growth rate, distribution of weight among plant parts, or in the leaf area and rate of transpiration of water from leaves. Some other factor enables efficient translocation of hydrophobic organic contaminants in the xylem of zucchini. [source] Absorption of copper(II) by creosote bush (Larrea tridentata): Use of atomic and x-ray absorption spectroscopyENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2001Jorge Luis Gardea-Torresdey Abstract Larrea tridentata (creosote bush), a common North American native desert shrub, exhibits the ability to take up copper(II) ions rapidly from solution. Following hydroponic studies, U.S. Environmental Protection Agency method 200.3 was used to digest the plant samples, and flame atomic absorption spectroscopy (FAAS) was used to determine the amount of copper taken up in different parts of the plant. The amount of copper(II) found within the roots, stems, and leaves was 13.8, 1.1, and 0.6 mg/g, respectively, after the creosote bush was exposed to a 63.5-ppm copper(II) solution for 48 h. When the plant was exposed to a 635-ppm copper(II) solution, the roots, stems, and leaves contained 35.0, 10.5, and 3.8 mg/g, respectively. In addition to FAAS analysis, x-ray microfluorescence (XRMF) analysis of the plant samples provided further confirmation of copper absorption by the various plant parts. X-ray absorption spectroscopy (XAS) elucidated the oxidation state of the copper absorbed by the plants. The copper(II) absorbed from solution remained as copper(II) bound to oxygen-containing ligands within the plant samples. The results of this study indicate that creosote bush may provide a useful and novel method of removing copper(II) from contaminated soils in an environmentally friendly manner. [source] Use of a novel nonantibiotic triple marker gene cassette to monitor high survival of Pseudomonas fluorescens SBW25 on winter wheat in the fieldFEMS MICROBIOLOGY ECOLOGY, Issue 2 2008Lotta Jäderlund Abstract Pseudomonas fluorescens SBW25 was tagged with a triple marker gene cassette containing gfp, encoding green fluorescent protein; luxAB, encoding luciferase; and telABkilA, encoding tellurite resistance, and the tagged strain was monitored in the first Swedish field release of a genetically modified microorganism (GMM). The cells were inoculated onto winter wheat seeds and the GMM cells (SBW25,tgl) were monitored in the field from September 2005 to May 2006 using plating, luminometry and microscopic analyses. Cell numbers were high on all sampling occasions and metabolically active cells were detected on all plant parts. Field results were similar to those obtained in a parallel phytotron study, although the amount of SBW25,tgl detected on shoots was significantly higher in the phytotron than in the field. After winter, cell counts were 100-fold higher on the roots and root-associated soil compared with prewinter measurements, although the cells had a lower relative metabolic activity. The wheat seeds were naturally infested with Microdochium nivale, but no treatment resulted in reduction of disease symptoms. No SWB25,tgl cells were ever found in bulk soil or uninoculated plants. The Swedish field trial results complement and contrast with prior field studies performed with the same parent organism in the United Kingdom under different soil, plant and climatic conditions. [source] Chemical composition of essential oils from needles, branches and cones of Pinus pinea, P. halepensis, P. pinaster and P. nigra from central ltalyFLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2003F. Macchioni Abstract The composition of the essential oils from the needles, branches and female cones of four species of Pinaceae, Pinus pinea, P. halepensis, P. pinaster and P. nigra, has been analysed and comparative chemical evaluations were obtained. In P. pinea the major compound of the essential oils of all the three plant parts is limonene (58.9,62.5%), in P. halepensis, -pinene (18.1%,53.6%) and myrcene (13.7,42.1%), in P. pinaster, -pinene (24.7,40.4%) and , -pinene (21.7,29.2%), and in P. nigra, -pinene (28.4,61.7%). Copyright © 2003 John Wiley & Sons, Ltd. [source] Modelling the concentrations of nitrogen and water-soluble carbohydrates in grass herbage ingested by cattle under strip-grazing managementGRASS & FORAGE SCIENCE, Issue 1 2008N. J. Hoekstra Abstract There is scope of increasing the nitrogen (N) efficiency of grazing cattle through manipulation of the energy and N concentrations in the herbage ingested. Because of asymmetric grazing by cattle between individual plant parts, it has not yet been established how this translates into the concentrations of N and water-soluble carbohydrates (WSC) in the herbage ingested. A model is described with the objective of assessing the efficacy of individual tools in grassland management in manipulating the WSC and N concentrations of the herbage ingested by cattle under strip-grazing management throughout the growing season. The model was calibrated and independently evaluated for early (April), mid- (June, regrowth phase) and late (September) parts of the growing season. There was a high correlation between predicted and observed WSC concentrations in the ingested herbage (R2 = 0·78, P < 0·001). The correlation between predicted and observed