Abstract
Introduction: Seed deterioration is an inevitable physiological process that gradually reduces seed quality, germination capacity, seedling establishment, and final crop productivity. This process is mainly associated with biochemical and structural alterations such as membrane degradation, increased lipid peroxidation, enzyme inactivation, and depletion of storage reserves. In oilseed crops such as canola (Brassica napus L.), seed deterioration represents a major limitation to achieving optimal field performance and stable yield. Therefore, identifying simple, low-cost, and effective strategies to mitigate its adverse effects is of great importance. Seed priming is widely recognized as an efficient approach to improve seed performance under both optimal and stressful conditions. Among different priming agents, B vitamins have received increasing attention due to their central roles as coenzymes in metabolic pathways, including energy production, amino acid metabolism, nucleic acid synthesis, and antioxidant regulation. Despite these physiological roles, comparative evidence on the effectiveness of different B vitamins in alleviating seed deterioration effects remains limited, particularly under varying levels of aging stress.
Materials and Methods: The present study was conducted to investigate the effects of seed priming with B vitamins on physiological, biochemical, and yield-related traits of canola under different levels of seed deterioration. Laboratory and field experiments were carried out at Shahrood University of Technology using a factorial experiment based on a randomized complete block design with three replications. Treatments included three levels of seed deterioration (0, 50, and 100 hours of accelerated aging at 40°C) and seven priming treatments consisting of non-primed control, distilled water, and 100 mg L⁻¹ solutions of thiamine (B1), riboflavin (B2), pantothenic acid (B5), pyridoxine (B6), and niacin (B3). Seeds were primed prior to sowing under controlled conditions. Measured traits included chlorophyll a, carotenoids, grain yield, seed oil content, and seed protein content. Standard agronomic and physiological measurements were recorded and statistically analyzed to determine treatment effects and interactions.
Results: The results indicated that seed deterioration significantly affected most of the studied traits. Increasing deterioration levels led to a marked reduction in chlorophyll a and carotenoid content, indicating impairment of the photosynthetic system. Grain yield also decreased substantially from 158.44 g m⁻² in non-deteriorated seeds to 89.40 g m⁻² and 87.60 g m⁻² under 50 and 100 hours of accelerated aging, respectively. Similarly, seed oil content decreased by approximately 16% under severe deterioration compared with the non-deteriorated control. Protein content also declined progressively with increasing seed deterioration, demonstrating a negative impact on seed quality and nutritional value. Seed priming with B vitamins improved grain yield across all deterioration levels compared with the non-primed control. All vitamin-based priming treatments resulted in significant increases in grain yield, indicating their beneficial role in enhancing crop performance under both normal and deteriorated seed conditions. However, the magnitude of response varied depending on the level of seed deterioration and the specific physiological trait. In particular, seed protein content showed differential responses to priming treatments across deterioration levels. Under severe deterioration conditions, all priming treatments increased protein content compared with the non-primed control, whereas under non-severe conditions, the responses were more variable and depended on the type of vitamin applied.
Conclusion: seed deterioration had a pronounced negative effect on physiological traits, grain yield, and seed quality in canola. Seed priming with B vitamins partially mitigated some of these adverse effects; however, its effectiveness was not uniform across all traits and was strongly dependent on the severity of seed deterioration. While significant improvements were observed in grain yield and protein content under specific conditions, the response pattern was trait-dependent rather than universal. These findings suggest that B-vitamin seed priming can be considered a supportive agronomic strategy to improve the performance of deteriorated seeds, although it does not fully reverse the negative impacts of aging. Further studies are recommended to investigate the underlying physiological and molecular mechanisms, including antioxidant activity, metabolic regulation, and gene expression responses, as well as to optimize priming protocols for field application under diverse environmental conditions. Overall, the findings of this study indicate that seed exhaustion and pretreatment each independently affect some physiological, qualitative, and functional traits, and the type of plant response to pretreatments depends on the trait under study and the severity of deterioration.