Plastic particles and their additives promote plant invasion through physicochemical mechanisms on seed germination

Plant invasions pose a major threat to terrestrial biodiversity, and microplastic pollution in soil could exacerbate this problem. Seed germination, a crucial stage for plants, can be affected by microplastics through both physical interference of plastic particles and chemical leaching from plastic additives. We conducted a greenhouse experiment using native and invasive plant species of European grasslands, and evaluated individual and combined effects of plastic particles and additives on germination parameters. We found that plastic particles primarily affected seed germination as physical agents, while additives from these particles exerted a comparatively lesser impact. Particles negatively affected seed germination of all native species. Germination velocity, synchrony and total germination decreased by ~30%, ~11% and ~11%, respectively, in soils containing plastic particles compared to those without. Certain species were negatively affected by plastic additives. For Achillea mil..., We performed an experiment in a glasshouse under controlled conditions. 
Plastic was cut and sieved through a 1 mm mesh to produce microplastic films ~1 mm² in size and then exposed to UV-C for degradation. Microplastic films was mixed with water and incubated for 15 days at 40°C to extract the additives (water-extractable additives). We thus have the following treatment: Plastic particles, additives, plastic particles+ additives, and a control without microplastics. Then, we collected grassland soil and mixed it with the plastic at a 0.4% of concentration, according to the treatments. Seeds of 4 natives species and 3 invasive species were sown and their germination was recorded. At the end of the experiment, we calculated different germination parameters., , # Plastic particles and their additives promote plant invasion through physicochemical mechanisms on seed germination

[https://doi.org/10.5061/dryad.w6m905qzr](https://doi.org/10.5061/dryad.w6m905qzr)

## Description of the data and file structure

We collected germination of seeds of native and invasive species of grasslands environment. We did so in soil mixed with pieces (particles), additives, (particles and additives), and in control soil without microplastics added. We registered the germination every two days for until 64 days. 

### Files and variables

#### File: germ\_counts\_p\_day\_Lena\_FU.csv

**Description:** 

##### Variables

* pot: Experimental unit 
* treatment: We summarized the 4 treatments used: pieces (particles), additives, particles+ additives, and control.
* pieces: It refers to the particles from where the additives were extracted. This is the physical effect of microplastics. 
* additives: It refers to the additives extracted from the plastic particles. This...