Wyniki wyszukiwania - Biblioteka Nauki

1

Effects of cadmium stress on root tip cells and some physiological indexes in Allium cepa var. agrogarum L.

100%

Zou J. , Yue J. , Jiang W. , Liu D.

Acta Biologica Cracoviensia. Series Botanica

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2012

|

tom 54

|

nr 1

EN

Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions.

2

A Low-Loss Ka-Band Distributed Metal-Air-Metal MEMS Phase Shifter

100%

Chen A. , Jiang W. , Chen Z. , Li Y.

Przegląd Elektrotechniczny

|

2013

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tom R. 89, nr 7

77--80

EN

A 4-bit wideband distributed phase shifter has been developed for Ka-band operation. The design results show that the digital shifter has four basic phases of 11.25o, 22.5o, 45o, 90o and thus 16 kinds of phase states can be constructed from the combination of them. The simulation results also demonstrates that the insertion coefficient is better than -1.37 dB, the phase error is less than 3.983o at 30GHz, and the reflection coefficient is lower than -10dB from 25GHz to 35GHz for each state. This low-loss distributed metal-air-metal MEMS phase shifter can be well applied to phased arrays.

PL

W artykule opisano 4-bitowy szerokopasmowy przesuwnik fazy zaprojektowany do pasma Ka. Przesuwnik ma cztery ]główne fazy: 11.25o, 22.5o, 45o, 90o i 16 kombinacji między nimi. Błąd jest mniejszy niż 3.983o przy 30GHz.

3

Cadmium accumulation and its effects on growth and gas exchange in four populus cultivars

100%

Gu J. , Qi L. , Jiang W. , Liu D.

Acta Biologica Cracoviensia. Series Botanica

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2007

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tom 49

|

nr 2

7-14

4

Estimation of system reliability by using the PLS-regression based corrected response surface method

100%

Liu H. , Jiang W. , Hulio Z. H. , Wang Q.

Eksploatacja i Niezawodność

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2016

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tom Vol. 18, no. 2

260--270

EN

A new computational method, referred as PLS-regression (PLSR) based corrected response surface method, has been developed for predicting the reliability of structural and mechanical systems subjecting to random loads, material properties, and geometry. The method involves a Corrected-Response Surface Model (C-RSM) based on the Partial Least Squares Regression Method (PLSRM) combined with some correction factors, and Monte Carlo Simulation (MCS), which is named as the Corrected-Partial Least Squares Regression-Response Surface Method (C-PLSRRSM). In order to develop an accurate surrogate model for the region determining the reliability of the system, a proper coefficient is presented to determine the sampling region of the input random variables. Due to a small number of original function evaluations, the proposed method is effective, particularly when a response evaluation entails costly finite-element, mesh-free, or other numerical analysis. Three numerical examples involving reliability problems of two structural systems and a mechanical system illustrate the method developed. Results indicate that the proposed method provides accurate and computationally efficient estimates of reliability. The proposed correction method, the PLSR based corrected response surface (C-PLSR-RS), can be the accurate surrogate model for calculating system reliabilities, especially for the implicit performance functions.

PL

Nowa metoda obliczeniowa o nazwie "poprawiona metoda powierzchni odpowiedzi oparta na regresji PLS" (C-PLSRRSM) została opracowana dla potrzeb przewidywania niezawodności systemów konstrukcyjnych i mechanicznych poddanych obciążeniom losowym oraz charakteryzujących się losową geometrią oraz losowymi właściwościami materiałowymi. W metodzie uwzględniono pewne czynniki korekcyjne oraz symulację Monte Carlo. W celu opracowania odpowiedniego modelu zastępczego dla regionu stanowiącego o niezawodności systemu, przedstawiono współczynnik, który pozwala określić obszar pobierania próbek wejściowych zmiennych losowych. Ze względu na niewielką liczbę ocen funkcji początkowych, proponowana metoda jest skuteczna zwłaszcza wtedy, gdy ocena odpowiedzi wymaga kosztownej analizy numerycznej metodą elementów skończonych czy metodą automatycznie generowanej siatki (free mesh). Opracowaną metodę zilustrowano za pomocą trzech przykładów numerycznych dotyczących niezawodności dwóch systemów konstrukcyjnych oraz jednego układu mechanicznego. Wyniki wskazują, że proponowana metoda zapewnia dokładne i wydajne obliczeniowo oszacowanie niezawodności. Proponowana metoda C-PLSR-RS może stanowić trafny model zastępczy do obliczania niezawodności systemu, zwłaszcza w przypadku uwikłanych funkcji stanu granicznego.

