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Abstract. Arthrocnemum macrostachyum is a perennial species acting as a primary colonizer of salt pans in Mediterranean high salt marshes. Salicornia ramosissima, an annual, occurs in salt pans under Arthrocnemum canopies and in open areas. The aim of this study was to analyse, in wild populations and a transplant experiment, how S. ramosissima population dynamics and growth are affected by A. macrostachyum. The environmental conditions within the patches of Arthrocnemum were less stressful than in the open areas, with lower radiation levels and salinity concentrations. In the inner areas of A. macrostachyum patches, density‐dependent mortality processes of S. ramosissima seedlings led to low densities of adult individuals with greater morphological development and reproductive success than in open areas. However, at the edges of Arthrocnemum patches facilitation of seedling survival favoured high densities. Environmental stress hindered development, decreased reproduction and premature death. These results are in agreement with the general theory of factors controlling vegetation distribution that biotic interactions dominate in low stress environments, while abiotic interactions dominate under harsher environmental conditions. A. macrostachyum plays an essential role in the succession in these salt pans, facilitating seed production and stimulating nucleation processes in S. ramosissima. 相似文献
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耐盐酶在高盐浓度下仍具备催化活性和稳定性,在高盐食品和海产品加工、洗涤及其它高盐环境生物技术领域被广泛应用;耐盐基因在高盐条件下可以使微生物维持正常功能,获取并研究不同环境中的耐盐基因对揭示微生物的耐盐机制,以及实现其在高盐环境中的定向应用具有的重要意义。宏基因组学避开纯培养技术探知微生物的多样性及其功能,为我们提供了一种发现新基因、开发新的微生物活性物质和研究微生物群落结构及其功能的新技术。文中结合本课题组的研究工作,综述了利用宏基因组学获取耐盐酶类及耐盐基因的策略,同时着重介绍利用宏基因组学从海洋、土壤、胃肠道等环境中获取耐盐酶类及耐盐基因的研究。 相似文献
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《Plant Physiology and Biochemistry》1999,37(1):65-71
The physiological changes induced by a daily increase of NaCl level, over a period of 4 d, were studied in leaves of the salt-sensitive cultivated tomato species Lycopersicon esculentum and its wild salt-tolerant relative Lycopersicon pennellii. A higher solute contribution to the osmotic adjustment was observed in NaCl-treated leaves of L. pennellii than in those of L. esculentum. This response together with the higher accumulation of inorganic solutes in the wild species and of organic solutes in the cultivated species verified the different salt tolerance mechanisms operating in the two species in the short-term. With regard to the changes induced by salt stress on the free polyamine levels, the putrescine and spermine levels increased with salinity, whereas the spermine levels decreased in both tomato species; nevertheless, the main difference between the two species lays in an earlier and greater accumulation of putrescine induced by salinity in L. pennellii than in L. esculentum. The changes in putrescine levels were associated to changes in amino acids related to its synthesis, and the changes were different in both species. In L. esculentum, the high concentrations of some intermediate compounds (glutamate and arginine) were related to the low accumulation rate of both proline and putrescine. In contrast, in L. pennellii, important reductions in glutamate and arginine levels were found at the end of the salinization period. Moreover, in this last situation, a decline in the putrescine level ran parallel to a high proline accumulation, which suggests that the higher the stress level, the higher the deviation of glutamate to proline occurring in the salt tolerant species. It could be concluded that an early accumulation of the diamine putrescine seems to be associated with salt tolerance in the short-term. 相似文献
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Advances in salt tolerance 总被引:6,自引:0,他引:6
Summary Advances in and prospects for the development of salt tolerant crops are discussed. The genetic approach to the salinity problem
is fairly new, but research has become quite active in a short span of time. Difficulties and opportunities are outlined.
