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1.
Khavari-Nejad RA 《Plant physiology》1977,60(1):44-46
The effects of 10(-2)m alpha-hydroxy-2-pyridinemethanesulfonic acid (alphaHPMS) on the CO(2) compensation point, photosynthetic CO(2) uptake, CO(2) evolution into CO(2)-free air in light, and stomatal movement, in excised tomato leaves (Lycopersicon esculentum Mill. Eurocross BB-F(1) Hybrid) were studied. It was found that alpha-HPMS had a transient lowering effect on the CO(2) compensation point of treated leaves within the first 5 minutes of application. The net photosynthetic CO(2) uptake was inhibited by alpha-HPMS treatment. The inhibition increased with time and was enhanced in an O(2)-free atmosphere. The CO(2) evolution into CO(2)-free air in light was inhibited by alpha-HPMS. The inhibition was O(2)-dependent because the effect was observed only in 21% O(2) but not in O(2)-free N(2). Stomatal apertures were affected by alpha-HPMS, but the effect was transient and was observed 15 to 30 minutes after the application. The time course of this closure did not account for the observed inhibition of net CO(2) uptake. 相似文献
2.
R. A. Khavari-Nejad R. Shekaste Band F. Najafi M. Nabiuni Z. Gharari 《Russian Journal of Plant Physiology》2013,60(3):375-382
Proline metabolism is implicated in plant responses to abiotic stresses, including the chilling stress. During proline catabolism, the two-step oxidation of proline is performed by the continuous actions of proline dehydrogenase (ProDH), which produces Δ1-pyrroline-5-carboxylate (P5C), and P5C dehydrogenase (P5CDH), which oxidizes P5C to glutamate. The Arabidopsis thaliana chilling mutants chs1 and chs2 are sensitive to chilling temperatures of 13–18°C. For a better understanding of Arabidopsis responses to chilling stress, 4-week-old wild-type (WT) and chs1 and chs2 lines, with three plants in each group, were subjected to chilling stress (13°C), cold stress (4°C), or remained under normal conditions (23°C); and several factors including the expression of ProDH2 and P5CDH genes, POX (peroxidase) and SOD (superoxide dismutase) activities, as well as MDA and proline contents were examined. Our results showed an increase in the proline content in all lines under chilling conditions. In addition, a greater expression of ProDH2 and a lower expression of P5CDH were observed, leading us to speculate a greater breakdown of proline into P5C and a consequent overproduction of ROS in the ETC cycle. The higher POX and SOD activities and a higher MDA content in chs mutants at 13°C are in line with this speculation. Finally, cold-treated plants (4°C) only showed an increase in proline levels. 相似文献
3.
Sheida Yousefi Mobasherat Jajroud Ramazan Ali Khavari-Nejad 《Journal of biomolecular structure & dynamics》2018,36(11):2908-2916
The nanoparticle (NP)-induced conformational changes of protein and NP agglomeration have gained a remarkable interest in medical and biotechnological fields. Herein, the effect of human hemoglobin (Hb) on the colloidal stability of cerium oxide NP (CNP) was investigated by dynamic light scattering (DLS), zeta potential, and TEM analysis. In addition, the effect of CNP on the heme degradation and structural changes of Hb was studied using fluorescence, circular dichroism (CD), and UV–visible (UV–vis) spectroscopic methods. DLS and TEM analysis showed that the presence of Hb can increase the mean diameter of CNP. Zeta potential measurements revealed that CNP demonstrated a higher charge distribution relative to CNP/Hb complex. Besides, fluorescence studies indicated that two fluorescent heme degradation products are revealed during the interaction of CNP with Hb. Near UV-CD spectroscopy also showed that the microenvironmental changes of heme groups occur after interaction of Hb with CNP. The result of thermal behavior of Hb confirmed the structural changes of protein, which referred to decrease in the Hb stability in the presence of CNP. Indeed, the finding related to structural and functional changes of Hb induced by CNP may be crucial to obtain information regarding the side effects of NPs. Finally, this data reveal much insight into the effects of the interaction on protein structural changes and NP agglomeration, and can correlate the zeta potential of NP-protein complexes with the nature of the principle NP-protein interaction. 相似文献
4.
Neda Soltani Ramezan Ali Khavari-Nejad Mojtaba Tabatabaei Yazdi Shadman Shokravi Eduardo Fernández-Valiente 《World journal of microbiology & biotechnology》2006,22(6):571-576
Summary Our objective was to evaluate the physiological response of Fischerella ambigua FS18 to the combined influence of pH (5, 7 and 9) and light intensity (3 and 300 μmol photon m−2 s−1). Growth rates were similar at pH 9 and pH 7. There was no growth at pH 5. Increasing light intensity did not have any considerable
influence on growth rates. Chlorophyll concentration was higher at pH 7 at all light intensities. Chlorophyll concentration
decreased with increasing light intensity from 3 to 300 μmol photon m−2 s−1. Synthesis of the phycobiliproteins (PBP), phycocyanin (PC) and allophycocyanin (APC) had the highest rate in pH 7. Increasing
irradiance decreased the concentrations of all PBPs. The light-saturated photosynthetic rate was clearly higher at high light
intensity. With respect to nitrogenase activity, the highest rate was at pH 9 and 300 μmol photon m−2 s−1. Irradiance did not affect significantly this activity at pH 7. This cyanobacterium seems to be alkalophilic with maximum
nitrogenase activity and photosynthesis at pH 9. It can also adapt its photosynthetic apparatus to the variable factors that
are found in rice fields. 相似文献
5.
6.
