The Effect of Gibberellic Acid and Stratification On

The dormancy characteristics and optimum conditions for seed germinationof alstroemeria ligtu had not been explained. in vitro and in vivo alstroemeria(a. ligtu hybrid) seed germination tests were conducted in a randomized completelydesign at two different treatments (gibberellic acid (ga3) 0, 100, 200and 400 mg/l with and without stratification in 5±1°c) in four replications.seeds were planted in the soil mixture (peat/sand/perlite 1:1:1) or 1/2 msmedia (1% sucrose, 0.7% agar and ph to 5.8). after 3-weeks keeping in thestratification conditions, transferred to the growth chamber (21°c and 16hphotoperiod). shoot and root length, number of root and leaf, root and shootfresh and dry weight, seed germination percentage, germination rate and meangermination time were recorded during experiment. stratification had a significanteffect on seed germination (p < 0.05). soaking for 24 h in 100 mg/l ga3supplemented with stratification under in vitro and in vivo conditions increasedgermination up to 76.67% and 70.00%, respectively. mean germination time(mgt) decreased with duration of stratification and concentration of ga3.seeds treated with 100 mg.l-1 ga3 plus 21 days of stratification produced theseedlings with the higher number of leaf, length of shoot, shoot and root dryweight in both in vivo and in vitro conditions. non-stratified seeds without ga3application fail to germinate, whereas seeds chilled for 21 days had 36.6%,40.0% germination under in vivo and in vitro, respectively. stratification wassuccessful in breaking seed dormancy; stratification at 5±1°c for 21 days or100 mg/l ga3+21 days of stratification overcame seed dormancy and increasedthe germination percentage of a.ligtu hybrid seeds. thus, seeds of a.ligtuhybrid species probably exhibit a combination of physiological dormancy. ingeneral, in vivo germination rates were lower than in vitro rates.