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1.
Mónica Calvo-Polanco Melanie D. Jones Janusz J. Zwiazek 《Acta Physiologiae Plantarum》2009,31(3):515-522
In the present study, we investigated the effects of pH treatments on NaCl tolerance in mycorrhizal and non-mycorrhizal American
elm. American elm (Ulmus americana) seedlings were inoculated with Hebeloma crustuliniforme, Laccaria bicolor or with both mycorrhizal fungi and subsequently subjected to different pH solutions (pH 3, 6 and 9) containing 0 mM (control)
and 60 mM NaCl for 4 weeks. Inoculation with the mycorrhizal fungi did not have a large effect on seedling dry weights when
the pH and NaCl treatments were considered independently. However, when the inoculated seedlings were treated with 60 mM NaCl
at pH 3 or 6, shoot to root ratios and root hydraulic conductivity were higher compared with non-inoculated plants, likely
reflecting changes in seedling water flow properties. At pH 6, transpiration rates were about twofold lower in non-inoculated
plants treated with NaCl compared with non-treated controls. For NaCl-treated H. crustuliniforme- and L. bicolor-inoculated plants, the greatest reduction of transpiration rates was at pH 9. Treatment with 60 mM NaCl reduced leaf chlorophyll
concentrations more in non-inoculated compared with inoculated plants, with the greatest, twofold, decrease occurring at pH
6. At pH 3, root Na concentrations were higher in inoculated than non-inoculated seedlings; however, there was no effect of
inoculation on root Na concentrations at pH 6 and 9. Contrary to the roots, the leaves of inoculated plants had lower Na concentrations
at pH 6 and 9, but not at pH 3. The results point to an interaction between ECM fungi and root zone pH for salt tolerance
of American elm. 相似文献
2.
To examine the mechanisms of earlier reported alleviation of fluoride injury in ectomycorrhizal plants by NaCl, jack pine
(Pinus banksiana) and white spruce (Picea glauca) seedlings were subjected to 1 mM and 5 mM KF in the presence of either 60 mM NaCl or 10% polyethylene glycol 3350 (PEG)
for 2 weeks. Before the treatments, seedlings had either been inoculated with the ectomycorrhizal fungus Suillus tomentosus or remained non-inoculated. The inoculation with S. tomentosus reduced Na uptake by shoots and roots of jack pine seedling and by roots of white spruce that were treated with 60 mM NaCl.
Mycorrhizal associations also drastically decreased fluoride uptake by jack pine seedlings, but did not affect shoot fluoride
concentrations in white spruce. When NaCl was replaced by PEG in the 5 mM KF treatment solution, shoot fluoride concentrations
were reduced by more than twofold without corresponding reductions in transpiration rates in mycorrhizal and non-mycorrhizal
white spruce seedlings. When fluoride was present in the treatment solution, Na concentrations were lower in shoots and roots
of both jack pine and white spruce mycorrhizal and non-mycorrhizal seedlings. The results suggest that Suillus tomentosus may help alleviate the effects of soil fluoride and salinity in jack pine and that fluoride uptake in white spruce is sensitive
to osmotic stress. 相似文献
3.
We reported earlier that boron stimulates hypocotyl growth in several Arabidopsis ecotypes but not in the boron-deficient mutant bor1-1. Others have shown that boron influences the metabolism and transport of the plant hormone auxin. We investigated how boron,
in interaction with light, influences Arabidopsis hypocotyl growth responses to the exogenous auxins 1-NAA, 2,4-D and IAA. In either light condition, 1-NAA similarly inhibited
hypocotyl growth in bor1-1 and the corresponding WT (Col-0), while in both genotypes, boron did not essentially affect the extent of the inhibition.
