DIRECT ORGANOGENESIS FROM SHOOT TIP EXPLANTS OF Juniperus polycarpos L.: OPTIMIZING BASAL MEDIA AND PLANT GROWTH REGULATORS ON PROLIFERATION AND ROOT FORMATION

Juniper is a valuable tree species in forestry and rejuvenate wild natural habitat of Iran. However, sexual propagation of mentioned juniper is difficult, which necessitate to use micropropagation as biotechnological tools to propagate juniper in vitro. To develop micropropagation direct organogenesis experiments into shoot proliferation and roots formation, the effects of six culture media including Murashige and Skoog (MS), Woody Plant Medium (WPM), Schenk and Hildebrandt (SH), Olive media (OM), Driver and Kuniyuki Walnut (DKW), and Momeni and Ganji-Moghadam (MG) supplemented with various concentration of kinetin (KIN), BA (benzyl adenine), IBA (Indole 3-butaryic acid), and NAA (naphthalenecetic acid) were investigated. It was found that hormone concentration, basal media and their interaction had significant effect on shoot proliferation. The all of media except DKW equally displayed survival % when shoot tip used as explant. Explants inoculated with different concentrations of KIN and BA except to 1mgL-1 BA failed to show any detrimental effect of the culture for survival and also media × PGRs (plant growth regulators) was ineffectual. When 5 mgL-1 KIN and 5 mgL-1 BA were used, highest results obtained for shoot number and shoot length, respectively. In direct organogenesis, the use of OM medium supplemented with 5 mgL-1 KIN or 5 mgL-1 BA was promising for shoot number and elongation using shoot tips explants. Our experiments showed that J. polycarpos is a difficult species to induce adventitious roots under in vitro conditions. So, when IBA and NAA were added to media induced any adventitious roots in explants and thus was ineffective. Our study is first in vitro propagation of J. polycarpos, we have been able to achieve much success for shoot proliferation. However, the results of this pioneering study provide a foundation for further research regarding the in vitro regeneration of J. polycarpos.