Effect of Phytoaccumulation of Arsenic and Chromium on Structural and Ultrastructural Changes of Brake Fern (Pteris vittata)

Abstract

structural and ultrastructural changes caused by bioaccumulation of as and cr in brake fern (Pteris vittata), a known arsenic hyperaccumulator, were investigated. Potted plants of brake fern were exposed to metal treatments of as and cr for three weeks. leaf, stem and root samples were collected periodically and fixed for lM (light Microscopy), seM (scanning electron Microscopy) and teM (transmission electron Microscopy) to evaluate anatomical changes. the fresh weights, dry weights, rWc (relative Water content) and plant heights were obtained before the brake fern plants were harvested for metal accumulation analysis. the as accumulated mainly in the shoots while cr accumulated mainly in the roots of the metal-treated plants. significant changes in the ferns physical characters, including fresh weight, dry weight, rWc, and plant height were observed for only cr-treated plants but not for as-treated plants. Microscopic studies reveal the cr accumulation resulted in dehydration and collapse of internal structure of leaves and cellular breakdown of roots. the as-treated plants showed no significant structural changes in leaves, stems and roots compared to control plants. clotted depositions were observed in roots and stems of plant groups treated with highest concentration of cr and as when compared to control (t0) group. Our study indicates that cr has a profound impact on physiology and structure of fern plants. the accumulation of cr resulted in decrease in growth rate, total biomass and rWc. We believe that brake fern plants can uptake, translocate and sequester as because it caused no significant structural changes in leaves, stems and roots of the plants.

Arsenic toxicity in Acacia mangium willd. and mimosa Caesalpiniaefolia benth. seedlings

“…However, the determination of the quantity and quality of these compounds required to improve As resistance will need further studies. Sridhar et al (2011) observed clumpy deposits on the roots and stem of As-contaminated Pteris vittata, a hyperaccumulating fern. The authors suggested these deposits could be related to a detoxification mechanism.…”

Arsenic accumulation in Brassicaceae seedlings and its effects on growth and plant anatomy

“…According to Sridhar et al (2011) andDe Temmerman et al (2004), species that are sensitive to pollutants translocate low amounts of them to the shoots when compared to hyperaccumulator ones. In addition to the low arsenic amounts that were detected in the shoots, the studied species presented anatomical alterations and growth decrease.…”

Quantification of inorganic arsenic exposure and cancer risk via consumption of vegetables in southern selected districts of Pakistan

“…As is released from both natural sources (parent rocks) and also from various anthropogenic activities such as agricultural practices, irrigation with As-contaminated water (Waqas et al, 2015), the improper applications of arsenical fertilizers, insecticides, herbicides, use of poultry litter with As-based intestinal palliatives (Jia et al, 2012; Oti, 2015; Zhu et al, 2008), mining activities, and petroleum refineries (Martínez-Sánchez et al, 2011; Khan et al, 2014; Kabata-Pendias, 2011). Soil is a major sink of As, which can lead to contamination of vegetables because of its high mobility and uptake rate (Sridhar et al, 2011). The bioavailability of As and its subsequent bioaccumulation in vegetables (tomato, cucumber, cauliflower, pea, lettuce, spinach, cabbage, onion, radish, turnip, carrot, potato, etc) depend on soil texture, pH, organic matter content and composition, redox condition, water regime, mineral composition, and microbial activity (e.g., Bergqvist et al, 2014; Khan et al, 2015a; Smith et al, 2009).…”