Effects of moist chilling, gibberellic acid, and scarification on seed dormancy in the rare endemic Pedicularis olympica (Scrophulariaceae)

Authors: SERAP KIRMIZI, GÜRCAN GÜLERYÜZ, HÜLYA ARSLAN, FATMA SELCEN SAKAR

Abstract: We investigated the germination requirements of a rare endemic plant species, Pedicularis olympica Boiss. (Scrophulariaceae), which grows in wet habitats on Uludağ Mountain, Turkey. We studied the effects of scarification, moist chilling (+4 °C) for 15 days, different doses of gibberellic acid (GA_{3}; 100, 150, and 250 ppm) and combined hormone and moist chilling treatments under dark (20 °C) and photoperiod (20/10 °C; 12/12 h, respectively) conditions. GA_{3} was able to break dormancy. The highest germination rate was found in the seeds treated with 250 ppm GA_{3}; 64% of these seeds germinated when treated with moist chilling and incubated in the dark, while 75% germinated under photoperiod conditions. Moreover, mean germination times were significantly lower in the seeds treated with 250 ppm GA_{3}. Significant differences in final germination percentages and mean germination times were found only for treatments under photoperiod conditions. Scarification also permitted germination; the highest germination rate (78%) was found with 15 min of scarification. Dormancy was not broken by moist chilling for up to 90 days. The germination requirements of dormant P. olympica seeds are found to be consistent with characteristics of its habitat. This can be considered an ecological advantage for the species^{'} establishment and persistence.

Keywords: Seed dormancy, Pedicularis olympica, endemic, stratification, gibberellic acid, scarification

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