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41.
42.
Crassostrea madrasensis is an important fouling oyster in tropical industrial cooling water systems. C. madrasensis individuals attach to surfaces by cementing one of their two valves to the substratum. Therefore, oyster fouling creates more problems than mussel fouling in the cooling conduits of power stations, because unlike the latter, the shell of the former remains attached to the substratum even after the death of the animal. However, there are no published reports on the tolerance of this species to chlorination and heat treatment. The mortality pattern and physiological behaviour (oxygen consumption and filtration rate) of three size groups (13 mm, 44 mm and 64 mm mean shell length) of C. madrasensis were studied at different residual chlorine concentrations (0.25, 0.5, 0.75, 1, 2, 3 to 5 mg lm 1) and temperatures (30°C to 45°C). The effect of shell size (=age) on C. madrasensis mortality in the presence of chlorine and taking into account temperature was significant, with the largest size group oysters showing highest resistance. At 1 mg lm 1 residual chlorine, the 13 mm and 64 mm size group oysters took 504 h (21 d) and 744 h (31 d), respectively to reach 100% mortality. At 39°C, the 13 mm size group oysters took 218 min to reach 100% mortality, whereas the 64 mm size group oysters took 325 min. The oxygen consumption and filtration rate of C. madrasensis showed progressive reduction with increasing residual chlorine concentrations. However, the filtration rate and oxygen consumption responses of C. madrasensis were not significantly different between 30°C (control) and 37.5°C. There was a sharp decrease in the filtration rate and oxygen consumption at 38.5°C. A comparison of the present mortality data with previous reports on other bivalves suggests that the chlorine tolerance of C. madrasensis lies in between that of Perna viridis and Perna perna, while its temperature tolerance is significantly higher than that of the other two bivalve species. However, in power station heat exchangers, where simultaneous chlorine and thermal stresses are existent, C. madrasensis may have an edge over other common foulants, because of its high temperature tolerance. 相似文献
43.
E. L. Kothny 《Plant and Soil》1979,53(4):547-550
Summary Palladium is taken up by vegetation, generally with a ratio ash/soil>1. A high concentration in leaves ofJuglans hindsii in early spring is followed by a large drop during initial growth. The concentration increases toward the end of the season and is resorbed before abscission. 相似文献
44.
R. Jason B. Reynolds Elizabeth A.H. Pilon-Smits 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(11):2372-2382
Background
Selenium (Se) hyperaccumulation occurs in ~50 plant taxa native to seleniferous soils in Western USA. Hyperaccumulator tissue Se levels, 1000–15,000?mg/kg dry weight, are typically 100 times higher than surrounding vegetation. Relative to other species, hyperaccumulators also transform Se more into organic forms.Scope of review
We review abiotic and biotic factors influencing soil Se distribution and bioavailability, soil being the source of the Se in hyperaccumulators. Next, we summarize the fate of Se in plants, particularly hyperaccumulators. We then extensively review the impact of plant Se accumulation on ecological interactions. Finally, we discuss the potential impact of Se hyperaccumulators on local community composition and Se cycling.Major conclusions
Selenium (hyper)accumulation offers ecological advantages: protection from herbivores and pathogens and competitive advantage over other plants. The extreme Se levels in and around hyperaccumulators create a toxic environment for Se-sensitive ecological partners, while offering a niche for Se-resistant partners. Through these dual effects, hyperaccumulators may influence species composition in their local environment, as well as Se cycling.General significance
The implied effects of Se hyperaccumulation on community assembly and local Se cycling warrant further investigations into the contribution of hyperaccumulators and general terrestrial vegetation to global Se cycling and may serve as a case study for how trace elements influence ecological processes. Furthermore, understanding ecological implications of plant Se accumulation are vital for safe implementation of biofortification and phytoremediation, technologies increasingly implemented to battle Se deficiency and toxicity. 相似文献45.
