Effect of warm stratification, GA3 and H2O2 on seed germination of Caucasian maple (Acer monspessulanum subsp. ibericum M.B.)

In order to break dormancy and germinate the seeds of Caucasian maple, they were collected from altitude of 1900 m of Googli Forest located in Savadkooh (north of Iran). Following pre-treatment of warm stratification (0, 4, 8, 12 weeks with 20°C), the seeds were soaked for 24 hours in two separate examinations 1) GA3 (0, 250, 500, 1000 mg/lit) and 2) H₂O₂ (0, 1, 2, 3%) and immediately moved into cold stratification environment (4°C, for 41 weeks, with consideration of warm stratification period). Both examinations were carried out as factorial with three replicates based on completely randomized design. Water absorption test revealed that in spite of the hard coat, the seeds were permeable to water. Results emphasized the positive effects of warm pretreatment on germination characters, whereas seed germination increased from 13 to 76% and germination speed from 1.4 to 3.8 unit/week. However, the lag time decreased from 20 to 13 weeks and germination period of 50 percent of seeds (T₅₀)from 10 to 6 weeks. Influence of GA3 and H₂O₂ increased with increase of concentration as well as warm stratification period, whereas GA3 in 500 and 1000 mg/lit was 64% and H₂O₂ in 2 and 3% was 56 and 73%, respectively. With increasing warm pre-treatment period, the general trend of germination speed enhanced in all concentrations of both promoters. Generally, stratification (warm-cold) without using the promoters mentioned here is easier and more economic for dormancy breaking of Caucasian maple seed.