О научном журнале«Физиология растений»
Журнал Физиология растений (Russian Journal of Plant Physiology) - самый популярный журнал по физиологии растений, издаваемый на территории бывшего Советского Союза. Журнал охватывает все разделы современной физиологии растений, а также близкие аспекты биофизики, биохимии, цитологии, анатомии, генетики и др. Журнал публикует экспериментальные и теоретические статьи, обзоры, краткие сообщения и описания новых методов исследования. К публикации также принимаются хроники Российских и международных симпозиумов и рецензии на новые книги. Некоторые номера журнала представляют собой сборники статей, освещающих определенные проблемы физиологии растений и содержащие новую информацию о быстро развивающихся ее областях. Редколлегия журнала крайне заинтересована в сотрудничестве исследователей из разных стран и принимает к публикации также рукописи, представленные на английском языке. Журнал представляет интерес для университетов, научно-исследовательских институтов, библиотек, научных работников и аспирантов как надежный периодический источник информации.
Архив научных статейиз журнала «Физиология растений»
ANALYSIS OF DNA METHYLATION OF SPIRODELA POLYRHIZA (GRATER DUCKWEED) IN RESPONSE TO ABSCISIC ACID USING METHYLATION-SENSITIVE AMPLIFIED POLYMORPHISM
CUI L., SHI H.J., WANG M.L., YANG Z.G., ZHAO Y., ZHAO Z. — 2015 г.
Spirodela polyrhiza is an a energy feedstock, which can produce a kind of dormant fronds called turions to survive cold. ABA can induce S. polyrhiza to form turions and is the most important hormone for plants to resist abiotic stresses. DNA methylation plays an important role in plant development by regulating gene expression. In this study, we studied DNA methylation variation in the fronds of S. polyrhiza treated with ABA and compared DNA methylation variation between fronds and turions, using the methylation-sensitive amplified polymorphism procedure. We selected 60 pairs of selective amplification primers to assess the status and levels of cytosine methylation. The results showed that ABA triggered the hemimethylation or internally full methylation of cytosine. With the prolongation of ABA treatment, the methylation of the total DNA increased. The alteration analysis of cytosine methylation showed that the number of demethylation events were much lower than those of methylation, which indicates that methylation was predominant. In addition, the methylation level in turions was higher than in the fronds. Moreover, the sequences of 14 differentially amplified DNA fragments were analyzed. According to Blast analysis, most of the 14 fragments were identified as genes or DNA involved in the abiotic stress response. The fragment M11 is homologous to ATPase. ABA may affect the methylation status of ATPase gene to regulate its expression to resist chilling. Our study showed that ABA might affect gene expression via changing the methylation status of the cytosine nucleotide.
BIOCHEMICAL AND PHYSIOLOGICAL RESPONSES OF BRASSICA NAPUS PLANTS TO HUMIC ACID UNDER WATER STRESS
GHARAVI-KOUCHEBAGH P., KHOSHVAGHTI H., LOTFI R. — 2015 г.
This study examines the effects of humic acid (HA, 3 and 6 mg/L) on some biochemical and physiological parameters of rapeseed (Brassica napus L.) plants under different water supply conditions (60, 100, and 140 mm evaporation from class A pan). Water stress decreased chlorophyll a (Chl a) and total chlorophyll (ChlT) content in plants but proline content partly increased with increasing water stress severity. Plants treated by HA had more Chl a and ChlT content under both well and limited water conditions. Application of HA improved the PSII and peroxidase activity of rapeseed plants under all irrigation treatments. Ascorbate peroxidase activity under severe water stress condition was increased by 70 and 95%, compared with that under moderate and well watering conditions, respectively. Catalase activity was 51 and 69% less under well watering than that of moderate and severe water stress conditions, respectively. The highest activity of ascorbate peroxidase was recorded in plants treated by 6 mg/L HA. HA-treated plants had 42, 8.5, and 15% more soluble protein content under well watering, moderate and severe water stress conditions, respectively, compared with control plants (non-humic acid). Malondialdehyde was increased with increasing the severity of water stress, application of HA significantly reduced the amount of this trait under water stress conditions. It was shown that application of HA increased the activity of antioxidant enzymes, improved PSII activity and consequently decreased lipid peroxidation in rapeseed plants.
