Initiation, maintenance and maturation of somatic embryos from thin apical dome sections in Pinus kesiya (Royle ex. Gord) promoted by partial desiccation and Gellan gum

Abstract

Embryogenic cultures were initiated and established in Pinus kesiya (Royle ex. Gord) using thin apical dome sections. Factors affecting initiation, including basal medium, growth regulators, and Phytagel concentration have been investigated. Maturation of somatic embryos of P. kesiya was achieved by partial desiccation and higher concentration of Gellan gum. Precultured thin apical dome sections with 0.3% activated charcoal at 4 °C for 3 days produced profusely growing embryogenic callus on induction medium (I). On subculture of such embryogenic callus on maintenance medium (II) resulted in the formation of proembryos. Partial desiccation up to 12, 24, 48, 72 and 96 h of embryogenic calli with proembryos prior to transfer to maturation medium (III) (60 g/l maltose, 37.84 μM ABA and 5 g/l Gellan gum) stimulated maturation of somatic embryos. Maturation frequency increased from 4.21 to 21.5% after 12 h of desiccation treatment, from 21.5 to 67.3% after 24 h of desiccation treatment. On the other hand non-desiccated calli produced least number of somatic embryos (4.21%) on maturation medium with the same ABA treatment and Gellan gum concentration. Embryos from desiccated calli matured on high Gellan gum (5 g/l) displayed improved germination frequencies on germination medium (IV).