neutral-detergent fibre (NDF) concentrations in the ingested herbage was lower (R2 = 0·49, P < 0·05) with a small absolute bias. Differences in the N concentration between laminae and sheaths, and between clean patches and fouled patches, were adequately simulated and it was concluded that the model could be used to assess the efficacy of grassland management tools for manipulating the WSC and N concentrations in the ingested herbage. Model application showed that reduced rates of application of N fertilizer and longer rotation lengths were effective tools for manipulating herbage quality in early and mid-season. During the later part of the growing season, the large proportion of area affected by dung and urine reduced the effect of application rate of N fertilizer on herbage quality. In contrast, relative differences between high-sugar and low-sugar cultivars of perennial ryegrass were largest during this period. This suggests that high-sugar cultivars may be an important tool in increasing N efficiency by cattle when risks of N losses to water bodies are largest. The model output showed that defoliation height affects the chemical composition of the ingested herbage of both the current and the subsequent grazing period. [source] Model predicting dynamics of biomass, structure and digestibility of herbage in managed permanent pastures.GRASS & FORAGE SCIENCE, Issue 2 2006Abstract To investigate seasonal and annual interactions between management and grassland dynamics, a simple mechanistic model of the dynamics of production, structure and digestibility in permanent pastures was constructed. The model is designed to respond to various defoliation regimes, perform multiple-year simulations and produce simple outputs that are easy to use as inputs for a model of ruminant livestock production. Grassland communities are described using a set of average functional traits of their constituent grass groups. The sward is subdivided into four structural compartments: green leaves and sheath, dead leaves and sheath, green stems and flowers, and dead stems and flowers. Each compartment is characterized by its biomass, age and digestibility. Only above-ground growth is modelled, using a light-utilization efficiency approach modulated by a seasonal pattern of storage and mobilization of reserves. Ageing of plant parts is driven by cumulative thermal time from 1 January and by biomass flows. Age affects senescence, abscission and digestibility of green compartments and, therefore, the quality of green leaves and stems can increase or decrease over time in relation to net growth and defoliation dynamics. The functional traits having the greatest impact on model outputs are seasonal effects, period of reproductive growth and effects of temperature on photosynthetic efficiency. The functional traits of the grass groups were parameterized for temperate pastures of the Auvergne region in France. The other model inputs are few: proportion of functional groups, basic weather data (incident photosynthetically active radiation, mean daily temperature, precipitation and potential evapotranspiration) and site characteristics (nitrogen nutrition index, soil water-holding capacity). In the context of a whole-farm simulator, the model can be applied at a field scale. [source] Variability of Endotoxin Expression in Bt Transgenic CottonJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2007H. Z. Dong Abstract Transgenic cotton expressing Bt (Bacillus thuringiensis) toxins is currently cultivated on a large commercial scale in many countries, but observations have shown that it behaves variably in toxin efficacy against target insects under field conditions. Understanding of the temporal and spatial variation in efficacy and the resulting mechanisms is essential for cotton protection and production. In this review, we summarize current knowledge on variability in Bt cotton efficacy, in particular on the induced variability by environmental stresses. We also discuss the resulting mechanisms and the countermeasures for the inconsistence in efficacy in Bt cotton. It is indicated that insecticidal protein content in Bt cotton is variable with plant age, plant structure or under certain environmental stresses. Variability in Bt cotton efficacy against target insect pests is mainly attributed to the changes in Bt protein content, but physiological changes associated with the production of secondary compounds in plant tissues may also play an important role. Reduction of Bt protein content in late-season cotton could be due to the overexpression of Bt gene at earlier stages, which leads to gene regulation at post-transcription levels and consequently results in gene silencing at a later stage. Methylation of the promotor may be also involved in the declined expression of endotoxin proteins. As a part of total protein, the insecticidal protein in plant tissues changes its level through inhibited synthesis, degradation or translocation to developing plant parts, particularly under environmental stresses, thus being closely correlated to N metabolism. It can be concluded that developing new cotton varieties with more powerful resistance, applying certain plant growth regulators, enhancing intra-plant defensive capability, and maintenance of general health