Página 1 dos resultados de 1390 itens digitais encontrados em 0.008 segundos

Salinity tolerance in Schinopsis quebracho colorado: Seed germination, growth, ion relations and metabolic responses

MELONI, D. A.; GULOTTA, M. R.; MARTINEZ, C. A.
Fonte: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD Publicador: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.42%
Soil salinity is a major abiotic stress influencing plant productivity worldwide. Schinopsis quebracho colorado is one of the most important woody species in the Gran Chaco, an and and salt-prone subtropical biome of South America. To gain a better understanding of the physiological mechanisms that allow plant establishment under salt conditions, germination and seedling growth of S. quebracho colorado were examined under treatment with a range of NaCl solutions (germination: 0-300 mmol l(-1) NaCl; seedling growth: 0-200 mmol l(-1) NaCl). The aim was to test the hypothesis that S. quebracho colorado is a glycophite that shows different salt tolerance responses with development stage. Proline content, total soluble carbohydrates and Na+, K+ and Cl- concentrations in leaves and roots of seedlings, and the chlorophyll concentration and relative water content of leaves were measured. Germination was not affected by 100 mmol l(-1) NaCl, but decreased at a concentration of 200 mmol l(-1). At 300 mmol l(-1) NaCl, germination did not occur. Seedling growth decreased drastically with increasing salinity. An increase in NaCl from 0 to 100 mmol l(-1) also significantly reduced the leaf relative water content by 22% and increased the proline concentration by 60% in roots. In contrast...

Study of salt stress tolerance in spelt

Pereira, Catarina de Vasconcelos
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /10/2014 ENG
Relevância na Pesquisa
56.5%
World population is increasing at an alarming rate while food productivity is decreasing due to the effect of various abiotic stresses. Soil salinity is one of the most important abiotic stress and a limiting factor for worldwide plant production. In addition to its important effects on yield, salt stress affects numerous cellular activities, including cell wall composition, photosynthesis, protein synthesis, ions and organic solutes. Up to 20% of the irrigated arable land in arid and semiarid regions is already salt affected and is still expanding. Improving salt tolerant varieties is of major importance, and efforts should be focused on finding adaptive mechanisms which are involved in salinity tolerance. In this study, several spelt wheat (Triticum aestivum var. Spelta) genotypes and one cultivar of modern bread wheat were used to screen them for salt tolerance. Spelt is an old-European cereal crop currently attracting renewed interest as a food grain because it is said to be harder than wheat and requires less fertilizer. Spelt wheat is also becoming very attractive genetic source by plant breeders due to its wide adaptation ability to various stressful conditions such as soil salinity. In this study morphological parameters (e.g....

Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.)

Ahmad,Maqshoof; Zahir,Zahir A.; Nazli,Farheen; Akram,Fareeha; Arshad,Muhammad; Khalid,Muhammad
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 EN
Relevância na Pesquisa
56.51%
Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

Xylem sap analysis reveals new facts of salt tolerance in rice genotypes

Roshandel,Parto
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2007 EN
Relevância na Pesquisa
56.41%
Salinity damage in rice and other salt-sensitive species is due to excessive transport of NaCl through the root system to the leaves and consequently low salt transport to the shoot can be a major trait determining salt resistance. Since the rapid uptake of sodium ions is such a crucial part of the response of rice to salinity, physiological experiments were carried out to compare bypass flow in two genotypes of rice (IR4630 and IR15324) differing in salt tolerance, because it has been suggested that an apoplastic pathway, bypass flow, is a major contributory pathway for Na+ entrance into rice plants. Experiments on the youngest fully expanded photosynthetic leaf (the third from the base), using PTS as a tracer for apoplastic movement and Philaenus spumarius (a xylem-feeding insect) as a means to sample the xylem sap, did not demonstrate any apparent difference in bypass flow between the two lines. The similarity of Na+ concentration in the xylem sap of both genotypes paralleled the results of PTS (a fluorescent dye used as an apoplastic tracer for the transpiration stream) measurements. Despite the similarity of Na+ concentration in the xylem sap of the third leaves, the Na+ concentration in the bulk of these leaves of IR15324 plants (the sensitive line) was about twice that of IR4630 (the tolerant line). Measurements of transpiration over 8 d of salinisation showed the similarity of rates in both lines providing evidence that the greater accumulation of NaCl in IR15324 than in IR4630 plants was unlikely to be due to a difference in the delivery of salt to the leaves by an apoplastic route. Results of the current work suggest that the difference in salt tolerance might be a consequence of damage to leaves 1 and 2 of IR15324 that allowed Na+ to leak into the phloem - and consequently move to leaf 3.

