Promoting Effect of Polyethylene Glycol on the Germination of Celery and Spinach Seeds

Abstract

Effects of benzyl adenine (BA), gibberellic acid (GA₃ or GA₄) and priming with polyethylene glycol (PEG) 6000 on the germination of celery seeds were investigated. In some priming treatments, BA and/or GA were added into the PEG solution. Concentration used for BA and GA were 10ppm and 50ppm respectively.
In spinach seeds, too, germination promotion effects of PEG treatment were studied, and also possibility of storage of seeds air-dried after PEG treatment was investigated.
PEG concentration used were -11.7 bars for celery seeds and -11.83--10.27 bars for spinach seeds.
PEG solution was added to two sheets of blotting paper to full moistening in a Petri dish, and seeds were sown on the blotting paper. After 7 or 14 days of treat ment, seeds were washed with tap water, and sown on the blotting paper moistened with deionized water in a Petri dish, and incubated in a germinator.
Results obtained are summarized as follows:
A. Celery
1. Germination of celery seeds were depressed at the germination temperature above 20°C. BA was much effective in promoting the germination. GA₄ was also effective to some extent, but GA₃ had no effect. Combined treatment of BA and GA₄ was most effective.
2. Priming with PEG solution enhanced the germination speed at 20, 25 and 30°C, and improved germination percentage at 25 and 30°C.
3. Remarkable effect was observed following 7 days of priming with PEG, but the larger effect was obtained by 14 days of priming.
4. As to the treatment temperature, one lot of seeds was favoured by the treatment at 15°C than at 20°C, but another lot of seeds was favoured at 20°C than at 15°C.
5. Treatment under light was more effective in promoting the germination than that under dark.
6. Addition of BA to the PEG solution enhanced the PEG treatment effect, but GA₄ did not.
7. The difference in effectiveness of BA and GA₄ between their use with and without PEG is considered to be due to the difference in treating methods. That is, in the case of treatment without PEG, seeds were continually in contact with such chemical(s) on the blotting paper till the end of germination experiment, but in the case of treatment with PEG, seeds were in contact with such chemical(s) only during the priming period, because seeds were thereafter germinated on the blotting paper moistened with pure water.
B. Spinach.
1. Germination speed of spinach seeds was enhanced by PEG treatments at 20, 25 and 30°C, and germination percentage was improved at 30°C.
2. When PEG-treated seeds were air-dried and stored for 7 or 14 days, germination percentage did not change, and germination speed lowered only a little, showing preservation of priming effect.