Cyclic voltammetry as a method for determining the viability of seeds: a case study on silver maple (Acer saccharinum L.)

Efficient and dependable techniques for determining seed viability are essential in agronomy, forestry, and safeguarding endangered plant species, as seeds represent the most effective way to preserve plant germplasm. Certain seeds can endure preservation for thousands of years, while others may survive only a few weeks. However, all seeds ultimately deteriorate over time during storage. Reactive oxygen species (ROS) and their imbalance with intracellular antioxidants are the primary causes of seed aging and deterioration. Consequently, developing highly effective analytical methods to measure the antioxidant capacity of stored seeds is becoming increasingly critical. This study examines the application of cyclic voltammetry (CV) using a glassy carbon electrode to characterize the antioxidant milieu in aging recalcitrant seeds of Acer saccharinum L. This is a versatile electrochemical method that can be easily applied to investigate a broad range of biological matrices because it does not require redox-active reagents to determine the total antioxidant capacity. Instead, it is explicitly based on the electrochemical behavior of antioxidants in samples and their physicochemical properties. Seed deterioration occurred when A. saccharinum seeds with a high moisture content (MC of 45%) were subjected to accelerated aging at 35 °C for up to 14 days. Oxidative stress and antioxidant depletion were monitored by measuring ROS levels, quantifying antioxidants through the Cu2+ reduction reaction (CUPRAC-BCA) and CV, and evaluating the glutathione half-cell reduction potential (EGSSG/2GSH). Compared with Cu2+ reduction measurements, which yielded misleading results, CV appeared to be a more reliable technique for differentiating seeds based on their total antioxidant capacity. CV measurements of 80% methanolic and 1x PBS extracts were highly correlated with seed viability, observed as total germination (R = 0.92 and 0.86, respectively, p ≤ 0.01 for both solvents). For the first time, we demonstrated a strong correlation between the CV results on the total antioxidant capacity and viability of seeds. This finding suggests that electrochemical techniques can be a quick and efficient method for evaluating seeds prior to germination, potentially from various species. This method enhances seed viability monitoring, achieving 92% accuracy and showing species-agnostic potential, pending validation in lipid-rich seeds.