BIOCHEMICAL RESPONSES OF THIOUREA IN AMELIORATING HIGH TEMPERATURE STRESS BY ENHANCING ANTIOXIDANT DEFENSE SYSTEM IN WHEAT
ASTHIR B., BAINS N.S., FAROOQ M., THAPAR R. — 2015 г.
In this study, effect of exogenously applied thiourea (TU, 6.6 mM) and dithiothreitol (DTT, 0.07 mM) as seed pretreatment or as foliar spray (at 90 days after sowing) in two wheat (Triticum aestivum L.) cvs. C 306 (heat tolerant) and PBW 343 (heat susceptible) at seedling and reproductive stages under high temperature (HT) stress was investigated. The heat tolerant cv. C 306 exhibited much lower membrane injury index (MII), thiobarbituric acid reactive substances (TBARs) and H2O2 contents, but such effect was not accompanied by higher activities of the enzymes involved in the reactive oxygen species scavenging system during both developmental stages. Application of TU under HT reduced MII and TBARs and H2O2 contents, but as a rule did not affect activities of antioxidant enzymes. Therefore pretreatment by TU/DTT, no doubt, improved the resistance against oxidative stress through increase in membrane stability parameters but their effect on antioxidant enzymes was not apparent under the prevailing conditions of the experiment.
CHARACTERISTIC VARIATION IN PIGMENT COMPOSITION, PHOTOSYNTHETIC CARBON ASSIMILATION AND PHYTONUTRIENTS CONTENT OF DENDROPHTHOE FALCATA, A HEMIPARASITE GROWING ON HOST TREES OF SALINE AND NON-SALINE ENVIRONMENTS
ARUMUGAM R., RAJKUMAR R., VENKATESALU V. — 2015 г.
The Indian mistletoe Dendrophthoe falcata (L.f) Ettingsh is highly specialized perennial flowering plant adapted to parasitic life on aerial parts of their hosts. Photosynthetic characteristics in leaves of D. falcata growing on a halophilic (Rhizophora mucronata) and a glycophilic (Albizia lebbeck) host trees were determined. The chlorophyll a/b ratio was low (1.01.5) and showed no significant difference between the leaf samples collected from both the host species. The CO2 assimilation rate (PN) was significantly low (5.2 ) in the parasite growing on R. mucronata, compared to the other host A. lebbeck ( ). There was no host-specific variation in the activity of ribulose-1,5-bisphosphate carboxylse (RuBPC) and phosphoenolpyruvate carboxylase (PEPC); however, D. falcata infecting R. mucronata showed significantly higher activity of RUBPC (6.63 mmol ). The Fourier transform infrared (FTIR) spectral studies revealed the presence of quercitrin in the leaf samples of D. falcata, which is reported as a taxonomic marker of the Loranthaceae family. The non host-specific hemiparasite, D. falcate, exhibited significant variation among the halophilic and glycophilic host trees, particularly in photosynthetic activity and nutrients accumulation.
CHLOROPHYLL CONTENT, LEAF GAS EXCHANGE AND GROWTH OF ORIENTAL LILY AS AFFECTED BY SHADING
GAO H., GUO Y.Y., LI Y.H., WANG E.J., XIE Z.K., XU Y.Z., YAN F., ZHANG Y.J. — 2015 г.
We evaluated the effects of light conditions on leaf gas exchange, chlorophyll content, and growth responses in the Oriental lily (Lilium auratum L.) cv. Sorbonne. The experiment involved application on increasing shade densities (0, 60, 75, and 80%) to Sorbonne, and was carried out in the Horqin Sandy Land of northern China. Shade tests showed that growth of the lily was primarily affected by the level of irradiance. Photoinhibition occurred in the 0 and 60% shade treatments, but not in the 75 and 80% shade treatments. Shade treatments led to increase in photosynthetic pigment content, enhancement in photosynthetic efficiency, and finally increase in the commercial value of the lily. Pn, on the other hand, was lowest in the 80% shade treatment. So irradiance less than that achieved in the 80% shade treatment limited carbon assimilation and led to decreased plant growth. Plants grown under 75% shade displayed the optimal traits determining commercial value (plant height, flower length, flower diameter). Trends in Pmax, AQY, LSP and LCP to shade confirmed that the lily is a shade-tolerant plant. Excessive light, therefore, was the primary photosynthetic process limiting lily quality. Growth under conditions of 75% shade is recommended to improve photosynthetic efficiency and alleviate photo damage, thus increasing the commercial value of the lily grown in the Horqin Sandy Land.
