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1.
Sugar, a final product of photosynthesis, is reported to be involved in the defense mechanisms of plants against abiotic stresses
such as salinity, water deficiency, extreme temperature and mineral toxicity. Elements involved in photosynthesis, sugar content,
water oxidation, net photosynthetic rate, activity of enzyme and gene expression have therefore been studied in Homjan (HJ),
salt-tolerant, and Pathumthani 1 (PT1), salt-sensitive, varieties of rice. Fructose-1,6-biphosphatase ( FBP) and fructokinase ( FK) genes were rapidly expressed in HJ rice when exposed to salt stress for 1–6 h and to a greater degree than in PT1 rice.
An increase in FBP enzyme activity was found in both roots and leaves of the salt-tolerant variety after exposure to salt
stress. A high level of sugar and a delay in chlorophyll degradation were found in salt-tolerant rice. The total sugar content
in leaf and root tissues of salt-tolerant rice was 2.47 and 2.85 times higher, respectively, than in the salt-sensitive variety.
Meanwhile, less chlorophyll degradation was detected. Salt stress may promote sugar accumulation, thus preventing the degradation
of chlorophyll. Water oxidation by the light reaction of photosynthesis in the salt-tolerant variety was greater than that
in the salt-sensitive variety, indicated by a high maximum quantum yield of PSII ( F
v/ F
m) and quantum efficiency of PSII (Φ PSII) with low nonphotochemical quenching (NPQ), leading to a high net photosynthetic rate. In addition, the overall growth performances
in the salt-tolerant variety were higher than those in the salt-sensitive variety. The FBP gene expression and enzyme activity, sugar accumulation, pigment stabilization, water oxidation and net photosynthetic rate
parameters in HJ rice should be further investigated as multivariate salt-tolerant indices for the classification of salt
tolerance in rice breeding programs. 相似文献
2.
Salt tolerance defined in terms of fruit yield under different NaCl concentrations (171.1 and 325.1 mM) is analyzed in 11 lines belonging to: Lycopersicon esculentum, L. cheesmanii, L. chmielewski, L. peruvianum and L. pimpinellifolium. Four L. pimpinellifolium lines and two L. cheesmanii lines tolerated the 171.1mM treatment; the latter species even tolerates 325.1 mM of NaCl. Changes in gene expression induced by salt treatment were also investigated by studying anther and leaf zymograms for L. esculentum and one salt-tolerant L. pimpinellifolium line, and leaf proteinograms for all lines. Changes in leaf PRX and MDH enzymatic systems were detected, mainly in the salt-sensitive genotype ( L. esculentum). Four saltrelated peptides from 14 500 to 40 000 daltons were found. A polyclonal antibody raised against one of these peptides (number 2), also binds another peptide, named 2, of much higher molecular weight, present both in control and salt-tolerant L. cheesmanii lines at the end of 171.1 mM treatment. The xero-halophyte shrub Atriplex halimus also showed a likely 2-homologous peptide with this treatment, while its counterpart C 3 species A. triangularis did not. 相似文献
3.
We compared growth, leaf gas exchange characteristics, water relations, chlorophyll fluorescence, and Na + and Cl − concentration of two cultivars (‘Koroneiki’ and ‘Picual’) of olive ( Olea europaea L.) trees in response to high salinity (NaCl 100 mM) and elevated CO 2 (eCO 2) concentration (700 μL L −1). The cultivar ‘Koroneiki’ is considered to be more salt sensitive than the relatively salt-tolerant ‘Picual’. After 3 months of treatment, the 9-month-old cuttings of ‘Koroneiki’ had significantly greater shoot growth, and net CO 2 assimilation ( ACO2) at eCO 2 than at ambient CO 2, but this difference disappeared under salt stress. Growth and ACO2 of ‘Picual’ did not respond to eCO 2 regardless of salinity treatment. Stomatal conductance ( gs) and leaf transpiration were decreased at eCO 2 such that leaf water use efficiency (WUE) increased in both cultivars regardless of saline treatment. Salt stress increased leaf Na + and Cl − concentration, reduced growth and leaf osmotic potential, but increased leaf turgor compared with non-salinized control plants of both cultivars. Salinity decreased ACO2, gs, and WUE, but internal CO 2 concentrations in the mesophyll were not affected. eCO 2 increased the sensitivity of PSII and chlorophyll concentration to salinity. eCO 2 did not affect leaf or root Na + or Cl − concentrations in salt-tolerant ‘Picual’, but eCO 2 decreased leaf and root Na + concentration and root Cl − concentration in the more salt-sensitive ‘Koroneiki’. Na + and Cl − accumulation was associated with the lower water use in ‘Koroneiki’ but not in ‘Picual’. Although eCO 2 increased WUE in salinized leaves and decreased salt ion uptake in the relatively salt-tolerant ‘Koroneiki’, growth of these young olive trees was not affected by eCO 2. 相似文献
5.
