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Effects of TiO_2 nanoparticles on the aquatic plant Spirodela polyrrhiza: Evaluation of growth parameters, pigment contents and antioxidant enzyme activities

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Journal of Environmental Sciences 2018年第2期30卷 130-138页

作者： Ali Movafeghi Alireza Khataee Mahboubeh Abedi Roshanak Tarrahi Mohammadreza Dadpour Fatemeh Vafaei Department of Plant Biology Faculty of Natural Sciences University of Tabriz Research Laboratory of Advanced Water and Wastewater Treatment Processes Department of Applied Chemistry Faculty of ChemistryUniversity of Tabriz Department of Materials Science and Nanotechnology Near East University Department of Horticultural Science Faculty of Agriculture University of Tabriz

Plants are essential components of all ecosystems and play a critical role in environmental fate of nanoparticles. However, the toxicological impacts of nanoparticles on plants are not well documented. Titanium dioxide nanoparticles（TiO2-NPs） are produced worldwide in large quantities for a wide range of purposes. In the present study, the uptake of TiO2-NPs by the aquatic plant Spirodela polyrrhiza and the consequent effects on the plant were ***, structural and morphological characteristics of the used TiO2-NPs were determined using XRD, SEM, TEM and BET techniques. As a result, an anatase structure with the average crystalline size of 8 nm was confirmed for the synthesized TiO2-NPs. Subsequently, entrance of TiO2-NPSto plant roots was verified by fluorescence microscopic images. Activity of a number of antioxidant enzymes, as well as, changes in growth parameters and photosynthetic pigment contents as physiological indices were assessed to investigate the effects of TiO2-NPs on S. polyrrhiza. The increasing concentration of TiO2-NPs led to the significant decrease in all of the growth parameters and changes in antioxidant enzyme activities. The activity of superoxide dismutase enhanced significantly by the increasing concentration of TiO2-NPs. Enhancement of superoxide dismutase activity could be explained as promoting antioxidant system to scavenging the reactive oxygen species. In contrast, the activity of peroxidase was notably decreased in the treated plants. Reduced peroxidase activity could be attributed to either direct effect of these particles on the molecular structure of the enzyme or plant defense system damage due to reactive oxygen species.

关键词： TiO2 nanoparticles Spirodela polyrrhiza Growth parameters Antioxidant enzymes pigment contents

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Effects of heavy metals (Pb^(2+) and Cd^(2+)) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

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Chinese Journal of Oceanology and Limnology 2009年第2期27卷 383-388页

作者： K. K. I. U. Arunakumara 张学成 College of Marine Life Sciences Ocean University of China Department of Crop Science Faculty of AgricultureUniversity of Ruhuna

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉（0, 0.5, 1, 2, 4, 6 and 8 mg/L）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/L Pb^2＋） metal concentration. The photosynthetic apparatus （thylakoid membranes） were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration （8 mg/L pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. Lethal concentration （96 h LC50） values （3.47 mg/L Cd^2＋ and 12.11 mg/L Pb^2＋） indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.

关键词： growth pigment contents Synechocystis sp. PCC 6803 ultrastructure

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In situ hyperspectral data analysis for pigment content estimation of rice leaves

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Journal of Zhejiang University Science 2003年第6期4卷 727-733页

作者：程乾黄敬峰王秀珍王人潮 InstituteofAgriculturalRemoteSensing＆InformationApplication ZhejiangUniversityHangzhou310029China

Analyses of the correlation between hyperspectral reflectance and pigment content including chlorophyll a, chlorophyll b and carotenoid of leaves in different sites of rice were reported in this paper. The hyperspectral reflectance of late rice during the whole growing season was measured using a Spectroradiometer with spectral range of 350-1050 nm and resolution of 3 nm. The chlorophyll a, chlorophyll b and carotenoid contents in rice leaves in rice fields to which different levels of nitrogen were applied were measured. The chlorophyll a content of upper leaves was well correlated with the spectral variables. However, the correlation between both chlorophyll b and caroteniod and the spectral variables was far from that of chlorophyll a. The potential of hyperspectral reflectance measurement for estimating chlorophyll a of upper leaves was evaluated using univariate correlation and multivariate regression analysis methods with different types of predictors. This study showed that the most suitable estimated model of chlorophyll a of upper leaves was obtained by using some hyperspectral variables such as SD r, SD b and their integration.

关键词： pigment contents Hyperspectral reflectance Rice leaves Correlation

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In situ hyperspectral data analysis for pigment content estimation of rice leaves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2003年第6期4卷 106-112页

作者：程乾黄敬峰王秀珍王人潮 Institute of Agricultural Remote Sensing & Information Application Institute of Agricultural Remote Sensing & Information Application Zhejiang University China Hangzhou 310029

关键词： pigment contents Hyperspectral reflectance Rice leaves Correlation

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