Study on germination and key enzymatic and non-enzymatic antioxidants involved in chickpea seed ageing during natural storage and accelerate ageing

Unfavorable environmental conditions and seed storage can cause some stresses such as oxidative stress in seeds and other plant tissues by reactive oxygen species production. ROS defense network, composed of antioxidant enzymes, antioxidants and ROS-producing enzymes, is responsible for maintaining ROS levels under non-toxic tight control. In plant cells, non enzymatic antioxidant as proline and ascorbic acid and antioxidant enzymes, such as superoxide dismutase, peroxidase, catalase, ascorbat peroxidase and glutathione reductase are considered to form a defensive team, whose combined purpose is to protect cells from oxidative damage. So this experiment laid out to study on effect of accelerate and natural ageing on enzymatic and non enzymatic antioxidant systems in chickpea seeds.
Material and The study was laid out in order to evaluate the effects of artificial ageing and natural storage on enzymatic and non enzymatic antioxidant systems in chickpea seeds in Gorgan University of Agricultural Science and Natural Resources at 2015. The experiment was conducted in completely randomized design with four replications. Treatments were 2 and 4 year natural storage as long term storage and 1-5 day artificial aging with control. For accelerated aging the seeds were placed in polyethylene dishes, on metal sieve into water bath at 43°C, and relative humidity of 100% for 1-5 days. For natural aging seeds was stored for two and four years at natural condition. After treatments, germination and, enzymatic and non enzymatic antioxidant activities measured. Statistical analysis was performed by SAS software.
Results showed that, in accelerated ageing condition, with increasing of ageing days, germination percentage, lipid peroxidation, hydrogen peroxide production and electrolyte leakage increased. Germination percentage in accelerate ageing was lower than natural storage. In lower levels of accelerate ageing until 3 days proline accumulation was higher than natural storage but, in natural storage was higher than 4 and 5 days of accelerate ageing. With increasing of natural storage period proline production increased but ascorbic acid decreased. Ageing changed activity of catalase, peroxidase, ascorbat peroxidase, superoxide dismutase and glutathione reductase enzymes. With increasing of accelerate ageing levels until 3 days catalase, superoxide dismutase and glutathione reductase activity increased. In lower ageing levels peroxidase and ascorbat peroxidase activity increased but in high ageing levels their activity decreased. In natural storage treatments with increasing of storage period catalase activity decreased.
Accelerate and natural ageing comparison showed that lower accelerate ageing levels had damaging on enzymatic and non enzymatic antioxidant systems less than natural storage treatments but in 5 days treatment reactive oxygen species accumulation over come on these systems and do not can to remove them and had more losses than natural storage treatments. In natural storage condition superoxide dismutase and glutathione reductase had more activity than 4 and 5 days accelerate aging and had more efficient than others in removing of reactive oxygen species and slowing of seed ageing. In 4 and 5 days accelerated ageing treatments catalase and peroxidase activity was more than natural storage and had a bold role in this matter