Investigation of germination and breaking seed dormancy of three forest species (Tilia playiphylus Scop., Sorbus aucuparia L and Acer monospessulanum L.)

The optimal treatment for breaking dormancy and seed germination of three forest species, Tilia playiphylus Scop. Sorbus aucuparia L and Acer monospessulanum L. were investigated. Largeleaved lime (Tilia playiphylus Scop.)is one of the important trees in North forests of Iran. Different parts of the tree are being used for different purposes. Its seeds don&rsquot germinate easily because of the existence of double dormancy (mechanical and physiological). Population of Montpellier maple (Acer monospessulanum) is decreased recently in west forests of Iran. Seeds of this species are dormant. Wild service tree (Sorbus aucuparia) is native in Europe and west Asia. This plant grows in limited areas of Northern forest of Iran. It&rsquos seeds have dormancy. In this investigation five treatments were applied to seeds of these three species following surface disinfection using 1% sodium hypochlorite. A complete randomizes design with 3 replicates include 25 seeds were used to compare the means treatments include: - 3 and 6 months chilling (4±1°C)on the top of paper or in sand - 2 concentration of gibrellic acid ( 250 and 500 ppm) after stratification - Scarification with concentrated sulfuric acid for 10 or 20 min - Pretreatment of seeds in alternate temperature(15/ 25°C, night/days) for 3 months in sand before chiling - Direct seeding ( with or without scarification ) in pots and maintaining in natural conditions in Alborz research center The results showed that sowing seeds in sand significantly (p0.01) increased germination rate and the best treatment was chilling for 6 months (33%, 33% and 13% Seed germination for Tilia, Acer and Sorbus respectively). Seed germination was not significantly increased by use of GA3 after chilling. Sulfuric acid did not show any effect on seed germination. There was not any significant difference between alternate temperatures before chilling and chilling for 6 months (3% increases). Number of germinated seeds in Tilia and Acer where increased when seeds scarified and cultured under the natural condition (32% vise 11% and 35.6% vise 11% respectively). Chilling (6 months) after surface disinfection was the most effective treatment for germination of large-leaved lime and Montpellier maple seeds. Scarification with sulfuric acid and chilling had no effect on seed germination of these species.