Improvement of seed germination, growth and biochemical characteristics of Borage (Borago officinalis L.) seedlings with seed priming under cadmium stress conditions

In order to investigate the effect of hormones and hydropriming on seed germination, growth and biochemical characteristics of borage seedlings under cadmium stress, a factorial experiment based on a completely randomized design was carried out with three replications. The experimental factors were cadmium stress (zero, 10, 50 and 100 mg/L) and seed Priming (hydropriming for 48 hours, hormonepriming with 150 ppm gibberellin for 48 hours, 4 mM salicylicacid concentration for 60 hours and control.The results showed that the percentage and rate of seed germination, seedling length and dry weight and peroxidase and catalase enzymes activity of seedling were decreased under cadmium stress, which indicates the negative effect of cadmium on seed germination, growth and antioxidant enzymes activity of borage seedling. Also, cadmium stress was led to significantly increased proline and percentage of abnormal seedlings. Hormone and hydropriming under cadmium stress conditions. Among the primed seeds, the highest germination rate, seedling length and dry weight and proline were obtained from seeds primed with of 4 mM salicylicacid for 60 hours, which was significantly higher than those of the control. For there more, at all levels of cadmium stress, seed priming with 150 ppm gibberellin for 48 hours, caused increase 2.25 fold 14.3 and 1.6 fold 1.85 in the activity of catalase and peroxidase enzymes respectively as compared to control. Generally, seed priming was reduced the negative effects of cadmium stress through increasing seed vigor and improving the biochemical properties of seedlings, and led to improve the seed germination and seedling growth under favorable and cadmium stress conditions.