scholarly journals Photosystem II of barley seedlings under cadmium and lead stress

2008 ◽  
Vol 53 (No. 12) ◽  
pp. 511-516 ◽  
Author(s):  
H.M. Kalaji ◽  
T. Loboda
Keyword(s):  
Heavy Metals ◽  
Photosystem Ii ◽  
Reaction Centers ◽  
Tolerance Mechanism ◽  
Energy Fluxes ◽  
Cadmium Treatment ◽  
Fluorescence Measurements ◽  
Stress Application ◽  
Cadmium And Lead ◽  
Specific Reactions

Chlorophyll a fluorescence measurements were carried out on two barley (<I>Hordeum vulgare</I> L.) cultivars Arabi Abiad and Arabi Aswad at 8 and 14 days after emergence to identify their early tolerance mechanism for heavy metals (25 and 50&mu;M of cadmium and lead). Transient fluorescence curves (OJIP curves) and energy flux models showed different specific reactions of photosystem II (PSII) of each cultivar to each type of stress. After 7 days of lead stress application plants of cv. A. Aswad showed weaker I and P peaks on the OJIP curve than control plants, and the appearance of a new K step; parameters of phenomenological energy fluxes for cv. A. Abiad were similar to those for control plants and only some silent reaction centers appeared. Generally, parameters of energy fluxes within PSII were directly shifted shortly (24 h) after the application of both heavy metals, especially in the case of plants grown under cadmium treatment. This suggests that these parameters could be good indicators for monitoring of these two pollutants in the environment at early stages of plant development.

Multiple Effects of Cadmium on the Photosynthetic Apparatus of Avicennia germinans L. as Probed by OJIP Chlorophyll Fluorescence Measurements

2007 ◽  
Vol 62 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
Daniel Gonzalez-Mendoza ◽  
Francisco Espadas y Gil ◽  
Jorge M. Santamaría ◽  
Omar Zapata-Perez
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Water Splitting ◽  
Performance Index ◽  
Photosynthetic Apparatus ◽  
Reaction Centers ◽  
Avicennia Germinans ◽  
Fluorescence Measurements ◽  
Active Reaction ◽  
Primary Photochemistry

Abstract The toxic effects of cadmium on the photosynthetic apparatus of Avicennia germinans were evaluated by means of the chlorophyll fluorescence transient O-J-I-P. The chlorophyll fluorescence transients were recorded in vivo with high time resolution and analyzed according to the OJIP-test that can quantify the performance of photosystem II. Cadmium-treated plants showed a decrease in yield for primary photochemistry, TR0/ABS. The performance index of photosystem II (PSII), PIABS, decreased due to cadmium treatment. This performance index is the combination of the indexes of three independent parameters: (1) total number of active reaction centers per absorption (RC/ABS), (2) yield of primary photochemistry (TR0/ABS), and (3) efficiency with which a trapped exciton can move an electron into the electron transport chain (ET0/TR0). Additionally, the F0/Fv registered the highest sensitivity to the metal, thus indicating that the water-splitting apparatus of the oxidizing side of PSII is the primary site of action of cadmium. In summary, cadmium affects several targets of photosystem II. More specifically the main targets of cadmium, according to the OJIPtest, can be listed as a decrease in the number of active reaction centers and damage to the activity of the water-splitting complex.

scholarly journals Concentration of cadmium and lead in vegetables and fruits

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Rusin ◽  
Joanna Domagalska ◽  
Danuta Rogala ◽  
Mehdi Razzaghi ◽  
Iwona Szymala
Keyword(s):  
Heavy Metals ◽  
Fruits And Vegetables ◽  
Significant Risk ◽  
Absorption Spectrometry ◽  
Food Groups ◽  
Chemical Contamination ◽  
Fresh Frozen ◽  
Processed Products ◽  
Cadmium And Lead ◽  
Vegetables And Fruits

AbstractChemical contamination of foods pose a significant risk to consumers. A source of this risk is due to the consumption of products contaminated with heavy metals such as cadmium (Cd) and lead (Pb). The aim of the study was to research the levels of Cd and Pb contamination of selected species of vegetables and fruits in the form of fresh, frozen, dried and processed products. The goal was to verify which of these food groups was more contaminated with heavy metals. The study covered 370 samples of fruits and vegetables including apples, pears, grapes, raspberries, strawberries, cranberries, as well as beetroots, celeries, carrots and tomatoes. The content of Cd and Pb was determined by atomic absorption spectrometry. Quantitative results were analyzed using statistical models: analysis of variance, outlier analysis, post-hoc multiple comparison Tukey test. The tests showed that the levels of Cd and Pb concentration in samples of fresh, processed, frozen and dried fruits and vegetables varied substantially. The highest concentrations were recorded in dried products. Several fruit and vegetable samples exceeded the maximum permissible concentrations of Cd and Pb. The contamination of these products could be a significant source of consumer exposure to heavy metals when these products are a part of the diet.

Mechanism of photoinduced electron transfer in photosystem II reaction centers

BIOPHYSICS ◽  
2007 ◽  
Vol 52 (1) ◽  
pp. 40-45 ◽  
Author(s):  
I. B. Klenina ◽  
W. O. Feikema ◽  
P. Gast ◽  
M. G. Zvereva ◽  
I. I. Proskuryakov
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Photoinduced Electron Transfer ◽  
Reaction Centers

scholarly journals The Uptake Mechanism of Cd(II), Cr(VI), Cu(II), Pb(II), and Zn(II) by Mycelia and Fruiting Bodies ofGalerina vittiformis

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Dilna Damodaran ◽  
Raj Mohan Balakrishnan ◽  
Vidya K. Shetty
Keyword(s):  
Heavy Metals ◽  
Heavy Metal Stress ◽  
Life Forms ◽  
Metal Stress ◽  
Fruiting Bodies ◽  
Tolerance Mechanism ◽  
Cellular Mechanisms ◽  
Uptake Mechanism ◽  
Cadmium Lead ◽  
Analytical Tools

Optimum concentrations of heavy metals like copper, cadmium, lead, chromium, and zinc in soil are essential in carrying out various cellular activities in minimum concentrations and hence help in sustaining all life forms, although higher concentration of these metals is lethal to most of the life forms.Galerina vittiformis, a macrofungus, was found to accumulate these heavy metals into its fleshy fruiting body in the order Pb(II) > Cd(II) > Cu(II) > Zn(II) > Cr(VI) from 50 mg/kg soil. It possesses various ranges of potential cellular mechanisms that may be involved in detoxification of heavy metals and thus increases its tolerance to heavy metal stress, mainly by producing organic acids and phytochelatins (PCs). These components help in repairing stress damaged proteins and compartmentalisation of metals to vacuoles. The stress tolerance mechanism can be deduced by various analytical tools like SEM-EDX, FTIR, and LC-MS. Production of two kinds of phytochelatins was observed in the organism in response to metal stress.

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