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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2010-6-29
pubmed:abstractText
Mesophyll protoplasts isolated from primary leaves of wheat seedlings were used to follow the localization of proteases and the breakdown of chloroplasts during dark-induced senescence. Protoplasts were readily obtained from leaf tissue, even after 80% of the chlorophyll and protein had been lost. Intact chloroplasts and vacuoles could be isolated from the protoplasts at all stages of senescence. All the proteolytic activity associated with the degradation of ribulose bisphosphate carboxylase in the protoplasts could be accounted for by that localized within the vacuole. Moreover, this localization was retained late into senescence. Protoplasts isolated during leaf senescence first showed a decline in photosynthesis, then a decline in ribulose bisphosphate carboxylase activity, followed by a decline in chloroplast number. There was a close correlation between the decline in chloroplast number and the loss of chlorophyll and soluble protein per protoplast, suggesting a sequential degradation of chloroplasts during senescence. Ultrastructural studies indicated a movement of chloroplasts in toward the center of the protoplasts during senescence. Thus, within senescing protoplasts, chloroplasts appeared either to move into invaginations of the vacuole or to be taken up into the vacuole.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jan
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
69
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
98-102
pubmed:dateRevised
2010-9-15
pubmed:year
1982
pubmed:articleTitle
Vacuolar localization of proteases and degradation of chloroplasts in mesophyll protoplasts from senescing primary wheat leaves.
pubmed:affiliation
Central Research and Development Department Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19801.
pubmed:publicationType
Journal Article