Whatever the light conditions and in the absence of boron, 2,4-D inhibited hypocotyl elongation in WT, while in BL seedlings,
high responsiveness to 2,4-D vanished when boron was added to the culture medium. Hypocotyl of bor1-1 seedlings in all boron concentrations tested and grown in the dark or RL responded to the auxin similar to WT plants. In
BL, the mutant hypocotyls retained full sensitivity to 2,4-D at 0.1 mM H3BO3 but lost that sensitivity by 2 mM. In both genotypes tested, in the dark or RL, IAA inhibited hypocotyl growth. Conversely,
IAA stimulated hypocotyl elongation in both genotypes developed in BL at 0.1 mM H3BO3. That stimulation disappeared when the boron supply increased to 2 mM. Our results suggest that specifically in BL, boron
reduces hypocotyl responsiveness to auxins 2,4-D or IAA via the functional transporter BOR1. Our results lead to a discussion
of how BL and BOR1 influence the mechanisms of auxin transport into and out of the cell. 相似文献
4.
Responses of ectomycorrhizal American elm (Ulmus
americana) seedlings to salinity and soil compaction 总被引:1,自引:0,他引:1
American elm (Ulmus americana) seedlings were either non-inoculated or inoculated with Hebeloma crustuliniforme, Laccaria bicolor and a mixture of the two fungi to study the effects of ectomycorrhizal associations on seedling responses to soil compaction and salinity. The seedlings were grown in the greenhouse in pots containing non-compacted (0.4 g cm?3 bulk density) and compacted (0.6 g cm?3 bulk density) soil and subjected to 60 mM NaCl or 0 mM NaCl (control) treatments for 3 weeks. All three fungal inocula had similar effects on the responses of elm seedlings to soil compaction and salt treatment. In non-compacted soil, ectomycorrhizal fungi reduced plant dry weights, root hydraulic conductance, but did not affect leaf hydraulic conductance and net photosynthesis. When treated with 60 mM NaCl, ectomycorrhizal seedlings had several-fold lower leaf concentrations of Na+ compared with the non-inoculated plants. Soil compaction reduced Na+ leaf concentrations in non-ectomycorrhizal plants and decreased dry weights, gas exchange and root hydraulic conductance. However, in ectomycorrhizal plants, soil compaction had little effect on the leaf Na+ concentrations and on other measured growth and physiological parameters. Our results demonstrated that ECM associations could be highly beneficial to plants growing in sites with compacted soil such as urban areas. 相似文献
5.
Tomáš Kocábek Zdeněk Svoboda Ali M. Al-Zwi Stephen A. Rolfe Martin Fellner 《Environmental and Experimental Botany》2009,67(1):101-111
We studied the effect of elevated boron (B) concentrations on the growth and development of Arabidopsis thaliana in vitro with respect to different light conditions. Two basic responses were observed. At high concentrations (above 5 mM) a clear toxicity effect of B on plant growth was apparent. Seedlings were short, stunted and pale. However at concentrations between 1 and 3 mM H3BO3, hypocotyl elongation was stimulated in all Arabidopsis ecotypes tested relative to plants grown at 0.1 mM H3BO3. The stimulation of hypocotyl elongation by elevated B was proportionally greater with increasing irradiance. We also showed that blue light (BL) and red light (RL) did not alter the sensitivity of Arabidopsis hypocotyls to boron, but, dependent on genotype, BL and RL increased or reduced capacity of boron-induced hypocotyl elongation. Analysis of photomorphogenic mutants indicated the existence of an interaction between boron and light signalling pathways during plant growth and development. This interaction was supported by the observation that the expression of the BOR1 gene in Arabidopsis hypocotyls was stimulated by BL and RL. Our results suggest that in etiolated or light-grown seedlings the stimulation of hypocotyl growth by boron can be mediated by cryptochromes and phytochromes. 相似文献
6.
