Anti-aging applications on seeds of eastern beech (Fagus orientalis L.) and Anatolian black (Pinus nigra Arnold. subsp. pallasiana Lamb. (Holmboe))

Storing seeds of plants, both for short-term and long-term periods, is crucial in bridging the gap between rich harvest years, ensuring effective seed supply to meet the demand. In this regard, optimal storage conditions such as temperature and humidity are critical factors. However, even when seeds are stored under suitable temperature and humidity conditions, they can still undergo oxidative deterioration over time due to natural aging effects, leading to potential deterioration of the seeds. In this context, the inevitable loss of seed viability must be addressed. Therefore, slowing seed deterioration and enhancing seed viability become increasingly important. This study focuses on determining the aging effects in seeds harvested during rich seed years, stored for a specified period to be used for subsequent production planning. The aim is to delay aging effects and improve reduced germination capacity accordingly. In this study, achieving the rejuvenation or restoration of seeds that have aged or experienced reduced germination capacity through different coating materials and priming applications is crucial for sustainable forestry from both biological and economic perspectives. Particularly, in the intermediate seed category, delaying aging and extending storage life are targeted for Oriental beech (Fagus orientalis L.) seeds, while improving germination capacity is aimed for Anatolian black pine (Pinus nigra Arnold. subsp. pallasiana Lamb. (Holmboe)) seeds, which belong to the orthodox seed group and exhibit a slower aging process. For this purpose, in Oriental beech seeds, chitosan (at 0.25%, 0.50%, and 0.75%), chitosan combined with BHT (100 ppm butylated hydroxytoluene) and BHA (200 ppm butylated hydroxyanisole), and chitosan with 10% propolis coating materials were used. In Anatolian black pine seeds, priming (seed pre-treatment) materials included chitosan (at 0,25%, 0,50%, and 0,75%), humic acid (at 3%, 6%, and 12%), and seaweed extract (at 0,30%, 0,60%, and 1,20%). Analysis conducted on Oriental beech seeds revealed that during storage, electrical conductivity (EC), malondialdehyde (MDA), and hydrogen peroxide (H2O2) levels increased in the control group seeds over time. Conversely, there was a significant decrease observed in total oil content, total phenolic compounds, total free radical scavenging activity (DPPH assay), total soluble protein, and superoxide dismutase (SOD) enzyme activities. In addition, it was observed that the aging process in Anatolian black pine seeds progressed slowly over long-term storage. In this context, analysis of aged seeds (harvested in 2006) revealed an increase in electrical conductivity (EC), malondialdehyde (MDA), and hydrogen peroxide (H2O2) levels, as well as in superoxide dismutase (SOD) and peroxidase (POD) enzyme activities. Conversely, a decrease was noted in catalase (CAT) enzyme activity, total soluble protein, total oil content, total phenolic compounds, and DPPH (free radical scavenging) activity. The coating materials used in Oriental beech seeds were found to have a significant effect in delaying aging, with chitosan identified as particularly effective among these materials. In Anatolian black pine aged seeds, chitosan application significantly increased both the rate and percentage of germination compared to the control group seeds. Conversely, seaweed extract application was found to significantly reduce the average germination time compared to the control.