5

Chromium accumulation and its effects on other mineral elements in Amaranthus viridis L.

100%

Zou J. , Wang M. , Jiang W. , Liu D.

Acta Biologica Cracoviensia. Series Botanica

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2006

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tom 48

|

nr 1

EN

Chromium accumulation and its effects on other mineral elements in Amaranthus viridis L. were investigated using inductively coupled plasma atomic emission spectrometry (ICP-AES) and resin adsorption. The aim was to understand why A. viridis can grow well in soils heavily contaminated by Cr, what the forms of Cr in soils and residues are, and what effects Cr has on the distribution of Mn. Fe, Cu and Zn in the plant. The results indicated that A. viridis is not a hyperaccumulator, although it can grow well in soil containing a high concentration of Cr. The Cr concentration in plant tissues from a contaminated site was about 11 times higher than in those from an uncontaminated site. At both the contaminated and uncontaminated sites, Cr was accumulated primarily in its shoots, and in roots in much lower concentrations. The levels of Cr in A. viridis tissues were as follows: leaf > root > stem. Cr occurred predominantly as Cr(III). There was very little Cr(VI) in the polluted soil where A. viridis grew close to a waste heap discarded by a chromium(VI) production factory. The possible mechanisms for Cr accumulation of A. viridis and the effects of Cr on uptake and accumulation of the other mineral elements in A. viridis are briefly discussed.

6

Antioxidant response system and chlorophyll fluorescence in chromium [VI] - treated Zea mays L. seedlings

88%

Zou J. , Yu K. , Zhang Z. , Jiang W. , Liu D.

Acta Biologica Cracoviensia. Series Botanica

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2009

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tom 51

|

nr 1

23-33

EN

The effects of different concentrations of Cr(VI) (1 µM, 10 µM, 100 µM) applied for 7, 14 or 21 days on initiation of high lipid peroxidation level (POL) and consequent changes in the enzymatic-antioxidant protective system and minimization of photosystem II (PSII) activity were studied in maize seedlings. Chromium (VI) caused an increase in the electrical conductivity of the cell membrane, and malondialdehyde (MDA) content (a peroxidation product) reflected peroxidation of membrane lipids leading to the loss of the membrane's selective permeability. It also induced distinct and significant changes in antioxidant enzyme activity. Versus the control, superoxide dismutase (SOD, EC 1.15.1.1.), catalase (CAT, EC 1.11.1.6.) and peroxidase (POD, EC 1.11.1.11.) activity in maize seedling roots and leaves was progressively enhanced by the different Cr(VI) doses and stress periods, except for decreases in SOD and POD activity in leaves exposed to 100 µM Cr(VI) for 21 days. The different Cr(VI) concentrations changed chlorophyll (chl) content differently. The 10 µM and 100 µM doses of Cr(VI) decreased the chl a/b ratio and quenched the chl a fluorescence emission spectra. These effects reflect disturbance of the structure, composition and function of the photosynthetic apparatus as well as PSII activity.

7

Performance of water-soluble composite sulfate sand core for magnesium alloy castings

88%

Jiang P. , Liu F. , Fan Z. , Jiang W. , Liu X.

