title: Comparative anatomy and morphology of Vitis vinifera (Vitaceae) somatic embryos from solid- and liquid-culture-derived proembryogenic masses.
abstract: Ontogeny of somatic embryos of grapevine (Vitis vinifera) produced from solid- and liquid-culture-derived proembryogenic masses (PEM) was compared using light and scanning electron microscopy. Somatic embryos produced from solid-medium-derived PEM (SPEM) had large cotyledons, little or no visible suspensor structure, and a relatively undeveloped concave shoot apical meristem, whereas those from liquid-medium-derived PEM (LPEM) had smaller cotyledons, a distinct suspensor, and a flat-to-convex shoot apical meristem. The convex shoot apical meristem in LPEM-derived somatic embryos formed as early as the heart stage of development; it was 4-6 cell layers deep and rich in protein. Suspensors persisted in fully developed and mature LPEM-derived somatic embryos. The SPEM-derived somatic embryos exhibited dormancy, as do mature zygotic embryos, which also have a rudimentary suspensor, whereas LPEM-derived embryos were not dormant. We hypothesize that the presence of a persistent suspensor in LPEM-derived somatic embryos modulates development, ultimately resulting in rapid germination and a high plant-regeneration rate.
authors.affiliation: Mid-Florida Research and Education Center, Institute of Food Agricultural Sciences, University of Florida, 2725 Binion Road, Apopka, Florida 32703-8504 USA.
authors.forename: S
authors.initials: S
authors.lastname: Jayasankar
authors.forename: Bhaskar R
authors.initials: BR
authors.lastname: Bondada
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Li
authors.forename: D J
authors.initials: DJ
authors.lastname: Gray