Monday, November 13, 2006

Biochemical Stress Responses in Arsenic Hyperaccumulator Fern Pteris vittata: A Comparative Greenhouse Study Using Organic and Inorganic Arsenical Pesticides.

Chacharee Therapong, Rupali Datta, Dibyendu Sarkar, and Devanand Pachanoor. The University of Texas at San Antonio, 6900 N. Loop 1604 West, San Antonio, TX 78249

Arsenic (As) contamination in soil occurs from both natural sources and anthropogenic activities.  Use of arsenical pesticides in agriculture is a major public health concern because As has been identified as a class A human carcinogen by USEPA.  The use of plants to clean up As contaminated soils has recently gained increased attention because it is relatively inexpensive and environment-friendly compared to other traditional methods such as soil washing and excavation.  Chinese Brake fern Pteris vittata is a known As hyperaccumulating plant due to its capacity to take up and accumulate high levels of As from soils. In this study, As stress response of Chinese Brake fern to organic and inorganic arsenical pesticides was investigated.  A greenhouse column was set up to evaluate the uptake and antioxidant response of Chinese Brake fern to arsenical pesticides sodium arsenate and dimethylarsinic acid (DMA) added at two concentrations: 150 and 350 mg As/kg.  All the treatments were conducted in triplicates.  The plants were harvested after a growth period of 6 months. Growth parameters such as biomass and root and shoot lengths were monitored in control and arsenical pesticide treated plants.  Arsenic accumulation in plant tissue was analyzed using GFAAS.  Activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and Glutathione peroxidase (GPx) were determined.  Results indicate the important role of antioxidant enzymes in As tolerance and accumulation in Chinese Brake fern.

Handout (.pdf format, 6513.0 kb)