Linked Life Data

15770486

Source:http://linkedlifedata.com/resource/pubmed/id/15770486

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2005-8-31
pubmed:abstractText
Senescence and reserve mobilization are integral components of plant development, are basic strategies in stress mitigation, and regulated at least in part by cytokinin. In the present study the effect of altered cytokinin metabolism caused by senescence-specific autoregulated expression of the Agrobacterium tumefaciens IPT gene under control of the P(SAG12) promoter (P(SAG12)-IPT) on seed germination and the response to a water-deficit stress was studied in tobacco (Nicotiana tabacum L.). Cytokinin levels, sugar content and composition of the leaf strata within the canopy of wild-type and P(SAG12)-IPT plants confirmed the reported altered source-sink relations. No measurable difference in sugar and pigment content of discs harvested from apical and basal leaves was evident 72 h after incubation with (+)-ABA or in darkness, indicating that expression of the transgene was not restricted to senescing leaves. No difference in quantum efficiency, photosynthetic activity, accumulation of ABA, and stomatal conductance was apparent in apical, middle and basal leaves of either wild-type or P(SAG12)-IPT plants after imposition of a mild water stress. However, compared to wild-type plants, P(SAG12)-IPT plants were slower to adjust biomass allocation. A stress-induced increase in root:shoot ratio and specific leaf area (SLA) occurred more rapidly in wild-type than in P(SAG12)-IPT plants reflecting delayed remobilization of leaf reserves to sink organs in the transformant. P(SAG12)-IPT seeds germinated more slowly even though abscisic acid (ABA) content was 50% that of the wild-type seeds confirming cytokinin-induced alterations in reserve remobilization. Thus, senescence is integral to plant growth and development and an increased endogenous cytokinin content impacts source-sink relations to delay ontogenic transitions wherein senescence in a necessary process.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
221
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
801-14
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Effects of senescence-induced alteration in cytokinin metabolism on source-sink relationships and ontogenic and stress-induced transitions in tobacco.
pubmed:affiliation
Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 7080, Uppsala, 750 07, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't