Phytotoxicity and Accumulation of Antibiotics in Water Lettuce (Pistia stratiotes) and Parrot Feather (Myriophyllum aquaticum) Plants under Hydroponic Culture Conditions

The aim of this research was to investigate the accumulation of antibiotics in two kinds of plants. The hydroponic culture solution included a mixture of antibiotics, including three commonly used antibiotics in South Korea: norfloxacin (NOR), sulfamethazine (SMZ), and tetracyclines (TC). None of these antibiotics were detected in the shoots of water lettuce plants, only in the roots. However, in parrot feather plants, antibiotics were detected in both the shoots and the roots, with higher amounts detected in the shoots than in the roots. SMZ and TC were most likely to be detected in the roots and shoots of water lettuce and parrot feather plants, and about one-third of the NOR administered was later detected in the plants. The BCF (bioconcentration factor) of antibiotics ranged from 0.24 to 0.78, while that of NOR was much lower, ranging from 0.24 to 0.38. The SMZ (0.59–0.64) and TET (0.72–0.78) exhibited higher uptake accumulation in the water lettuce tissues compared with the parrot feather plants.

Separate and Combined Effects of Chlortetracycline and Oxytetracycline on Growth and Antioxidant Enzymes in Myriophyllum Aquaticum

As two typical tetracyclines, chlortetracycline (CTC) and oxytetracycline (OTC) coexist widely in water. In the experiment, Myriophyllum aquaticum (Vell.) Verdc was exposed to the orthogonal hydroponic environment with the concentrations of CTC and OTC at 1, 10, and 50 mg/L for 7 days (7 D) and 14 days (14 D). The results showed that the plant height, relative growth rates (RGR), and photosynthetic pigment contents of M. aquaticum decreased significantly after 14 D of CTC/ OTC, which was stronger than that after 7 D, and the toxicity of CTC was stronger than OTC. The combined toxicity of the two on the RGR and total chlorophyll content was mainly synergistic or additive after 7 D. After 14 D, the interaction changed to antagonism or addition, and the response of total chlorophyll content was more obvious than that of RGR. After 7 D of combined treatments, the malondialdehyde (MDA) content decreased significantly, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities responded to different combined concentrations, respectively, and CAT was the main protective enzyme of M. aquaticum. After 14 D of combined treatments, the hydrogen peroxide (H2O2) content increased significantly, the MDA content increased first and then decreased, and POD was the main protective enzyme among the three antioxidant enzymes. Overall, this study provided the first insight into the single and combined toxicity of CTC and OTC on the growth and physiology of M. aquaticum at different time periods, revealing the reversal of the combined toxicity with time of exposure.

Invasive alien plant species in Romania of European Union concern

An assessement of the alien plants of Romania was conducted which considered the requirements of Regulation 1143/2014 of the European Union (EU). Thus, available data about the presence, invasiveness, distribution, pathways of introduction and their known impact in the territory of Romania were analysed. We found that of 36 plant species of EU concern, four are already established in Romania and widespread, at least locally or regionally: Ailanthus altissima, Asclepias syriaca, Elodea nuttallii and Impatiens glandulifera. For Humulus scandens there are some reports, but its presence and status require confirmation. Heracleum sosnowskyi and Ludwigia peploides are confirmed for only one location for each species. The presence of Cabomba caroliniana and Myriophyllum aquaticum in Romania is not confirmed. Most of the records are intentional introductions for ornamental purposes. Regarding their invasiveness, given the geographical origin and history of invasion in warmer climate regions (e.g., tropical, subtropical), many of the species listed as being of EU concern do not currently constitute a real threat to Romania, for the time being, but may do in a climate change scenario for the 2070s. Data about the impact of alien plant species and their management in Romania are scattered or completely missing. Coordinated institutional efforts are needed to increase the efficiency of the management of alien species at national and local level. These efforts should include: enhancing the legislation and the capacity of public institutions to manage invasive species, increasing the research interest in the science of this topic and promoting real measures to mitigate, control and remove alien plants.

Improving Plant-Based Genotoxicity Bioassay for Trace Metal-Contaminated Water: Insights from Myriophyllum Aquaticum (Vell.) Verdc. and Cd.

In this work, we evaluated whether the species Myriophyllum aquaticum (Vell.) Verdc. can be a promising material for devising reliable ecotoxicological tests for Cd contaminated waters. Plants of M. aquaticum were exposed to Cd, using different concentrations and exposure times, in order to address as many possible effects as possible of its presence. Plant growth and Cd accumulation were monitored along the treatment period and Cd genotoxicity was assessed by analyzing Cd-induced changes in the AFLP fingerprinting profiles. Root and shoot growth was reduced already at the lowest Cd concentration used (1 mg L-1). Shoots showed a higher Cd sensitivity and a lower accumulation, thus being chosen as the more suitable organ for the genotoxic analysis. DNA variation was observed starting from 2.5 mg L-1, indicating that the metal-induced depression of plant growth at the lower concentration did not necessarily imply a genotoxic effect. Similar results were obtained in the time-dependent experiment, since Cd effect on DNA fingerprinting profile was observed after three days of exposure and without a significant growth decrease growth. Therefore, our results showed that M. aquaticum proved to be a suitable model system for the investigation of Cd genotoxicity through AFLP fingerprinting profile, whereas the more classic eco-toxicological tests based only on biometric parameters could underestimate the risk associated to undetected Cd genotoxicity.

Myriophyllum aquaticum (parrot's feather).

M. aquaticum (parrot-feather) is an invasive submerged/emergent aquatic weed characteristic of sub-tropical to warm-temperate regions, but found as far north as the UK (recorded from at least 33 countries: native to perhaps 6 of these, all in South America). It was recorded as an alien as early as 1906 in Florida, and 1919 in South Africa. It is a particular problem of small water bodies, irrigation channel networks, and small streams, where it primarily impedes flow and causes a range of associated environmental problems, such as water deoxygenation. Long-distance spread via the aquarium/garden trade has been a notable anthropogenic vector. Once introduced to a new region it spreads rapidly, primarily by vegetative stem fragmentation, male plants are rarely recorded outside the native range so seed production is (so-far) negligible as a vector. It is listed as a notifiable/prohibited weed in many countries and states worldwide.