Salinity varies spatially, temporally, qualitatively, and quantitatively. In addition, the responses of plants to salt stress
vary during their life cycle. Selection and breeding, including the use of wide crosses, are considered the best short-term
approaches to the development of salt tolerant crops, but the new biotechnological and molecular biological techniques will
make increasingly important contributions. Cooperation is called for among soil and water scientists, agronomists, plant physiologists
and biochemists, cytologists, and plant geneticists, breeders, and biotechnologists. Given such cooperation and adequate support
for these endeavors, the potential for increasing productivity in salt-affected areas can be realized. 相似文献
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Excluded salt accumulated at mangrove roots must be transported away from the root zone by diffusive processes, due to the low permeability of most mangrove soils. The diffusion coefficient for salt in mangrove soils determines the rate of this diffusive transport but has not been determined experimentally before. In this work we used a 12-month long-time series of salt concentration profiles measured in a sediment core over which fresh water was continuously circulated, to determine the diffusion coefficient for salt in the soil. Salt concentrations were measured using an electrical conductivity probe that was developed for use in hypersaline (salt concentration up to and in excess of 120g/l) conditions. A modified formula was experimentally determined to relate electrical conductivity to salt concentration and temperature, applicable up to a salt concentration of 200g/l. This was done because standard formulae relating these variables do not apply in the hypersaline conditions often encountered in salt flat sediments. The salt concentration profiles were used in a simple mathematical model to determine a sediment diffusion coefficient for salt in a salt flat sediment. This value of D=(4.6±0.2) ×10–5m2/day was approximately half that calculated theoretically. 相似文献
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Drosophila larvae change from exhibiting attraction to aversion as the concentration of salt in a substrate is increased. However, some aversive concentrations appear to act as positive reinforcers, increasing attraction to an odour with which they have been paired. We test whether this surprising dissociation between the unconditioned and conditioned response depends on the larvae's experience of salt concentration in their food. We find that although the point at which a NaCl concentration becomes aversive shifts with different rearing experience, the dissociation remains evident. Testing larvae using a substrate 0.025 M above the NaCl concentration on which the larvae were reared consistently results in aversive choice behaviour but appetitive reinforcement effects. 相似文献
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Huang X Zhang Y Jiao B Chen G Huang S Guo F Shen Y Huang Z Zhao B 《Journal of experimental botany》2012,63(15):5463-5473
A novel gene named TaSC was cloned from salt-tolerant wheat. Northern blot showed that the expression of TaSC in salt-tolerant wheat was up-regulated after salt stress. Real-time quantitative PCR analyses showed that TaSC expression was induced by salt and ABA in wheat. Localization analysis showed that TaSC proteins were localized to the plasma membrane in transgenic Arabidopsis thaliana. The overexpression of TaSC in Col-0 and atsc (SALK_072220) Arabidopsis strains resulted in increased salt tolerance of the transgenic plants. TaSC overexpression in Col-0 and atsc signi?cantly up-regulated the expression of AtFRY1, AtSAD1, and AtCDPK2. AtCDPK2 overexpression in atsc rescued the salt-sensitive phenotype of atsc. The TaSC gene may improve plant salt tolerance by acting via the CDPK pathway. 相似文献
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Haddy FJ 《Life sciences》2006,79(17):1585-1592
Certain things have not changed since my colleague and I last reviewed the role of dietary salt in hypertension [Haddy, F.J., Pamnani, M.B., 1995. Role of dietary salt in hypertension. Journal of the American College of Nutrition 14, 428-438]. Over half of hypertensives are still salt sensitive, i.e., they respond to a high NaCl intake with a rise in blood pressure. This can be ameliorated by restricting NaCl intake, supplementing potassium intake, and consuming diuretics. Some things have changed. We now have more insight into mechanism; we suspected that volume expansion and endogenous Na(+),K(+)-ATPase inhibitors were the connection between excessive salt intake and the hypertension, but we were not certain as to the nature of the inhibitors. Now it appears that the inhibitors are steroids released from the adrenal gland and are members of the cardenolide family, e.g., ouabain, and the bufadienolide family, e.g., marinobufagenin. This presents new possibilities in therapy, including antibodies to these agents and competitive inhibitors to their binding to Na(+),K(+)-ATPase. 相似文献