【目的】揭示陕北花马盐湖沉积物原核微生物群落组成,并分析其潜在的耐盐功能基因。【方法】构建盐湖沉积物宏基因组16S r RNA文库和fosmid文库,利用Illumina HiSeq高通量测序及生物信息技术分析细菌古菌群落组成和耐盐菌株(5-5)外源宏基因组的潜在耐盐基因。【结果】获得18978条有效的16Sr RNA序列,共5221个OTUs,包括23个门,155个属,其中广古菌门(Euryarchaeota)和变形菌门(Proteobacteria)为优势菌门,盐杆状菌属(Halorhabdus)、盐红菌属(Halorubrum)及假单胞菌属(Pseudomonas)等16个属为优势属,以及嗜盐单胞菌属(Halomonas)、冷弯菌属(Psychroflexus)及不动细菌属(Acinetobacter)等139个属为非优势属。从4126个fosmid文库菌株中筛选出37株耐盐菌株,其中菌株5-5、2E4和2F4对不同浓度的NaCl、CuSO_4、ZnSO_4及CdSO_4具有耐受性,从5-5的外源宏基因组序列中获得61个Unigene,其中12个Unigene的同源基因编码的蛋白质如无机焦磷酸酶、转座酶、亚碲酸钾抗性蛋白及钙调蛋白等广泛参与其他生物的耐盐逆境。【结论】盐湖沉积物中蕴藏着丰富多样的细菌古菌类群以及潜在耐盐功能基因资源。 相似文献
6.
Fifteen genotypes of faba bean ( Vicia faba L.) were inoculated with salt-tolerant Rhizobium leguminosarum biovar. viciae strain GRA 19 in solution culture with 0 (control) and 75 m M NaCl added immediately after transplanting. Genotypes varied in their tolerance of high levels of NaCl. Physiological parameters (dry weight of shoot and root, number and dry weight of nodules) were not affected by salinity in lines VF46, VF64 and VF112. Faba bean line VF60 was sensitive to salt stress. Host tolearance appeared to be a major requisite for nodulation and N 2 fixation under salt stress. Tolerant line VF112 sustained nitrogen fixation under saline conditions. Activity of the ammonium assimilation enzymes glutamine synthetase and glutamate synthase, and soluble protein content, were reduced by salinity in all genotypes tested. Evidence presented here suggests a need to select faba bean genotypes that are tolerant to salt stress.Abbreviations ARA
acetylene reduction activity
- NADH-GOGAT
NADH-dependent glutamate synthase
- GS
glutamine synthetase 相似文献
7.
