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51.
Summary Transverse sections of leaves of some aluminium-accumulating and nonaccumulating species of the cerrado vegetation of central
Brazil were coloured using aluminon to identify the tissues where aluminium occurs or is deposited. None of the tissues of
the nonaccumulating species showed evidence of high concentrations of Al. All of the aluminium accumulating species showed
high concentrations of Al in all of the elements of the phloem of the midrib and the secondary veins and total absence of
it in the vessel members, xylem fibres and the palisade parenchyma. Walls and contents of the collenchyma of the midrib, epidermal
cells, guard cells of the stomata and spongy parenchyma showed evidence of high concentrations of Al in the accumulating species. 相似文献
52.
Cushion and shrub plants are typical high mountain nurse plants. In Magellanic tundras of the Cordillera del Sarao on the coast of Chile, the carnivorous plant Drosera uniflora grows in association with cushions of Donatia fascicularis and the shrubs Chusquea montana var. nigricans and Lepidothamnus fonkii. The different microhabitats for recruitment, in addition to the limited gene flow of D. uniflora, enable us to hypothesise that this plant manifests putative local adaptations, expressed in seed germination and population abundance. Our aim was to evaluate the local adaptation of D. uniflora to cushion and shrub microhabitats by estimating germination and abundance. Local adaptation of seed germination was determined by means of reciprocal transplant experiments. Abundance was determined in small plots located inside, on the edge and outside the nurse plants. Seed origin and growth substrate play a decisive role in D. uniflora germination. Seeds that originate from cushions plant habitat and germinate in the same substrate do so in greater numbers than when those which originate from shrubby habitats. Conversely, seeds that originate from shrubby habitat and germinate in the same substrate do not exhibit significant differences. Abundance was always greater inside than outside of the nurse plants. We concluded that availability and quality of different microhabitats for seed germination and recruitment, together with a limited gene flow, would trigger putative local adaptations in D. uniflora, modulating a long history of interactions with the plants that act as nurse plants. 相似文献
53.
54.
Biomass production,total protein,chlorophylls, lipids and fatty acids of freshwater green and blue-green algae under different nitrogen regimes 总被引:1,自引:0,他引:1
Two green algae (Chlorella vulgaris and Scenedesmus obliquus) and four blue-green algae (Anacystis nidulans, Microcystis aeruginosa, Oscillatoria rubescens and Spirulina platensis) were grown in 81 batch cultures at different nitrogen levels. In all the algae increasing N levels led to an increase in the biomass (from 8 to 450 mg/l), in protein content (from 8 to 54 %) and in chlorophyll. At low N levels, the green algae contained a high percentage of total lipids (45 % of the biomass). More than 70 % of these were neutral lipids such as triacylglycerols (containing mainly 16:0 and 18:1 fatty acids) and trace amounts of hydrocarbons. At high N levels, the percentage of total lipids dropped to about 20 % of the dry weight. In the latter case the predominant lipids were polar lipids containing polyunsaturated C16 and C18 fatty acids. The blue-green algae, however, did not show any significant changes in their fatty acid and lipid compositions, when the nitrogen concentrations in the nutrient medium were varied. Thus the green but not the blue-green algae can be manipulated in mass cultures to yield a biomass with desired fatty acid and lipid compositions. The data may indicate a hitherto unrecognized distinction between prokaryotic and eukaryotic organisms. 相似文献
55.
56.
Ravi P. Ghorpade Arvind Chopra Tukaram D. Nikam 《Physiology and Molecular Biology of Plants》2010,16(2):159-165
This study aims to establish an efficient protocol for development of seedlings of an endangered medicinally important forest tree Boswellia serrata Roxb., for mass plantation and consistent supply of salai guggul. The green mature fruits served as source of seeds. The excised green zygotic embryos were cultured on Gamborg (B5), McCown and Loyd (WPM) and Schenk and Hildebrandt (SH) media fortified with different concentration of sucrose and on Murashige and Skoog (MS) medium containing 3 % sucrose, polyvinylpyrrolidone (PVP) (0–300 mg l−l), Gibberellic acid (GA3), Indoleacetic acid (IAA), Naphthaleneacetic acid (NAA), Indole-3-Butyric acid (IBA) or 2,4-dichlorophenoxyacetic acid (2,4 D) and 6-benzylaminopurine (BA) or kinetin (Kin) individually. The highest frequency of embryo germination (96 %) and conversion into seedling was obtained on MS medium containing 3 % sucrose together with 200 mg l−l PVP; other media were either inferior or induced abnormalities in the seedlings including callus formation from the zygotic embryos. Fully developed seedlings could be successfully established in soil with about 94 % survival. The embryos from mature dry seeds did not respond for germination in any of the experiments. In conclusion, selection of zygotic embryo from green mature seeds and their in vitro germination is important for propagation of B. serrata. 相似文献
57.