Changes in physiological indicators associated with salt tolerance in two contrasting cashew rootstocks

Ferreira-Silva,Sérgio L.; Silveira,Joaquim A.G.; Voigt,Eduardo L.; Soares,Lucilene S.P.; Viégas,Ricardo A.
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2008 EN
Relevância na Pesquisa
66.49%
In order to identify salt tolerance indicators, several physiological variables were evaluated in two contrasting cashew (Anacardium occidentale L.) rootstocks in response to salt stress. The tolerant CCP 09 genotype showed better growth performance after two weeks under a large range of NaCl salinity (50, 100, 150 and 200 mM). The NaCl treatments induced a significant drop in transpiration as a consequence of an increased stomatal resistance in both genotypes. No significant differences in Na+, Cl, and K+ concentrations were found in both roots and leaves regardless of rootstocks. The tolerant genotype exhibited lower relative water content and less negative leaf osmotic potential as compared with the sensitive genotype and, therefore, these variables could not be related to salt tolerance. Salt stress caused more significant changes in protein and amino acid concentrations in roots than in leaves. Among the physiological indicators, leaf membrane damage was closely associated with the differences in salt tolerance between the two cashew genotypes. Furthermore, under NaCl salinity the tolerant rootstock showed greater ability to accumulate compatible organic solutes (amino acids, proline and soluble sugars) in leaves in addition to maintaining the soluble sugar concentration in roots as compared with the sensitive rootstock.

Salt-induced changes in antioxidative enzyme activities in root tissues do not account for the differential salt tolerance of two cowpea cultivars

Maia,Josemir M; Voigt,Eduardo L; Macêdo,Cristiane E. C; Ferreira-Silva,Sérgio L; Silveira,Joaquim A. G
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
56.43%
The salt stress effect in root growth and antioxidative response were investigated in two cowpea cultivars which differ in salt tolerance in terms of plant growth and leaf oxidative response. Four-day-old seedlings (establishment stage) were exposed to 100 mM NaCl for two days. The roots of the two cultivars presented distinct response in terms of salt-induced changes in elongation and dry weight. Root dry weight was only decreased in Pérola (sensitive) cultivar while root elongation was mainly hampered in Pitiúba (tolerant). Root relative water content remained unchanged under salinity, but root Na+ content achieved toxic levels as revealed by the K+/Na+ ratio in both cultivars. Then, root growth inhibition might be due to ionic toxicity rather than by salt-induced water deficit. Although electrolyte leakage markedly increased mainly in the Pérola genotype, lipid peroxidation decreased similarly in both salt-stressed cultivars. APX and SOD activities were reduced by salinity in both cultivars reaching similar values despite the decrease in Pitiúba had been higher compared to respective controls. CAT decreased significantly in Pitiúba but did not change in Pérola, while POX increased in both cultivars. The salt-induced decrease in the CAT activity of Pitiúba root is...