Salinity has been identified as key abiotic stress factor limiting rice production in many countries around the globe, including Bangladesh. In the present study, we examined the effects of salt-induced toxicity on growth of rice landraces for screening salt-tolerant genotypes by assessing morpho-physiological, biochemical, and molecular responses. Screening of 28 rice genotypes at seedling stage was performed at 12 dS m−1 salinity level in hydroponic media. Most of the rice genotypes showed an apparent reduction in growth traits, while a fewer showed less reduction under salinity stress. Euclidean clustering and heatmap based on morpho-physiological parameters dissected rice genotypes into three major clusters, viz., susceptible, moderately tolerant, and tolerant. Results of cluster analysis revealed Nonabokra, Hogla, Ghunsi, Holdegotal, Nonabokra, and Kanchon as salt-tolerant rice genotypes. These genotypes also were grouped using three microsatellite markers, viz., RM493, RM3412b, and RM140 that were closely linked to saltol QTL showed Hogla, Ghunsi, Holdegotal, Nonabokra, Kanchon, BINA dhan-8, and BINA dhan-10 as salt-tolerant genotypes considering genetic similarity in dendrogram. The positive relationships of Na+/K+ ratio with hydrogen peroxide (H2O2) and malondialdehyde (MDA), and antioxidant enzymes’ activity in the tolerant rice genotypes indicated their importance for improving salinity tolerance. The salt-tolerant landraces showed lower Na+/K+ ratio, high proline accumulation, lower H2O2 accumulation and MDA content, and higher catalase and ascorbate peroxidase activities. Higher antioxidant enzymes’ activity and lower H2O2 accumulation in tolerant genotypes indicate their abilities to fight against oxidative stress. Based on all morpho-physiological clustering, biochemical response, and molecular dendrogram, Nonabokra, Hogla, Ghunsi, Holdegotal, and Kanchon were identified as the salt-tolerant landraces. Therefore, these identified salt-tolerant landraces could be useful to improve breeding program for the development of salt-tolerant high-yielding rice cultivars in future. 相似文献
8.
Adaptation to salt in the cyanobacterium Nostocmuscorum, is composed of a few mechanisms which together lead to the generation of a salt-tolerant cell. The initial mechanism combines a stimulation of photosynthetic activity with the accumulation of sucrose as an osmoregulator. The secondary mechanism involves the adaptation of N 2 fixation activity and protein biosynthesis. The adaptation is most efficient in response to NaCl-induced stress and functions only partially under stress induced by either KCl or a nonionic osmoticum such as mannitol. 相似文献
9.
The intake of mycotoxin-contaminated feeds can lead to nutrient losses and may have adverse effects on animal health and on
productivity. The aims of this study were (1) to determine the mycobiota present in poultry feed samples, and (2) to evaluate
the natural occurrence of aflatoxin B 1, fumonisin B 1 and zearalenone. Fungal counts were similar between all culture media tested (10 3 CFU g −1). The most frequent genus isolated was Penicillium spp. (41.26%) followed by Aspergillus spp. (33.33%) and Fusarium spp. (20.63%). High precision liquid chromatography was applied to quantify aflatoxin B 1 and fumonisin B 1. Thin layer chromatography was used to determine zearalenone levels. Aflatoxin B 1 values ranged between 1.2 and 17.5 μg kg −1. Fumonisin B 1 levels ranged between 1.5 and 5.5 μg g −1. Zearalenone levels ranged between 0.1 and 7 μg g −1. The present study shows the simultaneous occurrence of two carcinogenic mycotoxins, aflatoxin B 1 and fumonisin B 1, together with another Fusarium mycotoxin (zearalenone) in␣feed intended for poultry consumption. Many samples contained AFB 1 levels near the permissible maximum and it could affect young animals. A synergistic toxic response is possible in animals
under simultaneous exposure. 相似文献
10.
本文旨在分离筛选出在高盐环境中具有潜在应用可能性的菌株。在筛选耐盐酵母的过程中分离出一株耐盐菌株,采用形态特征观察、生理生化实验和16S rDNA基因测序进行菌株鉴定,鉴定结果显示该菌为沃氏葡萄球菌( Staphylooccus warneri),命名为SW-1。进一步对其药敏特性、耐盐性和表面疏水性进行检测,结果表明,该菌株对大部分抗生素极敏感,在含20%(质量分数)NaCl的LB培养基中仍能良好生长,对氯仿、乙酸乙酯和正丁醇的疏水率依次为43%、34%和39%。沃氏葡萄球菌SW-1在高盐条件下能快速适应环境积累生物量,具有优良的生物学特性,为开发和利用耐盐菌株提供参考。 相似文献
11.