CLONING AND EXPRESSION ANALYSIS OF FOUR DELLA GENES IN PEANUT1
AN J., HOU L., LI C., LI C.S., WANG C.X., WANG X.J., XIA H., ZHAO C.Z., ZHAO Y.X., ZHENG Y.X. — 2015 г.
Peanut (Arachis hypogaea L.), as a source of oil and protein, is the second-most important grain legume cultivated in the world. Peanut is a relatively drought-tolerant crop; however, the molecular biology research of peanut is far behind other crops; the molecular mechanisms of its stress resistance are poorly understood. DELLA proteins, negative regulators of gibberellin signaling pathway in plants, promote survival of plants in adverse environments. In this study, four DELLA homologue genes were isolated using peanut transcriptome sequences. Molecular phylogenetic analysis revealed that these four AhDELLAs fall into three distinct groups: AhDELLA1 and AhDELLA2 clustered into two distinct groups, while AhDELLA3 and AhDELLA4 were in one group, which was separated from other DELLAs. qRT-PCR results showed that these four DELLA genes expressed differentially in various peanut tissues. The AhDELLA1 and AhDELLA2 genes were expressed ubiquitously in different tissues. AhDELLA3 and AhDELLA4 showed much higher expression level in flowers and seeds as compared with other tissues. The expression of four AhDELLA genes was temporally induced by PEG 6000 treatment. The AhDELLA3 and AhDELLA4 transcripts were significantly induced by NaCl treatment, while the expression of AhDELLA1 and AhDELLA2 did not change much under salt stress. The possible role of DELLA proteins in peanut development and responses to abiotic stresses is discussed.
CLONING, EXPRESSION, AND CHARACTERIZATION OF PHYA GENE FROM IPOMOEA BATATAS
JIANG Y.S., TAO X., WANG J.X., YAN Y., ZHANG Y. — 2015 г.
Phytochrome A (phyA), as a photoreceptor, has a profound influence on plant growth and development and participates in many important physiological processes, such as seed germination, seeding de-etiolation, and flowering. On the basis of transcriptome database of sweet potato (Ipomoea batatas (L.) Lam), phyA gene was cloned and sequenced. The gene has an open reading frame (ORF) of 3384 bp, encodes a protein with 1127 amino acid residues and a mol wt of 125.03 kD. More interestingly, it was found that there were three highly homologous phyA cDNA isoforms in sweet potato. In addition, when the genomic sequence of phyA gene was obtained by PCR using sweet potato genomic DNA as a template, it contained 4 exons and 3 introns with a total size of 4957 bp. The cDNA of phyA gene was inserted into the vector pET-32a(+) and successfully expressed in Escherichia coli BL21(DE3). The results of quantitative real-time PCR indicated that the expression level of phyA gene was higher in stem, followed by leaf, and the lowest in tuberous root. Besides, the expression of phyA mRNA in the mature leaf showed an obvious circadian rhythm in a day: mRNA accumulation gradually increased in darkness and decreased in the daylight.
COMPARATIVE RESPONSE OF ANNUAL MEDICAGO SPP. TO SALINITY
KARAMI M., KHODAMBASHI M., RAFIEI F., SHIRAN B. — 2015 г.
The present study was conducted to evaluate the morphological and physiological traits and the expression profile of antioxidant genes in four annual Medicago genotypes (M. truncatula Karaj; M. truncatula Qom; M. polymorpha; M. laciniata) under salinity. The experiment was carried out in a randomized complete block design, in which salinity (0 and 100 mM NaCl) allotted to main plots and genotypes assigned to subplots. The results indicated that salinity significantly increased Na+ content and decreased K+ content thereby increased the ratio of Na+/K+ in all annual Medicago genotypes. Salinity caused reduction in dry weight of shoot and root in all plants. Total chlorophyll and carotenoid contents declined by virtue of salt stress and such reduction was more remarkable in M. truncatula compared to M. polymorpha and M. laciniata. In a reverse manner, salinity increased anthocyanin content in all Medicago genotypes. Salinity augmented the overexpression of glutathione S-transferase (GST), glyoxalase I (GLXI), glutaredoxin (GRX), and peroxidase (PERX) genes in annual Medicago genotypes. Nevertheless, the overexpression of GLXI, GRX, and PERX genes was greater in M. truncatula plants than in M. polymorpha and M. laciniata plants. The expression of antioxidants genes in M. polymorpha and M. laciniata plants was greater than in M. truncatula and M. truncatula plants. In conclusion, M. polymorpha and M. laciniata were regarded as salt-tolerant species by less reduction in chlorophyll and carotenoid contents, less increase in anthocyanin content, and higher expression of GLXI, GRX, and PERX.
