Arsenic-induced morphogenic response in roots of arsenic hyperaccumulator fern Pteris vittata

• Published in: Journal of hazardous materials 2012-10, Vol.235-236, p.271-278
• Main Authors: Forino, Laura Maria Costantina, Ruffini Castiglione, Monica, Bartoli, Giacomo, Balestri, Mirko, Andreucci, Andrea, Tagliasacchi, Anna Maria
• Format: Article
• Language: English
• Subjects: Applied sciences; Arsenic - pharmacology; As stress; Border-like cells; Cell Differentiation - drug effects; Cell Nucleolus - drug effects; Exact sciences and technology; Morphogenic response; Nucleolus; Phytoremediation; Plant Roots - cytology; Plant Roots - drug effects; Plant Roots - growth & development; Pollution; Pteris - cytology; Pteris - drug effects; Pteris - growth & development; Root hairs; Soil Pollutants - pharmacology
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2012.07.051

► We studied arsenic hyperaccumulation in Pteris vittata starting from the root system. ► As elicited modifications in root hair number, length and differentiation pattern. ► A modulation in nucleolar activity was detected following As treatments. ► As influenced the production of border-like cells, shown for the first time in ferns. ► As-induced morphogenic responses improved the absorbance features of root. On the assumption that arsenic induces stress morphogenetic responses involved in As tolerance and hyperaccumulation in the Pteris vittata fern, we analyzed the root system of young sporophytes grown in 250, 334, and 500μM As for five days and for 14 days. Anatomical and histological analyses were performed in plants grown for five days to evaluate the number, position, length and differentiation pattern of root hairs. AgNOR staining, employed to study nucleolus behavior in root apices, showed that arsenic influences nucleolar activity (evaluated by nucleolus size, number and absorbance) in the root meristem. In plants treated with 250 and 334μM As an acropetal shift of root hair development and an increase in hair length and density were observed, linked to an ectopic pattern of differentiation. The opposite trend was recorded in plants treated with 500μM As. It is worth noting the presence of living border-like cells, not yet observed in ferns, and their increase following As treatments. Analysis and vitality of border-like cells were surveyed after 14 days of treatments. In conclusion As treatments elicited a stress-induced morphogenic response which, by modifying the differentiation pattern, number and length of root hairs, modulating nucleolar activity and interacting with the rhizosphere by inducing border-like cell production, may adjust the rate of root uptake and its metabolic activity.