Physiological and biochemical traits as tools to screen sensitive and resistant varieties of tomatoes exposed to salt stress

Fariduddin,Qazi; Mir,Bilal Ahmad; Ahmad,Aqil
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 EN
Relevância na Pesquisa
56.27%
The present study was conducted to evaluate salt tolerance in seven different pure-line cultivars of tomato (Solanum lycopersicum L.) viz. K-21, Pusa Ruby, Pusa Gorav, Hera research, Selection N5, PKM-1 and S-22 based on several physiological and biochemical traits. Seedlings were transplanted to the pots, being exposed to different salinity levels in the form of NaCl (0, 50, 100, or 150 mM) at a 35-day stage of growth for six days. The plants exposed to salt stress presented a significant decline in growth, photosynthetic parameters, maximum quantum yield of PSII and leaf water relations, which were drastically reduced in variety S-22, while variety K-21 was the least affected. Electrolyte leakage was superior in proportion to an increase in salinity levels. Proline content and activity of antioxidant enzymes catalase, peroxidase, and superoxide dismutase were found maximum in variety K-21. Almost all the growth and physiological and biochemical traits had a significant genotypic variation, indicating that these parameters could be used as novel screening criteria for selecting the tolerant and sensitive cultivars exposed to salt stress.

Macroevolutionary patterns of salt tolerance in angiosperms

Bromham, L.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.63%
BACKGROUND: Halophytes are rare, with only 0·25% of angiosperm species able to complete their life cycle in saline conditions. This could be interpreted as evidence that salt tolerance is difficult to evolve. However, consideration of the phylogenetic distribution of halophytes paints a different picture: salt tolerance has evolved independently in many different lineages, and halophytes are widely distributed across angiosperm families. In this Viewpoint, I will consider what phylogenetic analysis of halophytes can tell us about the macroevolution of salt tolerance. HYPOTHESIS: Phylogenetic analyses of salt tolerance have shown contrasting patterns in different families. In some families, such as chenopods, salt tolerance evolved early in the lineage and has been retained in many lineages. But in other families, including grasses, there have been a surprisingly large number of independent origins of salt tolerance, most of which are relatively recent and result in only one or a few salt-tolerant species. This pattern of many recent origins implies either a high transition rate (salt tolerance is gained and lost often) or a high extinction rate (salt-tolerant lineages do not tend to persist over macroevolutionary timescales). While salt tolerance can evolve in a wide range of genetic backgrounds...

Functional analysis of AtHKT1 in Arabidopsis shows that Na+ recirculation by the phloem is crucial for salt tolerance

Berthomieu, P.; Conejero, G.; Nublat, A.; Brackenbury, W.; Lambet, C.; Savio, C.; Uozumi, N.; Oiki, S.; Yamada, K.; Cellier, F.; Gosti, F.; Simonneau, T.; Essah, P.; Tester, M.; Very, A.; Sentenac, H.; Casse, F.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
Relevância na Pesquisa
56.27%
Two allelic recessive mutations of Arabidopsis, sas2-1 and sas2-2, were identified as inducing sodium overaccumulation in shoots. The sas2 locus was found (by positional cloning) to correspond to the AtHKT1 gene. Expression in Xenopus oocytes revealed that the sas2-1 mutation did not affect the ionic selectivity of the transporter but strongly reduced the macro scopic (whole oocyte current) transport activity. In Arabidopsis, expression of AtHKT1 was shown to be restricted to the phloem tissues in all organs. The sas2-1 mutation strongly decreased Na+ concentration in the phloem sap. It led to Na+ overaccumulation in every aerial organ (except the stem), but to Na+ underaccumulation in roots. The sas2 plants displayed increased sensitivity to NaCl, with reduced growth and even death under moderate salinity. The whole set of data indicates that AtHKT1 is involved in Na+ recirculation from shoots to roots, probably by mediating Na+ loading into the phloem sap in shoots and unloading in roots, this recirculation removing large amounts of Na+ from the shoot and playing a crucial role in plant tolerance to salt.; Pierre Berthomieu, Geneviève Conéjéro, Aurélie Nublat, William J. Brackenbury, Cécile Lambert, Cristina Savio, Nobuyuki Uozumi...