Smocovitis V 《American journal of botany》1997,84(12):1625-1637
This is an historical paper examining the scientific background of George Ledyard Stebbins, Jr. (b. 1906), one of the foremost botanists of this century and one of the architects of the evolutionary synthesis, the intellectual event that brought together genetics and selection theory in the interval between 1920 and 1950. It considers his scientific influence and research, beginning with his Harvard education in 1924 and ending in 1950 with the publication of his book Variation and Evolution in Plants. The paper also more broadly assesses the contributions of other botanists to the evolutionary synthesis, including discussion of the work of Edgar Anderson (1897-1967) and others. It also traces the larger historical patterns of American botany, which saw a shift from East Coast botany as exemplified by Harvard botany, to West Coast botany, as exemplified by California botany. 相似文献
46.
Centrin homologues in higher plants are prominently associated with the developing cell plate 总被引:3,自引:0,他引:3
A. J. Del Vecchio J. D. I. Harper K. C. Vaughn A. T. Baron J. L. Salisbury R. L. Overall 《Protoplasma》1997,196(3-4):224-234
Summary Centrin and calmodulin are members of the EF-hand calcium-binding superfamily of proteins. In this study we compared localisation and immunoblotting of centrin with calmodulin in several monocot (onion and wheat) and dicot (mung bean andArabidopsis) plants. We confirmed that an anti-calmodulin antibody recognised a 17 kDa protein in all species tested and localises to the cytoplasm, mitotic matrix and with microtubules of the preprophase band and phragmoplast. In contrast, immunoblotting using anti-centrin antibodies shows that plant centrins vary from 17 to 20 kDa. Immunofluorescence microscopy with anti-centrin antibodies revealed only weak centrin immunoreactivity in the cytoplasm, nucleus, nuclear envelope, phragmoplast and mitotic matrix in meristematic cells. There was a slightly more intense perinuclear labelling in large differentiating onion cells and between separating anaphase chromosomes. While centrin is known to localise to the mitotic spindle poles in animal and algal cells, there was no appreciable immunoreactivity at the spindle poles in higher plants. In contrast, there was an intense immunofluorescence signal with anti-centrin antibodies in the developing cell plate. Further characterisation of the cell plate labelling by immunogold electron microscopy shows centrin immunoreactivity was closely associated with vesicles in the cell plate. Our observations suggest that centrin may play a role in cell plate formation.Abbreviations BSA
bovine serum albumin
- MTs
microtubules
- MTOCs
microtubule organising centres
- PBS
phosphate buffered saline
- PBST
phosphate buffered saline with Tween-20 相似文献
47.
ZHAO Fu-Wei YAO Yao TANG Jun-Dun XIE Zhen-Guo YANG Sheng-Guo YU Yong-Fu WU Jian-Yong ZHOU Jiang-Ju ZHANG Shi-Ling LI Ping YANG Shao-Jun LEI Qi-Yi XUE Da-Yuan 《Plant Diversity》2014,36(2):261-266
For many years, traditional knowledge, techniques and know how have been applied in the process of fermentation of traditional liquor and also in the process of making its starter culture by Miao ethnic group who lives in Leigongshan Mountain, Southwest China. To protect liquor culture of Miao people, and in order to document and transmit it from generation to generation, we have conducted a series of surveys on the techniques and the process of brewing traditional liquor and making starter culture; and we have documented the plants which have been used for starter culture via ethnobotanical and taxonomical approaches, such as key informants interview, participatory rural appraisal, and ethnobotanical inventory. It has been demonstrated that the traditional liquor in Miao communities resembles other Xiaoqu alcoholic in terms of both the producing process and techniques. Thirty five species of plants used in starter culture, which belong to 19 families and 28 genera, were identified and inventoried. Piloselloides hirsuta (Asteraceae) and Indigofera bungeana (Fabaceae) are the most frequently employed ones among all of the plants. Fresh and tender stems, leaves, or shoots of the plants are parts of plants which are used to make distiller’s yeast; while the whole plant is barely used. The traditional knowledge associated with starter culture would fail to be handed down in a few decades, due to erosion of modernization and losses of young (female) labor and the ethnic language as well. More researche should be carried out as soon as possible to promote liquor culture of Miao people, e.g. census on plants in starter culture and valuation of its biological activities. 相似文献
48.