Archives of Civil and Mechanical Engineering

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2016

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tom Vol. 16, no. 3

494--502

EN

A novel water-soluble sand core hardened by twice microwave heating was fabricated using composite solution of magnesium sulfate and sodium sulfate as a binder. The tensile strength, water absorption rate, gas evolution and water-soluble rate of the water-soluble composite sulfate sand core (WCSSC) were studied. The micro-morphology of WCSSC was observed by scanning electron microscope (SEM). The results show that tensile strength of WCSSC is 1.2 MPa, and the 4 h storage tensile strength exceeds 1 MPa, and also the water-soluble rate is about 42.65 kg/(min m2), which indicates that WCSSC possesses good moisture resistance and water-soluble collapsibility. The microscopic analysis demonstrates that there are some micro-cracks or holes in the bonding bridge that decreases the strength of WCSSC after being put in humidistat for several hours.

8

Particleboards with partially liquefied bark of different particle sizes

88%

Jiang W. , Adamopoulos S. , Petric M. , Sernek M. , Medved S.

Drewno. Prace Naukowe. Doniesienia. Komunikaty

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2021

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tom 64

|

nr 207

9

Effect of Cu2plus concentration on growth, antioxidant enzyme activity and malondialdehyde content in garlic [Allium sativum L.]

88%

Meng Q. , Zou J. , Zou J. , Jiang W. , Liu D.

Acta Biologica Cracoviensia. Series Botanica

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2007

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tom 49

|

nr 1

95-101

EN

The effects of different concentrations (10-5 M, 10-4 M. 10-3 M) of Cu2+ on growth, antioxidant enzyme activity and malondialdehyde (MDA) content were investigated in hydroponically grown Allium sativum L. The results indicated that the growth of garlic seedlings was not inhibited under treatment with 10-5 M Cu2+. Garlic seedlings exposed to 10-4 M and 10-3 M Cu2+ exhibited significant growth reduction. With increasing Cu2+ concentration and treatment time, superoxide dismutase (SOD) activity increased in leaves and roots, and peroxidase (POD) activity increased in leaves. In roots of plants exposed to 10-4 M and 10-3 M Cu2+, POD activity increased within 9 d and then dropped, but was still higher than in the control at the end of the experiment. Catalase (CAT) activity increased in seedlings grown at 10-5 M and l0-4 M, whereas a highly toxic level of Cu2+ (10-3 M) markedly inhibited CAT activity. SOD and POD activity were higher in roots than in leaves, whereas CAT activity was higher in leaves than in roots under both control and Cu2+ treatments. There was no obvious effect on MDA content in the seedlings treated with 10-5 M Cu2+; at 10-4 M and 10-3 M Cu2+ it increased. The mechanisms of Cu2+ toxicity and Cu2+ tolerance in garlic are briefly discussed.

10

Ultrastructural and photosynthetic response of Populus 107 leaves to cadmium stress

88%

Ge W. , Jiao Y. , Zou J. , Jiang W. , Liu D.

Polish Journal of Environmental Studies

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2015

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tom 24

|

nr 2

EN

As Populus 107 is an efficient phytoextraction plant, it was used in the present investigation in order to better understand the mechanisms of detoxification and tolerance of Cd. Cd-induced impacts on photosynthetic parameters (chlorophyll content, soluble protein, and chlorophyll fluorescence) and ultrastructural changes in leaves of Populus 107 exposed to 50 μM, 100 μM, and 500 μM for 40 days were carried out. The results showed that in the Cd-treated cells, almost all the chloroplasts seemed to be affected. Cd induced several significant ultrastructural changes, including swollen chloroplast thylakoids, dissolved thylakoid grana, disintegrated chloroplasts, and numerous plastoglobuli in chloroplasts. Data from chlorophyll fluorescence showed that Fv/Fm, Fv ’/Fm’, ΦPSII, ETR, and qP decreased while qN increased in leaves of Populus 107 exposed to Cd when compared to control. The content of soluble protein increased with increasing Cd concentration and declined with prolonged duration of treatment. The soluble protein content in leaves treated with 50 μM Cd reached the maximum, which was 14.29% more than that of control. The content in leaves exposed to 500 μM Cd were only 61.76% of control. At the end of the experiment the contents of chlorophyll a, b, and a+b of Populus 107 treated with 500 μM Cd decreased to the minimum, which were 47.69%, 37.10%, and 45.49% of control, and respectively, and significantly (P < 0.05) lower than control. The toxic mechanisms of Cd are briefly explained.

