Halloin JM, De Zoeten GA, Walker JC.The effects of tentoxin
on chlorophyll synthesis and plastid structure in cucumber and
cabbage.
Plant Physiol. 1970 Mar;45(3):310-4.
To determine if chlorosis caused by tentoxin, a toxin
produced by Alternaria tenuis Nees., is due to interference with
chlorophyll synthesis directly or to disruption of normal
chloroplast development, the effects of the toxin on these
processes in cucumber (Cucumis sativus L.) and cabbage (Brassica
oleracea L., var. capitata) were studied. Cucumber cotyledons
are highly sensitive to the toxin but exhibited no interference
with the conversion of protochlorophyll(ide) to chlorophyll(ide)
or with the general time course pattern of chlorophyll
synthesis, although there was a 90% reduction in chlorophyll
concentration. In cabbage, which shows no chlorosis in the
presence of the toxin, there was a slight stimulation of
chlorophyll synthesis in the presence of the toxin. Electron
microscopy revealed that in cucumber, toxin treatment interferes
with development of prolamellar bodies and lamellae, and results
in deformed plastids. No such effects were noted in
toxin-treated cabbage tissues. Plastids in toxin-treated
cotyledons of both cucumber and cabbage contained more starch
than plastids in nontreated tissues. It was concluded that
tentoxin acts through disruption of normal plastid development,
rather than through direct interference with chlorophyll
synthesis.
PMID: 5463696
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