## 4 Discussion
### Sinapis Alba L. Response to LDPE Microplastic: Petri Dish Experiment  
In our study, the Petri dish experiment seed germination of _S. alba_ was evaluated across three treatment groups, Control (0% LDPE) and two concentrations of LDPE MPs (0.01% and 1%). After seven days of exposure, the germination percentage was 92% for Control, 94% for LDPE 0.01% treatment, and 90% for 1% LDPE treatment. The higher GSI values in this experiment were calculated in the Control treatment, followed by 0.01% LDPE MP and 1% LDPE MP treatments. In sprout height, no statistically significant differences of LDPE MP between the two concentration treatments in the Petri dish experiment were found.  
Plant responses to microplastic exposure appear to be highly species-specific, with studies reporting a range of physiological effects. For example, wheat (_Trticulum aestivum_) has exhibited reduced germination rates in the presence of MPs, while cress (_Lepidium sativum_) showed delayed germination, attributed to MP particles obstructing water uptake through essential seed capsule pores [5; 23]. The effect of microplastics on the germination process is also time-dependent. A significant decrease in germination was observed in the first 8 h after exposure of _L. sativum_ seeds to larger (4800 nm) particles and higher concentrations (\(10^{7}\)) of MPs, compared to particles of 50 nm and a concentration of \(10^{3}\). A negative effect of MPs on germination rate disappeared in the following 24 h. A delay in germination in the first 8 h was probably due to physical obstruction. Although MP particles were observed on the surface of cress roots and root hairs, this had no effect on root growth [5], which is in line also with our study where particles were observed on the surface of roots and roots hair. In addition, other influencing factors such as seed quality, room temperature, and errors in the preparation of the experiment may also affect seed germination, GSI, and sprout development. In other research, the type and size of microplastics significantly influence their impact on germination rates. The authors in [57] report that MPs with a particle size of 100 nm significantly reduced seed germination in  
\begin{table}
\begin{tabular}{c c c c} \hline
**Comparison** & **Estimate** & **Lower CI** & **Upper CI** \\ \hline LDPE 1\%–Control & \(-0.3114\) & \(-10.608\) & \(0.4380\) \\ LDPE 5\%–Control & \(-0.4473\) & \(-12.219\) & \(0.3273\) \\ LDPE 5\%–LDPE 1\% & \(-0.1359\) & \(-0.9029\) & \(0.6311\) \\ \hline \end{tabular}
\end{table}
Table 3: [PERSON]’s test for differences in root length between treatments in the pot experiment.  
wheat (_T. aestivum_ L.) compared to larger particles measuring 5 \(\upmu\)m. Additionally, the concentration of MPs in soil plays a critical role, with studies indicating a dose-dependent relationship, where higher MP levels were linked with more noticeable negative effects. In a study on lettuce (_Lactuca sativa_ L.), increasing MP concentrations led to reductions in plant weight, height, root length, and leaf number [15]. Effects of 1% concentration of three MP polymers on rice (_Oryza sativa_ L.) growth over a 15-day period revealed inhibited root elongation, reduced shoot height, and decreased rice fresh weight [45].  
These outcomes highlight the complexity of plant-MP interactions and suggest that the impact of MPs is not uniform across species. Consequently, there is a critical need for broader, species-diverse investigations to comprehensively assess the ecological implications of MP contamination [5; 40].