of the transgenic crop are important in realizing the full transgenic potential in Bt cotton. [source] Assessing impacts of large herbivores on shrubs: tests of scaling factors for utilization rates from shoot-level measurementsJOURNAL OF APPLIED ECOLOGY, Issue 1 2007DANIELLE M. BILYEU Summary 1Accurate methods for estimating the intensity of browsing by herbivores are fundamental to understanding the ecology of shrub communities. Quantifying browse utilization on shrubs at large scales is difficult because shrubs have complex, spatially variable growth forms. Most existing methods estimate browsing rate at the scale of linear current-year shoots or twigs. How such fine-scale estimates relate to the proportion of current-year growth consumed from whole plants or plots is often unknown. The relationship is likely to be complex because herbivores selectively browse more productive plants and plant parts. 2Using a clipping experiment designed to mimic elk Cervus elaphus browsing, we quantified how utilization estimates at the scale of individual current-year shoots of two willow species, Salix bebbiana and Salix geyeriana, relate to actual mass removed at the scale of rooted stems. Three approaches to scaling were examined: (i) taking an average, (ii) multiplying by the proportion of shoots clipped and (iii) multiplying by a novel scaling factor that weights utilization by productivity. To address how to scale-up from stems to plots, we applied the most accurate stem-level method to elk-browsed willow and compared plot-level estimates by two scaling approaches. 3In scaling from shoots to stems, the novel scaling factor was most successful and resulted in accurate estimates for up to c. 45% of current annual growth clipped. In scaling from the stem to the plot, elk preference for more productive stems caused a simple average of stem-level utilization to differ from a productivity-weighted average by 15%. 4Synthesis and applications. In order to reflect accurately the proportion of biomass consumed at a whole-plant level, fine-scale estimates of utilization should be weighted by an estimate of pre-browse productivity, as this is mathematically equivalent to summing pre-browse and post-browse mass before calculating the proportion consumed. In developing methods to estimate utilization at plot scales, an important consideration is the choice of sampling unit, which should be both amenable to unbiased sampling and tractable in terms of measuring productivity. [source] Determination of the soil organic carbon, nitrogen, available phosphorus and the combined aboveground plant materials in the semi-arid Mbulu District, TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 3 2009Mligo Cosmas Abstract Soil of the semi-arid Mbulu District is part of the tropical soils, covered with sparse trees, shrubs or grasses in which domestic grazing animals have prevented the wide spread of vegetation cover. The study aimed at determining soil organic carbon (OC), total nitrogen (N), available phosphorus (P) and the combined aboveground plant materials. Six study sites were established in which soil samples were collected at the depths of 0,5, 6,10 and 11,20 cm. Soil samples were analysed for OC, N and P as well as the levels of N and P in the combined aboveground materials of Panicum coloratum and Hyparrhenia filipendula. The percentage concentrations of OC, N and P were high in the top soil than in the deeper soil horizons. However, analysis of variance showed significant differences of OC in some sites whereas no difference for N and P between soil depth classes. OC was highly related with N and P along soil depth classes. It was concluded that the availability of N and P was because of the decomposition of organic matter in the soil. Soil N and P were highly related with the same in the combined aboveground plant materials. It was concluded that the increased concentration of N and P in the soil resulted into availability of the same in P. coloratum and H. filipendula. There was a very high variation in N and P among sites with different levels of intensity of grazing. It was concluded that grazing animals contributes to the redistribution of soil elements in the rangelands because they graze upon plant parts but the excreta are dropped away from the grazed spot. Résumé Le sol du district semi-aride de Mbulu fait partie de ces sols tropicaux couverts d'arbres, de buissons et d'herbes rares où le pâturage des animaux domestiques a empêché une large dispersion du couvert végétal. L'étude visait à déterminer le carbone organique (CO) du sol, l'azote (N) total, le phosphore (P) disponible et l'ensemble combiné de la matière végétale aérienne. Six sites d'étude furent établis, où l'on a récolté des échantillons de sol à des profondeurs de 0 à 5 cm, 6 à 10 cm, et 11 à 20 cm. Les échantillons de sols ont été analysés pour le CO, le N et le P ainsi que les niveaux de N et de P dans la matière végétale aérienne composée de Panicum coloratum et Hyparrhenia filipendula. Le pourcentage des concentrations de CO, N et P était plus élevé dans la couche supérieure du sol que dans les couches plus profondes. Cependant, une analyse de variance a révélé des différences significatives du CO dans certains sites alors qu'il n'y avait pas de différences