Abstract

Wild pear (Pyrus glabra) is an endemic and medicinally important endangered plant species of Zagros Mountain. Interventions on behalf of conservation are necessary to protect this species. The seeds show very low germination (%), and these low rates represent a major obstacle to successful regeneration. In this study, the viability, germination (%), germination rate, pattern of germination and enzymes activities during seed germination under cold stratification were assessed. The experimental treatments used were cold stratification (CS), CS with cool water for 24 h, CS with gibberellic acid at 1000 ppm and at 1500 ppm for 48 h. The mean seed viability was 42.25 ± 1.9%. The highest germination rate was obtained under cold stratification for a period of 50 days. The activity of catalase was low during germination. Peroxidase activity increased with increasing periods of CS. Amylase activity was always high compared to the other enzymes, which showed a limited range of variation. The best time for germination could be inferred by determining the time at which the enzymatic activities are equal. The study found that the seed dormancy of the wild pear is of the morphological type. The embryo needs a 50-day cold period at a temperature of 5°C to begin germination. The study demonstrated that the low regeneration rate of this species is caused by the low percentage of viable seeds.

Key words: Seed germination, viability, treatments, catalase, peroxidase, amylase.

Abbreviation

CAT, Catalase; H₂O₂, hydrogen peroxide; POD, peroxidase; PD, physiological dormancy; MD, morphological dormancy; PY, physical dormancy; MPD, morpho-physiological dormancy; CS, cold stratification.