Linked Life Data

16399010

Source:http://linkedlifedata.com/resource/pubmed/id/16399010

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2006-1-9
pubmed:abstractText
The correlation between structural changes of the vascular bundles and needle yellowing was examined for needles of damaged spruce (Picea abies (L.) Karst.) growing at a Mg-deficient and ozone polluted mountain site in the Central Black Forest (840m a.s.l.). In the previous year's sun-exposed needles, the following sequence of events was observed: (1) rapid needle yellowing, (2) hypertrophy and anomalous divisions of cambium cells, (3) phloem collapse, and, (4) production of atypical xylem tracheids. Under defined shade (reduction of the photosynthetically active photon flux density of the ambient light by 85-90%), the needles remained green, while the phloem collapsed completely within the first 6 weeks of shading; subsequently, a reversal of the collapse was observed. Under both light conditions, the content of Mg not bound to chlorophyll (Mg(free)) was in the range of 0.1 mg g(-1) needle dry matter, and hardly changed throughout the investigation period. After Mg fertilization, the Mg(free) level of the previous year's needles increased to 0.2 mg g(-1) dry matter, the light-exposed needles remained green, and the vascular bundles developed no anomalies. The data show that the rapid needle yellowing of ozone-exposed Mg-deficient needles did not depend on the collapse of the phloem. Mg deficiency played a key role in the development of anomalous vascular bundles under light, and also appears to explain the transient changes in sieve cell structure under shade. The role of Mg deficiency, rather than ozone pollution, in the damage of the sieve cells was confirmed in a long-term ozone exposure experiment with young clonal spruce growing under defined conditions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0176-1617
pubmed:author
pubmed:issnType
Print
pubmed:volume
163
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
195-205
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Structural changes in the vascular bundles of light-exposed and shaded spruce needles suffering from Mg deficiency and ozone pollution.
pubmed:affiliation
Botanisches Institut I, Universität Karlsruhe (TH), Kaiserstr. 12, D-76128 Karlsruhe, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't