pour N ni P aux différentes profondeurs de sol. Le CO était fortement liéà N et à P selon les classes de profondeur. On en a conclu que la disponibilité de N et de P était due à la décomposition de la matière organique dans le sol. Le N et le P du sol étaient fortement liés aux mêmes éléments présents dans la matière végétale aérienne combinée. On a conclu que la concentration accrue de N et de P dans le sol résultait de la concentration de ces mêmes éléments dans P. coloratum et H. filipendula. Il y a avait une très grande variation de N et de P entre des sites où l'intensité de pâturage était différente. On a conclu que les animaux qui pâturent contribuent à la redistribution des éléments du sol dans tous les endroits fréquentés étant donné qu'ils mangent des plantes à certains endroits mais que leurs excréments peuvent être rejetés ailleurs que les zones pâturées. [source] Effects of elevated carbon dioxide and increased nitrogen deposition on bog vegetation in the NetherlandsJOURNAL OF ECOLOGY, Issue 2 2001Monique M. P. D. Heijmans Summary 1,We studied the effects of elevated atmospheric CO2 and increased N deposition on the plant species composition of a Sphagnum -dominated bog ecosystem in the Netherlands. Large peat monoliths (surface area 1 m2, depth 0.6 m) with intact bog vegetation were kept outdoors in large containers and were exposed to elevated CO2 or increased N deposition for three growing seasons. Elevated CO2 conditions (target concentration 560 µmol CO2 mol,1) were created using MiniFACE technology. In a separate experiment, N deposition was increased by 5 g N m,2 year,1 by adding dissolved NH4NO3 at 3 week intervals during the growing season. 2,Elevated atmospheric CO2 increased height growth of Sphagnum magellanicum, the dominant Sphagnum species, in the second and third growing seasons. Vascular plant biomass was not significantly affected by elevated CO2, but growth of species growing close to the moss surface was influenced negatively by the increased Sphagnum height growth. Elevated CO2 did not change allocation to below-ground plant parts. 3,Adding N increased above-ground vascular plant biomass. The shallow-rooted species Vaccinium oxycoccus responded most to the increased N deposition. Sphagnum growth was significantly reduced in the third growing season. This reduction was likely the result of the increased vascular plant cover, given the observed negative relation between vascular plant cover and Sphagnum growth. 4,The observed shifts in species composition as a result of species-specific responses to treatments, and interactions between peat mosses and vascular plants will have important consequences for the sequestration of carbon in the bog ecosystem. [source] Polycapillary-optics-based micro-XANES and micro-EXAFS at a third-generation bending-magnet beamlineJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2009Geert Silversmit A focusing system based on a polycapillary half-lens optic has been successfully tested for transmission and fluorescence µ-X-ray absorption spectroscopy at a third-generation bending-magnet beamline equipped with a non-fixed-exit Si(111) monochromator. The vertical positional variations of the X-ray beam owing to the use of a non-fixed-exit monochromator were shown to pose only a limited problem by using the polycapillary optic. The expected height variation for an EXAFS scan around the Fe K -edge is approximately 200,µm on the lens input side and this was reduced to ,1,µm for the focused beam. Beam sizes (FWHM) of 12,16,µm, transmission efficiencies of 25,45% and intensity gain factors, compared with the non-focused beam, of about 2000 were obtained in the 7,14,keV energy range for an incoming beam of 0.5 × 2,mm (vertical × horizontal). As a practical application, an As K -edge µ-XANES study of cucumber root and hypocotyl was performed to determine the As oxidation state in the different plant parts and to identify a possible metabolic conversion by the plant. [source] Role of mineral nutrition in minimizing cadmium accumulation by plantsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2010Nadeem Sarwar Abstract Cadmium (Cd) is a highly toxic heavy metal for both plants and animals. The presence of Cd in agricultural soils is of great concern regarding its entry into the food chain. Cadmium enters into the soil,plant environment mainly through anthropogenic activities. Compounds of Cd are more soluble than other heavy metals, so it is more available and readily taken up by plants and accumulates in different edible plant parts through which it enters the food chain. A number of approaches are being used to minimize the entry of Cd into the food chain. Proper plant nutrition is one of the good strategies to alleviate the damaging effects of Cd on plants and to avoid its entry into the food chain. Plant nutrients play a very important role in developing plant tolerance to Cd toxicity and thus, low Cd accumulation in different plant parts. In this report, the role of some macronutrients (nitrogen, phosphorus, sulfur and calcium), micronutrients (zinc, iron and manganese), and silicon (a beneficial nutrient) has been discussed in detail as to how these nutrients play their role in decreasing Cd uptake and accumulation in crop plants. Copyright © 2010 