Linked Life Data

16815838

Source:http://linkedlifedata.com/resource/pubmed/id/16815838

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2006-7-3
pubmed:abstractText
Larch (Larix gmelinii (Rupr.) Rupr.) cone scales are green, but little is known of their photosynthetic role in cone development or about how they differ in gas exchange characteristics from needle leaves. In contrast to leaf photosynthesis (Pleaf), we found that stomatal regulation of cone photosynthetic rate (Pcone) was marginal because the photosynthetic carbon came from internal recycling of respiratory carbon dioxide (CO2). Photosynthetic recycling of respired CO2 was confirmed by the finding that the intercellular CO2 concentration (Ci) in cone scales was much higher than ambient [CO2]; also, there was a positive correlation between Pcone and Ci, whereas Pleaf was almost constant as Ci varied. Low chlorophyll (Chl) concentration was a limiting factor for Pcone, but not for Pleaf, as indicated by the correlation between Pcone and chlorophyll concentration. Moreover, chlorophyll utilization efficiency (Psat/Chl a+b) for cone scales was lower than that for leaves. In both cones and leaves, nitrogen (N) was positively correlated with photosynthetic capacity (P), but the P/N value was much lower for cones than for leaves. For both organs, the ratio of respiration to N was broadly similar. Although mature cones have no photosynthetic capacity, Pcone of young cones was as high as 5.3 micromol m(-2) s(-1), about 1.26 times the value of Pleaf, and accounted for the refixation of 30-40% of the respiratory CO2 produced by cones, equivalent to the photosynthetic capacity of a bundle of short shoots near each cone. Thus, Pcone may be an important additional source of photosynthate for cones, given the weak assimilating capacity of leaves that are not fully expanded during cone development.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0829-318X
pubmed:author
pubmed:issnType
Print
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1363-8
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Carbon dioxide exchange of larch (Larix gmelinii) cones during development.
pubmed:affiliation
Key Laboratory of Forest Plant Ecology of the Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't