Arnold, Marianne , Gould, Jean .
In vitro conditions for examination of early cotyledonary to maturation stage cotton embryos.
Cotton (Gossypium spp.) is an important fiber crop worldwide; however, the nutritious seeds have limited use in human food or animal feed because the gossypol in the seed is toxic. Gossypol is synthesized and stored in glands of the developing cotton embryo. Embryos develop in stages, globular, heart, torpedo, cotyledonary and maturation. Gossypol synthesis begins after the cotton embryos have reached the cotyledonary stage and increases until the seed matures. A culture system was needed to study gland development in excised early-stage cotyledonary embryos, since existing methods have drawbacks. Embryos grown in planta or in ovulo are either not accessible for continuous monitoring or are destroyed in observation. Somatic embryos have been used to approximate zygotic embryo development, but present too many problems and artifacts. Gossypol glands develop in cultured zygotic cotyledonary embryos but current in vitro systems are inefficient and produce developmental abnormalities. Cotton embryo development is usually described by DPA (days post anthesis) regardless of variety or growing conditions. We classified cotyledonary stage embryos based on size because size is a better estimate of developmental stage. We adopted shoots per embryo (S/E), as a measure of successful embryo development because most excised zygotic embryos developed roots in early experiments while few produced shoots. The growth regulators IAA and kinetin were tested on embryos but did not increase S/E over controls. Three embryo size groups were tested (1.5-2.2 mm; 2.2-3mm; 3-4mm), with three basal media (MS, BT, SH), glucose and sucrose. The effects of desiccation, continuous light, and agar concentration during culture initiation were investigated; however, only light had a significant effect on S/E.
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1 - Texas A&M University, Ecosystem Science & Management; Molecular & Environmental Plant Sciences
2 - Texas A&M University, Ecosystem Science & Management; Molecular & Environmental Plant Sciences, 305 Horticulture-Forest Science Building, College Station, TX, 77843-2135, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM