Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
15,372
result(s) for
"Stream plants."
Sort by:
Rivers and streams
Examines why rivers and streams are important to life on Earth, including the relationships among rivers, humans, aquatic animals, and the rest of natural world.
Book
Antidepressant potential of Musa species peel extract in a rat model through modulation of oxidative stress, neurotransmitters, and CREB signaling pathway
Depression is associated with oxidative stress, monoaminergic dysregulation, and impaired neuroplasticity. This study evaluated the effects of banana (Musa species) peel extract (MSPE) in a dexamethasone-induced rat model of depression. Five groups of adult male Wistar rats (n = 7 per group) were used, with four groups receiving dexamethasone (1 mg/kg, i.p., 14 days) to induce depressive-like alterations, while one group served as a normal control. Treated groups received MSPE (300 mg/kg, p.o.), fluoxetine (10 mg/kg), or their combination alongside dexamethasone. Behavioral assessment demonstrated depressive-like alterations in dexamethasone-exposed animals, which were partially ameliorated in MSPE-treated groups. Dexamethasone exposure significantly reduced superoxide dismutase (SOD) activity (75 ± 10 U/mg protein) and reduced glutathione (GSH; 3.5 ± 0.4 nmol/mg protein), while elevating malondialdehyde (MDA; 4.0 ± 0.5 nmol/mg protein), and markedly depleted brain serotonin (125 ± 30 ng/g) and dopamine (100 ± 20 ng/g), alongside a reduction in the p-CREB/CREB ratio to 0.6 ± 0.1 versus 1.2 ± 0.1 in controls (p < 0.01). MSPE treatment restored SOD to 160 ± 12 U/mg protein and GSH to 6.8 ± 0.6 nmol/mg protein, reduced MDA to 1.8 ± 0.3 nmol/mg protein, partially recovered serotonin (350 ± 45 ng/g) and dopamine (180–195 ng/g) levels, and elevated the p-CREB/CREB ratio to 1.0 ± 0.1 (p < 0.01 vs. dexamethasone group). LC–QTOF–MS profiling identified several polyphenolic constituents in MSPE, notably ferulic acid (206 µg/g DW), catechin (177 µg/g DW), rutin (158 µg/g DW), and hesperidin (152 µg/g DW), which may contribute to these effects. Combined MSPE and fluoxetine treatment produced biochemical responses comparable to or slightly greater than either treatment alone. Overall, these findings suggest that Musa peel extract may influence oxidative, monoaminergic, and CREB signaling pathways relevant to stress-related neurobiological alterations.
Journal Article
Power peaks against installed capacity in tidal stream energy
Owing to the natural variability of tidal flow, the curve of available power against time at the site of a tidal stream plant is typically spiky. This means that, for the power peaks to be fully exploited, the installed capacity of the plant would have to be large relative to its mean power output. In practice, a balance should be struck between the percentage of the total resource that is exploited and the installed power (and installation cost) of the plant. The purpose of this study is to examine this problematic through a case study: a tidal stream plant proposed for Ria de Ortigueira, a large estuary in north-west Spain with a tidal range of 4.5 m. A numerical model of the estuary hydrodynamics is implemented, calibrated and successfully validated using field data. The model is used to determine the tidal flow patterns. The question of the installed capacity is examined for the two areas with the greatest potential as tidal stream sites. It is shown that the nominal power that is required can be greatly reduced by relinquishing the peaks of the power curve, with only a slight reduction in the energy output.