ECTOPIC EXPRESSION OF SUBUNIT A OF VACUOLAR H+-ATPASE FROM APPLE ENHANCES SALT TOLERANCE IN TOBACCO PLANTS
DONG Q.L., FANG M.J., HAO Y.J., LIU D.D., WANG Q.J., YAO Y.X. — 2015 г.
Vacuolar H+-ATPase (VHA) as one of plant proton pumps in the tonoplast plays a very important role in plant growth and stress tolerances. In this paper, we reported that expression of the apple (Malus domestica B.) vacuolar H+-ATPase subunit A (MdVHA-A) was induced by salt stress in apple in vitro shoot cultures. Additionally, MdVHA-A overexpression enhanced the resistance to salinity in the transgenic tobacco (Nicotiana tabacum L.) plants. Compared to control tobacco plants, the transgenic plants exhibited the higher Na+, K+, and proline content but lower MDA content in leaves and roots. Therefore, these results indicate that expression of MdVHA-A can enhance plant tolerance to salt stress by modulating internal stores of ions and solutes.
EFFECT OF 5-AZAC ON THE GROWTH, FLOWERING TIME AND SEXUAL PHENOTYPE OF SPINACH
DENG C.L., GAO W.J., LI S.F., LU L.D., YUAN J.H., ZHANG G.J. — 2015 г.
Spinach (Spinacia oleracea L.) is a diploid dioecious plant with a pair of heteromorphic sex chromosomes X and Y. Plant DNA methylation, a known process for genome epigenetic modification, regulates gene expression in plants. To explore the effects of DNA methylation on spinach growth and sexual development, spinach seeds were treated with the demethylating reagent 5-azaC. The resulting phenotypes were then investigated, including germination percentage, root length, plant height, flowering time, and sexual phenotype. Results showed that 5-azaC at a low concentration ( ) only slightly influenced spinach development but promoted seed germination. The germination percentage, root length, and plant height negatively correlated with 5-azaC at 100 1000 . The flowering time significantly reduced at all four treatments with 5-azaC. In addition, 5-azaC influenced the sexual phenotype of spinach and remarkably increased the percentage of monoecious individuals. These results may suggest that vegetative and reproductive growth are both epigenetically regulated by DNA methylation.
EFFECT OF LASER IRRADIATION AND ETHYLENE ON CHILLING TOLERANCE OF WHEAT SEEDLINGS
CHEN Y.P., LIU Q. — 2015 г.
In order to determine the mechanism of laser-enhanced chilling tolerance in wheat (Triticum aestivum L.) seedlings, the seeds were exposed to different treatments, and some physiological and biochemical parameters were measured in 5-day-old seedlings. The results showed that in wheat seedlings subjected to 1-aminocyclopropane-1-carboxylic acid (ACC) followed by chilling stress (CS), the concentrations of H2O2, O , and malondialdehyde (MDA) were lower, while the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as the soluble protein content (SPC) and the seedling length (SL) were higher than those in chilling stress treatment. When wheat seedlings were subjected to aminooxyacetic acid (AOA) followed by chilling stress, the results were different from those in which the seedlings were subjected to ACC. Although ACC and AOA treatments followed by laser irradiation led to an increase in the aforementioned enzyme activities, SPC, and SL, with a simultaneous decrease in concentrations of H2O2, O , and MDA, the effect of ACC treatment followed by laser irradiation was more favorable than that of AOA treatment followed by laser light. Similarly, the oxidative damage induced by chilling stress was alleviated in treatment with ACC+LR and AOA+LR, but alleviation effects of ACC+LR+CS were more prominent than in the treatment AOA+LR+CS. These results suggest that the laser light and ethylene have a positive synergistic effect, thus enhancing chilling tolerance in wheat seedlings.
EFFECT OF SHORT-TERM PHOSPHATE STARVATION ON ACID PHOSPHATASE ACTIVITY OF CARPINUS PUBESCENS AND EURYCORYMBUS CAVALEREI
HONG K., YI Y., ZHANG X.M. — 2015 г.
