Linked Life Data

20630988

Source:http://linkedlifedata.com/resource/pubmed/id/20630988

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2010-9-15
pubmed:abstractText
Second year needles of Lodgepole pine (Pinus contorta L.) were exposed for 6 weeks to either simulated control summer ['summer'; 25 °C/250 photon flux denisty (PFD)], autumn ('autumn'; 15°C/250 PFD) or winter conditions ('winter'; 5 °C/250 PFD). We report that the proportion of linear electron transport utilized in carbon assimilation (ETR(CO2)) was 40% lower in both 'autumn' and 'winter' pine when compared with the 'summer' pine. In contrast, the proportion of excess photosynthetic linear electron transport (ETR(excess)) not used for carbon assimilation within the total ETR(Jf) increased by 30% in both 'autumn' and 'winter' pine. In 'autumn' pine acclimated to 15°C, the increased amounts of 'excess' electrons were directed equally to 21 ?kPa O2-dependent and 2 ?kPa O2-dependent alternative electron transport pathways and the fractions of excitation light energy utilized by PSII photochemistry (?(PSII)), thermally dissipated through ?(NPQ) and dissipated by additional quenching mechanism(s) (?(f,D)) were similar to those in 'summer' pine. In contrast, in 'winter' needles acclimated to 5 °C, 60% of photosynthetically generated 'excess' electrons were utilized through the 2 ?kPa O2-dependent electron sink and only 15% by the photorespiratory (21 ?kPa O2) electron pathway. Needles exposed to 'winter' conditions led to a 3-fold lower ?(PSII), only a marginal increase in ?(NPQ) and a 2-fold higher ?(f,D), which was O2 dependent compared with the 'summer' and 'autumn' pine. Our results demonstrate that the employment of a variety of alternative pathways for utilization of photosynthetically generated electrons by Lodgepole pine depends on the acclimation temperature. Furthermore, dissipation of excess light energy through constitutive non-photochemical quenching mechanisms is O2 dependent.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1471-9053
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
51
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1555-70
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Regulation of energy partitioning and alternative electron transport pathways during cold acclimation of lodgepole pine is oxygen dependent.
pubmed:affiliation
Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, Ottawa, ON K1A0C6, Canada. leonid.savitch@agr.gc.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't