Improvement of pea (Pisum sativum) seed vigour response by fish protein hydrolysates in combination with acetyl salicylic acid

Acetyl salicylic acid (ASA) and fish protein hydrolysate (FPH) were used for stimulation of vigour of pea (Pisum sativum) seeds. Pea seeds were pre-hydrated in water which contained 50 mu M of ASA, 2 ml 1(-1) of FPH (standardized mackerel hydrolysates) and 2 ml 1(-1) of a combination of ASA and FPH (ASA/FPH) for 24 h and followed by germination in potting soil for 5 and 10 days. After 5 and 10 days, the average plant height and weight increased in plants with FPH and ASA/FPH treatments, but decreased slightly in plants with ASA treatment. After 10 days, the average plant height with FPH and ASA/FPH treatments increased by 9% (23.3 mm) and 11% (28.8 mm) respectively, while the average fresh weight of seedling increased by 15% (13 mg) for both treatments, respectively. The average phenolics content and guaiacol peroxidase (GPX) activity of pea seedling increased following ASA and FPH treatment alone on day 5. Antioxidant activity in all pea seedlings was high on day 10 compared to day 5. On either day there were no difference in antioxidant activity between treatments. Glucose-6-phosphate dehydrogenase (G-6-PDH) activity and free proline content were higher on day 5 than on day 10. The average G-6-PDH activity in pea seedling treated with FPH and ASA/FPH was higher than ASA and control treatments. The plant response to ASA/FPH was better than FPH treatment alone. These results suggest that combination of 50 mu M of ASA and FPH with the concentration of 2 ml 1(-1) (ASA/FPH) can enhance seed performance of peas according to some criteria of seedling vigour and thus have potential for use as a seed treatment. (C) 1999 Elsevier Science Ltd. All rights reserved.