engleski

Application of low-cost sensor systems in Lemna toxicity tests

The relation between respiration and photosynthesis reflects the exchange of CO2 with the atmosphere in plants. Until now, only a few studies have measured whole-plant or plant-community CO2 release/uptake directly and continuously without disturbances. Although the methods implemented in these studies are of high accuracy, they are still cost ineffective, require complex experimental setups, and provide discrete and discontinuous output data. This work presents an application of real-time continuous monitoring of the emission and uptake rate of CO2 in Lemna toxicity test, implementing a low-cost Arduino platform-based respiratory activity measuring system prototype (ResTox). Lemna plants were cultured and maintained as described in standard protocols. Each experimental set consisted of six test chambers (including control) for each test compound and one reference chamber. In each chamber containing culturing medium 21 fronds were placed. The plants were exposed to known concentrations of toxicants: metals and herbicides. Metal treatments consisted of Hg, Cu, Cd and Co, while herbicides chosen were diquat, tembotrione, nicosulfuron and clopyralid. Concentration ranges were chosen based on preliminary tests. The experimental setup was kept in darkness for 3h, and during that time respiratory activity was recorded. During the next 3h period the lights were switched on and CO2-assimilation was recorded. All measurements were made with an Arduino platform-based respiratory activity measuring system for real-time emission/uptake CO2 measurements, a prototype developed and assembled by the research team. Measurements of CO2 concentrations were reported as dynamic curves. The results of CO2 measurements demonstrated a hormetic effect of examined supstances: low doses of metals and herbicides stimulated CO2 exchange rate, while at high doses they inhibited CO2 exchange rate. The approach presented in this work enabled evaluation of acute toxicity mechanisms using CO2 exchange flux rate as an endpoint during phytotoxicity experiments.

phytotoxicity ; heavy metals ; herbicides ; CO2-sensors

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