Mechanisms of Cl⁻ transport contributing to salt tolerance; Mechanisms of Cl(-) transport contributing to salt tolerance

Teakle, N.; Tyerman, S.
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
66.51%
Mechanisms of Cl(-) transport in plants are poorly understood, despite the importance of minimizing Cl(-) toxicity for salt tolerance. This review summarizes Cl(-) transport processes in plants that contribute to genotypic differences in salt tolerance, identifying key traits from the cellular to whole-plant level. Key aspects of Cl(-) transport that contribute to salt tolerance in some species include reduced net xylem loading, intracellular compartmentation and greater efflux of Cl(-) from roots. We also provide an update on the biophysics of anion transport in plant cells and address issues of charge balance, selectivity and energy expenditure relevant to Cl(-) transport mechanisms. Examples are given of anion transport systems where electrophysiology has revealed possible interactions with salinity. Finally, candidate genes for anion transporters are identified that may be contributing to Cl(-) movement within plants during salinity. This review integrates current knowledge of Cl(-) transport mechanisms to identify future pathways for improving salt tolerance.; Natasha L. Teakle & Stephen D. Tyerman

Manipulation of alternative oxidase can influence salt tolerance in Arabidopsis thaliana

Smith, C.; Melino, V.; Sweetman, C.; Soole, K.
Fonte: Blackwell Munksgaard Publicador: Blackwell Munksgaard
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
66.27%
The growth and development of plants can be limited by environmental stresses such as salinity. It has been suggested that the non-phosphorylating alternative respiratory pathway in plants, mediated by the NAD(P)H dehydrogenase [NAD(P)H DH] and alternative oxidase (AOX), is important during environmental stresses. The involvement of this alternative pathway in a stress response may be linked to its capacity to uncouple carbon metabolism from adenylate control and/or the minimization of the formation of destructive reactive oxygen species (ROS). Salinity stress is a widespread, adverse environmental stress, which leads to an ionic imbalance, hyperosmotic stress and oxidative stress, the latter being the result of ROS formation. In this study, we show that salinity stress of Arabidopsis thaliana plants resulted in the formation of ROS, increased levels of Na+ in both the shoot and the root and an increase in transcription of Ataox1a, Atndb2 and Atndb4 genes, indicating the formation of an abridged non-phosphorylating electron transport chain in response to salinity stress. Furthermore, plants constitutively over-expressing Ataox1a, with increased AOX capacity, showed lower ROS formation, 30–40% improved growth rates and lower shoot Na+ content compared with controls...

A comparison of hydroponic and soil-based screening methods to identify salt tolerance in the field in barley

Tavakkoli, E.; Fatehi, F.; Rengasamy, P.; McDonald, G.
Fonte: Oxford Univ Press Publicador: Oxford Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
56.61%
Success in breeding crops for yield and other quantitative traits depends on the use of methods to evaluate genotypes accurately under field conditions. Although many screening criteria have been suggested to distinguish between genotypes for their salt tolerance under controlled environmental conditions, there is a need to test these criteria in the field. In this study, the salt tolerance, ion concentrations, and accumulation of compatible solutes of genotypes of barley with a range of putative salt tolerance were investigated using three growing conditions (hydroponics, soil in pots, and natural saline field). Initially, 60 genotypes of barley were screened for their salt tolerance and uptake of Na+, Cl–, and K+ at 150 mM NaCl and, based on this, a subset of 15 genotypes was selected for testing in pots and in the field. Expression of salt tolerance in saline solution culture was not a reliable indicator of the differences in salt tolerance between barley plants that were evident in saline soil-based comparisons. Significant correlations were observed in the rankings of genotypes on the basis of their grain yield production at a moderately saline field site and their relative shoot growth in pots at ECe 7.2 [Spearman’s rank correlation (rs)=0.79] and ECe 15.3 (rs=0.82) and the crucial parameter of leaf Na+ (rs=0.72) and Cl– (rs=0.82) concentrations at ECe 7.2 dS m−1. This work has established screening procedures that correlated well with grain yield at sites with moderate levels of soil salinity. This study also showed that both salt exclusion and osmotic tolerance are involved in salt tolerance and that the relative importance of these traits may differ with the severity of the salt stress. In soil...

