Here we investigated the impact of nano- and microplastics on the freshwater duckweed species Spirodela polyrhiza, a vascular plant. S. polyrhiza was exposed for 120h to concentrations ranging from 102 to 106 particles·mL-1. We assessed impacts on growth and chlorophyll production, and explored adsorption and absorption by way of confocal microscopy. For both nano- and micronized particles no concentration-dependent impacts on growth were found (expressed as fresh weight, frond and root sizes). In addition, chlorophyll contents were not significantly impacted. Confocal microscopy indicated that nano-sized plastic particles adsorbed externally to the duckweed, especially to the roots. Internalized plastic particles could not be detected. Nevertheless, given their important role in ecosystems as a food source for a range of organisms, the adsorption of plastic particles to S. polyrhiza roots as detected in this study can result in the transfer of plastic particles to diverse herbivorous species within the ecosystem.
chlorophyll measurements
Determination of photosynthetic activity by duckweed (Spirodela polyrhiza) exposed to 50nm and 500nm plastic particles in concentrations of 102, 104 and 106 particles mL-1 for 120 hours. The photosynthetic activity, which was measured through chlorophyll contents, of the exposed duckweed was compared to non-exposed control organisms, with 3 replicates per treatment. The experiment measured the endpoints of chlorophyll a, chlorophyll b and total chlorophyll contents after 120 hours, employing spectrophotometrical determination of absorbance.
chlorophyll.csv
data_dictionary
Data dictionary for all endpoints
freshweight
Growth inhibition study that experimentally exposed duckweed (Spirodela polyrhiza) to 50nm and 500nm plastic particles in concentrations ranging from 102 to 106 particles mL-1 for 120 hours and compared these to non-exposed control organisms, with 8 replicates per exposure treatment. The fresh weight was determined 0 hours and 120 hours of exposure to plastic particles by carefully patting the individual plants dry and subsequently transferring them to an analytical balance with a precision of four decimals.
frond
Growth inhibition study that experimentally exposed duckweed (Spirodela polyrhiza) to 50nm and 500nm plastic particles in concentrations ranging from 102 to 106 particles mL-1 for 120 hours and compared these to non-exposed control organisms, with 8 replicates per exposure treatment. The frond area was recorded at the beginning (0 hours of exposure) and a the end of the experiment (120 hours of exposure) by taking a vertical photograph of the test wells, which were placed onto millimeter paper for scale purposes, with a Nikon D3100 digital single lens reflex camera (Nikon, Miniato, Tokyo, Japan) and a 18-55mm lens (Nikon, Miniato, Tokyo, Japan). The frond area was determined to a precision of four digits on the acquired images using the image analysis software Fiji (Schindelin et al., 2012). Frond numbers were counted manually on the acquired images.
roots
Growth inhibition study that experimentally exposed duckweed (Spirodela polyrhiza) to 50nm and 500nm plastic particles in concentrations ranging from 102 to 106 particles mL-1 for 120 hours and compared these to non-exposed control organisms, with 8 replicates per exposure treatment. The root length was recorded at 0 hours and 120 hours of exposure by transferring single plants onto millimeter paper and taking a vertical photograph using a USB microscope (Dino-Lite USB, AnMo Electronics Corporation, New Taipei City, Taiwan). The root length was measured with a precision of four digits on the acquired images employing Fiji (Schindelin et al., 2012), and the root number was determined manually.
Dovidat et al Metadata
Metadata file
