IN VITRO توليد انبوه ريز نهال گونه جنگلي در شرايط

Mass production of Eucalyptus gunnii plantlets under in vitro conditions

E. gunnii is a fast-growing forest species from Myrtaceae family. It is a native of Tasmania, where altitude and temperature is lower than the other parts of Australia. It prefers light textured, well drained, moist and neutral to slightly acidic soils. This tree is much desired for its silvery-bluish color leaves and year round fine aromatic fragrance and high resistance to cold and freezing climate. It is an important species for forest plantation on coastal plains of Caspian Sea of Iran. Traditional asexual propagation methods are not effective due to difficulties in production or proliferation of adventitious roots. Unique traits of elite genotypes can be transmitted through in vitro micropropagation. Various types of explants were examined in different experiments, including shoot tips, axillary buds, lignotuber and epicormic shoots. Several experiments were carried out to determine the best disinfectant chemical, appropriate conditions and materials to prevent phenolic compound exudation, explant characteristics, media type and cytokinin auxin ratio. Epicormic shoot explants in DEU medium at 0.5 mg L-1 of Kinetin with 0.01 mg L-1 of NAA gave better rate of adventitious shoot production with fewer calluses. The highest adventitious root obtained with a mixture of NAA and IBA at 0.5 mg L-1 each. Micropropagation of plantlets were successfully hardened and adapted either in the propagator or in the greenhouse with survival rate of 75.2 %.