Constitutive overexpression of soybean plasma membrane intrinsic protein GmPIP1;6 confers salt tolerance

Zhou, L.; Wang, C.; Liu, R.; Han, Q.; Vandeleur, R.K.; Du, J.; Tyerman, S.; Shou, H.
Fonte: BioMed Central Ltd Publicador: BioMed Central Ltd
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
Relevância na Pesquisa
66.42%
BACKGROUND: Under saline conditions, plant growth is depressed via osmotic stress and salt can accumulate in leaves leading to further depression of growth due to reduced photosynthesis and gas exchange. Aquaporins are proposed to have a major role in growth of plants via their impact on root water uptake and leaf gas exchange. In this study, soybean plasma membrane intrinsic protein 1;6 (GmPIP1;6) was constitutively overexpressed to evaluate the function of GmPIP1;6 in growth regulation and salt tolerance in soybean. RESULTS: GmPIP1;6 is highly expressed in roots as well as reproductive tissues and the protein targeted to the plasma membrane in onion epidermis. Treatment with 100 mM NaCl resulted in reduced expression initially, then after 3 days the expression was increased in root and leaves. The effects of constitutive overexpression of GmPIP1;6 in soybean was examined under normal and salt stress conditions. Overexpression in 2 independent lines resulted in enhanced leaf gas exchange, but not growth under normal conditions compared to wild type (WT). With 100 mM NaCl, net assimilation was much higher in the GmPIP1;6-Oe and growth was enhanced relative to WT. GmPIP1;6-Oe plants did not have higher root hydraulic conductance (Lo) under normal conditions...

The status of Eurostus dussumierii and Hypsirhina chinensis (Reptilia, Squamata, Serpentes): With comments on the origin of salt tolerance in homalopsid snakes

Kumar, A.; Sanders, K.; George, S.; Murphy, J.
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
66.27%
The Kerala mud snake, Enhydris dussumierii Duméril, Bibron & Duméril, has long been known only from syntypes collected in the nineteenth century, but more recent specimens have provided the opportunity for molecular work. Using Bayesian phylogenetic analysis of 2200 base pairs of cytb, 16S, and c-mos, we recovered the Kerala mud snake as the sister species to the Chinese mud snake, Enhydris chinensis (Chinese–Vietnamese endemic). The DNA results establish the position of dussumierii and chinensis as separate from the Enhydris clade, and together they form the sister group to most of the other fanged homalopsids ((Bitia+Cantoria) + (Erpeton+Gerarda+Fordonia) + (Myron+Pseudoferania) + (Enhydris punctata) + (Homalopsis+Enhydris bocourti) + (Cerberus)). Here we resurrect Ferania Gray for Enhydris sieboldii Gray, establish a new genus for the E. chinensis clade (bennettii+chinensis), and apply the generic replacement name Dieurostus Berg to E. dussumierii Duméril, Bibron & Duméril. A biogeographic scenario is proposed based on the ecology, distribution and salt tolerance of the species composing a hypothesized (not supported with molecular evidence) Asian coastal lineage that is distributed from Pakistan's Indus River delta to temperate coastal China.; A. Biju Kumar...

Predicting species' tolerance to salinity and alkalinity using distribution data and geochemical modelling: a case study using Australian grasses

