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6.2 Plant Embryogenesis — Test 1
Q1. The first division of the Arabidopsis zygote is asymmetric, producing:✓ A small apical cell and a larger basal cell
Q2. The factor that establishes the apical-basal embryonic axis in plant embryos is mainly:✓ An auxin gradient
Q3. PIN proteins during plant embryogenesis function to:✓ Direct the flow of auxin and establish auxin gradients
Q4. In Arabidopsis embryogenesis, the hypophysis is first recognisable at the:✓ Globular stage
Q5. The root apical meristem of the mature Arabidopsis embryo is derived from:✓ The embryo proper plus the hypophysis (uppermost suspensor cell)
Q6. The heart stage of Arabidopsis embryogenesis is marked by:✓ Rapid cell division in two regions either side of the apex (forming cotyledon primordia)
Q7. During the torpedo stage of Arabidopsis embryogenesis:✓ Cells elongate along the axis and the cotyledons develop further
Q8. The adaxial-abaxial (upper-lower) distinction of the cotyledons first becomes apparent at the:✓ Torpedo stage
Q9. At the mature (final) stage of seed development, the embryo:✓ Loses water and becomes metabolically inactive (quiescent)
Q10. 'Orthodox' seeds are characterised by their ability to:✓ Tolerate desiccation, losing most of their water
Q11. Abscisic acid (ABA) during seed development acts to:✓ Inhibit precocious germination and promote dormancy
Q12. Precocious germination (vivipary) is the germination of seeds:✓ Without passing through the normal quiescent/dormant stage
Q13. The scutellum in a germinating grass (cereal) seed functions to:✓ Absorb nutrients from the starchy endosperm and pass them to the embryo
Q14. WOX2 and WOX8 transcription factors in the Arabidopsis zygote are notable because they are:✓ Present in both the egg cell and the zygote, helping pattern the embryo
Q15. WOX8 (with WOX9) in the early Arabidopsis embryo regulates the development of the:✓ Basal (suspensor) lineage
Q16. The suspensor in a plant embryo functions to:✓ Anchor the embryo and channel nutrients/hormones from the maternal tissue
Q17. The correct order of Arabidopsis embryo stages is:✓ Zygote → globular → heart → torpedo → mature
Q18. In plant embryogenesis (unlike in animals), morphogenesis relies on oriented cell division and expansion because:✓ Plant cells have rigid walls and cannot migrate
Q19. The auxin maximum at the basal pole of the early embryo specifies the:✓ Root pole (and the future root meristem)