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1.
The effect of cadmium on growth and contents of glutathione (GSH) and phytochelatins (PCs) were investigated in roots and
leaves of tomato plants (Lycopersicon esculentum Mill. cv. 63/5 F1). The accumulation of Cd increased with external Cd concentrations and was considerably higher in roots
than in leaves. Dry mass production decreased under Cd treatment especially in leaves. In both roots and leaves, exposure
to Cd caused an appreciable decline in GSH contents and increase in PCs synthesis proportional to Cd concentrations in the
growth medium. At the same Cd concentration, PCs production was higher in roots than in leaves. The implication of glutathione
in PC synthesis was strongly suggested by the use of buthionine sulfoximine (BSO). The major fraction of Cd accumulated by
tomato roots was in the form of a Cd-PCs complex. 相似文献
2.
To determine the effects of phosphorus nutrition on chilling tolerance of photosynthetic apparatus, tomato (Lycopersicon esculentum Mill. cv. Kenfengxin 2002) plants were raised under different P contents and subjected to 7 d of chilling at 9/7 °C. After
chilling (2 h or 7 d) plant growth, P content in tissue, gas exchange and chlorophyll fluorescence were measured. Decreasing
P concentration [P] in the nutrient solution markedly reduced plant growth and the chilled plants exhibiting higher optimum
[P] than the unchilled plants. Decreasing [P] significantly decreased light saturated net photosynthetic rate (PNsat), maximum carboxylation velocity of Rubisco (Vcmax), maximum potential rate of electron transport contributed to Rubisco regeneration (Jmax), quantum efficiency of photosystem (PS) 2 (ΠPS2) and O2 sensitivity of PNsat (PSO2) and this trend was especially apparent in chilled plants. 相似文献
3.
Shoot and root mass of tobacco plants treated with only 0.05 μM boron was decreased by 25 and 50 %, respectively, when compared
to plants sufficiently supplied with B (2 and 5 μM). Leaf B content of 0.05 μM B-treated plants decreased (about 80–90 %)
when compared to 2 μM B treated plants; this drop of B content were not as marked (about 25–45 %) in roots. Leaf and root
nitrate contents in B-deficient plants were 45–60 % and 35–45 % lower, respectively, than those from 2 and 5 μM B treated
plants. It is suggested that B deficiency might decrease nitrate uptake rather than nitrate reductase activity in tobacco
plants. 相似文献
4.
Contribution of putrescine degradation to proline accumulation in soybean leaves under salinity 总被引:1,自引:1,他引:0
Proline accumulation was studied in the leaves of Glycine max (L.) Merr. subjected to salt stress in the presence of aminoguanidine (AG, a specific inhibitor of diamine oxidase, DAO)
and exogenous putrescine (Put). Both DAO activity and proline content were increased while endogenous Put content was decreased
in soybean leaves under 50 to 150 mM NaCl. There was a negative correlation between proline accumulation and endogenous Put
content. The addition of AG during NaCl stress inhibited DAO activity, caused Put accumulation and a 15 to 20 % decrease in
proline content. Application of 1 mM Put to NaCl solution markedly increased proline content. The promotive effect of Put
application could be alleviated by the treatment with Put plus AG. Moreover an application of AG had no effect on proline
accumulation in soybean seedlings grown under normal condition. These results indicate that the quantitative contribution
of Put degradation to proline formation is 15 to 20 %. 相似文献
5.
6.
Expression of tea cytosolic glutamine synthetase is tissue specific and induced by cadmium and salt stress 总被引:3,自引:0,他引:3
Glutamine synthetase (GS) showed highest expression and activity in bud (youngest topmost leaf) of Camellia sinensis, lower in older leaves, while lowest activity in stem and roots. GS expression and activity was increased by ammonium and
nitrate and also by cadmium and salt stress but decreased by copper, aluminum, drought, cold and heat stress. 相似文献
7.
8.
In vivo activity of recombinant human lewis fucosyltransferase III in leaves of Nicotiana tabacum L.
S. Lhernould P. Labrousse D. Lejolly R. Léonard M. Carlué G. Costa 《Biologia Plantarum》2008,52(2):267-274
Fucosylation in plants occurs in glycoproteins and polysaccharides but the function of fucosylation is largely unknown. We
aimed to analyze the effects of over-expression of human fucosyltransferase III (hFucT III) on in vivo
N-glycan accumulation in tobacco plant leaves and focused on comparing the amount of Lewis a (Lea)-epitope accumulation in transgenic and in wild-type plants. Fucosyltransferase assays, Western blot and mass spectrometry
were used to identify, quantify and analyse Lea
N-glycans. We found that constitutive overexpression of hFucT III activity had no effect on Lea complex type N-glycans accumulation. Our results suggest that tobacco recombinant hFucT III acts more as a hydrolase than as a transferase. 相似文献
9.