Saslis-Lagoudakis, C. H.; Hua, X.; Bui, E.; Moray, C.; Bromham, L.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.51%
BACKGROUND AND AIMS: Salt tolerance has evolved many times independently in different plant groups. One possible explanation for this pattern is that it builds upon a general suite of stress-tolerance traits. If this is the case, then we might expect a correlation between salt tolerance and other tolerances to different environmental stresses. This association has been hypothesized for salt and alkalinity tolerance. However, a major limitation in investigating large-scale patterns of these tolerances is that lists of known tolerant species are incomplete. This study explores whether species' salt and alkalinity tolerance can be predicted using geochemical modelling for Australian grasses. The correlation between taxa found in conditions of high predicted salinity and alkalinity is then assessed. METHODS: Extensive occurrence data for Australian grasses is used together with geochemical modelling to predict values of pH and electrical conductivity to which species are exposed in their natural distributions. Using parametric and phylogeny-corrected tests, the geochemical predictions are evaluated using a list of known halophytes as a control, and it is determined whether taxa that occur in conditions of high predicted salinity are also found in conditions of high predicted alkalinity. KEY RESULTS: It is shown that genera containing known halophytes have higher predicted salinity conditions than those not containing known halophytes. Additionally...

Grafting raises the salt tolerance of tomato through limiting the transport of sodium and chloride to the shoot

Estañ, María T.; Martínez-Rodríguez, María M.; Pérez-Alfocea, Francisco; Flowers, Timothy J.; Bolarín, María C.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
66.5%
With the aim of determining whether grafting could improve salinity tolerance of tomato (Lycopersicon esculentum Mill.), and what characteristics of the rootstock were required to increase the salt tolerance of the shoot, a commercial tomato hybrid (cv. Jaguar) was grafted onto the roots of several tomato genotypes with different potentials to exclude saline ions. The rootstock effect was assessed by growing plants at different NaCl concentrations (0, 25, 50, and 75 mM NaCl) under greenhouse conditions, and by determining the fruit yield and the leaf physiological changes induced by the rootstock after 60 d and 90 d of salt treatment. The grafting process itself did not affect the fruit yield, as non-grafted plants of cv. Jaguar and those grafted onto their own root showed the same yield over time under non-saline conditions. However, grafting raised fruit yield in Jaguar on most rootstocks, although the positive effect induced by the rootstock was lower at 25 mM NaCl than at 50 and 75 mM NaCl. At these higher levels, the plants grafted onto Radja, Pera and the hybrid VolgogradskijxPera increased their yields by 80%, with respect to the Jaguar plants. The tolerance induced by the rootstock in the shoot was related to ionic rather than osmotic stress caused by salinity...

Salt tolerance of barley (Hordeum vulgare L.) cultivars at the germination stage: Analysis of the response functions

Martínez-Cob, Antonio; Aragüés Lafarga, Ramón; Royo, Antonio
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 81662 bytes; application/pdf
ENG
Relevância na Pesquisa
66.32%
The definitive version is available at: http://www.springerlink.com/content/100326/; Two models, initially proposed by Van Genuchten (1983) for evaluating salinity-yield response curves at the adult stage, were applied to study the salinity response of 24 barley cultivars at the germination stage. According to the calculated salinity threshold, ECt (the solution electrical conductivity, EC, at which germination starts to decrease), and EC50 (the solution EC at which germination is reduced by 50%) parameters, both models give similar results, although model 2, a sigmoid-form curve, fits the observed data slightly better than model 1, a piecewise response function. Also, the results suggest that, for model 1, ECt seems to be the most reliable parameter for screening barley germplasm because it clearly discriminates the relative salt-tolerance of the studied cultivars and, furthermore, it basically determines their salinity response for the 100 to 50% germination interval. On the other hand, the model 1 s parameter — percent germination decrease per unit salinity increase bove ECt—is less relevant because of its smaller variation interval and lack of correlation with EC50, indicating that the salinity response of the studied cultivars for the 50% germination value is independent of this parameter.; The authors thank the Instituto Agronómico Mediterráneo de Zaragoza for a fellowship granted to A. Martínez-Cob...

