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Song R.,Henan Agricultural University | Song R.,Key Laboratory of Crop Physiological Ecology and Farming System | Zhao C.-Y.,Henan Agricultural University | Zhao C.-Y.,Key Laboratory of Crop Physiological Ecology and Farming System | And 13 more authors.
Acta Physiologiae Plantarum | Year: 2013

The effect of sulphate nutrition on arsenic (As) concentration, photosynthetic and chlorophyll fluorescence parameters of rice was investigated in hydroponically grown rice seedlings (Oryza sativa L.), using three sulphate levels (1.8 μM, 0.7 mM, or 1.5 mM). The results showed that sulphate deficiency decreased As accumulation in root, but increased the translocation of As from root to shoot. Sulphate deficiency reduced maximum quantum yield (Fv/Fm), minimum fluorescence and electron transport rate (ETR) of a dark-adapted leaf. Compared with low sulphate treatments (1.8 μM), significant increases were observed in the parameters of rapid light curves, rETRmax and I k of photosystem I (PSI) and photosystem II (PSII) of rice grown in the high sulphate treatments (1.5 mM) regardless of As additions. Therefore, an adequately high sulphate supply may result in less As translocation from root to shoot, and protecting the reaction pathways of PSI and PSII of rice seedlings grown in higher As-contaminated medium. © 2013 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków. Source


Gao L.,University of Sichuan | Tang Y.,University of Sichuan | Bossard C.,Saint Marys College of California | Wang Y.,Jiuzhaigou Administrative Bureau | Han Z.,Zealquest Scientific Technology Co.
Journal of Mountain Science | Year: 2011

This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates (ETR max) were measured as rapid light curves (RLCs) by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 °C. Nonphotochemical quenching (NPQ) of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield (F v/F m) of submerged marestail in Five Colored Lake showed full recovery at 1700 h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highest in Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant's ecophysiological reactions. © 2011 Science Press and Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg. Source


Hong-Ying H.,South China Normal University | Hong-Ying H.,Xiangnan College | Wen-Ling L.,South China Normal University | Li-Ying S.,South China Normal University | And 4 more authors.
Pakistan Journal of Botany | Year: 2010

cpr5 is predicted to be a putative transmembrane protein involved in several cellular processes, including signal transduction plant defense and trichome development. The mutation of the cpr5 gene increases the resistance of Arabidopsis to pathogens. In this study, we show an In vitro increased resistance of cpr5 leaves to hydrogen peroxide-induced photooxidation. Both fluorescence parameters (including Fv/Fm, φPSII, qP and NPQ) and the activities of two anti-oxidative enzymes (SOD and APX) were used to evaluate the response of mutant and wild-type leaves to H2O2 treatment. During a 360-min., treatment, both mutant and wild-type leaves showed a time course dependent decrease trend in Fv/Fm values. However, the decrease rate for mutant leaves (0.046/min) was nearly twenty five-fold lower than that for wild-type leaves (0.101/min). The leaves of cpr5 dramatically delayed the reduction of φPSII values and showed a different profile of φPSII from the wild-type. At 240 min., of treatment, the value of φPSII for the mutant leaves was nearly six-fold as that of the wild-type. The rates of cellular membrane leakage were constitutively lower in the cpr5 leaves than in the wild-type. In addition, the cpr5 leaves showed slightly higher activities of the SOD and APX enzymes than did the wild type. These results indicated that cpr5 mutant increased both anti-oxidative capability and the stability of PSII to H2O2-induced photooxidation. Source


Zhou Q.,CAS Wuhan Institute of Hydrobiology | Zhou Q.,University of Chinese Academy of Sciences | Chen W.,CAS Wuhan Institute of Hydrobiology | Zhang H.,Zealquest Scientific Technology Co. | And 6 more authors.
Journal of Environmental Sciences (China) | Year: 2012

A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W × 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3×104 cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 μm in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium. © 2012 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Source

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