Society of Chemical Industry [source] Chemical composition and antimicrobial activity of Anzer tea essential oilJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2007ekero Abstract Anzer tea (Thymus praecox, subsp. caucasicus var. caucasicus) naturally grows in the eastern Black Sea region of Turkey. Anzer tea, a creeping plant with crimson-pink flowers, is important for honey production in the region. In the present study, content, composition and antimicrobial properties of Anzer tea's essential oil were investigated. Essential oil content of dried aerial plant parts varied between 1.53% and 2.05%. Essential oil composition was studied by means of gas chromatography,mass spectrometry, and 26 components were identified. The major components were thymol (47.45%), ,-terpinene (8.73%), p -cymene (8.30%), terpinyl acetate (4.88%) and carvacrol (4.66%). Essential oil was also screened for its antibacterial activity. In a screen for antibacterial activity, Anzer tea essential oil had significant activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Candida albicans. Copyright © 2007 Society of Chemical Industry [source] Effect of nitrogen fertilisation on below-ground carbon allocation in lettuceJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2002Y Kuzyakov Abstract The aims of this study were to investigate the effect of nitrogen (N) fertilisation on the below-ground carbon (C) translocation by lettuce and the CO2 efflux from its rhizosphere. Two N fertilisation levels (80 and 160,kg N,ha,1) and two growth stages (43 and 60 days) were tested. 14C pulse labelling of shoots followed by 14C monitoring in the soil, roots, microbial biomass and CO2 efflux from the soil was used to distinguish between root-derived and soil organic matter-derived,C. The 14C allocation in the below-ground plant parts was 1.5,4.6 times lower than in the leaves. The total quantity of C translocated into the soil was much lower than in the case of cereals and grasses, amounting to 120 and 160,kg C,ha,1 for low and high N respectively. N fertilisation diminished the proportion of assimilated C translocated below ground. About 5,8% of the assimilated C was respired into the rhizosphere. Root-derived CO2 (the sum of root respiration and rhizomicrobial respiration) represented about 15,60% of the total CO2 efflux from the planted soil. Two peaks were measured in the 14CO2 efflux: the first peak (4,5,h after labelling) was attributed to root respiration, whilst the second peak (12,h after labelling) was attributed to microbial respiration of exudates. Twelve days after labelling, 0.15,0.25% of the assimilated C was found in the microbial biomass. The higher microbial activity in the lettuce rhizosphere doubled the soil organic matter decomposition rate compared with unplanted soil. © 2002 Society of Chemical Industry [source] Botrytis cinerea: the cause of grey mould diseaseMOLECULAR PLANT PATHOLOGY, Issue 5 2007BRIAN WILLIAMSON SUMMARY Introduction:,Botrytis cinerea (teleomorph: Botryotinia fuckeliana) is an airborne plant pathogen with a necrotrophic lifestyle attacking over 200 crop hosts worldwide. Although there are fungicides for its control, many classes of fungicides have failed due to its genetic plasticity. It has become an important model for molecular study of necrotrophic fungi. Taxonomy:, Kingdom: Fungi, phylum: Ascomycota, subphylum: Pezizomycotina, class: Leotiomycetes, order: Helotiales, family: Sclerotiniaceae, genus: Botryotinia. Host range and symptoms: Over 200 mainly dicotyledonous plant species, including important protein, oil, fibre and horticultural crops, are affected in temperate and subtropical regions. It can cause soft rotting of all aerial plant parts, and rotting of vegetables, fruits and flowers post-harvest to produce prolific grey conidiophores and (macro)conidia typical of the disease. Pathogenicity:,B. cinerea produces a range of cell-wall-degrading enzymes, toxins and other low-molecular-weight compounds such as oxalic acid. New evidence suggests that the pathogen triggers the host to induce programmed cell death as an attack strategy. Resistance:, There are few examples of robust genetic host resistance, but recent work has identified quantitative trait loci in tomato that offer new approaches for stable polygenic resistance in future. Useful websites:,http://www.phi-base.org/query.php, http://www.broad.mit.edu/annotation/genome/botrytis_cinerea/Home.html, http://urgi.versailles.inra.fr/projects/Botrytis/, http://cogeme.ex.ac.uk [source] On the mechanism of selectivity of the corn herbicide BAS 662H: a combination of the novel auxin transport inhibitor diflufenzopyr and the auxin herbicide dicambaPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2002Klaus Grossmann Abstract BAS 662H, a 1:2.5 combination of the semicarbazone-type auxin transport inhibitor diflufenzopyr and the auxin herbicide dicamba, is used as a post-emergence herbicide in corn. The combination has been observed to provide more effective broadleaf weed control and improved tolerance in corn than typical rates of dicamba used alone. In order to analyze this phenomenon, the uptake, translocation, metabolism and action of both compounds, applied alone and in combination, were investigated in Amaranthus retroflexus L, Galium aparine L