Somatic embryo induction and plant regeneration from cold-stored embryogenic callus of K. Septemlobus

Abstract

Somatic embryogenesis is as an excellent technology for potential use in plant mass production, germplasm conservation, or genetic engineering. We examined the effect of cold storage using 3 embryogenic callus lines with different levels of embryogenesis competence derived from immature zygotic embryo cultures of Kalopanax setemlobus. Somatic embryo induction, germination and plant conversion were evaluated after 1, 3 and 6 months storage at 4°C in the dark. Most cold-stored embryogenic calli formed somatic embryos normally even after 6 months; however, the induction rate was gradually decreased by increasing the storage period. The most competent line tended to show a slight decline in somatic embryo induction rate, as compared with other lines after cold storage. In general, cold storage resulted in reduced somatic embryo germination and plant regeneration, although 93% somatic embryo germination and 91% plant conversion were achieved regardless of the storage period. Cold storage led to cell browning and degradation. Additionally, the cell structures were confirmed by the aceto-carmine and evans blue dye evaluation. Collectively, our results showed that embryogenic callus of K. Septemlobus could be preserved at 4°C without subculture for 6 months, and suggested the need for storage of relatively more competent embryogenic calli lines to support somatic embryo induction.