Langenfeld-Heyser R Gao J Ducic T Tachd P Lu CF Fritz E Gafur A Polle A 《Mycorrhiza》2007,17(2):121-131
In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive poplar hybrid Populus × canescens, growth and stress responses of Paxillus involutus (strain MAJ) were tested in liquid cultures in the presence of 20 to 500 mM NaCl, and the effects of mycorrhization on mineral
nutrient accumulation and oxidative stress were characterised in mycorrhizal and non-mycorrhizal poplar seedlings exposed
to 150 mM NaCl. Paxillus involutus was salt tolerant, showing biomass increases in media containing up to 500 mM NaCl after 4 weeks growth. Mycorrhizal mantle
formation on poplar roots was not affected by 150 mM NaCl. Whole plant performance was positively affected by the fungus because
total biomass was greater and leaves accumulated less Na+ than non-mycorrhizal plants. Energy dispersive X-ray microanalysis using transmission electron microscopy analysis of the
influence of mycorrhization on the subcellular localisation of Na+ and Cl− in roots showed that the hyphal mantle did not diminish salt accumulation in root cell walls, indicating that mycorrhization
did not provide a physical barrier against excess salinity. In the absence of salt stress, mycorrhizal poplar roots contained
higher Na+ and Cl− concentrations than non-mycorrhizal poplar roots. Paxillus involutus hyphae produced H2O2 in the mantle but not in the Hartig net or in pure culture. Salt exposure resulted in H2O2 formation in cortical cells of both non-mycorrhizal and mycorrhizal poplar and stimulated peroxidase but not superoxide dismutase
activities. This shows that mature ectomycorrhiza was unable to suppress salt-induced oxidative stress. Element analyses suggest
that improved performance of mycorrhizal poplar under salt stress may result from diminished xylem loading of Na+ and increased supply with K+. 相似文献
7.
The effects of different concentrations of NaCl on the activities of antioxidative enzymes in the shoots and roots of soybean (Glycine max [L.] Merr cv. Pershing) inoculated or not with an arbuscular mycorrhizal fungus, Glomus etunicatum Becker & Gerdemann, were studied. Furthermore, the effect of salt acclimated mycorrhizal fungi on the antioxidative enzymes in soybean plants grown under salt stress (100 mM NaCl) was investigated. Activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were increased in the shoots of both mycorrhizal (M) and nonmycorrhizal (NM) plants grown under NaCl salinity. Salinity increased SOD activity in the roots of M and NM plants, but had no effect on CAT and polyphenol oxidase activities in the roots. M plants had greater SOD, POD and ascorbate peroxidase activity under salinity. Under salt stress, soybean plants inoculated with salt pre-treated mycorrhizal fungi showed increased SOD and POD activity in shoots, relative to those inoculated with the non pre-treated fungi. 相似文献
8.
The effects of long-term NaCl and KCl treatment on plant growth and antioxidative responses were investigated in Chenopodium album, a salt-resistant species widely distributed in semi-arid and light-saline areas of Xinjiang, China. Growth parameters [plant
height, branch number, leaf morphology and chlorophyll (Chl) content], the level of oxidative stress [superoxide anion radical
(O2
−), hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations], activity of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT),
peroxidase (POX)], the contents of non-enzymatic antioxidants [carotenoids (Car) and ascorbic acid (AsA)] and expression of
selected genes were investigated. Plants were grown in the presence of 0, 50, and 300 mM NaCl or KCl for 2 months. Growth
was stimulated by 50 mM NaCl or KCl, maintained stable at 300 mM NaCl, but was inhibited by 300 mM KCl. Three hundred mM NaCl
did not affect O2
−, H2O2, MDA, Car and AsA, but increased the activities of SOD, CAT and POX compared to the controls. RT-PCR analysis suggested that
expression of some genes encoding antioxidant enzymes could be induced during long-term salt stress, which was consistent
with the enzyme activities. Treatment with 300 mM KCl was associated with elevated oxidative stress, and significantly decreased
Car and AsA contents. These results suggest that an efficient antioxidant machinery is important for overcoming oxidative
stress induced by treatment with high NaCl concentrations in C. album. Other strategies of ion regulation may also contribute to the differential tolerance to Na and K at higher concentrations. 相似文献
9.