Journal Article
Plant distribution and abundance in relation to physical conditions and location within Danish stream systems
The distribution of obligate submerged plants, amphibious plants and terrestrial plants in streams was examined in relation to water depth, substrate and distance to the banks using univariate and mulitivariate analyses. The analyses were based on recordings in more than 40000 quadrats (25×25 cm) in 208 unshaded sites in the predominantly small and shallow (<1.6 m) Danish streams. Also, the distribution of plant abundance and richness from the source to the outlet of the stream system was determined. The submerged plants in Danish streams include 87 terrestrial, 22 amphibious and 30 obligate submerged taxa. The distribution of plant types was mainly related to water depth and distance to the bank among the physical conditions, while the type of bottom substrate had no significant influence. Terrestrial plants and amphibious plants (excluding Sparganium emersum) dominated in shallow water near the bank, but declined rapidly with increasing depth and distance to the bank, reflecting the importance of dispersal by ingrowth from populations on the banks to the water among these plants. Accordingly, these two plant groups constituted a higher proportion of total plant abundance in small streams than large streams. S. emersum dominated on great depth and distance to the banks, probably reflecting the lengthwise dispersal of this species from upstream to downstream parts of the stream system, the tolerance of the species to weed cutting and the adaptation to grow at low light intensities. Obligate submerged plants dominated at intermediate depths and at all distances from the bank except from 0 to 50 cm. This distribution reflects the ability of these species to disperse lengthwise in streams and live permanently submerged. The species number of all species and obligate submerged plants was lower in the smallest stream sites compared to larger downstream sites, while there was no difference for terrestrial and amphibious plants. The downstream increase of submerged species can be explained by the increase of habitat area and the dispersal of plants with the current, implying that the species pool accumulates with distance from the source. This result is at variance with a maximum richness of submerged plant species predicted for intermediate-sized streams according to the River Continuum Concept developed for large North American streams having forested shallow upstream sections and unshaded, deep downstream sections both unsuitable to submerged plant growth. The results for Danish streams imply that both the longitudinal connection through the flowing water and the transversal connection to the local species on the banks are important for plant distribution in the streams.[PUBLICATION ABSTRACT]
Journal Article
Ecophysiology of nickel phytoaccumulation: a simplified biophysical approach
Solute active transport or exclusion by plants can be identified by the values of the Transpiration Stream Concentration Factor (TSCFxylem:solution solute concentration ratio). The aim of this study was to estimate this parameter for Ni uptake by the Ni-hyperaccumulator Leptoplax emarginata or the Ni-excluder Triticum aestivum cultivar oFidel'. The Intact Plant TSCF for nickel (IPTSCFNi) was calculated as the ratio between the nickel mass accumulation in the leaves and the nickel concentration in solution per volume of water transpired. Predominantly, Ni active transport occurred for L. emarginata, with IPTSCFNi values of 4.77.2 and convective component proportions of the root Ni uptake flow of only 1520% for a range of Ni concentrations in solutions of 216 mol Ni l(1), regardless of the growth period and the time of Ni uptake. Hyperaccumulator roots were permeable to both water and nickel (mean reflection coefficient for Ni, sigma(Ni), of 0.06), which was mainly attributed to an absence of exodermis. Results provide a new view of the mechanisms of Ni hyperaccumulation. By contrast, the wheat excluder was characterized by an extremely low mean IPTSCFNi value of 0.006, characterizing a predominantly Ni sequestration in roots. From a methodological viewpoint, the omicroscopic' TSCFNi, measured directly on excised plants was 2.4 times larger than its recommended omacroscopic' IPTSCFNi counterpart. Overall, IPTSCF and sigma determined on intact transpiring plants appeared to be very useful biophysical parameters in the study of the mechanisms involved in metal uptake and accumulation by plants, and in their modelling.
Journal Article
Assessment of technological options and economical feasibility for cyanophycin biopolymer and high-value amino acid production
Major transitions can be expected within the next few decades aiming at the reduction of pollution and global warming and at energy saving measures. For these purposes, new sustainable biorefinery concepts will be needed that will replace the traditional mineral oil-based synthesis of specialty and bulk chemicals. An important group of these chemicals are those that comprise N-functionalities. Many plant components contained in biomass rest or waste stream fractions contain these N-functionalities in proteins and free amino acids that can be used as starting materials for the synthesis of biopolymers and chemicals. This paper describes the economic and technological feasibility for cyanophycin production by fermentation of the potato waste stream Protamylasse[trade mark sign] or directly in plants and its subsequent conversion to a number of N-containing bulk chemicals.
Journal Article
Stoichiometry and kinetics of single and mixed substrate uptake in Aspergillus niger
In its natural environment, the filamentous fungus Aspergillus niger grows on decaying fruits and plant material, thereby enzymatically degrading the lignocellulosic constituents (lignin, cellulose, hemicellulose, and pectin) into a mixture of mono- and oligosaccharides. To investigate the kinetics and stoichiometry of growth of this fungus on lignocellulosic sugars, we carried out batch cultivations on six representative monosaccharides (glucose, xylose, mannose, rhamnose, arabinose, and galacturonic acid) and a mixture of these. Growth on these substrates was characterized in terms of biomass yields, oxygen/biomass ratios, and specific conversion rates. Interestingly, in combination, some of the carbon sources were consumed simultaneously and some sequentially. With a previously developed protocol, a sequential chemostat cultivation experiment was performed on a feed mixture of the six substrates. We found that the uptake of glucose, xylose, and mannose could be described with a Michaelis–Menten-type kinetics; however, these carbon sources seem to be competing for the same transport systems, while the uptake of arabinose, galacturonic acid, and rhamnose appeared to be repressed by the presence of other substrates.