Daniela Wagner Jens Schneider-Mergener Christoph Forreiter 《Journal of Plant Growth Regulation》2005,24(3):226-237
Small heat shock proteins (sHSPs) are the most abundant stress proteins in plants. Usually not expressed under permissive
conditions, they can accumulate to more than 2% of the total cellular protein content during heat stress. At present several
points of evidence indicate that these proteins act as molecular chaperones by keeping partially denatured proteins in a folding-competent
state. In plants sHSPs are encoded by a multigene family, which can be segregated into several classes according to their
subcellular position and/or sequence homology. Curiously, two different classes appear in the cytoplasm. Their specific role
during heat shock remains elusive. Here we present some evidence that both classes of sHSPs enhance recovery of reporter protein
activity in the presence of HSP70. Applying peptide arrays prepared by SPOT synthesis and in situ analysis by confocal laser scanning microscopy, we could further show that the two classes of sHSP are attached to each other
and are able to interact with non-native proteins both in vivo and in vitro. Although both of the sHSPs act similarly as molecular chaperones, immunohistochemistry experiments support the hypothesis
that the two have different cellular functions in the development of heat-induced cytoplasmic heat shock granules under elevated
temperatures.
Daniela Wagner Deceased 24 Feburary 2004. 相似文献
49.
Siddique M Gernhard S von Koskull-Döring P Vierling E Scharf KD 《Cell stress & chaperones》2008,13(2):183-197
The small heat shock proteins (sHsps), which are ubiquitous stress proteins proposed to act as chaperones, are encoded by
an unusually complex gene family in plants. Plant sHsps are classified into different subfamilies according to amino acid
sequence similarity and localization to distinct subcellular compartments. In the whole Arabidopsis thaliana genome, 19 genes were annotated to encode sHsps, of which 14 belong to previously defined plant sHsp families. In this paper,
we report studies of the five additional sHsp genes in A. thaliana, which can now be shown to represent evolutionarily distinct sHsp subfamilies also found in other plant species. While two
of these five sHsps show expression patterns typical of the other 14 genes, three have unusual tissue specific and developmental
profiles and do not respond to heat induction. Analysis of intracellular targeting indicates that one sHsp represents a new
class of mitochondrion-targeted sHsps, while the others are cytosolic/nuclear, some of which may cooperate with other sHsps
in formation of heat stress granules. Three of the five new proteins were purified and tested for chaperone activity in vitro.
Altogether, these studies complete our basic understanding of the sHsp chaperone family in plants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
50.
Kaj Sand-Jensen 《Hydrobiologia》2008,610(1):307-319
Swift flow in streams may physically influence the morphology and distribution of plants. I quantified drag as a function
of velocity, biomass and their interaction on the trailing canopy of seven European stream species in an experimental flume
and evaluated its importance for species distribution. Drag increased at a power of 1.3–1.9 with velocity and 0.59–0.77 with
biomass in 75% of the measurements. Velocity and biomass interacted because higher velocity causes reconfiguration and greater
internal shelter to unimpeded flow and higher biomass enhances shelter among neighbouring shoots. Increase of drag with velocity
did not differ systematically among inherently streamlined or non-streamlined species while increase of drag with biomass
was smallest among non-streamlined shoots which provide greater mutual shelter. At low shoot density, inherently streamlined
species usually experienced the lowest drag conducive to colonisation and growth in swift flow. At high shoot density, no
systematic differences in drag existed between the two morphologies. No clear relationship existed between drag forces, morphology
and field distribution of species as a function of current velocity probably because a variety of environmental conditions
and plant traits influences distribution. Drag on the trailing canopy usually increased 15- to 35-fold for a 100-fold increase
of biomass suggesting that an even distribution of plants at low density across the stream bed offers greater resistance to
downstream flow than an uneven distribution with the same biomass confined to dense patches surrounded by open flow channels.
Thus, management strategies to ensure a patchy plants distribution should be suitable for combining agricultural drainage
and ecological stream quality.
Handling editor: S. M. Thomaz 相似文献