The objective of this research was to test the effect of phosphate starvation on the plant growth and acid phosphatase activity of Carpinus pubescens and Eurycorymbus cavalerei. Growth parameters of both trees with-P and +P exhibited little change. The Pi content in leaves of both Pi-free trees decreased to about 6570% of the control after cultivation for two to three weeks. Root Pi content of both Pi deprivation trees were by 30-45% lower than that of the Pi supply. Phosphate starvation significantly increased both intracellular and extracellular acid phosphatase activities. Intracellular and extracellular acid phosphatase activities were negatively correlated with Pi content in roots, while intracellular acid phosphatase activities were significantly positively correlated with Pi content in leaves under Pi starvation. These results indicated that excreted acid phosphatase mainly released Pi from organic phosphorus compounds, while intracellular acid phosphatase in leaves regulated the redistribution of Pi in tissues for adaptation to a calcareous soil with a low phosphate level.
EFFECT OF WATERLOGGING ON PHOTOSYNTHETIC AND BIOCHEMICAL PARAMETERS IN PIGEONPEA
BANSAL R., SRIVASTAVA J.P. — 2015 г.
We studied the effect of waterlogging stress on photosynthetic and biochemical parameters in pigeonpea [Cajanus cajan (L.) Millsp.] genotypes viz. ICPL-84023 (waterlogging resistant) and MAL-18 (waterlogging susceptible). Plants at early growth stage (20 days) were subjected to stress by keeping the pots in water filled containers. Stress was imposed for six days. Waterlogging reduced carbon exchange rate, stomatal conductance, intercellular CO2 concentration and transpiration rate. Photosynthesis was limited by stomatal as well as non stomatal components under waterlogging. Reduction in chlorophyll, starch and increase in alcohol dehydrogenase activity along with the membrane injury was reported under waterlogging. High carboxylation efficiency, more chlorophyll content, starch availability, alcohol dehydrogenase activity and membrane stability were associated with better survival of ICPL-84023 under waterlogging.
EFFECTS OF EXOGENOUS NITRIC OXIDE ON PHYSIOLOGICAL CHARACTERISTICS OF PERENNIAL RYEGRASS UNDER CADMIUM AND COPPER STRESSES
BAI X.Y., DONG Y.J., KONG J., LIU S., XU L.L. — 2015 г.
The effects of sodium nitroprusside (SNP, a donor of NO) on cadmium (Cd) and copper (Cu) toxicity in ryegrass seedlings (Lolium perenne L.) were studied. Plant growth, chlorophyll content, the accumulation of superoxide anion (O ), lipid peroxidation, and the activities of antioxidant enzymes were asesed. Cd, Cu, and especially Cd+Cu caused serious chlorosis, inhibited the growth of ryegrass seedlings, and increased dramatically the accumulation of Cd and/or Cu in both shoots and roots. However, the addition of 100 SNP alleviated significantly the toxic effects induced by Cd or Cu, and especially by Cd+Cu, which was manifested in the increased plant growth, chlorophyll content, and the activation of antioxidant enzymes. Moreover, exogenous NO improved effectively the absorption of mineral elements. In addition, exogenous NO diminished markedly the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA), and proline, but increased the content of ascorbic acid (AsA) and inhibited the translocation of Cd and Cu from roots to shoots. These data also suggested that the alleviating effect of NO may be better when the metal stresses are more serious. NO might act as one of the potential antioxidants to improve plant resistance to the Cd and/or Cu stress.
EFFECTS OF HIGH SALINITY ON PHYSIOLOGICAL AND ANATOMICAL INDICES DURING THE EARLY STAGES OF POPULUS EUPHRATICA GROWTH
AYUP M., CHEN Y., RAJPUT V.D. — 2015 г.
The effects of salinity stress on stomatal aperture and density, xylem vessels, the activities of antioxidant enzymes, such as superoxide dismutase (SOD) and peroxidase (POD), and xylem embolism (PLC values) in Populus euphratica in the arid ecosystem of China were studied. Pot experiment was conducted at different concentrations of salt (50, 100, 150, and 200 mM NaCl) contained in the water used for irrigation during three months. The POD activity increased with the increase in the severity of NaCl stress, but SOD activity varied at different salt levels. Results indicated that salt treatment reduced stomatal aperture and thus, evidently, leaf photosynthetic capacity. The significant reduction in the stomatal area, in the length of stomata openings, and an increase in stomata density were noticed. Salinity stress affected water transport, reducing native PLC value, whereas xylem vessel section areas were also decreased. Presented results open the possibility of genetic improvement for selecting the salt-tolerant Populus spp. to reclaim salinized lands.