A new chemolithoautotrophic, facultatively alkaliphilic, extremely salt-tolerant, sulfur-oxidizing bacterium was isolated from an alkaline hypersaline lake in the Altai Steppe (Siberia, Russia). According to 16S rDNA analysis and DNA–DNA hybridization, strain HL 17 T was identified as a new species of the genus Thialkalivibrio belonging to the subdivision of the Proteobacteria for which the name Thialkalivibrio halophilus is proposed. Strain HL 17 T is an extremely salt-tolerant bacterium growing at sodium concentrations between 0.2 and 5 M, with an optimum of 2 M Na +. It grew at high concentrations of NaCl and of Na 2CO 3/NaHCO 3 (soda). Strain HL 17 T is a facultative alkaliphile growing at pH range 7.5–9.8, with a broad optimum between pH 8.0 and 9.0. It used reduced inorganic sulfur compounds (thiosulfate, sulfide, polysulfide, elemental sulfur, and tetrathionate) as energy sources and electron donors. In continuous culture under energy limitation, thiosulfate was stoichiometrically oxidized to sulfate. In sodium carbonate medium under alkaline conditions, the maximum growth rate was similar, while the biomass yield was lower as compared with the NaCl-grown culture. The maximum sulfur-oxidizing capacity measured in washed cells was higher in the soda buffer independent of the growth conditions. The compatible solute content of the biomass was higher in the sodium chloride-grown culture than in the sodium carbonate/bicarbonate-grown culture. The data suggest that the osmotic pressure differences between soda and NaCl solutions might be responsible for the difference observed in compatible solutes production. This may have important implications in overall energetic metabolism of high salt adaptation. 相似文献
12.
The Plumbaginaceae (non-core Caryophyllales) is a family well known for species adapted to a wide range of arid and saline habitats. Of its salt-tolerant species, at least 45 are in the genus Limonium; two in each of Aegialitis, Limoniastrum and Myriolimon, and one each in Psylliostachys, Armeria, Ceratostigma, Goniolimon and Plumbago. All the halophytic members of the family have salt glands and salt glands are also common in the closely related Tamaricaceae and Frankeniaceae. The halophytic species of the three families can secrete a range of ions (Na +, K +, Ca 2+, Mg 2+, Cl −, HCO 3−, SO 42-) and other elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Salt glands are, however, absent in salt-tolerant members of the sister family Polygonaceae. We describe the structure of the salt glands in the three families and consider whether glands might have arisen as a means to avoid the toxicity of Na + and/or Cl − or to regulate Ca 2+ concentrations with the leaves. We conclude that the establishment of lineages with salt glands took place after the split between the Polygonaceae and its sister group the Plumbaginaceae. 相似文献
13.
For the high frequency selection of salt-tolerant doubled haploids (DHs) using rice anther culture, the efficiency of anther culture was investigated with different genotype, media condition and NaCl concentrations. The six F 1 hybrids obtained by backcross or three-way cross between indica and japonica differed in salt tolerance. The efficiencies of callus induction and plant regeneration was decreased by NaCl concentration and salt tolerance of donor variety, and those in japonicas were higher than those in indicas. The percentages of callus induction in Gyehwa 5 (japonica, tolerant) and IR61633-B-2-2-1 (japonica, sensitive) were 21.1 and 13.5% on agar medium containing 0.3% NaCl, respectively. The plant regeneration of callus derived from anther floating culture in liquid media was less than that on solid medium. In four F 1 hybrids, the frequencies of high salt-tolerant DHs were 21.4 and 8.9% in 0.3% NaCl medium and the control, respectively. The high frequency of salt-tolerant DHs could be selected in the callus induction medium (0.3% NaCl) and in the combinations crossed with salt-tolerant japonica as the third parent. 相似文献
14.
Photosynthetic pathways ( e.g. C 3, C 4) and morphological functional types ( e.g. trees, shrubs, high perennial grasses, perennial forbs) were identified for the native species from the Saskatchewan mixed
prairie, using the data from references published between 1950 and 2003. Of the total 219 identified species in 145 genera
and 45 families, 208 species in 137 genera and 44 families were found with C 3 photosynthesis, and most of these species are dominants ( e.g. Agropyron dasystachyum Hook. and Stipa spartea var. curtiseta Hitchc.). 11 species in 10 genera and 3 families were identified with C 4 photosynthesis ( e.g. Atriplex argentea Nutt., Andropogon scoparius Michx., Boutelou gracilis Lag., Calamovilfa longifolia Hook.). The amount of total identified C 4 species in the region is much less than that from the South Dakota mixed prairie (27 species). Gramineae is the leading family with C 4 photosynthesis (8 species), Chenopodiaceae ranks the second (2 species). Relatively less forb types [50 % perennial forbs (PEF) and 12 % annual forbs (ANF)] and more
graminoid types (25 %) composition suggested that the rangelands in the region are relatively stable. Lacking of the knowledge
on the optimal traits for PFTs classification in the region, further studies ( e.g. C 3 and C 4 plant identification and optimal trait selection) are needed to explore the relationships between PFTs and vegetation variations,
as well as land-use and climate changes. 相似文献
15.
