Changes in the growth and antioxidant enzyme activity of seedlings originating from wheat seeds subjected to accelerated ageing test

Abstract

Abstract. The objective of this study was to investigate the reaction processes of seedlings originating from wheat seeds after they were subjected to accelerated ageing, which imitated low-temperature storage. Germination, vigor, morphological characteristics, relative chlorophyll content and antioxidant enzyme activity were measured in seedlings and young plants of wheat (Triticum aestivum L.) after processes of accelerated ageing of the seeds. The ageing procedures of the seeds were done according to the standard conditions (40±0.5°C and 100% air relative humidity) of the International Seed Testing Association for 72 and 120 hours of treatments of the Bulgarian varieties Geya-1 and Sadovo 772. For the control were used seeds, which were not subjected to the accelerated ageing conditions. The coleoptile of 5 days seedlings and second leaf of 10 and 15 days plants in seedling stage, following the seed accelerated ageing procedure, was measured in the laboratory and the greenhouse. The seed germination rate and vigor, fresh and dry weight of growing coleoptiles were inhibited after different periods of ageing exposure and well correlated with increased accumulation of total hydrogen peroxide, malondialdehyde content, guaiacol peroxidase activity and rate of cells membrane stability index. The negative changes of chlorophyll content index, fresh and dry weight and leaf area of the leaves of young plants descending from aged seeds sowed in pots were found. It was established that the modern variety Geya-1 was more tolerant to the applied ageing condition than the older Sadovo 772. In conclusion, we considered that accelerated ageing could be used as a model for estimation of seed deterioration in wheat after long-term storage.