Effects of some pretreatments on seed germination of nine different drought-tolerant shrubs

This study was carried out to determine the effects of some pretreatments including soaking in concentrate H2SO4 GA(3). floating in hot water and cold stratification and their combinations on seed germination and to investigate how to overcome dormancy of seeds of some drought-tolerant plants. The species used in this study were Arbutus andrachne L., Cistus creticus L., Colutea armena Bois. Huet., Cotinus coggyria Scop., Coloneaster numullaria Fisch.&Mey., Elaeagnus angustifolia L.. Jasminum fruticans L., Paliurlis spina-christii Mill. and Rhus coriaria L. The seeds were sown in polyethylene pots under greenhouse conditions and on seedbeds under open field conditions. The statistical approach was a randomized complete block design with three replications. The results (highest germination percentage) for each species were as follow: C. creticus; soaking in hot water for I minute both under greenhouse (66.89%) and open field (44.89%) conditions, C. coggyria; soaking ill H2SO4 for 20 minutes with cold stratification for 60 days (87.30%) nuclear greenhouse conditions, C. numullaria: soaking in H2SO4 for 90 minutes with cold stratification for 60 days (53.67%) under greenhouse conditions, J. fruticans; cold stratification for 60 days under greenhouse (85,56%) conditions, E. angustifolia; soaking in running water at 15 degrees C for 10 days with cold stratification for 30 days both under greenhouse (64.26%) and open field (54.89%) conditions. Paliurus spina-christii; soaking in H2SO4 for 40 or 80 minutes both under greenhouse (65.05 or 62.85%) and open field (54.99 or 49.38%) conditions, R. coriaria; soaking in H2SO4, for 30 minutes with cold stratification for 60 days both under greenhouse (54.53%) and open field (39.78%) conditions. None of the treatments that were applied to A. andrachne and C. armena gave statistically significant improvement over the control.