11

Simulation study of the impact of L-shaped and T-shaped branch of GIS on the propagation of ultrahigh frequency electromagnetic wave

88%

Yong Q. , Jiang W. , Haifeng Y. , Gehao S. , Xiuchen J.

Przegląd Elektrotechniczny

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2013

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tom R. 89, nr 1a

223--226

EN

This article simulates the propagation of ultrahigh frequency (UHF) electromagnetic wave excited by partial discharge in L-shaped and Tshaped branch of GIS using finite-difference time-domain (FDTD) algorithm. We examine the effect of L-shaped and T-shaped branch of GIS on time domain waveform and frequency components of UHF electromagnetic wave. It is found that L-shaped branch of GIS significantly attenuates the electric field strength of UHF electromagnetic wave propagating in GIS cavity. Electromagnetic waves attenuated by L-shaped branch mainly have the frequency of 300MHz-2000MHz or above 3000MHz. Electric field strength of some frequency components is enhanced. When propagating in Tshaped branch, the frequency components of electromagnetic wave are more significantly attenuated along the bending path than along the straight path.

PL

W artykule opisano wyniki symulacji propagacji fali elektromagnetycznej o ultra-wysokiej częstotliwości, wywołanej wyładowaniem niezupełnym w gałęzi typu L i T aparatury rozdzielczej GIS, z wykorzystaniem algorytmu różnic skończonych w dziedzinie czasu (FDTD). Stwierdzono, że gałąź L znacząco osłabia siłę wnikania pola elektrycznego fali elektromagnetycznej UHF w GIS. W gałęzi T, częstotliwości składowe są bardziej tłumione w zagięciach charakterystyki niż na odcinkach prostych.

12

Insensitive HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) Nanocrystals Fabricated by High-Yield, Low-Cost Mechanical Milling

88%

Wang Y. , Jiang W. , Song X. , Deng G. , Li F.

Central European Journal of Energetic Materials

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2013

|

tom Vol. 10, no. 2

277--287

EN

A mechanical approach had been adopted for fabricating HMX nanoparticles. This fabrication method avoided the recrystallization process and was different from the traditional methods employed to prepare nanoexplosives. In particular, the high yield and low cost increased the possibility of its industrial application. Specifcally, HMX particles, that had a mean size of 0.27 μm, were prepared by mechanical milling; a signifcant proportion of nano-HMX (<100 nm) were present and these were observed by TEM and SEM images. The thermal decomposition of HMX samples before and after pulverization was investigated by TG/DSC analysis. The results indicated that there was no obvious difference between the thermographs of raw and pulverized HMX. The HMX samples were investigated by friction, impact, and shock sensitivity tests. High safety was confrmed since pulverized HMX was far more insensitive than raw HMX; indeed the shock sensitivity of pulverized HMX was about 60 percent lower than that of raw HMX.

13

Mechanical Spectroscopy of Equal-Channel Angular Pressed Fe-Cr Alloys and Tungsten

88%

Hao T. , Tang H. , Jiang W. , Wang X. , Fang Q.

Archives of Metallurgy and Materials

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2015

|

tom Vol. 60, iss. 3A

2101--2106

EN

nternal friction technique was used to investigate the microstructural stability of equal-channel angular pressed (ECAP) 9Cr1Mo steel (T91), Fe-18wt.%Cr alloy, and pure W. Several non-relaxation internal friction peaks are observed in three ECAP-strained specimens, which are related to the microstructural transition from a severely deformed state to a static recovery state of dislocations, and to recrystallized state. Along with the disappearance of the P1 peak, another relaxation internal friction peak P2 is observed during the second heating run only in Fe-18wt.%Cr alloy, and it does not disappear even during subsequent third heating run. This peak is not observed in T91 steel and W. The P2 peak is likely associated with a process of grain boundary (GB) sliding. Unlike T91, no abundant carbide precipitates distribute on GBs to pin GB and repulse GB sliding, thus, the P2 peak only occurs in Fe-18wt.%Cr alloy. It is concluded that high-temperature internal friction measurements are required to detect the grain boundary peak in pure W.

