STORAGE RESERVES IN PECAN SOMATIC EMBRYOS DERIVED FROM SUSPENSION-CULTURE

Pre-globular stage embryo masses from hormone-free liquid suspension c ultures of pecan (Carya illinoinensis Koch) have been induced to devel op into somatic embryos (SE) on semi-solid medium; however, plant reco very from these embryos has been poor. Lack of storage reserve accumul ation may be a critical factor. In this study, the effect of modified solid media treatments on somatic embryo storage reserve accumulation was appraised. Media were modified with various combinations of abscis ic acid, maltose, casein hydrolysate, and filter paper overlays. Embry os were assessed for triglyceride and protein accumulation, compared w ith levels found within zygotic embryos. High concentrations of maltos e with sucrose generated reserves in the somatic embryos more closely approaching mature zygotic embryos. Although some treatments stimulate d significant reserve deposition, this was associated with unacceptabl e degeneration in embryo morphology. In general, embryos were repetiti ve (perpetually undergoing renewed rounds of embryogenesis) while on t he various media. Reserve-enhancing treatments were identified which m ay benefit plant recovery from suspension-derived pecan somatic embryo s.