Huang Yi Mónica Calvo Polanco Michael D. MacKinnon Janusz J. Zwiazek 《Environmental and Experimental Botany》2008,62(3):357-363
Roots of trembling aspen (Populus tremuloides Michx.) and paper birch (Betula papyrifera Marsh.) seedlings were inoculated with Hebeloma crustuliniforme or Laccaria bicolor and treated with 25 mM NaCl for 6 weeks. Both tree species appeared to be relatively tolerant of the applied NaCl treatment and did not develop visible leaf symptoms that are characteristic of salt injury. Salt treatment reduced total dry weights in aspen and birch, but did not significantly affect transpiration rates and root hydraulic conductance. Salt-treated ectomycorrhizal aspen maintained higher root hydraulic conductance compared with non-mycorrhizal plants. Na and Cl concentrations increased in shoots and roots of mycorrhizal and non-mycorrhizal aspen and birch in response to NaCl treatment. Roots of NaCl-treated aspen inoculated with H. crustuliniforme had over twofold higher concentrations of Na compared with non-mycorrhizal NaCl-treated plants. Similarly to aspen, Na and Cl concentrations increased in roots and shoots of NaCl-treated birch seedlings. However, in birch, there were no significant differences in Na and Cl concentrations between mycorrhizal and non-mycorrhizal plants. The results suggest that salt exclusion by the ectomycorrhizal associations is host-specific or/and that the processes leading to salt exclusion are activated in ectomycorrhizal plants by a threshold salt level which may vary between plant species. 相似文献
10.
Contributions of arbuscular mycorrhizal fungi to growth,photosynthesis, root morphology and ionic balance of citrus seedlings under salt stress 总被引:5,自引:0,他引:5
A pot study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi (Glomus mosseae and Paraglomus occultum) and salt (NaCl) stress on growth, photosynthesis, root morphology and ionic balance of citrus (Citrus tangerine Hort. ex Tanaka) seedlings. Eighty-five-day-old seedlings were exposed to 100 mM NaCl for 60 days to induce salt stress.
Mycorrhizal colonization of citrus seedlings was not affected by salinity when associated with P. occultum, but significantly decreased when with G. mosseae. Compared with the non-mycorrhizal controls, mycorrhizal seedlings generally had greater plant height, stem diameter, shoot,
root and total plant biomass, photosynthetic rate, transpiration rate and stomatal conductance under the 0 and 100 mM NaCl
stresses. Root length, root projected area and root surface area were also higher in the mycorrhizal than in the non-mycorrhizal
seedlings, but higher root volume in seedlings with G. mosseae. Leaf Na+ concentrations were significantly decreased, but leaf K+ and Mg2+ concentrations and the K+/Na+ ratio were increased when seedlings with both G. mosseae and P. occultum. Under the salt stress, Na+ concentrations were increased but K+ concentrations decreased in the mycorrhizal seedlings. Under the salt stress, Ca2+ concentrations were increased in the seedlings with P. occultum or without AM fungi (AMF), but decreased with G. mosseae. Ratios of both Ca2+/Na+ and Mg2+/Na+ were also increased in seedlings with G. mosseae under the non-salinity stress, while only the Mg2+/Na+ ratio was increased in seedlings with P. occultum under the salt stress. Our results suggested that salt tolerance of citrus seedlings could be enhanced by associated AMF
with better plant growth, root morphology, photosynthesis and ionic balance. 相似文献
11.
The present study investigates the regulatory role of exogenous selenium (Se) in the antioxidant defense and methylglyoxal
(MG) detoxification systems in rapeseed seedlings exposed to salt stress. Twelve-day-old seedlings, grown in Petri dishes,
were supplemented with selenium (25 μM Na2SeO4) and salt (100 and 200 mM NaCl) separately and in combination, and further grown for 48 h. The ascorbate (AsA) content of
the seedlings decreased significantly with increased salt stress. The amount of reduced glutathione (GSH) and glutathione
disulfide (GSSG) increased with an increase in the level of salt stress, while the GSH/GSSG ratio decreased. In addition,
the ascorbate peroxidase (APX) and glutathione S-transferase (GST) activity increased significantly with increased salt concentration (both at 100 and 200 mM NaCl), while
glutathione peroxidase (GPX) activity increased only at moderate salt stress (100 mM NaCl). Glutathione reductase (GR) activity
remained unchanged at 100 mM NaCl, while it was decreased under severe (200 mM NaCl) salt stress. Monodehydroascorbate reductase
(MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT), glyoxalase I (Gly I), and glyoxalase II (Gly II) activities decreased
upon the imposition of salt stress, whereas a sharp decrease of these activities was observed under severe salt stress (200 mM
NaCl). Concomitant increases in the levels of H2O2 and lipid peroxidation (MDA) were also measured. Exogenous Se treatment alone had little effect on the non-enzymatic and
enzymatic components. However, further investigation revealed that Se treatment had a synergistic effect: in salt-stressed
seedlings, it increased the AsA and GSH contents; GSH/GSSG ratio; and the activities of APX, MDHAR, DHAR, GR, GST, GPX, CAT,
Gly I, and Gly II. As a result, addition of Se in salt-stressed seedlings led to a reduction in the levels of H2O2 and MDA as compared to salt stress alone. These results suggest that the exogenous application of Se rendered the plants
more tolerant to salt stress-induced oxidative damage by enhancing their antioxidant defense and MG detoxification systems. 相似文献
12.