Summary Seedlings of nine tropical species varying in growth and carbon metabolism were exposed to twice the current atmospheric level of CO 2 for a 3 month period on Barro Colorado Island, Panama. A doubling of the CO 2 concentration resulted in increases in photosynthesis and greater water use efficiency (WUE) for all species possessing C 3 metabolism, when compared to the ambient condition. No desensitization of photosynthesis to increased CO 2 was observed during the 3 month period. Significant increases in total plant dry weight were also noted for 4 out of the 5 C 3 species tested and in one CAM species, Aechmea magdalenae at high CO 2. In contrast, no significant increases in either photosynthesis or total plant dry weight were noted for the C 4 grass, Paspallum conjugatum. Increases in the apparent quantum efficiency (AQE) for all C 3 species suggest that elevated CO 2 may increase photosynthetic rate relative to ambient CO 2 over a wide range of light conditions. The response of CO 2 assimilation to internal C i suggested a reduction in either the RuBP and/or Pi regeneration limitation with long term exposure to elevated CO 2. This experiment suggests that: (1) a global rise in CO 2 may have significant effects on photosynthesis and productivity in a wide variety of tropical species, and (2) increases in productivity and photosynthesis may be related to physiological adaptation(s) to increased CO 2. 相似文献
16.
In bean ( Phaseolus vulgaris L.) seedlings well supplied with water, rates of transpiration ( E) and CO 2 assimilation ( P
N) of the primary leaves were measured under blue (BR) or red (RR) irradiance of 150 µmol(photon) m –2 s –1. The leaf conductance to H 2O vapour transfer ( g
H2O), as well as the intercellular concentrations of H 2O vapour ( e
i) and of CO 2 ( C
i) were calculated. Under BR, g
H2O was significantly greater, but P
N was lower, and E similar as compared with corresponding values found under RR. The increase of stomata aperture under BR was evident although C
i was higher and e
i was lower than under RR. Results agree with the suggestion that BR directly activates guard cell metabolism and in well watered plants determines mainly the stomata aperture. 相似文献
17.
Cholinergic muscarinic receptors, when stimulated by arecoline, can activate cytosolic phospholipase A 2 (cPLA 2) to release arachidonic acid (AA) from membrane phospholipid. This signal can be imaged in the brain in vivo using quantitative
autoradiography following the intravenous injection of radiolabeled AA, as an increment in a regional brain AA incorporation
coefficient k*. Arecoline increases k* significantly in brain regions having muscarinic M 1,3,5 receptors in wild-type but not in cyclooxygenase (COX)-2 knockout mice. To further clarify the roles of COX enzymes in the
AA signal, in this paper we imaged k* following arecoline (5 mg/kg i.p.) or saline in each of 81 brain regions of unanesthetized rats pretreated 6 h earlier with
the non-selective COX inhibitor flurbiprofen (FB, 60 mg/kg s.c.) or with vehicle. Baseline values of k* were unaffected by FB treatment, which however reduced by 80% baseline brain concentrations of prostaglandin E 2 (PGE 2) and thromboxane B 2 (TXB 2), eicosanoids preferentially derived from AA via COX-2 and COX-1, respectively. In vehicle-pretreated rats, arecoline increased the brain PGE 2 but not TXB 2 concentration, as well as values for k* in 77 of the 81 brain regions. FB-pretreatment prevented these arecoline-provoked changes. These results and those reported
in COX-2 knockout mice suggest that the AA released in brain following muscarinic receptor-mediated activation is lost via COX-2 to PGE 2 but not via COX-1 to TXB 2, and that increments in k* following arecoline largely represent replacement by unesterified plasma AA of this loss. 相似文献
18.