PL

Technika tarcia wewnętrznego została użyta do zbadania stabilności mikrostruktury poddanych wyciskaniu przez kanał kątowy stali 9Cr1Mo (T91), stopu Fe-18wt%Cr, i czystego W. Zaobserwowano wiele nie-relaksacyjnych pików tarcia wewnętrznego w trzech próbkach odkształconych przez ECAP, które są związane z przejściem ze stanu silnie odkształconego do statycznego stanu zdrowienia dyslokacji, i do stanu zrekrystalizowanego. Wraz z zanikiem piku P1, tylko w przypadku stopu Fe-18wt%Cr obserwowany jest inny pik P2 relaksacji tarcia wewnętrznego podczas drugiego ogrzewania, i nie znika nawet w kolejnym trzecim etapie ogrzewania. Pik ten nie jest obserwowany w stali T91 i W. Pik P2 prawdopodobnie związany jest procesem poślizgu granicy ziaren. W przeciwieństwie do stali T91, brak bogatych w węglik wydzieleń na granicach ziaren, które by unieruchomiły granice i uniemożliwiły poślizg, stąd pik P2 występuje tylko w przypadku stopu Fe-18wt.%Cr. Stwierdzono, że pomiary tarcia wewnętrznego w wysokiej temperaturze są potrzebne, aby wykryć pik granicy ziarna w czystym W.

14

Electrostatic Hazards Assessment of Nitramine Explosives: Resistivity, Charge Accumulation and Discharge Sensitivity

75%

Peng Q. , Cao W. , Zhou W. , He Z. , Jiang W. , Chen W.

Central European Journal of Energetic Materials

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2016

|

tom Vol. 13, no. 3

755--769

EN

The electrostatic hazards of nitramine explosives (RDX, HMX) were assessed in this paper. The resistivities of different particle-size RDX and HMX were tested by a device designed and manufactured according to the standard ISO/IEC 80079-20-2:2016. This work shows that the resistivities of uncompacted RDX and HMX increase as the particle size decreases. Charging characteristics test experiments were also carried out using a so-called sieve method. Using this method, the influence of aperture size on charge accumulation of RDX was studied, and the characteristics of electrostatic accumulation of different particle-size RDX and HMX sieved with 50 mesh standard sieve were compared. The results show that the absolute value of the charge accumulation increases as the mesh number increases (i.e. the aperture size decreases), and increases as the particle size is decreased, indicating that nano-sized RDX and nano-sized HMX accumulate static electricity more easily than conventional micron-sized ones. Finally, the electrostatic discharge (ESD) sensitivity of nano-sized RDX and nano-sized HMX was investigated. Nano-sized nitramine explosives were found to have a higher ESD sensitivity than micron-sized ones.

15

Characterization and expression analysis of the maize RING-H12 finger protein gene ZmXERICO responsive to plant hormones and abiotic stresses

75%

Gao Y. , Li H. , Deng D. , Chen S. , Jiang W. , Chen J.

