Abstract

Sunflower (Helianthus annuus L. cv. Morden) seeds lose viability at a rapid pace under accelerated ageing (AA) condition. Pretreatment of the seeds with salicylic acid and ascorbic acid for 8 h before imposition of accelerated ageing treatment in desiccator (99.1% RH and 32 ± 2°C) or continuous treatment of the seeds with Eucalyptus oil vapour for 60 days in a separate desiccator under the same ageing condition slowed down the ageing-induced rapid loss of germination. Plant performance was found to be much better when they were developed from seeds which underwent chemical pretreatment measured in terms of field emergence capacity, root length, shoot length, fresh weight and dry weight of plants. Plant potential was also higher in the pretreatments as evidenced from the treatment-induced higher chlorophyll, protein, DNA and RNA levels as well as activities of catalase and peroxidase enzymes in spite of adverse storage situation. Yield attributes like diameter and fresh weight of capitulum, seed number per capitulum, 1000 seed weight were found significantly higher in plants raised from pretreated seed samples. Results, therefore, pointed out that in spite of experiencing accelerated ageing treatment, the chemical-pretreated seeds retained higher seed vigor and produced healthier plants which resulted in enhancement of crop yield.

Key words: Eucalyptus oil, accelerated ageing, ascorbic acid, salicylic acid, seed viability, sunflower, yield.