Zahoor Ahmad Sajid Faheem Aftab 《In vitro cellular & developmental biology. Plant》2009,45(5):540-549
The present investigation envisaged revealing the role of exogenous application of ascorbic acid in increasing resistance
against NaCl stress. Shoot apices from 60-d-old, in vitro-grown plants of two commercially important cultivars of Solanum tuberosum L., cvs. Desiree and Cardinal, were inoculated on Murashige and Skoog (MS) medium supplemented with 0.5 mM ascorbic acid
for 72 h as a pretreatment. Pretreated and non-pretreated shoot apices were transferred to MS medium containing different
concentrations of NaCl (0–140 mM; eight treatments). Results were recorded for morphological (shoot length, shoot number,
root length, root number, and number of nodes) and biochemical features (protein, peroxidase, catalase, and superoxide dismutase
activities) after 60 d of salt treatment. Similarly, 60-d-old, well-proliferated callus cultures were also pretreated with
ascorbic acid for 24 h and transferred to an optimized callus proliferation medium containing different concentrations of
salt. Results were recorded after 60 d of salt treatment for percentage relative fresh weight growth and biochemical parameters.
Salinity severely inhibited all the growth parameters in both the cultivars. Pretreatment with ascorbic acid to both salt-treated
plants and callus cultures showed significant differences with respect to almost all of the growth and biochemical parameters
studied. Protein content as well as catalase and superoxide dismutase activities increased significantly in both the cultivars,
although peroxidase activity showed a decreasing trend in ascorbic acid-pretreated plants as well as callus cultures. 相似文献
13.
Salinity adversely affects plant growth and development. Halotolerant plant-growth-promoting rhizobacteria (PGPR) alleviate
salt stress and help plants to maintain better growth. In the present study, six PGPR strains were analyzed for their involvement
in salt-stress tolerance in Arachis hypogaea. Different growth parameters, electrolyte leakage, water content, biochemical properties, and ion content were analyzed in
the PGPR-inoculated plants under 100 mM NaCl. Three bacterial strains, namely, Brachybacterium
saurashtrense (JG-06), Brevibacterium
casei (JG-08), and Haererohalobacter (JG-11), showed the best growth of A. hypogaea seedlings under salt stress. Plant length, shoot length, root length, shoot dry weight, root dry weight, and total biomass
were significantly higher in inoculated plants compared to uninoculated plants. The PGPR-inoculated plants were quite healthy
and hydrated, whereas the uninoculated plant leaves were desiccated in the presence of 100 mM NaCl. The percentage water content
(PWC) in the shoots and roots was also significantly higher in inoculated plants compared to uninoculated plants. Proline
content and soluble sugars were significantly low, whereas amino acids were higher than in uninoculated plants. The MDA content
was higher in uninoculated plants than in inoculated plants at 100 mM NaCl. The inoculated plants also had a higher K+/Na+ ratio and higher Ca2+, phosphorus, and nitrogen content. The auxin concentration was higher in both shoot and root explants in the inoculated plants.
Therefore, it could be predicted that all these parameters cumulatively improve plant growth under saline conditions in the
presence of PGPR. This study shows that PGPR play an important role in inducing salinity tolerance in plants and can be used
to grow salt-sensitive crops in saline areas. 相似文献
14.