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Anne Bülow-Olsen 《Ecography》1983,6(2):194-198
Germination of caryopses and seeds of Festuca rubra L. coll. from wet, dry and dune areas in the salt marsh at Skallingen, Jutland, Denmark, was tested in deionized water and diluted sea water. A strong correlation was found between percentage of germination and the topography of the collection sites. Further it was found that salt tolerance for the most salt tolerant populations, growing on low dunes, was provided partly by the husks rather than only being a characteristic of the seed. In less salt tolerant populations from low and dry areas, husks had no influence on germination percentage in 25% sea water. 相似文献
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In order to study the role of peripheral taste sensitivity inmediating increases in salt intake of the rat, the effects ofsodium deprivation and adrenalectomy on chorda tympani nerveresponses to taste stimulation were determined. Sodium deprivationresulted in a reduction in whole nerve responsivity to suprathresholdNaCl concentrations requiring a 10-fold increase in concentrationto elicit the same neural signal of control preparations. Saltintake of sodium deprived rats was predicted by adjusting datain a 10-min intake test from control rats for the reduced neuralsignal and lower salivary sodium levels of sodium deprived rats.The whole nerve responses to LiCl and KCl, as well as to NaCl,were reduced after sodium deprivation and adrenalectomy. Themultifiber response of the chorda tympani is comprised of theindividual responses of NaCl sensitive N-best fibers and HCl/NaClsensitive H-best fibers. After sodium deprivation N-best fibers'responses to suprathreshold concentrations of NaCl were reduced;H-best fibers' responses were not affected by sodium deprivation.Future studies will determine the effect of KCl and other saltson responses of N-best and H-best fibers. Applying Beidler'sbiophysical model to the single fiber data suggests that sodiumdeprivation influences receptor mechanisms for NaCl of N-bestfibers and not H-best fibers. Because repeated NaCl stimulationresulted in increased chorda tympani responsivity to NaCl, wesuggest that sodium deprivation may alter the salt receptorsimply by disuse. Altered receptor sensitivity may be an adaptivemechanism to influence salt consumption by a shift in suprathresholdNaCl intensity. 相似文献
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Engineering salt tolerance in plants 总被引:32,自引:0,他引:32
Recent progress has been made in the identification and characterization of the mechanisms that allow plants to tolerate high salt concentrations. The understanding of metabolic fluxes and the main constraints for the production of compatible solutes (i.e. feedback inhibition and the limitation of substrate supply) open up the possibility of genetically engineering entire pathways that could lead to the production of osmoprotectants. This, together with the identification of the different sodium transporters (in particular vacuolar and plasma membrane Na(+)/H(+) antiporters) that could provide the needed ion homeostasis during salt stress, opens the possibility of engineering crop plants with improved salt tolerance. 相似文献
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Natural hypersaline waters are widely distributed around the globe, as both continental surface waters and sea floor lakes, the latter being maintained by the large density difference between the hypersaline and overlying marine water. Owing to the extreme salt concentrations, close to or at saturation (approximately 35%, w/v), such waters might be expected to be devoid of life but, in fact, maintain dense populations of microbes. The majority of these microorganisms are halophilic prokaryotes belonging to the Domain Archaea, 'haloarchaea'. Viruses infecting haloarchaea are a vital part of hypersaline ecosystems, in many circumstances outnumbering cells by 10-100-fold. However, few of these 'haloviruses' have been isolated and even fewer have been characterised in molecular detail. In this review, we explore the methods used by haloviruses to replicate within their hosts and consider the implications of haloviral-haloarchaeal interactions for salt lake ecology. 相似文献
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Carlos Eduardo Braga de Abreu Gyedre dos Santos Araújo Ana Cristina de Oliveira Monteiro-Moreira José Hélio Costa Hugo de Brito Leite Frederico Bruno Mendes Batista Moreno José Tarquinio Prisco Enéas Gomes-Filho 《Plant cell reports》2014,33(8):1289-1306