Abstract:

The production of artificial seeds by encapsulating shoot tips or minibuds has received considerable attention in recent years.To accomplish conversion of the encapsulated shoot tips is one of the key questions in this area.In this paper some tests were carried out using the shoot tips of Eucaluptus camaldulensis as propagules in order to determine the effects of different kinds of auxin(NAA, IBA, IAA), shoot growth state, NAA in the encapsulation matrix and rooting pretreatment on their conversion.The results showed that NAA had a better effect on rooting of the shoot tips than IBA and IAA had.Shoot state was closely related to the conversion of encapsulated shoot tips.The vigor, healthy and tender shoot tips showed higher conversion rate after encapsulated.The problem of rooting and conversion for encapsulated shoot tips can not be solved with the method of adding NAA in the encapsulation matrix.The shoot tips was firstly pretreated on modified H rooting medium containing 2mg/L NAA, then the tip with the medium on its base was encapsulated with calcium alginate including modified H medium nutrition.This method significantly raised the rate of rooting and conversion of the encapsulated shoot tips 81.3 % rooting rate and 83.3 % conversion rate were obtained 2 and 3 weeks after they were cultured for germination respectively.

Key words: Eucaluptus camaldulensis, Shoot tips, Artificial seeds, Conversion