and corn (Zea mays L). When plants at the third-leaf stage were foliarly treated with diflufenzopyr and dicamba equivalent to field rates of 100 and 250,gha,1, respectively, diflufenzopyr synergistically increased dicamba-induced 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity and ethylene formation in G aparine and even more in A retroflexus, followed by accumulations of (+)-abscisic acid (ABA) in the shoot tissue within 20,h. This correlated with subsequent growth inhibition, hydrogen peroxide overproduction and progressive tissue damage. Diflufenzopyr also enhanced the activity of other auxin herbicides, such as quinclorac and picloram, and of the synthetic auxin, 1-naphthaleneacetic acid. After foliar and root application of [14C]diflufenzopyr, alone or as BAS 662H, considerably lower tissue concentrations and systemic translocation of radioactivity beyond treated plant parts were found in corn, compared to G aparine and particularly A retroflexus. Furthermore, diflufenzopyr decreased foliar uptake of [14C]dicamba by c,50% selectively in corn, compared to the treatment alone. Metabolism of [14C]diflufenzopyr was more rapid in corn than in the weed species. In combination, the two compounds had no mutual effect on their metabolic degradation. In BAS 662H, diflufenzopyr synergizes the herbicidal activity of dicamba in sensitive weed species. In corn this effect is prevented by a more rapid metabolism of diflufenzopyr, coupled with lower uptake and translocation. Selectivity of BAS 662H is additionally favoured by a higher crop tolerance to dicamba because of reduced foliar uptake of this herbicide in corn under the influence of diflufenzopyr. © 2002 Society of Chemical Industry [source] Antiproliferative effects of different plant parts of Panax notoginseng on SW480 human colorectal cancer cellsPHYTOTHERAPY RESEARCH, Issue 1 2009Chong-Zhi Wang Abstract The chemical constituents and antiproliferative effects on SW480 human colorectal cancer cells of different plant parts of P. notoginseng were evaluated. The contents of saponins in extracts from root, rhizome, flower and berry of P. notoginseng were determined using high performance liquid chromatography. The contents and proportions of saponins were different among the four plant parts. Using the cell counting method, the antiproliferative effects were evaluated and the results indicated all four extracts, at 0.05,1.0 mg/mL, showed concentration-related antiproliferative effects on the cancer cells. The flower extract had stronger effects compared with the other three extracts; at 1.0 mg/mL, it inhibited the cell growth by 93.1% (p < 0.01). The antiproliferative effects of major saponins in notoginseng, notoginsenoside R1, ginsenosides Rb1, Rb3 and Rg1, were also evaluated, and the observed effects of major constituents support the pharmacological activities of extracts. The effects of notoginseng extracts on cell cycle and apoptosis of SW480 cells were determined using flow cytometry. Notoginseng extract can arrest the cells in S and G2/M phases. Remarkably apoptosis induction activities of notoginseng extracts were observed with the flower extract possessing the most potent effect, supporting the antiproliferative effect. Copyright © 2008 John Wiley & Sons, Ltd. [source] A physiological overview of the genetics of flowering time controlPLANT BIOTECHNOLOGY JOURNAL, Issue 1 2005Georges Bernier Summary Physiological studies on flowering time control have shown that plants integrate several environmental signals. Predictable factors, such as day length and vernalization, are regarded as ,primary', but clearly interfere with, or can even be substituted by, less predictable factors. All plant parts participate in the sensing of these interacting factors. In the case of floral induction by photoperiod, long-distance signalling is known to occur between the leaves and the shoot apical meristem (SAM) via the phloem. In the long-day plant, Sinapis alba, this long-distance signalling has also been shown to involve the root system and to include sucrose, nitrate, glutamine and cytokinins, but not gibberellins. In Arabidopsis thaliana, a number of genetic pathways controlling flowering time have been identified. Models now extend beyond ,primary' controlling factors and show an ever-increasing number of cross-talks between pathways triggered or influenced by various environmental factors and hormones (mainly gibberellins). Most of the genes involved are preferentially expressed in meristems (the SAM and the root tip), but, surprisingly, only a few are expressed preferentially or exclusively in leaves. However, long-distance signalling from leaves to SAM has been shown to occur in Arabidopsis during the induction of flowering by long days. In this review, we propose a model integrating physiological data and genes activated by the photoperiodic pathway controlling flowering time in early-flowering accessions of Arabidopsis. This model involves metabolites, hormones and gene products interacting as long- or short-distance signalling molecules. [source] Lowering seed gossypol content in glanded cotton (Gossypium hirsutum L.) linesPLANT BREEDING, Issue 6 2008G. B. Romano Abstract Cottonseed is a rich source of high quality protein, but its value as an animal feed is