Journal Article
Impacts of flow augmentation on river channel processes and riparian vegetation
The Little Bow River Project was implemented in 2003 and includes Alberta's newest dam. The Project involves tripling the diversion of water from the Highwood River to the Little Bow River and subsequently storing the water in the Twin Valley Reservoir. This MSc Thesis provided part of the environmental monitoring for that Project and particularly investigated the impacts of augmented flows on the river channel and riparian vegetation along the upper reach of the Little Bow River. An initial component of the long-term study was to determine the existing associations between fluvial geomorphic characteristics and riparian plant communities. Poplar (Populus balsamifera L.), willow (Salix bebbiana Sargent and S. exigua Nutt.) and wolf-willow (Elaeagnus commutata Bernh.) communities were located along the upper section of the river, where the channel had a steeper gradient and was narrower and more sinuous. Cattail (Typha latifolia L.) and grass (grasses and sedges) communities were generally located along the lower section of the river that was shallower in gradient, wider and straighter. Plant community distribution also reflected impacts from cattle grazing. Initial channel and vegetation responses in the first two years following the increase in flow augmentation were slight and included bank slumping, sediment scour and inundation of flooded zones. The initial responses are consistent with the primary prediction of channel widening and this will probably be associated with some changes in the adjacent riparian plant communities.
Dissertation
Global separation of plant transpiration from groundwater and streamflow
Soil water is usually assumed to be equally available for all purposes, supplying plant transpiration as well as groundwater and streamflow; however, a study of hydrogen and oxygen isotopes from 47 globally distributed sites shows that in fact the water used by plants tends to be isotopically distinct from the water that feeds streamflow.
There's water, and there's water
Soil water is usually assumed to be available for all purposes in equal measure, supplying plant transpiration as well as groundwater and streamflow. Building on prior but limited studies, Jaivime Evaristo
et al
. have assembled a dataset of hydrogen and oxygen isotopes — drawn from widely distributed sites — and show that ecohydrological separation is the rule. Water used by plants tends to be isotopically distinct from that used for streamflow, suggesting that hydrological separation of precipitation inputs creates distinct pools of water resources. This finding implies that that existing land surface model parameterizations of plant physiological processes and streamflow can be made more realistic through the incorporation of ecohydrological separation.
Current land surface models assume that groundwater, streamflow and plant transpiration are all sourced and mediated by the same well mixed water reservoir—the soil. However, recent work in Oregon
1
and Mexico
2
has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater and streamflow. These findings have not yet been widely tested. Here we use hydrogen and oxygen isotopic data (
2
H/
1
H (δ
2
H) and
18
O/
16
O (δ
18
O)) from 47 globally distributed sites to show that ecohydrological separation is widespread across different biomes. Precipitation, stream water and groundwater from each site plot approximately along the δ
2
H/δ
18
O slope of local precipitation inputs. But soil and plant xylem waters extracted from the 47 sites all plot below the local stream water and groundwater on the meteoric water line, suggesting that plants use soil water that does not itself contribute to groundwater recharge or streamflow. Our results further show that, at 80% of the sites, the precipitation that supplies groundwater recharge and streamflow is different from the water that supplies parts of soil water recharge and plant transpiration. The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation–transpiration partitioning. Future land surface model parameterizations should be closely examined for how vegetation, groundwater recharge and streamflow are assumed to be coupled.
Journal Article
HeadwaterstreamSNevada
Providing historical data on riparian plant biodiversity and physico-chemical parameters of stream water in Mediterranean mountains helps to assess the effects of climate change and other human stressors on these sensitive and critical ecosystems. This database collects data from the main natural headwater streams of the Sierra Nevada (southeastern Spain), a high mountain (up to 3479 m above sea level [m asl]) recognized as a biodiversity super hotspot in the Mediterranean basin. On this mountain, rivers and landscapes depend on snowmelt water, representing an excellent scenario for evaluating global change’s impacts. This dataset covers firstto third-order headwater streams at 41 sites from 832 to 1997 m asl, collected from December 2006 to July 2007. Our goal is to supply information on the vegetation associated with streambanks, the essential physico-chemical parameters of stream water, and the physiographic features of the subwatersheds. Riparian vegetation data correspond to six plots sampled at each site, including total canopy, individual number, height and DBH (diameter at breast height) in woody species, and cover percentage for herbs. Physico-chemical parameters were measured in situ (electric conductivity, pH, dissolved O₂ concentration, stream discharge) and determined in the laboratory (alkalinity, soluble reactive phosphate-phosphorus [SRP], total phosphorus [TP], nitrate-nitrogen [NO⁻ ₃ –N], ammonium-nitrogen [NH⁺ ₄ –N], total nitrogen [TN]). Watershed physiographic variables comprise drainage area, minimum altitude, maximum altitude, mean slope, orientation, stream order, stream length, and land cover surface percentage. We recorded 197 plant taxa (67 species, 28 subspecies, and 2 hybrids), representing 8.4% of the Sierra Nevada vascular flora. Due to the botanical nomenclature used, the database can be linked to FloraSNevada database, contributing to Sierra Nevada (Spain) as a laboratory of global processes. This data set can be freely used for non-commercial purposes. Users of these data should cite this data paper in any publications resulting from its use.
Journal Article