Acta Physiologiae Plantarum

|

2012

|

tom 34

|

nr 4

EN

Really interesting new gene (RING)-H2 proteins are widely represented in plants and play important roles in the regulation of many developmental processes as well as in plant–environment interactions. In the present report, a full-length cDNA encoding a putative RING-H2 protein with high sequence homology to Arabidopsis thaliana RING-H2 gene XERICO, designated as ZmXERICO, was isolated from maize. The full-length cDNA of ZmXERICO contained a 435 bp open reading frame encoding a precursor protein of 145 amino acid residues. Comparative and bioinformatics analyses revealed that ZmXERICO showed a high degree of homology with RING-H2 proteins and contained the transmembrane domain (TM) and RING-H2 motif. In our study, ZmXERICO was analyzed for expression profiles in various organs (root, stem, leaf, stamen, pistil and seed) and responding to exogenous hormone treatment and abiotic stresses using real-time PCR. The results showed that the expression of ZmXERICO was different regulated after treated by gibberellins acid-3 (GA₃) and GA biosynthetic inhibitor paclobutrazol between in light and darkness. Moreover, the expression of ZmXERICO under different abiotic stresses was analyzed at different time points. The ZmXERICO was up-regulated in salt, drought, abscisic acid and cold stress. These expression results suggested that ZmXERICO played an important role in plant hormones signal pathways and light signal pathways, and that ZmXERICO might be involved in plant defense system against environmental stresses in maize.

16

An efficient regeneration system via direct and indirect organogenesis for the medicinal plant Dysosma versipellis (Hance) M.Cheng and its potential as a podophyllotoxin source

75%

Jiang W. , Chen L. , Pan Q. , Qiu Y. , Shen Y. , Fu C.

Acta Physiologiae Plantarum

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2012

|

tom 34

|

nr 2

EN

Dysosma versipellis (Hance) M. Cheng is an endangered plant due to overharvesting for the extraction of podophyllotoxin. Thus, the in vitro technique is valuable for the propagation of this species. When the explants of rhizome buds were cultured on Murashige and Skoog’s (MS) medium with 6-benzyladenine (BA) (1.0 mg l⁻¹), gibberellic acid (GA₃) (0.5 mg l⁻¹) and zeatin (Zea) (0.5 mg l⁻¹), multiple buds were regenerated directly on the explants without callusing within 6 weeks. Callus was induced from the leaf segment cultures on MS basal medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) (0.5 mg l⁻¹) and BA (0.2 mg l⁻¹) within 4 weeks. The adventitious buds were differentiated when the calli were subcultured on MS medium supplemented with BA (1.0 mg l⁻¹) and thidiazuron (TDZ) (0.2 mg l⁻¹) within 6 weeks. The adventitious buds obtained from callus and the rhizome-buds rooted with a frequency of 100% on half strength MS medium fortified with indole-3-butyric acid (IBA) 0.5 mg l⁻¹ and activated charcoal (AC) 0.5 g l⁻¹ for 4 weeks. The rooted shoots were successfully transplanted from a mixture of vermiculite:soil (1:1 v/v) to the field with a survival rate of 85%. Podophyllotoxin production in calli, cultured rhizomes, rhizomes of transplanting plants from the garden and rhizomes in the wild field was confirmed by high-performance liquid chromatography (HPLC) analysis. Our results suggest that calli, cultured rhizomes and rhizomes of transplanting plants would be the potential sources of podophyllotoxin.

17

Effect of hydroxyl radical on the scission of cellular wall polysaccharides in vitro of banana fruit at various ripening stages

75%

Cheng G. , Duan X. , Yang B. , Jiang Y. , Lu W. , Luo Y. , Jiang W.

|

nr 2

EN

Fruit ripening is generally attributed to disassembly of cellular wall, particularly due to solubilisation and depolymerisation of pectin and hemicellulose. Experiments were conducted to test effects of hydroxyl radicals (OH) on the scission of cellular wall polysaccharides from pulp tissues of banana fruit at different ripening stage. Cellular wall materials were isolated from pulp tissues of banana fruit at different ripening stages. Two pectic fractions, water soluble pectin (WSP) and acid soluble pectin (ASP), and two hemicellulosic fractions, 1 M KOH soluble hemicellulose (HC1) and 4 M KOH soluble hemicellulos (HC2), were obtained from the cellular wall materials from pulp tissues, respectively. Effects of OH induced by the Fenton reaction on the scission of pectin and hemicellulose in vitro were investigated. As fruit ripening progressed, the sugar components of the WSP, HC1 and HC2 attacked by OH showed obvious molecular-mass downshifts. Thus, OH caused the disassembly of polysaccharides (WSP, ASP, HC1 and HC2) from cellular walls of pulp tissues of banana fruit, demonstrated by the reduced molecular mass distribution. Moreover, OH production in pulp tissues increased significantly as banana fruit ripened, which further help account for the role of OH in accelerated fruit ripening.

