Effect of Ca2+ on programmed death of guard and epidermal cells of pea leaves.
The effect of Ca2+ on programmed death of guard cells (GC) and epidermal cells (EC) determined from destruction of the cell nucleus was investigated in epidermis of pea leaves. Ca2+ at concentrations of 1-100 microM increased and at a concentration of 1 mM prevented the CN(-)-induced destruction of the nucleus in GC, disrupting the permeability barrier of GC plasma membrane for propidium iodide (PI). Ca2+ at concentrations of 0.1-1 mM enhanced drastically the number of EC nuclei stained by PI in epidermis treated with chitosan, an inducer of programmed cell death. The internucleosomal DNA fragmentation caused by CN(-) was suppressed by 2 mM Ca2+ on 6 h incubation, but fragmentation was stimulated on more prolonged treatment (16 h). Presumably, the disruption of the permeability barrier of plasma membrane for PI is not a sign of necrosis in plant cells. Quinacrine and diphenylene iodonium at 50 microM concentration prevented GC death induced by CN(-) or CN(-) + 0.1 mM Ca2+ but had no influence on respiration and photosynthetic O2 evolution in pea leaf slices. The generation of reactive oxygen species determined from 2',7'-dichlorofluorescein fluorescence was promoted by Ca2+ in epidermal peels from pea leaves.
Kiselevsky
D B
DB
Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
Kuznetsova
Yu E
YE
Vasil'ev
L A
LA
Lobysheva
N V
NV
Zinovkin
R A
RA
Nesov
A V
AV
Shestak
A A
AA
Samuilov
V D
VD
D017209:Apoptosis; D002118:Calcium / Q000494:pharmacology*; D002467:Cell Nucleus / Q000187:drug effects; D048271:Chitosan / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology; D009861:Onium Compounds / Q000494:pharmacology; D018532:Pisum sativum / Q000378:metabolism*; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D011796:Quinacrine / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism
D003486:Cyanides; D009861:Onium Compounds; D017382:Reactive Oxygen Species; C007517:diphenyleneiodonium; D048271:Chitosan; D011796:Quinacrine; D002118:Calcium