limited by gossypol, a toxic polyphenolic compound contained in glands located throughout the plant. This compound helps protect the plant from pests. Totally glandless varieties have been developed, but not adopted as these plants are left vulnerable to pests. This study describes a breeding strategy to decrease the levels of gossypol in the seed while maintaining a high enough concentration of toxin in vegetative plant parts to offer protection from pests. Preliminary studies indicated that crosses between varieties with different gland densities and distributions produced a range of glanding patterns. By selecting within the resulting progeny, we have identified F7 generation progeny that have <0.30% total gossypol in the seed, while still possessing glands at critical locations on the vegetative plant parts. These new lines will be a valuable source of germplasm for developing low seed gossypol varieties. Seed from these varieties would provide a new source of inexpensive protein for animal feeding rations. [source] Intercellular adhesion and cell separation in plantsPLANT CELL & ENVIRONMENT, Issue 7 2003M. C. JARVIS ABSTRACT Adhesion between plant cells is a fundamental feature of plant growth and development, and an essential part of the strategy by which growing plants achieve mechanical strength. Turgor pressure provides non-woody plant tissues with mechanical rigidity and the driving force for growth, but at the same time it generates large forces tending to separate cells. These are resisted by reinforcing zones located precisely at the points of maximum stress. In dicots the reinforcing zones are occupied by networks of specific pectic polymers. The mechanisms by which these networks cohere vary and are not fully understood. In the Poaceae their place is taken by phenolic cross-linking of arabinoxylans. Whatever the reinforcing polymers, a targeting mechanism is necessary to ensure that they become immobilized at the appropriate location, and there are secretory mutants that appear to have defects in this mechanism and hence are defective in cell adhesion. At the outer surface of most plant parts, the tendency of cells to cohere is blocked, apparently by the cuticle. Mutants with lesions in the biosynthesis of cuticular lipids show aberrant surface adhesion and other developmental abnormalities. When plant cells separate, the polymer networks that join them are locally dismantled with surgical precision. This occurs during the development of intercellular spaces; during the abscission of leaves and floral organs; during the release of seeds and pollen; during differentiation of root cap cells; and during fruit ripening. Each of these cell separation processes has its own distinctive features. Cell separation can also be induced during cooking or processing of fruit and vegetables, and the degree to which it occurs is a significant quality characteristic in potatoes, pulses, tomatoes, apples and other fruit. Control over these technological characteristics will be facilitated by understanding the role of cell adhesion and separation in the life of plants. [source] Effects of active silicon uptake by rice on 29Si fractionation in various plant parts,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2009Jan Reent Köster Rice (Oryza sativa L.) accumulates large amounts of silicon which improves its growth and health due to enhanced resistance to biotic and abiotic stresses. Silicon uptake and loading to xylem in rice are predominantly active processes performed by transporters encoded by the recently identified genes Lsi1 (Si influx transporter gene) and Lsi2 (Si efflux transporter gene). Silicon deposition in rice during translocation to upper plant tissues is known to discriminate against the heavier isotopes 29Si and 30Si, resulting in isotope fractionation within the plant. We analyzed straw and husk samples of rice mutants defective in Lsi1, Lsi2 or both for silicon content and ,29Si using isotope ratio mass spectrometry (IRMS) and compared these results with those for the corresponding wild-type varieties (WT). The silicon content was higher in husk than in straw. All the mutant rice lines showed clearly lower silicon content than the WT lines (4,23% Si of WT). The ,29Si was lower in straw and husk for the uptake defective mutant (lsi1) than for WT, albeit ,29Si was 0.3, higher in husk than in straw in both lines. The effect of defective efflux (lsi2) differed for straw and husk with higher ,29Si in straw, but lower ,29Si in husk while WT showed similar ,29Si in both fractions. These initial results show the potential of Si isotopes to enlighten the influence of active uptake on translocation and deposition processes in the plant. Copyright © 2009 John Wiley & Sons, Ltd. [source] Food mechanical properties in three sympatric species of Hapalemur in Ranomafana National Park, MadagascarAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Nayuta Yamashita Abstract We investigated mechanical dietary properties of sympatric bamboo lemurs, Hapalemur g. griseus, H. aureus, and H. (Prolemur) simus, in Ranomafana National Park, Madagascar. Each lemur species relies on bamboo, though previous behavioral observations found that they specialize on different parts of a common resource (Tan: Int J Primatol 20 1999 