This article outlines the subsector of the information and communication technology (ICT) industry concerned with reducing the economy's environmental impact, dubbed ICT‐enabled low carbon technologies (ICTeLCTs). The article is based on a study funded by United Kingdom (UK) Trade and Investment, a division of the UK Department for Business, Innovation and Skills. ICTeLCTs can be segmented into specialist and generalist operators. Specialists focus on one or two ICT applications to monitor or reduce environmental issues, while generalists supply products and services enabling a firm or a private household to reduce the environmental impact of its activities. The subsector can be further segmented into green ICT, energy management, building management, carbon accounting, waste management, intelligent transport systems (ITSs), and water management. The main factors driving ICTeLCTs include legislation, voluntary environmental standards, corporate social responsibility (CSR) activities, customer demand, and competitive market factors. Policy makers should continue to drive the growth of ICTeLCTs with the introduction and refinement of environmental legislation regulating energy use and markets. 相似文献
58.
Floristic inventory of wild plants comprised of total 129 plant species belonging to 42 families and 101 genera. Location wise UAP contributed greater amount of plant species (53%), followed by PFI (29%), UoP (15%) and Islamia College (3%). Majority of the plants were annual herbs (58%), followed by perennial herbs (29%), trees (10%) and shrubs (3%), respectively. The leading families included Poaceae, contributed 18% of all the plant species. Habitat wise, 44% of them grew in grassy plains, abandoned lands and mismanaged lawns, followed by roadsides (34%), undulating grassy plains (15%) and stony grounds with uneven topography along with stream banks and drainage ditches (7%). Still some of plant species were used as ornamentals, while some shrubs were use in fencing around fields; others were utilized as green manure, for fishing, sheltering and religious purposes. Exploring and identifying the wild flora of the campus and compiling as a handbook would help to monitor new plants introductions particularly of noxious invasive weeds in the campuses in future. 相似文献
59.
Amanda D. Rodewald 《Journal of Field Ornithology》2012,83(1):73-84
ABSTRACT Use of early successional habitat by mature forest birds during the postfledging period is well documented, but reasons for this habitat shift remain elusive. Although forest‐breeding songbirds are primarily insectivorous during the nestling and early fledgling periods due to high protein requirements, older fledglings may adopt a heavily frugivorous diet. Our objectives were to use stable isotopes to examine the dietary trophic level of juveniles of three species of mature forest songbirds to determine if juvenile songbirds heavily consume fruit resources during the postfledging period and to evaluate a possible link between diet and energetic condition. We collected the outer right rectrix and several body feathers from 34 Wood Thrushes (Hylocichla mustelina), 34 Ovenbirds (Seiurus aurocapilla), and 35 Scarlet Tanagers (Piranga olivacea) captured in regenerating clearcuts in southeastern Ohio in 2005 and 2006. We also collected fruit and arthropod samples from each clearcut. Isotopic values of body feathers were significantly higher (more enriched) than those of rectrices in all cases except values of δ13C for Ovenbirds where we found no difference between body and rectrix feathers. These results suggest that juvenile songbirds did not undergo a strong shift to frugivory during the postfledging period, and arthropods were the primary source of protein during the period when rectrix and body feathers were growing. In addition, the energetic condition of birds was not related to the isotopic signature of feathers. Although our results are inconsistent with the hypothesis that juveniles move into regenerating clearcuts enabling them to shift to a primarily frugivorous diet during the postfledging period, they may consume fruit for nonprotein requirements, such as lipids and carbohydrates. 相似文献
60.