Needle-like crystals of either aragonite (“uh-RAG-uh-nite”) or calcium bound to this anion are called raphides (“RAFF-id-eez”) and are found in the idioblasts (“ID-ee-oh-blasts”) of plants like pineapples and calla lilies. For 10 points each:
[10m] Name this ion used by some plants as a sink to help regulate apoplastic calcium concentrations. High dietary intake of this ion is a risk factor for kidney stones.
ANSWER: oxalate (“OX-uh-late”) [or C2O4 2− (“C-two-O-four-two-minus”)]
[10e] Calcium oxalate crystal formation in idioblasts would overload cells with calcium without an abundance of this membranous organelle to sequester it. This organelle has smooth and rough subtypes.
ANSWER: endoplasmic reticulum [or ER; accept sarcoplasmic reticulum or SR]
[10h] Oxalate crystal sequestration may also be involved in plant tolerance to this metal, whose toxic plus-three cation (“CAT-eye-on”) limits root growth in acidic soil.
ANSWER: aluminum [or Al; or aluminium]
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