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Introduction of Seed Development and Arabidopsis Embryo Development. By Bekah Charney and Thi Nguyen HC70AL Spring 2006. What is the life cycle of an Arabidopsis Plant?. 2n Adult Sporophyte. 2n Adult Sporophyte. Meiosis. Meiosis. Many mitosis. Many mitosis. n n n n
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Introduction of Seed Development and Arabidopsis Embryo Development By Bekah Charney and Thi Nguyen HC70AL Spring 2006
What is the life cycle of an Arabidopsis Plant? 2n Adult Sporophyte 2n Adult Sporophyte Meiosis Meiosis Many mitosis Many mitosis n n n n Haploid spores n n n n Haploid spores n Adult Gametophyte n Adult Gametophyte Mitosis Mitosis n Gametes n Gametes 2n Zygote 2n Zygote Many Mitosis Many Mitosis 2n Adult Sporophyte 2n Adult Sporophyte
Embryo Development EMBRYO SAC GLOBULAR HEART TORPEDO MATURATION
Globular Stage • Stage which precedes cotyledon development • Embryo proper is spherical • Note the suspensor
Heart Stage • Globular embryo develops into two-lobed form • Suspensor acts as an “umbilical cord,” providing nutrients to the embryo.
Torpedo Stage • Cotyledons and axis grow longer • Embryo may remain straight or become curved
Mature Embryo • Cotyledons curve and provides nutrition to plant, enough to get plant started with photosynthesis • Suspensor disappears • Endosperm has been used for nutrients and now is used up
A A a a A A Aa Aa AA AA a a Aa Aa aa aa Mutations that are Lethal Lethal to Zygote Lethal to Gamete Phenotype: live to dead seeds 3:1 Genotype: AA to Aa 1:2 Phenotype: live to dead seeds 1:1 Genotype: AA to Aa 1:1
Acknowledgements • We would like to thank Ria, Jon, XingJun and Tomo for allowing us to use their Nomarski photographs and their assistance in general in helping to make to this presentation • We would also like to thank Mike, Brandon, Jessica, the rest of the HC70AL class and Dr. Goldberg for being there for us all quarter!