Practice question

Cotyledons are embryonic leaves formed during heart stage transition from radial to bilateral symmetry via localized auxin maxima at apical margins mediated by PIN1 convergence points. They accumulate storage compounds including triacylglycerols, cruciferin proteins, starch, and late embryogenesis abundant proteins providing essential nutrition during germination before true leaves become photosynthetically competent. Enclosing shoot meristem they protect SAM during seed desiccation and dormancy. Number and fusion status sensitive to auxin patterning governed by GNOM, PINOID, and GURKE lipid pathways, making cotyledon morphology key readout of embryonic patterning fidelity.