We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Mechanistic insights into the size-dependent bioaccumulation and phytotoxicity of polyethylene microplastics in tomato seedlings
AI summary Read the abstract
Researchers investigated how polyethylene microplastics of different sizes affect tomato seedlings and found that the smallest particles (1-50 micrometers) caused the most severe damage, reducing shoot weight by 42.3% and root length by 55.1%. The study revealed that microplastic uptake and toxicity are strongly size-dependent, with smaller particles more easily absorbed and translocated through plant tissues, triggering significant oxidative stress.
Microplastic (MP) contamination in agricultural soils poses a growing threat to crop health, yet the size-dependent mechanisms governing their uptake and phytotoxicity remain poorly understood. This study investigated the physiological and biochemical responses of tomato (Solanum lycopersicum L.) seedlings exposed to polyethylene (PE) microplastics of four distinct particle sizes at a constant mass concentration (1% w/w): T1 (1-2 mm), T2 (0.2-1 mm), T3 (50-200 μm), and T4 (1-50 μm). Results showed that PE exposure significantly inhibited plant growth in a size-dependent manner. The T4 treatment (1-50 μm) caused the most severe phytotoxicity, reducing shoot fresh weight by 42.3% and total root length by 55.1% compared to the control, indicating that micro-sized particles severely restrict root system expansion. This growth retardation was accompanied by aggravated oxidative stress, evidenced by a 263.4% surge in malondialdehyde (MDA) content (reaching 29.8 nmol/g FW) in the T4 group. To mitigate this stress, the antioxidant defense system was significantly activated, with SOD, POD, and CAT activities increasing by 122.2%, 194.1%, and 177.8%, respectively. The bioaccumulation of PE in plant tissues was highly non-linear and fitted well to the Freundlich isotherm model (R2 > 0.97). Notably, the uptake and mobility of MPs were strongly governed by particle size, as reflected by the bioconcentration factor (BCF) and translocation factor (TF). Both indices exhibited a sharp increase as particle size decreased: root BCF surged from 0.016 (T1) to 0.840 (T4), while TF rose from 0.125 to 0.286, confirming the exponentially higher bioavailability and upward translocation potential of micro-sized particles (T4). Physiologically, small-sized MPs (T3, T4) induced non-stomatal limitations to photosynthesis. Furthermore, Variance Partitioning Analysis (VPA) revealed a distinct mechanistic shift around a critical size threshold: while growth inhibition under large-sized MP exposure (T1, T2) was primarily driven by disruptions in indole-3-acetic acid (IAA) homeostasis (explaining 32.4% of variation), the toxicity of small-sized MPs was predominantly governed by oxidative stress responses (explaining 38.6% of variation). These findings highlight that environmental risk assessments based solely on mass concentration may underestimate the hazards of micro-sized fragments, which exert toxicity through fundamentally different physiological pathways compared to larger particles. Ultimately, the identified shifts in hormonal balance and oxidative status provide a valuable mechanistic framework for evaluating the potential impacts of microplastic stress on the nutritional composition and overall quality of tomato fruits in subsequent growth stages.
More Papers Like This
Microplastic accumulation and oxidative stress in sweet pepper (Capsicum annuum Linn.): Role of the size effect
AI summary Read the abstract
Researchers grew sweet peppers in soil containing microplastics of two different sizes and found that smaller particles were taken up and accumulated in the plant roots and stems more readily than larger ones. The microplastics triggered oxidative stress in the plants, with smaller particles causing more damage to the plants' cellular defense systems. This study shows that microplastics in agricultural soil can enter food crops, with smaller particles posing the greatest risk to both plant health and food safety.
Absorption, accumulation, physiological responses, and mechanistic insights into tomato (Solanum lycopersicum L.) to polystyrene microplastics
AI summary Read the abstract
Tomato plants grown with polystyrene microplastics absorbed the particles through their roots and moved them into stems and leaves, with smaller particles and higher amounts building up more. Exposure reduced root growth, plant height and weight, increased oxidative stress markers, and altered gene activity and chemical processes linked to plant hormones and cell membranes.
The dosage- and size-dependent effects of micro- and nanoplastics in lettuce roots and leaves at the growth, photosynthetic, and metabolomics levels
AI summary Read the abstract
Researchers studied the effects of polyethylene micro- and nanoplastics on lettuce plants, varying both particle size and concentration. They found that particle size played a pivotal role in influencing plant growth, photosynthetic activity, and metabolic processes, with nanoplastics generally causing more pronounced effects than larger microplastics. The study suggests that the smallest plastic particles pose the greatest risk to crop health by disrupting plant physiology at multiple levels.
Unraveling the impact of nano-microscale polyethylene and polypropylene plastics on Nicotiana tabacum: Physiological responses and molecular mechanisms
AI summary Read the abstract
Researchers exposed tobacco plants to polyethylene and polypropylene microplastics of different sizes and found that both types suppressed plant growth in a dose-dependent manner, with polypropylene being more toxic. The microplastics disrupted photosynthesis, triggered oxidative stress, and altered hormone signaling and defense pathways in the plants. These findings demonstrate that microplastic contamination in soil can impair crop growth at the molecular level, potentially affecting agricultural productivity.
The multifaceted mechanisms of microplastic inhibition of tomato plant growth: oxidative toxicity, metabolic perturbation, and photosynthetic damage
AI summary Read the abstract
Researchers exposed tomato seedlings to biodegradable and conventional microplastics and investigated photosynthetic performance, metabolic disruption, and oxidative stress responses. Both microplastic types inhibited tomato growth and caused oxidative damage, with impacts on the photosynthetic apparatus and metabolite profiles, challenging the assumption that biodegradable plastics are safer for agricultural systems.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.