Whcn 'Manzanillo' olive cmbryos were cxciscd al successivc dates and cultured 011 one¡hiTd strenglh Murashige-S koog medium. three Slagcs of diffcring growlh potential were observed: 1) An inllial stagc in which no germination was obtained. 2) An intermediate 'c riticar period in which germination and viabil ilY percenlage illcrcased according 10 date ,me! 3) A final stage. fram Ihe lime whcll ...

Introduction Quiescent and dormant embryos, germination: definitions Nuclear characteristics of the cell population in quiescent embryos Distribution of quiescent embryo cell nuclei in different phases of the cell cycle How is the high G\ cell level of quiescent embryos established? What are the mechanisms controlling G\ cell accumulation? Controversial observations on the high G\ accumulation ...

Many biologists studying environmentally induced parental effects have indirectly suggested that the parental environment alters seed mass by altering the amount of endosperm or embryo tissue in the seed. We tested this hypothesis by measuring the effects of parental temperature on total seed mass, seed coat mass, and embryo/endosperm mass in offspring of Plantago lanceolata. Parental temperatu...

Wheat (Triticum aestivum 1.) embryo germination is inhibited by natural (S)-(+)-abscisic acid (ABA). In this report we have determined critical structural features of the ABA molecule, particularly the methyl and ketone groups of the ABA ring, required for inhibitory activity. To examine the ring residues a series of new optically active ABA analogs have been synthesized in which the 4’-keto, 7...

Many biologists studying environmentally induced parental effects have indirectly suggested that the parental environment alters seed mass by altering the amount of endosperm or embryo tissue in the seed. We tested this hypothesis by measuring the effects of parental temperature on total seed mass, seed coat mass, and embryo/endosperm mass in offspring of Plantago lanceolata. Parental temperatu...

The focus of the current project was to establish somatic embryogenesis protocols for the tropical pine species Pinus oocarpa using immature zygotic embryos (ZEs) as explants. Somatic embryogenesis is best supported by mimicking natural seed-embryo developmental conditions, through a tissue culture medium formulation based on the mineral content of the seed nutritive tissue [megagametophyte (MG...

Arabidopsis exocyst subunit SEC3A has been reported to participate in embryo development. Here we report that SEC3A is involved during pollen germination. A T-DNA insertion in SEC3A leads to an absolute, male-specific transmission defect that can be complemented by the expression of SEC3A coding sequence from the LAT52 promoter or SEC3A genomic DNA. No obvious abnormalities in the microgametoge...

Loss of aquatic plant species has occurred in coastal and freshwater habitats throughout the world. In particular, population and habit loss of the submerged aquatic species, Vallisneria americana Michx., have made it a potential restoration candidate. For successful restoration, reliable seed sources are vital for producing plants or for direct seeding. Seed survival and their ability to retai...

BACKGROUND AND AIMS Germination studies of species from fire-prone habitats are often focused on the role that fire plays in breaking dormancy. However, for some plant groups in these habitats, such as the genus Leucopogon (Ericaceae), dormancy of fresh seeds is not broken by fire cues. In the field, these same species display a flush of seedling emergence post-fire. Dormancy and germination me...

Small heat shock proteins (sHSPs) function as ATP-independent molecular chaperones, and although the production and function of sHSPs have often been described under heat stress, the expression and function of sHSPs in fundamental developmental processes, such as pollen and seed development, have also been confirmed. Seed germination involves the breaking of dormancy and the resumption of embry...