Early Plant Formation

Early Plant Formation - formation of roots/shoots...

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Early Plant Formation root-shoot axis  - regulating amount/pattern of cell division >> 3D shape/form cells w/ multiple potentials restricted to meristemic regions apical meristems establish axis in embryogenesis tissue systems organized radially around axis food source for embryo - endosperm in angiosperms, megagametophyte in gymnosperms 1st division of zygote >> smaller cell becomes embryo, larger cell forms suspensor (links embryo to nutrient tissue in seed) o cells near suspensor >> root o cells at other end >> shoot embryo stops suspensor from developing into another embryo tissue systems  - dermal tissue, ground tissue, vascular tissue dermal tissue - from protoderm, outermost cells of embryo o divides w/ cell plate perpendicular to surface ground tissue - functions in food/water storage vascular tissue - from procambium at embryo core o functions in water/nutrient transport
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Unformatted text preview: formation of roots/shoots controlled independently morphogenesis - generation of form, produces the cotyledon(s) seeds need enough nutrients to support sporophyte until it can photosynthesize o cant bury seeds to deep germination - radicle (1st root) extends through seed coat orients so that roots grow down, shoots grow up starts when seed absorbs water, metabolism resumes most seeds must stratify (spend time in cold conditions) before germinating o ensures that seed will not sprout right before cold season amyloplasts- starch-storing plastids, provides metabolic reserves for young plant cotyledon >> scutellum (food source used before endosperm) aleurone- outer layer of endosperm, signaled by gibberellic acid to produce amylase seed very susceptible to disease/drought between germination and young plant stage...
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

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