The role of antioxidants, peroxidase and superoxide dismutase, in ameliorating oxidative stress associated with cryopreservation of Tamarindus indica seeds

The present study provides the first report on the cryopreservation of seeds of Tamarindus indica . Intact seeds were dehydrated to a moisture content of 6% (fresh weight basis) before immersion in liquid nitrogen. Following retrieval from cryogenic temperatures, it was apparent that plants regenerated from cryostored seeds displayed delayed germination compared with control seeds. However, this delay was transient and by 30 days, plants from both treatments were at a comparative developmental stage. Evaluation of biochemical indicators (proteins, chlorophyll, products of lipid peroxidation and antioxidants), and calculations of relevant Overall Coefficients of Variation (OCVs), were used to elucidate the mechanisms underlying the results obtained. It was found that levels of peroxidase and superoxide dismutase ( Medium to High OCVs) were elevated in plantlets (up to twofold in the most extreme cases) derived from cryopreserved seeds at 7 and 15 days. By 30 days, the levels of these antioxidants had declined to a range comparable to control plants. Therefore, we propose that the adaptive response of the antioxidant defense system in tamarind seeds played a role ameliorating the damage caused by oxidative stress (inferred by monitoring aldehydes) during cryopreservation.