EFFECTS OF NACL STRESS ON NITROGEN METABOLISM OF CUCUMBER SEEDLINGS
DU J., GUO S.R., SHAO Q.S., SHU S., SUN J., XING W.W. — 2015 г.
To investigate the effects of NaCl stress on plant growth, nitrogen assimilation, proline and soluble protein contents, and gene expression of enzymes of nitrogen metabolism, a hydroponic experiment using cucumber (Cucumis sativus L.) seedlings was performed. The seedlings were grown in nutrient solution supplemented with 0 or 84 mM NaCl for up to 9 days. Plant biomass, especially root biomass, was significantly decreased under NaCl stress. Salinity significantly increased ammonium content, but decreased nitrate and soluble protein contents in leaves and roots. Salt stress caused a significant increase in proline content, which peaked on day 3 of NaCl treatment. Moreover, salt stress significantly decreased activities of nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH) in the roots and leaves on the 3rd, 6th, and 9th day of NaCl treatment. A semi-quantitative RT-PCR approach showed that changes in NR, GS and GOGAT gene expression were consistent with the salt-induced changes in enzyme activities. These results suggest that salt stress-induced growth inhibition in cucumber seedlings may involve disruption of nitrogen absorption and decreased activities of enzymes associated with nitrogen assimilation.
EFFECTS OF NITRATE AND AMMONIUM ON GROWTH OF ARABIDOPSIS THALIANA PLANTS TRANSFORMED WITH THE ARR5::GUS CONSTRUCT AND A ROLE FOR CYTOKININS IN SUPPRESSION OF DISTURBANCES INDUCED BY THE PRESENCE OF AMMONIUM
AKHIYAROVA G.R., DANILOVA M.N., KOROBOVA A.V., KUDOYAROVA G.R., KUDRYAKOVA N.V., KULAEVA O.N., KUSNETSOV V.V., SHTRATNIKOVA V. YU. — 2015 г.
Determination of physiologically active cytokinins in transformed Arabidopsis thaliana (L.) Heynh. plants (ecotype Wassilevskija) by means of the ARR5::GUS gene expression analysis and by the immunohistochemical assay demonstrated an increase of the cytokinin content during leaf growth and its decrease after growth cessation. After leaf growth cessation cytokinins (CKs) were found only in chloroplasts. Nitrate but not ammonium salt increased the cytokinin content in leaves. The replacement of nitrate in nutrient medium with ammonium salts suppressed leaf and root growth and decreased the content of physiologically active CKs in them. In plants cultivated on a media with NH4Cl as a sole nitrogen source, 10-9 M trans-zeatin several-fold activated leaf growth, prevented a decrease in the chlorophyll a and b content, and reduced proline accumulation indicating suppression of the NH4Cl stress action. Thus, negative effects of NH4Cl as a sole nitrogen source depended on the cytokinin shortage.
EVIDENCE FOR THE FUNCTIONING OF A CL-/H+ ANTIPORTER IN THE MEMBRANES ISOLATED FROM ROOT CELLS OF THE HALOPHYTE SUAEDA ALTISSIMA AND ENRICHED WITH GOLGI MEMBRANES
ANDREEV I.M., BALNOKIN Y.V., BELYAEV D.V., KHALILOVA L.A., MYASOEDOV N.A., ORLOVA J.V., SHUVALOV A.V. — 2015 г.
