Inhibition of the gravitropic response of snapdragon spikes by the calcium-channel blocker lanthanum chloride.
Plant Physiol
; 118(2): 483-92, 1998 Oct.
Article
em En
| MEDLINE
| ID: mdl-9765533
ABSTRACT
The putative Ca(2+)-channel blocker LaCl3 prevented the gravitropic bending of cut snapdragon (Antirrhinum majus L.) spikes (S. Philosoph-Hadas, S. Meir, I. Rosenberger, A.H. Halevy [1996] Plant Physiol 110 301-310) and inhibited stem curvature to a greater extent than vertical and horizontal stem elongation at the bending zone. This might indicate that LaCl3, which modulates cytosolic Ca2+, does not influence general stem-growth processes but may specifically affect other gravity-associated processes occurring at the stem-bending zone. Two such specific gravity-dependent events were found to occur in the bending zone of snapdragon spikes sedimentation of starch-containing chloroplasts at the bottom of stem cortex cells, as seen in cross-sections, and establishment of an ethylene gradient across the stem. Our results show that the lateral sedimentation of chloroplasts associated with gravity sensing was prevented in cross-sections taken from the bending zone of LaCl3-treated and subsequently gravistimulated spikes and that LaCl3 completely prevented the gravity-induced, asymmetric ethylene production established across the stem-bending zone. These data indicate that LaCl3 inhibits stem curvature of snapdragon spikes by preventing several gravity-dependent processes. Therefore, we propose that the gravitropic response of shoots could be mediated through a Ca(2+)-dependent pathway involving modulation of cytosolic Ca2+ at various stages.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bloqueadores dos Canais de Cálcio
/
Cloroplastos
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Caules de Planta
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Gravitropismo
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Magnoliopsida
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Lantânio
Idioma:
En
Revista:
Plant Physiol
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Israel