Photosynthetic pathways (C 3, C 4, and CAM) and morphological functional types ( e.g. shrubs, high perennial grasses, short perennial graminaceous plants, annual grasses, annual forbs, perennial forbs, halophytes, and hydrophytes) were identified for the species from salinity grasslands in Northeastern China, using the data from both stable carbon isotope ratios ( 13C) and from the references published between 1993 and 2002. 150 species, in 99 genera and 37 families, were found with C 3 photosynthesis, and most of these species are dominants [ e.g. Leymus chinensis (Trin.) Tzvel., Calamagrostis epigeios (L.), Suaeda corniculata (C.A. Mey.) Bunge]. 40 species in 25 genera and 8 families were identified with C 4 photosynthesis [ e.g. Chloris virgata Sw., Aeluropus littoralis (Gouan) Parlat] and 1 species with CAM photosynthesis. Gramineae is the leading family with C 4 photosynthesis (27 species), Chenopodiaceae ranks the second (5 species). The significant increase of C 4 proportions with intense salinity suggested this type plant is remarkable response to the grassland salinization in the region. 191 species were classified into eight morphological functional types and the changes of most of these types ( e.g. PEF, HAL, and HPG) were consistent with habitats and vegetation dynamics in the saline grassland. My findings suggest that the photosynthetic pathways, combined with morphological functional types, are efficient means for studying the linkage between species and ecosystems in this type of saline grassland in Northeastern China.This revised version was published online in March 2005 with corrections to the page numbers. 相似文献
19.
The submersed macrophyte Vallisneria americana was grown for seven weeks in a greenhouse to test for differences in the ability of three different sediments to support growth stimulation in response to CO 2 enrichment at low pH. Plants accumulated 21- to 24-fold greater biomass at 10 × ambient CO 2 concentrations than at ambient CO 2 on all sediments. At both CO 2 levels, plants grown on sediment from an acidified lake accumulated ca. 81%, and those grown on oligotrophic lake sediment ca. 47% as much biomass as plants grown on alkaline lake sediment. Despite striking CO 2 and sediment effects on biomass accumulation, there was no significant interaction (using log-transformed data) between CO 2 and sediment effects, indicating that all sediments allowed similar proportionate growth responses to CO 2 enrichment. Plants grown on the less fertile sediments showed greater relative allocation to horizontal versus vertical growth by producing more rosette-bearing stolons in relation to plant height (leaf length) than plants grown on relatively fertile, alkaline lake sediment. Tissue analysis suggested that sediment effects on Vallisneria growth could be attributed neither to mineral putrient (nitrogen and phosphorus) limitation nor to aluminum toxicity in these low pH treatments. In any case, CO 2 availability can be an important regulator of submersed macrophyte growth at low pH on a variety of sediment types, including those from oligotrophic and acidic lakes. 相似文献
20.
Photosynthetic pathway Types (C 3, C 4, and CAM) and life forms of native species from Hulunbeier rangelands, north China were studied. Of the total 258 species, 216 species in 132 genera and 42 families had C 3 photosynthetic pathway, including dominant herbs, e.g. Stipa baicalensis Roshev. and Leymus chinensis (Trin.) Tzvel., Filifolium sibiricum Kitam. and Arudinella hirta (Thunb.) Koidz. 38 species in 28 genera and 10 families were found with C 4 photosynthesis, and 4 species in 2 genera and 1 family had CAM photosynthetic pathway. The occurrence of C 4 species was common in Gramineae and Chenopodiaceae, and the two families were leading ones within C 4 plants. More than 52 % of the total 258 species were in H form, 21 % in Th form, 19 % in G form; the other life form Types, e.g. Ch, M, N, and HH, formed less than 3 %. 68 % of C 4 species were in Th form and 24 % in H form, indicating that these Types were the dominant life forms for C 4 species in the rangeland region. The occurrence of C 4 species was closely related with plant habitats, disturbed lands had the highest C 4 abundance (55 % of the total C 4 species), followed by grasslands and sandy soil, and forests had the lowest C 4 abundance (8 %). Hence the occurrence of C 4 species could be efficient indicator for rangeland dynamics in Hulunbeier rangelands. 相似文献
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