18

Effects of aluminum on nucleoli in root tip cells, root growth and the antioxidant defense system in Vicia faba L.

75%

Zhang H. , Zhang S. , Meng Q. , Zou J. , Jiang W. , Liu D.

Acta Biologica Cracoviensia. Series Botanica

|

2009

|

tom 51

|

nr 2

99-106

EN

The effects of different concentrations of Al (10 μM, 50 μM, 100 μM) on nucleoli in root tip cells, root growth, antioxidant enzyme activity and malondialdehyde (MDA) content were investigated in hydroponically grown Vicia faba L. Aluminum significantly inhibited root growth of V. faba treated with 50 μM and 100 μM Al. In the nucleolus in root tip cells, some particulates containing argyrophilic proteins were extruded from the nucleus into the cytoplasm, and some were scattered in the nucleus after Al stress. Superoxide dismutase (SOD) activity in leaves and roots exposed to different concentrations of Al was mostly higher than in the control. Seedlings exposed to 100 μM Al showed significantly higher peroxidase (POD) activity in roots than in the control. POD activity increased much more in roots than in leaves. Catalase (CAT) activity was lower in roots than in leaves. Malondialdehyde (MDA) content in leaves and roots of plants exposed to 50 μM and 100 μM Al was significantly higher than in the other groups and the control at 6 to 9 days of treatment. These results suggest that alterations in nucleoli and altered antioxidant enzyme activity and MDA content in V. faba can serve as useful biomarkers for detection of Al toxicity. The mechanisms of Al toxicity and tolerance in V. faba are briefly discussed

19

Protein interactions of SOC1 with SVP are regulated by a few crucial amino acids in flowering pathways of Brassica juncea

75%

Li C. , Gu H. , Jiang W. , Zou C. , Wei D. , Wang Z. , Tang Q.

Acta Physiologiae Plantarum

|

2019

|

tom 41

|

nr 04

EN

SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) is a vital flowering signal integrator to promote flowering, which is inhibited by a MADS-box transcription factor, SHORT VEGETATIVE PHASE (SVP). However, it remains elusive about how SOC1 interacts with SVP in flowering pathways of Brassica juncea. Here, B. juncea SOC1 (BjuSOC1) gene was cloned and it expressed differently between stem apexes and leaves during the low-temperature vernalization and long-day photoperiod pathways. Yeast two-hybrid and BiFC assays indicated that BjuSOC1 directly interacted with BjuSVP in vitro and in vivo. Interestingly, further studies indicated that mutants of BjuSOC1K108V, BjuSOC1R109L, BjuSOC1C137K could no more interact with BjuSVP, and BjuSVPR137L also led to loss of the protein interaction. It suggested that the 108th, 109th, and 137th of BjuSOC1 and 137th of BjuSVP regulated the protein interactions between BjuSOC1 and BjuSVP. The results provided valuable information for further study on the control of flowering time in B. juncea.

20

Cd subcellular localization in root tips of Hordeum vulgare

63%

Shi Q. , Wang J. , Zou J. , Jiang Z. , Wang J. , Wu H. , Jiang W. , Liu D.

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nr 2

EN

The effects of Cd on the subcellular localization in root tip cells of Hordeum vulgare were investigated by Energy dispersive x-ray analysis (EDXA) in order to further understand Cd toxic mechanisms in plants. EDXA showed that Cd ions were localized in meristem, elongation, and mature zone in the root tips. In transverse section of the mature zone, Cd was accumulated in epidermal, cortical, and vessel cells, and the level of Cd is in the order: epidermal cells < vessel cells < cortical cells. In cortical cells Cd ions were observed in cytoplasm and walls.