Hamid Sobhanian Ferdous Rastgar Jazii Khadija Razavi Vahid Niknam Setsuko Komatsu 《Russian Journal of Plant Physiology》2010,57(6):784-791
To investigate the salt tolerance mechanisms, Aeluropus lagopoides as a halophytic plant was used. Plants were treated with 0, 150, 450, 600, and 750 mM NaCl and harvested at 0, 4, 8, and
10 days after treatment and 1 day and 1 week after recovery. Optimal growth, measured as fresh and dry weights, occurred at
150 mM NaCl, but it was suppressed by 450, 600, and 750 mM NaCl. Recovery significantly increased fresh and dry weights only
in 750 mM NaCl-treated plants. Water content was decreased after NaCl treatment and increased after recovery. Na+ and proline contents and activity of superoxide dismutase (SOD) were increased after NaCl treatment and decreased after recovery
in all treated plants. In contrast, K+ content and ascorbate peroxidase activity decreased after NaCl treatment and increased after recovery in all treated plants.
Catalase (CAT) was activated only in 750 mM NaCl-treated plants. Total content of soluble protein was slightly changed after
NaCl treatment. It was concluded that proline accumulation for osmotic adjustment, SOD activation for O2·− scavenging, and CAT activation at the higher level of salt stress to detoxify produced H2O2 were main A. lagopoides strategies under salt stress. A. lagopoides salt tolerance was not based on the restriction of Na+ uptake. 相似文献
15.
White spruce [Picea glauca (Moench) Voss] seedlings were inoculated with Hebeloma crustuliniforme and treated with 25 mM NaCl to examine the effects of salinized soil and mycorrhizae on root hydraulic conductance and growth. Mycorrhizal seedlings had significantly greater shoot and root dry weights, number of lateral branches and chlorophyll content than non-mycorrhizal seedlings. Salt treatment reduced seedling growth in both non-mycorrhizal and mycorrhizal seedlings. However, needles of salt-treated mycorrhizal seedlings had several-fold higher needle chlorophyll content than that in non-mycorrhizal seedlings treated with salt. Mycorrhizae increased N and P concentrations in seedlings. Na levels in shoots and roots of salt-treated mycorrhizal seedlings were significantly lower and root hydraulic conductance was several-fold higher than in non-mycorrhizal seedlings. A reduction of about 50% in root hydraulic conductance of mycorrhizal seedlings was observed after removal of the fungal hyphal sheath. Transpiration and root respiration rates were reduced by salt treatments in both groups of seedlings compared with the controls, however, both transpiration and respiration rates of salt-treated mycorrhizal seedlings were as high as those in the non-mycorrhizal seedlings that had not been subjected to salt treatment. The reduction of shoot Na uptake while increasing N and P absorption and maintaining high transpiration rates and root hydraulic conductance may be important resistance mechanisms in ectomycorrhizal plants growing in salinized soil. 相似文献
16.
Background
Little information is available on the amelioration of boron (B) on aluminum (Al)-induced photosynthesis inhibition. Sour pummelo (Citrus grandis) seedlings were irrigated for 18 weeks with nutrient solution containing 4 B levels (2.5, 10, 25 and 50 μM H3BO3) × 2 Al levels (0 and 1.2 mM AlCl3·6H2O). The objectives of this study were to determine how B alleviates Al-induced growth inhibition and to test the hypothesis that Al-induced photosynthesis inhibition can be alleviated by B via preventing Al from getting into shoots. 相似文献17.
Abdulkhaliq Alshoaibi 《Phyton》2021,90(3):731-745
Seeds of three Saudi pearl millet cultivars (Pennisetum spicatum) from three regions (Madinah, Khulais and Jaizan) were inoculated with arbuscular mycorrhizal fungus Glomus mosseae obtained from the Agriculture Research Center of Giza, Egypt to enhance their salt tolerance. Five different NaCl concentrations (0, 30, 60, 90, and 120 mM) were used for treating cultivars with and without mycorrhiza. Growth rates, chlorophyll content, chlorophyll fluorescence (Fv/Fm), proline content and gas exchange were measured to determine the effect of salinity on these cultivars. The results indicated that compared to cultivars without mycorrhiza, all cultivars with mycorrhiza had enhanced growth and physiological parameters including shoot and root length, area and number of leaves, fresh and dry weights of shoots and roots, chlorophyll contents and gas exchanges at 0 and 30 mM of salinity. In addition, the measurements of the different growth rates showed higher growth performance of the cultivars from Madinah and Khulais than the cultivar from Jaizan. However, all cultivars with and without mycorrhiza showed significant reductions in growth rates, chlorophyll contents and gas exchanges at a salinity of 60 mM than those grown at 0 and 30 mM. Moreover, the values of Fv/Fm were significantly reduced in all cultivars with and without mycorrhiza grown at 60 mM than in those grown at 0 mM and 30 mM. Proline contents indicated a progressive increase with the elevation of NaCl concentration stress. The proline contents in the mycorrhiza-inoculated cultivars were significantly higher than those in the non-inoculated cultivars. On the other hand, all cultivars with and without mycorrhiza underwent senescence within four weeks of growth at salinity concentrations of 90 mM and 120 mM. Therefore, relatively low salinity must be maintained to achieve high growth rates and gas exchanges of these inoculated cultivars. 相似文献
18.