Molecular mechanisms of the salt tolerance response in the halophile Vibrio parahaemolyticus

Ongagna Yhombi, Yvon Serge
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
56.35%
Boyd, E. Fidelma; In order to investigate the functionality of specialized genomic features in the osmotic stress tolerance of Vibrio parahaemolyticus , we divided the research project in three parts: (1) Examine the role of the ectoine and glycine betaine biosynthesis systems in the NaCl stress response, (2) Determine the role of the four putative Betaine Carnitine Choline transporter (BCCT) homologues in the NaCl stress response, and (3) Determine the role of two ProXWV (ProU1 and ProU2) homologues in the NaCl stress response. The role of the two synthesis systems in the NaCl stress response. We demonstrated that V. parahaemolyticus had an extended salt tolerance range up to 10.5% NaCl in complex media and a 6% NaCl tolerance in defined M9 minimal media. We demonstrated that exogenously supplied compatible solutes or their precursors in defined media relieved the growth constraint caused by high NaCl. By using proton Nuclear Magnetic Resonance spectroscopy (1 HNMR) analysis, we determined for the first time the profile of compatible solutes synthesized and accumulated by this organism. Furthermore, we showed that V. parahaemolyticus cells could perform de novo synthesis of ectoine and glutamate in a NaCl dependent manner. By comparative growth analysis in defined media amended to high osmolarity containing exogenously supplied compatible solutes or their precursors...

Tolerância à salinidade em feijão (Phaseolus vulgaris L); Salt tolerance in bean (Paseolus vulgaris) cell culture

Broetto, F.; Lima, G.P.P.; Brasil, O.G.
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/1995 POR
Relevância na Pesquisa
56.31%
Uma das aplicações das técnicas da cultura de tecidos no melhoramento é a identificação de linhas de células que apresentam tolerância à salinidade. Vários autores obtiveram linhas de células tolerantes ao estresse salino; e estudo de mecanismos bioquímicos da tolerância a sais em plantas tem demonstrado altas correlações entre estes e o acúmulo de macromoléculas em tecido de plantas superiores. Para verificar essas correlações em feijão (Phaseolus vulgaris cv IAC carioca), calos oriundos de eixos embrionários foram cultivados em meio sólido, suplementado com NaCl nas concentrações de 0 a 60 mM. Após 13 dias de incubação, os calos foram coletados e analisados quanto ao crescimento relativo, teor de proteínas, teor de prolina e atividade da peroxidase. Os parâmetros analisados mostraram decréscimo no crescimento relativo e no de proteínas em resposta ao NaCl. Paralelamente, observou-se aumento significativo no conteúdo de prolina e atividade da enzima peroxidase.; One of the applications of the tissue culture technique in plant improvement is the identification of cell lines which show salinity tolerance. Several authors were able to obtain saline stress-tolerant cell lines and show that mechanisms of tolerance to salts have a strong correlation between this phenomenon and a high macromolecule concentration in plant tissues. Callus obtained from embrionic axis of Phaseolus vulgarís cv. IAC carioca in solid medium...

Response of chile pepper (Capsicum annuum L.) to salt stress and organic and inorganic nitrogen sources: II. Nitrogen and water use efficiencies, and salt tolerance

Huez-López,Marco A.; Ulery,April L.; Samani,Zohrab; Picchioni,G.; Flynn,R. P.
Fonte: Universidad Autónoma de Yucatán, Facultad de Medicina Veterinaria Publicador: Universidad Autónoma de Yucatán, Facultad de Medicina Veterinaria
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
66.44%
The response to two nitrogen sources on water and nitrogen use efficiencies, and tolerance of salt-stressed chile pepper plants (Capsicum annuum L.) cv. Sandia was investigated in a greenhouse experiment. Low, moderate and high (1.5, 4.5, and 6.5 dS m-1) salinity levels, and two rates of organic-N fertilizer (120 and 200 kg ha-1) and 120 kg ha-1 of inorganic fertilizer as ammonium nitrate were arranged in randomized complete block designs replicated four times. The liquid organic-N source was an organic, extracted with water from grass clippings. Water use decreased about 19 and 30% in moderate and high salt-stressed plants. Water use efficiency decreased only in high salt-stressed plants. Nitrogen use efficiency decreased either by increased salinity or increased N rates. An apparent increase in salt tolerance was noted when plants were fertilized with organic-N source compared to that of inorganic-N source.