Effects of Seed Priming Treatments on Germination and Seedling Growth of Common Vetch (Vicia sativa L.) Under Arsenic Stress

In this study, the inhibitory effects of increasing arsenic concentrations (0, 1, 2, 3 mg L-1) on the germination and early seedling development of common vetch (Vicia sativa L. cv. "Gülhan") seeds were determined. Furthermore, the potentials of hydropriming and gibberellic acid (GA3 5 mg L-1) seed priming treatments to mitigate heavy metal toxicity and preserve plant growth parameters were comparatively evaluated. The petri experiment was conducted in a factorial arrangement based on a Completely Randomized Design, where germination characteristics, seedling morphology, and biomass accumulation traits were assessed at the end of a 14-day incubation period. The experimental results revealed that the Pre-treatment x Arsenic Dose interaction had significant (p < 0.01) effect on all evaluated morphological and physiological parameters. Arsenic stress, in the unprimed hydropriming group, suppressed the final germination rate to 84.4%, while drastically reducing root length (2.20 cm at 2 mg L-1 arsenic dose) and net dry weight (0.28 g at 3 mg L-1 arsenic dose). Conversely, GA3 priming successfully maintained the final germination rate at 94.8% even under the highest arsenic dose (3 mg L-1), exhibiting a protective effect by preserving root length (4.40 cm) and total seedling length (8.90 cm). Within the scope of Principal Component and Cluster Analyses (PCA and HCA), the Ward dendrogram and biplot presentations confirmed the segregation of the dataset into two distinct homeostatic clusters designated as "Metabolic Stability" and "Physiological Collapse." Multivariate analyses further demonstrated that GA3-primed seedlings grouped within the same tolerance cluster as the non-stressed control plants despite the presence of arsenic, whereas the germination speed index operated via an independent physiological dynamic separate from subsequent seedling growth stability. In conclusion, it was determined that GA3 seed priming is an effective and practical agronomic strategy for alleviating arsenic heavy metal phytotoxicity and sustaining biomass stability in common vetch seedlings.