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- Title
Calcium Channels are Involved in Calcium Oxalate Crystal Formation in Specialized Cells of Pistia stratiotes L.
- Authors
VOLK, GAYLE M.; GOSS, LENORA J.; FRANCESCHI, VINCENT R.
- Abstract
• Background and AimsPistia stratiotes produces large amounts of calcium (Ca) oxalate crystals in specialized cells called crystal idioblasts. The potential involvement of Ca2+ channels in Ca oxalate crystal formation by crystal idioblasts was investigated.• Methods Anatomical, ultrastructural and physiological analyses were used on plants, fresh or fixed tissues, or protoplasts. Ca2+ uptake by protoplasts was measured with 45Ca2+, and the effect of Ca2+ channel blockers studied in intact plants. Labelled Ca2+ channel blockers and a channel protein antibody were used to determine if Ca2+ channels were associated with crystal idioblasts.• Key Results45Ca2+ uptake was more than two orders of magnitude greater for crystal idioblast protoplasts than mesophyll protoplasts, and idioblast number increased when medium Ca was increased. Plants grown on media containing 1–50 µm of the Ca2+ channel blockers, isradipine, nifedipine or fluspirilene, showed almost complete inhibition of crystal formation. When fresh tissue sections were treated with the fluorescent dihydropyridine‐type Ca2+ channel blocker, DM‐Bodipy‐DHP, crystal idioblasts were intensely labelled compared with surrounding mesophyll, and the label appeared to be associated with the plasma membrane and the endoplasmic reticulum, which is shown to be abundant in idioblasts. An antibody to a mammalian Ca2+ channel α1 subunit recognized a single band in a microsomal protein fraction but not soluble protein fraction on western blots, and it selectively and heavily labelled developing crystal idioblasts in tissue sections.• Conclusions The results demonstrate that Ca oxalate crystal idioblasts are enriched, relative to mesophyll cells, in dihydropyridine‐type Ca2+ channels and that the activity of these channels is important to transport and accumulation of Ca2+ required for crystal formation.
- Subjects
CALCIUM channels; CALCIUM oxalate; WATER lettuce; CRYSTALS; DIHYDROPYRIDINE
- Publication
Annals of Botany, 2004, Vol 93, Issue 6, p741
- ISSN
0305-7364
- Publication type
Article
- DOI
10.1093/aob/mch092