547,566; Tan: PhD dissertation 2000 State University of New York, Stony Brook). On the basis of these earlier behavioral ecology studies, we hypothesized that specialization on bamboo is related to differences in mechanical properties of specific parts. We quantified mechanical properties of individual plant parts from the diets of the bamboo lemur species using a portable tester. The diets of the Hapalemur spp. exhibited high levels of mechanical heterogeneity. The lemurs, however, could be segregated based on the most challenging (i.e., mechanically demanding) foods. Giant bamboo culm pith was the toughest and stiffest food eaten, and its sole lemur consumer, H. simus, had the most challenging diet. However, the mechanical dietary properties of H. simus and H. aureus overlapped considerably. In the cases where lemur species converged on the same bamboo part, the size of the part eaten increased with body size. Plant parts that were harvested orally but not necessarily masticated were the most demanding, indicating that food preparation may place significant loads on the masticatory apparatus. Finally, we describe how mechanical properties can influence feeding behavior. The elaborate procurement processes of H. simus feeding on culm pith and H. griseus and H. aureus feeding on young leaf bases are related to the toughnesses of protective coverings and the lemurs' exploitation of mechanical vulnerabilities in these plants. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Changes in soil C-isotopic composition in an agroecosystem under Free Air Carbon dioxide Enrichment (FACE) treatment during a crop rotation period,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2005Anette Giesemann FACE (Free Air Carbon dioxide Enrichment) has been used since 1999 to evaluate the effects of future atmospheric CO2 concentrations on an arable crop agroecosystem. The experiment conducted at the Institute of Agroecology at the Federal Research Centre in Braunschweig consists of a typical local crop rotation of winter barley, a cover crop, sugar beet and winter wheat. The atmospheric CO2 concentration of ambient air is about 375 ppm with a ,13C value of ,7 to ,9,, and 550,ppm (,13C value,=,,20.2,) during daylight hours in the rings fumigated with additional CO2. Thus, the surplus C can be traced in the agricultural system. Over the course of the first experimental period (3-year crop rotation period), the C-isotopic composition and the C concentration in soil were monitored monthly. Plant samples were analysed according to the relevant developmental stages of the crop under cultivation. A 13C depletion was observed in plant parts, as well as in soil samples from the FACE rings under CO2 enrichment, indicating that labelled C has reached both respective ecosystem compartments. Albeit farming management practice (especially ploughing) leads to a mixing of ,old' and ,new' C compounds throughout all soil horizons down to the end of the ploughing layer and resulted in a heterogeneous distribution of newly formed C compounds in the soil, isotope analysis of soil C reflected where the surplus C went. Copyright © 2005 John Wiley & Sons, Ltd. [source] Semi-quantitative tests of cyanide in foods and excreta of Three Hapalemur species in MadagascarAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2010Nayuta Yamashita Abstract Three sympatric Hapalemur species (H. g. griseus, H. aureus, and H. (Prolemur) simus) in Ranomafana National Park, Madagascar are known to eat bamboo food parts that contain cyanide. How these lemurs avoid cyanide poisoning remains unknown. In this study, we tested for the presence/absence of cyanide in bamboo lemur foods and excreta to (1) document patterns of cyanide consumption among species with respect to diet, (2) identify routes of elimination of cyanide from the gastrointestinal tract, and (3) determine whether cyanide is absorbed from the diet. We tested 102 food, urine, and fecal samples for hydrogen cyanide (HCN) during two "pre-dry" seasons (April 2006, May 2007) using commercially available Cyantesmo test strips. The test strips changed color in the presence of HCN, and we recorded color change on a scale of 0 (no change) to 5 (cobalt) at preset intervals with a final score taken at 24,hr. We detected cyanide in bamboo food parts and urine of all three Hapalemur species. Time to color change of the test strips ranged from almost instantaneous to >12,hr incubation. Of the foods tested, only bamboo contained cyanide, but results differed among bamboo species and plant parts of the same species. Specifically, branch shoot and culm pith of the giant bamboo produced strong, immediate reactions to the test paper, whereas parts of liana bamboos produced either weak or no color change. Cyanide was present in almost all urine samples but rarely in fecal samples. This suggests that dietary cyanide is absorbed in the gastrointestinal tract of the Hapalemur species and excreted, at least in part, by the kidneys. Samples from H. griseus exhibited lower, though still detectable, cyanide levels compared with H. simus and H. aureus. Differences among lemur species appear to be related to the specific bamboo parts consumed. Am. J. Primatol. 72:56,61, 2010. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||||||||