Root architecture and morphometric analysis of Arabidopsis thaliana grown in Cd/Cu/Zn-gradient agar dishes: A new screening technique for studying plant response to metals

• Published in: Plant physiology and biochemistry Vol. 91; pp. 20 - 27
• Main Authors: Bochicchio, Rocco, Sofo, Adriano, Terzano, Roberto, Gattullo, Concetta Eliana, Amato, Mariana, Scopa, Antonio
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01-06-2015
• Subjects: Agar - chemistry; Arabidopsis - drug effects; Arabidopsis - growth & development; Arabidopsis thaliana; Cadmium; Cadmium - chemistry; Copper; Copper - chemistry; Indoleacetic Acids - chemistry; Metals - chemistry; Plant Roots - drug effects; Plant Roots - growth & development; Reactive Oxygen Species - chemistry; Roots; Seedlings - drug effects; Seedlings - growth & development; Soil Pollutants - chemistry; Stress-induced morphogenic response; Zinc; Zinc - chemistry; Arabidopsis thaliana; Cadmium; SE; Arabidopsis; Roots; ROS; IAA; Copper; SIMR; Stress-induced morphogenic response; Zinc
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2015.03.010

A new screening strategy using Petri dishes with a gradient of distances between germinating seeds and a metal-contaminated medium was used for studying alterations in root architecture and morphology of Arabidopsis thaliana treated with cadmium, copper and zinc at sub-toxic concentrations. Metal concentrations in the dishes were determined by anodic stripping voltammetry on digested agar samples collected along the gradient, and kriging statistical interpolation method was performed. After two weeks, all agar dishes were scanned at high resolution and the root systems analyzed. In the presence of all the three metals, primary root length did not significantly change compared to controls, excepting for zinc applied alone (+45% of controls). In metal-treated seedlings, root system total length increased due to the higher number of lateral roots. The seedlings closer to the agar sectors including metals showed a marked curvature and a higher root branching in comparison to those further away from the metals. This behavior, together with an observed increase in root diameter in metal-treated seedlings could be interpreted as compensatory growth, and a thicker roots could act as a barrier to protect root from the metals. We therefore propose that the remodeling of the root architecture in response to metals could be a pollution ‘escaping strategy’ aimed at seeking metal-free patches.
•We studied root responses of Arabidopsis to Cd, Cu and Zn at sub-toxic concentrations.•An innovative screening strategy using Petri dishes with special metal gradients was used.•Metal content in dishes, and root architecture and morphology were measured and analyzed.•A strong and specific remodeling of the root architecture in response to metals occurred.