Yellow lupin (Lupinus luteus L.) plants were grown in hydroponic solution for 15 d under different copper concentrations (0.1, 0.5, 1.0, 10, 25 and 50
μM). With increasing Cu concentration total biomass was not affected, leaf area slightly decreased, while chlorophyll content
decreased considerably. Cu content increased significantly both in roots and in leaves, but the contents of other ions were
only slightly affected at the highest Cu concentration (Mn content decreased both in roots and in leaves, P content decreased
only in leaves and Zn content increased in roots). Superoxide dismutase (SOD) activity increased up to day 7 after copper
application. Peroxidase (GPOD) and polyphenol oxidase (PPO) activities also increased, while catalase (CAT) activity remained
constant. 相似文献
10.
B. Mittra S. Sharma A. B. Das S. L. Henry T. K. Das P. Ghosh S. Ghosh P. Mohanty 《Biologia Plantarum》2008,52(2):343-346
A 51-kDa soluble protein was over-expressed in wheat (Triticum aestivum) seedlings by the treatment of seeds before germination with 50 μM CdCl2 for 48 h and subsequently washed off Cd2+. This protein designated as Cd stress associated protein (CSAP), was purified. Polyclonal antibody was raised against CSAP
for localizing the protein in root tissue of treated and control seedlings. It was observed that CSAP was located below the
plasma membrane and outer periphery of the tonoplast. This unique type of organized localization of CSAP is suggestive of
defensive role against metal phytotoxicity. N-terminal analysis of CSAP and expressed sequence tags (EST) database search
of wheat sequences suggests that this protein has not been reported earlier in higher plants. 相似文献
11.
12.
The chlorophyll fluorescence (F) temperature curves in a linear time-temperature heating/cooling regime were used to study
heat-induced irreversible F changes in primary green leaves of spring barley (Hordeum vulgare L. cv. Akcent). The leaf segments were heated in a stirred water bath at heating rates of 0.0083, 0.0166, 0.0333, and 0.0500
°C s−1 from room temperature up to maximal temperature T
m and then linearly cooled to 35 °C at the same rate. The F intensity was measured by a pulse-modulated technique. The results
support the existence of the two critical temperatures of irreversible F changes postulated earlier, at 45–48 and 53–55 °C.
The critical temperatures are slightly dependent on the heating rate. Two types of parameters were used to characterize the
irreversibility of the F changes: the coefficient of irreversibility μ defined as the ratio of F intensity at 35 °C at the
starting/ending parts of the cycle and the slopes of tangents of linear parts of the F temperature curve. The dependence of
μ on T
m revealed a maximum, which moved from 54 to 61 °C with the increasing heating/cooling rate v from 0.0083 to 0.0500 °C s−1, showing two basic phases of the irreversible changes. The Arrhenius and Eyring approaches were applied to calculate the
activation energies of the initial increase in μ. The values varied between 30 and 50 kJ mol−1 and decreased slightly with the increasing heating rate. 相似文献
13.
Agrobacterium-mediated genetic transformation is the most widely used technology to obtain overexpression of recombinant proteins in plants.
Molecular events that occur within Agrobacterium during interactions with host plants have been studied extensively, and now we have a reasonable understanding the key factors
involved in the regulation of T-DNA nuclear import and genomic integration. By contrast, very little is known about the events
that take place in the host cells during genetic transformation by Agrobacterium. Here, we describe the plant-related factors including genotype, genes, proteins, competency of target tissues and phenolic
compounds that participate in Agrobacterium-mediated genetic transformation and discuss their possible roles in this process. Because Agrobacterium probably adapts existing cellular processes for its life cycle, identifying the processes in host cells during Agrobacterium infection might contribute to better understanding of basic biological processes as cell communication, intracellular transport
and DNA repair and recombination as well as to expanding the host range of Agrobacterium as a genetic engineering tool. 相似文献
14.
Cell wall composition in leaves and regenerating leaf-derived protoplasts was studied in Beta vulgaris L. and Nicotiana tabacum L. Several oligosaccharides that characterize arabinogalactan proteins (AGPs) and pectins were visualized in situ by a series of immunocytochemical reactions. The most conspicuous difference between the two species involved the expression
of AGP epitopes that bind LM2 and MAC207 in only sugar beet cells; both epitopes being characterized by the presence of glucuronic
acid (GlcA). Moreover, B. vulgaris leaves and protoplast-derived cells showed lower content of pectin side-chains bearing (1→4)-β-D-galactose residues as compared
to N. tabacum. 相似文献
15.