Cl-/H+ exchange activity in the membranes isolated from the root cells of the halophyte Suaeda altissima (L.) Pall. was originally revealed and characterized. The membrane vesicles were isolated by centrifugation of microsomes in a continuous iodixanol density gradient. The highest activity of latent inosine diphosphatase, a marker of Golgi membranes, was localized in the upper part of the gradient, indicating its enrichment with Golgi membranes. The same part of the gradient was characterized by the highest Cl-/H+ exchange rate. The Cl-/H+ exchange activity was detected as electrogenic рCl-dependent H+ transport monitored as changes in differential absorbance of a pH-probe acridine orange, or as changes in fluorescence excitation spectrum of a pH-probe pyranine loaded into the vesicles. Generation of transmembrane electric potential ( ) during the Cl-/H+ exchange was assayed as changes in differential absorbance of a -probe safranin O. Establishing the transmembrane рCl inward vesicles resulted in H+ efflux sensitive to DIDS (4,4-diisothiocyano-2,2-stylbene-disulfonic acid), an inhibitor of chloride transporters and channels, and generation of negative inside. To maintain the рCl-dependent H+ efflux from the vesicles, either the presence of a penetrating cation tetraphenylphosphonium neutralizing negative charges inside the vesicles or K+ diffusion potential across the membranes was required. The results demonstrate the activity of an electrogenic Cl-/H+ antiporter in the fraction enriched with Golgi membranes. We hypothesize that the Cl-/H+ antiporter is involved into the regulation of cytoplasmic Cl- concentrations by vesicular trafficking of Cl- from the cytoplasm to the vacuole by endosomes, derivatives of Golgi membranes.
F-ACTIN PARTICIPATES IN THE PROCESS OF THE “PARTITION-BUNDLE DIVISION”
CHEN H., HAN R. — 2015 г.
A special kind of mitosis in wheat (Triticum aestivum L.) seedlings was observed after their exposure to the enhanced ultraviolet B (UV-B) radiation and named as partition-bundle division. To explore the abnormal mitosis, we focused on the changes of actin filaments (F-actin) during somatic cell division. The results showed that there were cyclic changes of F-actin during the cell cycle. In the interphase, F-actin was present as long filaments and the F-actin ring surrounding the nucleus. In prophase and metaphase, F-actin was depolymerized into small fragments, which process accompanied nucleus disappearance. In the anaphase, the actin-depleted zone appeared and then a bright zone full of F-actin appeared, which was named as actin re-appeared zone designating the position of the cell plate. In the telophase, F-actin fragments were aggregated into filaments and the F-actin ring re-appeared. Under the influence of enhanced UV-B radiation, there existed several kinds of chromosome aberrations, including lagging chromosomes, the chromosome bridge, and partition-bundle division. In the normal wheat seedling root cells, F-actin surrounded chromosomes, acting as one of the components of the aster-like structure. When injured by the enhanced UV-B radiation, F-actin could not surround the chromosomes fully or is distributed unequally at the cell poles, thus leading to the partition-bundle division. This all indicates that F-actin participates in the process of the partition-bundle division in wheat seedlings when they suffer from enhanced UV-B radiation.
GENE EXPRESSION PROFILING IN SHOOT APICAL MERISTEM OF GOSSYPIUM HIRSUTUM
FAN S.L., LI J., PANG C.Y., SONG M.Z., WEI J.H., WU M., YU J.W., YU S.X., ZHANG J.F. — 2015 г.
Early maturity is a particularly important agronomic trait for cotton breeding in China and is determined by many morphological and phenological traits. The time of floral initiation is one of most important factors related to early maturation of cotton. The aim of this study was to identify differentially expressed (DE) genes related to floral initiation using the Arabidopsis thaliana GeneChip system on the shoot apical meristems (SAMs) of an early-maturing cotton cultivar. Compared with SAMs at 10 days, 365 genes were differentially expressed in the SAMs at 20 days. Of these, 210 and 155 transcripts were up- and down- regulated, respectively. The results of Gene Ontology (GO) annotation indicated that most genes fell into the four largest functional groups: metabolism, transposable elements, protein binding or cofactor requirements, and protein fate. These groups constituted 18.9, 11.8, 12.8 and 6.8% of the total DE genes, respectively. Many DE genes were identified, including those encoding the transcription factors SOC1-like floral activator MADS4, B3-domain containing transcription factor, MYB2, MYB85, and GHMADS-1. Our research found that the B3-domain containing transcription factor was similar to Arabidopsis genes encoding auxin response factor 36 and VERNALIZATION 1 (VRN1) and was one of 155 down-regulated ‘Apex-unique transcripts. The B3-domain containing transcription factor was 1128 bp long and was named GhV1 (GenBank accession No. GU929695). The induction of the transcripts we identified in the cotton SAM after 10 days of SD revealed that the transition to reproductive development occurred at this particular time point. These results allowed for a detailed description of temporal gene expression changes in the cotton SAM as it undergoes the floral initiation process.