| A cellular timetable of autumn senescence. | |
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MedLine Citation:
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PMID: 16299183 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We have studied autumn leaf senescence in a free-growing aspen (Populus tremula) by following changes in pigment, metabolite and nutrient content, photosynthesis, and cell and organelle integrity. The senescence process started on September 11, 2003, apparently initiated solely by the photoperiod, and progressed steadily without any obvious influence of other environmental signals. For example, after this date, senescing leaves accumulated anthocyanins in response to conditions inducing photooxidative stress, but at the beginning of September the leaves did not. Degradation of leaf constituents took place over an 18-d period, and, although the cells in each leaf did not all senesce in parallel, senescence in the tree as a whole was synchronous. Lutein and beta-carotene were degraded in parallel with chlorophyll, whereas neoxanthin and the xanthophyll cycle pigments were retained longer. Chloroplasts in each cell were rapidly converted to gerontoplasts and many, although not all, cells died. From September 19, when chlorophyll levels had dropped by 50%, mitochondrial respiration provided the energy for nutrient remobilization. Remobilization seemed to stop on September 29, probably due to the cessation of phloem transport, but, up to abscission of the last leaves (over 1 week later), some cells were metabolically active and had chlorophyll-containing gerontoplasts. About 80% of the nitrogen and phosphorus was remobilized, and on September 29 a sudden change occurred in the delta15N of the cellular content, indicating that volatile compounds may have been released. |
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Authors:
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Johanna Keskitalo; Gustaf Bergquist; Per Gardeström; Stefan Jansson |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2005-11-18 |
Journal Detail:
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Title: Plant physiology Volume: 139 ISSN: 0032-0889 ISO Abbreviation: Plant Physiol. Publication Date: 2005 Dec |
Date Detail:
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Created Date: 2005-12-12 Completed Date: 2006-03-20 Revised Date: 2010-09-21 |
Medline Journal Info:
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Nlm Unique ID: 0401224 Medline TA: Plant Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1635-48 Citation Subset: IM |
Affiliation:
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Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, S-901 87 Umea, Sweden. johanna.keskitalo@plantphys.umu.se |
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| MeSH Terms | |
Descriptor/Qualifier:
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Anthocyanins
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metabolism Carotenoids / metabolism Chlorophyll / metabolism Chloroplasts / metabolism Microscopy, Electron Mitochondria / metabolism Nitrogen / metabolism Phosphorus / metabolism Photobiology Photoperiod Photosynthesis Pigments, Biological / metabolism Plant Leaves / cytology, growth & development*, metabolism Populus / cytology, growth & development*, metabolism Seasons* |
| Chemical | |
Reg. No./Substance:
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0/Anthocyanins; 0/Pigments, Biological; 1406-65-1/Chlorophyll; 36-88-4/Carotenoids; 7723-14-0/Phosphorus; 7727-37-9/Nitrogen |
| Comments/Corrections | |
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