F. Nikravesh R. A. Khavari-Nejad H. Rahimian H. Fahimi 《Russian Journal of Plant Physiology》2012,59(5):648-655
Hairy root disease is caused by infection of wounded higher plants with Agrobacterium rhizogenes. Transformation of tissues or plants with A. rhizogenes, as well as transformation with rol genes, in addition to hairy roots, may produce alterations in the plant secondary metabolism. H2O2 and other ROS are involved as signals in secondary metabolite production pathways and play a key role in plant defense reactions. In this work the effects of A. rhizogenes rol genes on nicotine content, antioxidant enzymes activity, H2O2 production, the pattern of peroxidase (POX) and superoxide dismutase (SOD) isozymes in hairy roots and regenerated Nicotiana tabacum plants were studied. The rise in SOD and POX activities in the transformed lines TRa and TRb and the resulting regenerated plants and a decreased level of H2O2 in them as compared with the untransformed lines indicates that rol gene expression decreases H2O2 level probably by increasing production of antioxidant enzymes. A decreased H2O2 content in TRc line, in spite of similarity of antioxidant enzyme activity as compared to normal roots, indicates that rol genes activate other mechanisms except SOD and POX enzymes for reducing H2O2. 相似文献
7.
The effects of 0, 30, 60, and 90 mM NaCl, and 0 and 5 mM CaCl2 on certain parameters of photosynthesis and growth in alfalfa (Medicago sativa L. cv. Ghara yonjeh) plants were studied. The increasing NaCl concentration in the Hoagland nutrient solution decreased the contents of chlorophylls and the net photosynthetic rate, and increased the rate of respiration (RD) and CO2 compensation concentration in the leaves of treated plants. The contents of carotenoids (Car) were not significantly affected. The addition of 5 mM CaCl2 enhanced the RD and increased the Car contents in treated leaves. With the NaCl concentration in the culture medium increasing, the dry matter production in both root and shoot decreased, as well as the relative growth rate (RGR), net assimilation rate (NAR), and leaf area ratio (LAR). The addition of CaCl2 caused a partial elimination of the NaCl effects on the root and shoot, RGR and NAR, and it decreased the LAR. 相似文献
8.
Narges Oraghi Ardebili Sara Saadatmand Vahid Niknam Ramazan Ali Khavari-Nejad 《Acta Physiologiae Plantarum》2014,36(12):3199-3205
This research was conducted to screen various treatments of selenium (Se) and/or salicylic acid (SA) to mitigate signs of salinity on soybean. Seedlings were treated with three concentrations of Se (0, 25 and 50 mg l?1), two concentrations of SA (0 and 0.5 mM) and/or two concentrations of NaCl (0 and 100 mM). Se and/or SA had significant enhancing and alleviating effects on the chlorophyll a (Chl a) and carotenoid contents as well as, Chl a/b in the treated plants, but had adverse effects on the Chl b concentrations. The limiting effects of salinity on leaf area and dry mass were significantly eased by the Se and/or SA among which 25 mg l?1 Se and combined treatment of 50 mg l?1 Se and SA were the most effective. The utilization of Se and/or SA led to the improved proline and Mg contents, compared to the control. The supplemented Se and/or SA, especially the mixed ones, resulted in a significant decrease in Na/K ratios. Se and/or SA had significant inducing effects on enzymatic (peroxidase, catalase and superoxide dismutase) and non-enzymatic (ascorbate) antioxidant system. On the basis of the obtained results, it could be stated that the foliar utilization of Se in combination with SA may be used to relieve the signs of salinity stress. 相似文献
9.
Salar E. Khavari-Nejad R. A. Mandoulakani B. Abdollahi Najafi F. 《Russian Journal of Plant Physiology》2021,68(1):118-125
Russian Journal of Plant Physiology - Dracocephalum kotschyi Boiss has been known as a valuable source of rosmarinic acid (RA), a multifunctional phenolic bioactive compound. In this study, a... 相似文献
10.
S. H. Namdjoyan R. A. Khavari-Nejad F. Bernard T. Nejadsattari H. Shaker 《Russian Journal of Plant Physiology》2011,58(3):467-477
By using two safflower (Carthamus tinctorius L.) cultivars, Arak2811 and Goldasht, the experiments were conducted in order to study (i) the genotypic variation in cadmium
(Cd) tolerance, (ii) Cd concentrations in plants, and (iii) changes in the antioxidant defense systems in leaves, including
antioxidant enzymes and nonenzymatic antioxidants. Plants were grown under controlled environmental conditions and subjected
to Cd treatments (0, 25, 50, 75, and 100 μM Cd) for different time periods. Cd concentrations and cultivar-dependent response
to Cd were assessed. Of the two cultivars, Goldasht showed a greater sensitivity to Cd toxicity as judged from the severity
of Cd toxicity symptoms on leaves, much stronger enhancement in the MDA level, and decreases in dry matter production. Increasing
Cd supply markedly reduced the shoot and root dry weights in both cultivars, but at the higher Cd concentrations and longer
exposure durations, this decrease was more marked in cv. Goldasht. Plants accumulated substantial amount of Cd, especially
in the roots, the highest being in the roots of cv. Arak2811 at 100 μM Cd after 4 days. Cd-induced oxidative stress as was
indicated by the increase in lipid peroxidation with the increase in metal concentration and exposure duration. Under different
Cd stress levels, activities of antioxidant enzymes differed in the two cultivars. The results indicated that Cd tolerance
of cv. Arak2811 was related to the retention of Cd in the roots and avoiding the toxic effect by activation of the antioxidant
system. 相似文献