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001     28893
005     20190625112016.0
024 7 _ |2 pmid
|a pmid:12692313
024 7 _ |2 pmc
|a pmc:PMC166912
024 7 _ |2 DOI
|a 10.1104/pp.102.017202
024 7 _ |2 WOS
|a WOS:000185076400004
024 7 _ |a altmetric:158757
|2 altmetric
037 _ _ |a PreJuSER-28893
041 _ _ |a eng
082 _ _ |a 580
084 _ _ |2 WoS
|a Plant Sciences
100 1 _ |a van Dongen, J. T.
|b 0
|0 P:(DE-HGF)0
245 _ _ |a Phloem metabolism and function have to cope with low internal oxygen
260 _ _ |a Rockville, Md.: Soc.
|b JSTOR
|c 2003
300 _ _ |a 1529 - 1543
336 7 _ |a Journal Article
|0 PUB:(DE-HGF)16
|2 PUB:(DE-HGF)
336 7 _ |a Output Types/Journal article
|2 DataCite
336 7 _ |a Journal Article
|0 0
|2 EndNote
336 7 _ |a ARTICLE
|2 BibTeX
336 7 _ |a JOURNAL_ARTICLE
|2 ORCID
336 7 _ |a article
|2 DRIVER
440 _ 0 |a Plant Physiology
|x 0032-0889
|0 4987
|v 131
500 _ _ |a Record converted from VDB: 12.11.2012
520 _ _ |a We have investigated the consequences of endogenous limitations in oxygen delivery for phloem transport in Ricinus communis. In situ oxygen profiles were measured directly across stems of plants growing in air (21% [v/v] oxygen), using a microsensor with a tip diameter of approximately 30 microm. Oxygen levels decreased from 21% (v/v) at the surface to 7% (v/v) in the vascular region and increased again to 15% (v/v) toward the hollow center of the stem. Phloem sap exuding from small incisions in the bark of the stem was hypoxic, and the ATP to ADP ratio (4.1) and energy charge (0.78) were also low. When 5-cm stem segments of intact plants were exposed to zero external oxygen for 90 min, oxygen levels within the phloem decreased to approximately 2% (v/v), and ATP to ADP ratio and adenylate energy charge dropped further to 1.92 and 0.68, respectively. This was accompanied by a marked decrease in the phloem sucrose (Suc) concentration and Suc transport rate, which is likely to be explained by the inhibition of retrieval processes in the phloem. Germinating seedlings were used to analyze the effect of a stepwise decrease in oxygen tension on phloem transport and energy metabolism in more detail. Within the endosperm embedding the cotyledons-next to the phloem loading sites-oxygen decreased from approximately 14% (v/v) in 6-d-old seedlings down to approximately 6% (v/v) in 10-d-old seedlings. This was paralleled by a similar decrease of oxygen inside the hypocotyl. When the endosperm was removed and cotyledons incubated in a 100 mM Suc solution with 21%, 6%, 3%, or 0.5% (v/v) oxygen for 3 h before phloem sap was analyzed, decreasing oxygen tensions led to a progressive decrease in phloem energy state, indicating a partial inhibition of respiration. The estimated ratio of NADH to NAD(+) in the phloem exudate remained low (approximately 0.0014) when oxygen was decreased to 6% and 3% (v/v) but increased markedly (to approximately 0.008) at 0.5% (v/v) oxygen, paralleled by an increase in lactate and ethanol. Suc concentration and translocation decreased when oxygen was decreased to 3% and 0.5% (v/v). Falling oxygen led to a progressive increase in amino acids, especially of alanine, gamma-aminobutyrat, methionine, and isoleucine, a progressive decrease in the C to N ratio, and an increase in the succinate to malate ratio in the phloem. These results show that oxygen concentration is low inside the transport phloem in planta and that this results in adaptive changes in phloem metabolism and function.
