Germination responses to GA3 and short-time chilling of three endemic species: Tripleurospermum pichleri, Cirsium leucopsis and Senecio olympicus (Asteraceae)

Abstract

In the present study, the germination characteristics of three endemic species from Turkey, Tripleurospermum pichleri (Boiss.) Bornm., Cirsium leucopsis D.C and Senecio olympicus Boiss. (Asteraceae), were investigated. Germination was studied for fresh seeds, for seeds subjected to short-time chilling (15 days, moist +4 degrees C), to GA(3) (100, 150 and 250 ppm) and a combination of chilling and GA(3); in all cases seeds were incubated either at 20/10 degrees C day/night with light daytime or at 20 degrees C in darkness with daily short-time dim light (DSDL). In C. leucopsis seeds, all GA(3) treatments enhanced the final germination percentages. The mean germination time (MGT) of C. leucopsis was lower under DSDL than with photoperiod. The chilling treatment with GA(3) in DSDL significantly increased germination in S. olympicus seeds (from 45 to 87%). Germination increased to 55% in T. pichleri by chilling under photoperiod compared with 32% by chilling followed by DSDL. In conclusion, these three co-existing endemic Asteraceae species have different germination behaviours; something that should be taken into account for ex situ propagation. However, an efficient way to germinate all species is to use 250 ppm GA(3) and 20/10 degrees C with photoperiod.