The arbuscular mycorrhizal symbiosis can alleviate salt stress in plants by altering strigolactone levels in the host plant. The aim of this study was to investigate the mechanism by which strigolactones enhance salt stress tolerance in arbuscular mycorrhizal Sesbania cannabina seedlings. Strigolactone levels, as determined by means of germination bioassay, gradually increased with treatment time of NaCl applied. Inhibition of NADPH oxidase activity and chemical scavenging of H2O2 significantly reduced strigolactone-induced salt tolerance and decreased strigolactone levels. The H2O2-induced strigolactone accumulation was accompanied by increased tolerance to salt stress. These results strongly indicated that elevated H2O2 concentration resulting from enhanced NADPH oxidase activity regulated strigolactone-induced salt stress tolerance in arbuscular mycorrhizal S. cannabina seedlings. 相似文献
19.
不同强度盐胁迫下AM真菌对羊草生长的影响 总被引:3,自引:0,他引:3
不同浓度NaCl盐处理下,AM真菌对羊草(Leymus chinensis)的侵染能力和对植物生长的影响,从植物形态和离子含量角度探讨了AM真菌提高羊草耐盐性的作用机理。结果表明,在高盐胁迫下,AM真菌显著降低了盐胁迫效应,提高了羊草生物量,菌根效应明显。菌根化羊草的根茎比显著增加,并且N、P浓度较高,Na~+和Cl~-离子浓度较低,表明AM真菌即促进羊草对营养元素的吸收,又减少了离子毒害。菌根化羊草的Ca~(2+)和K~+离子浓度,以及P/Na~+和K~+/Na~+比高于非菌根化羊草,表明AM真菌可通过调节渗透势以避免或减缓盐胁迫造成的生理缺水。随着盐胁迫的增加,菌根化羊草对磷的依赖性逐渐转换为对钾的依赖性。研究结果有助于揭示AM真菌提高植物耐盐能力的作用机理,并对应用菌根技术修复盐化草地具有理论指导意义。 相似文献
20.
Amna Sajid Masood Jabir Hussain Syed Muhammad Farooq Hussain Munis 《International journal of phytoremediation》2015,17(10):981-987
Plants show enhanced phytoremediation of heavy metal contaminated soils particularly in response to fungal inoculation. Present study was conducted to find out the influence of Nickel (Ni) toxicity on plant biomass, growth, chlorophyll content, proline production and metal accumulation by L. usitatissimum (flax) in the presence of Glomus intraradices. Flax seedlings of both inoculated with G. intraradices and non-inoculated were exposed to different concentrations i.e., 250, 350 and 500 ppm of Ni at different time intervals. Analysis of physiological parameters revealed that Ni depressed the growth and photosynthetic activity of plants. However, the inoculation of plants with arbuscular mycorrhizae (G. intraradices) partially helped in the alleviation of Ni toxicity as indicated by improved plant growth under Ni stress. Ni uptake of non- mycorrhizal flax plants was increased by 98% as compared to control conditions whereas inoculated plants showed 19% more uptake when compared with the non-inoculated plants. Mycorrhizal plants exhibited increasing capacity to remediate contaminated soils along with improved growth. Thus, AM assisted phytoremediation helps in the accumulation of Ni in plants to reclaim Ni toxic soils. Based on our findings, it can be concluded that the role of flax plants and mycorrhizal fungi is extremely important in phytoremediation. 相似文献