536 _ _ |a Chemie und Dynamik der Geo-Biosphäre
|c U01
|2 G:(DE-HGF)
|0 G:(DE-Juel1)FUEK257
|x 0
588 _ _ |a Dataset connected to Web of Science, Pubmed
650 _ 2 |2 MeSH
|a Adaptation, Physiological
650 _ 2 |2 MeSH
|a Adenosine Triphosphate: metabolism
650 _ 2 |2 MeSH
|a Amino Acids: metabolism
650 _ 2 |2 MeSH
|a Biological Transport, Active: physiology
650 _ 2 |2 MeSH
|a Energy Metabolism
650 _ 2 |2 MeSH
|a Fermentation
650 _ 2 |2 MeSH
|a Glycolysis
650 _ 2 |2 MeSH
|a Malates: metabolism
650 _ 2 |2 MeSH
|a NAD: metabolism
650 _ 2 |2 MeSH
|a Oxygen: metabolism
650 _ 2 |2 MeSH
|a Phosphorus: metabolism
650 _ 2 |2 MeSH
|a Plant Structures: cytology
650 _ 2 |2 MeSH
|a Plant Structures: metabolism
650 _ 2 |2 MeSH
|a Ricinus: growth & development
650 _ 2 |2 MeSH
|a Ricinus: metabolism
650 _ 2 |2 MeSH
|a Seedling: growth & development
650 _ 2 |2 MeSH
|a Seedling: metabolism
650 _ 2 |2 MeSH
|a Succinic Acid: metabolism
650 _ 2 |2 MeSH
|a Sucrose: metabolism
650 _ 7 |0 0
|2 NLM Chemicals
|a Amino Acids
650 _ 7 |0 0
|2 NLM Chemicals
|a Malates
650 _ 7 |0 110-15-6
|2 NLM Chemicals
|a Succinic Acid
650 _ 7 |0 53-84-9
|2 NLM Chemicals
|a NAD
650 _ 7 |0 56-65-5
|2 NLM Chemicals
|a Adenosine Triphosphate
650 _ 7 |0 57-50-1
|2 NLM Chemicals
|a Sucrose
650 _ 7 |0 6915-15-7
|2 NLM Chemicals
|a malic acid
650 _ 7 |0 7723-14-0
|2 NLM Chemicals
|a Phosphorus
650 _ 7 |0 7782-44-7
|2 NLM Chemicals
|a Oxygen
650 _ 7 |a J
|2 WoSType
700 1 _ |a Schurr, U.
|b 1
|u FZJ
|0 P:(DE-Juel1)129402
700 1 _ |a Pfister, M.
|b 2
|0 P:(DE-HGF)0
700 1 _ |a Geigenberger, P.
|b 3
|0 P:(DE-HGF)0
773 _ _ |a 10.1104/pp.102.017202
|g Vol. 131, p. 1529 - 1543
|p 1529 - 1543
|q 131<1529 - 1543
|0 PERI:(DE-600)2004346-6
|t Plant physiology
|v 131
|y 2003
|x 0032-0889
856 7 _ |2 Pubmed Central
|u http://www.ncbi.nlm.nih.gov/pmc/articles/PMC166912
909 C O |o oai:juser.fz-juelich.de:28893
|p VDB
913 1 _ |k U01
|v Chemie und Dynamik der Geo-Biosphäre
|l Chemie und Dynamik der Geo-Biosphäre
|b Environment (Umwelt)
|0 G:(DE-Juel1)FUEK257
|x 0
914 1 _ |y 2003
915 _ _ |0 StatID:(DE-HGF)0010
|a JCR/ISI refereed
920 1 _ |k ICG-III
|l Phytosphäre
|d 31.12.2006
|g ICG
|0 I:(DE-Juel1)VDB49
|x 0
970 _ _ |a VDB:(DE-Juel1)23966
980 _ _ |a VDB
980 _ _ |a ConvertedRecord
980 _ _ |a journal
980 _ _ |a I:(DE-Juel1)IBG-2-20101118
980 _ _ |a UNRESTRICTED
981 _ _ |a I:(DE-Juel1)IBG-2-20101118
981 _ _ |a I:(DE-Juel1)ICG-3-20090406

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