Microbiological Processes of Submicrometer Plastics Affecting Submerged Plant Growth in a Chronic Exposure Microcosm

Abstract

Laboratory microcosms were designed to investigate the chronic influence of sedimental submicrometer plastics (sMPs) on the growth of an aquatic submerged plant, Vallisneria denseserrulata, and the involved microbiological processes. A dose− response experiment (0−1000 μg/g) showed that the growth of V. denseserrulata was not affected by 8-week exposure to sedimental sMPs (100 and 1000 nm) until the dose reached 1000 μg/g (i.e., 0.1% w/w) in wet sediment. The observed-effect dosage of 0.1% w/w sMPs significantly suppressed the plant height and biomass of V. denseserrulata by 19.19−22.26% and 10.81−15.80%, respectively. Changes in rhizosphere microbial community structure were detected under the observed-effect dosage, with relatively higher community diversity and weaker conflicting interaction. Sedimental sMPs decreased the stochasticity ratio of rhizosphere microbial community assembly by 11.0−27.7% compared with the control group. Furthermore, functional analysis showed that the ecological processes related to the carbon and nitrogen cycle were suppressed at the observed-effect dosage, among which phototrophy, nitrogen fixation, and nitrate reduction were significantly decreased by 68.30%, 23.56%, and 17.59%, respectively. Our results revealed the responses of an aquatic plant to sedimental sMPs exposures, and the adverse impacts of sMPs were associated with the ecological assembly processes of the rhizosphere microbial community.

Can “Risk-Sharing” Mechanisms Help Clonal Aquatic Plants Mitigate the Stress of Nanoplastics?

“…In this study, the high concentration of NPs significantly decreased the petiole diameter by 30%. Similar results were also obtained for the root diameter and volume of barley were reduced (exposed to 100 mg L −1 polystyrene NPs), 57 the plant height of Vallisneria denseserrulata was decreased (exposed to 1000 μg/g polystyrene NPs), 18 and the shoot length of Myriophyllum spicatum was reduced (exposed to the 3% sediment dry weight of polystyrene NPs). 14 Detrimental environmental conditions can significantly impact the metabolic state and energetic balance of photosynthetic organisms.…”

“…Adsorption and disturbance of NPs by root hairs can affect the plant basic metabolism 53 and ultimately lead to a reduction in biomass. Similar appearances were detected among Arabidopsis thaliana, 54 Lemna minor, 21 and Vallisneria denseserrulata 18 exposed to micro/nanoplastics. A concentration of >1000 mg L −1 of micro/nanoplastics significantly increased shoot biomass by 21%.…”

“…For instance, 0.1% w/ w of submicrometer plastics in sediment significantly decreased the biomass of submerged aquatic plants (Vallisneria denseserrulata), and suppressed the functions of the carbon and nitrogen cycles. 18 Due to polystyrene NP internalization, the overproduction of reactive oxygen species (ROS) induced in aquatic emergent plants might cause dysfunction of microbial nitrogen metabolism in constructed wetlands. 19 In addition, polystyrene NPs negatively affect functional genes related to nitrogen cycling in sludge, which in turn affects the nitrogen conversion efficiency.…”

“…What are the effects of NPs on nutrient cycling and individual growth in the cloning system? For instance, 0.1% w/w of submicrometer plastics in sediment significantly decreased the biomass of submerged aquatic plants ( Vallisneria denseserrulata ), and suppressed the functions of the carbon and nitrogen cycles . Due to polystyrene NP internalization, the overproduction of reactive oxygen species (ROS) induced in aquatic emergent plants might cause dysfunction of microbial nitrogen metabolism in constructed wetlands .…”

Diseased-induced multifaceted variations in community assembly and functions of plant-associated microbiomes

“…This is inconsistent with the prediction of the Anna Karenina principle, which suggested that the microbiome of diseased hosts may display greater compositional or functional variation compared to healthy ones (Arnault et al, 2023 ). Environmental perturbations such as pathogen invasion could lead to the development of new niches, and microbes nearby could then colonize the rhizosphere opportunistically, resulting in higher beta diversity (Macke et al, 2017 ; Yu et al, 2020 ; Lin et al, 2022 ).…”