We investigated the carbon isotope ratios and the diurnal pattern of malate accumulation in leaves and aerial roots of eight
species of Phalaenopsis grown in greenhouses. The leaves of all the species showed carbon isotope ratios and the diurnal patterns of malate content
typical of CAM plants. However, the aerial roots exhibited a large variation in the diurnal pattern of malate content among
species and even among plants within the same species, although carbon isotope ratios were always CAM-like values. Some aerial
roots showed the typical diurnal pattern of CAM, but others maintained high or low malate contents during a day without fluctuation.
In order to characterize more strictly the nature of the malate variation in the aerial roots, we further investigated a possible
variation of the diurnal pattern of malate among different aerial roots within an individual for Phalaenopsis amabilis and P. cornu-cervi. The diurnal pattern of malate content was varied even among different aerial roots within the same plant. Thus the photosynthetic
carbon metabolism in aerial roots of orchids is fairly complex. 相似文献
16.
L. Jaakola J. J. Koskimäki K. R. Riihinen A. Tolvanen A. Hohtola 《Biologia Plantarum》2008,52(2):391-395
The influence of artificial wounding on biosynthesis of flavonoids and hydroxycinnamic acids was studied in bilberry leaves
using two separate wounding experiments. In the first experiment bilberry leaves were wounded by cutting. The expression of
the first gene from flavonoid pathway, chalcone synthase (CHS) and a wound induced pathogenesis related PR-10 gene was analysed from samples collected immediately and after 3, 6, 24 h and 4 d from the wounding treatment. In the second
experiment annual shoots were removed. Proanthocyanidins, flavonol glycosides and hydroxycinnamic acids were quantified in
leaf samples after 0–5 d (experiment 1) and 5 weeks (experiment 2) from the treatment. In the first experiment, no change
was observed in the expression of CHS whereas increase in expression of PR-10 gene was detected after 6 h of wounding treatment. In both experiments, the contents of flavonol glycosides and hydroxycinnamic
acids were not influenced by the wounding treatment and the contents of proanthocyanidins were decreased. 相似文献
17.
18.
Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by environmental conditions. In our study,
young maize plants, cultivated in various ways in order to minimise the stressing effect of hypoxia, flooding, mechanical
impedance or nutrient starvation, were examined for the presence of aerenchyma in their primary roots. The area of aerenchyma
in the root cortex was correlated with the root length. Although 12 different maize accessions were used, no plants without
aerenchyma were acquired until an ethylene synthesis inhibitor was employed. Using an ACC-synthase inhibitor, it was confirmed
that the aerenchyma formation is ethylene-regulated and dependent on irradiance. The presence of TUNEL-positive nuclei and
ultrastructural changes in cortical cells suggest a connection between ethylene-dependent aerenchyma formation and programmed
cell death. Position of cells with TUNEL-positive nuclei in relation to aerenchyma-channels was described. 相似文献
19.
Effects of exogenous salicylic acid (SA) on plant growth, contents of Na, K, Ca and Mg, activities of superoxide dismutase
(SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR)
and catalase (CAT), and contents of ascorbate and glutathione were investigated in tomato (Lycopersicon esculentum L.) plants treated with 100 mM NaCl. NaCl treatment significantly increased H2O2 content and lipid peroxidation indicated by accumulation of thiobarbituric acid reactive substances (TBARS). A foliar spray
of 1 mM SA significantly decreased lipid peroxidation caused by NaCl and improved the plant growth. This alleviation of NaCl
toxicity by SA was related to decreases in Na contents, increases in K and Mg contents in shoots and roots, and increases
in the activities of SOD, CAT, GPX and DHAR and the contents of ascorbate and glutathione. 相似文献
20.
Indian mustard (Brassica juncea L. cv. Vitasso) plants exposed to 10, 30, 50 and 100 μM of Cd for 5 d in hydroponic culture were analysed with reference
to the distribution of Cd2+, the accumulation of biomass and antioxidants and antioxidative enzymes in leaves. Cd induced a decrease in plant biomass.
The maximum accumulation of Cd occurred in roots followed by stems and leaves. Cd induced a decrease in catalase (CAT) and
guiacol peroxidase (GPX) activities but an increase in ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR)
activities. Enhancement in dehydroascorbate reductase (DHAR) activity was also at 10 μM Cd. Glutathione reductase (GR) activity
showed pronounced stimulation after all treatments, but glutathione S-transferase (GST) and glutathione peroxidase (GPOX)
activities decreased. The effectiveness of ascorbate-glutathione cycle (AGC) was determined by the ratio of ascorbate to H2O2. This ratio decreased in the Cd-treated leaves which indicated that the cycle was disordered. 相似文献