Linked Life Data

14963707

Source:http://linkedlifedata.com/resource/pubmed/id/14963707

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-5-5
pubmed:abstractText
The regulation of developmental pathways in cultured microspores of tobacco ( Nicotiana tabacum L) and snapdragon ( Antirrhinum majus L) by medium pH is described for the first time. Unicellular tobacco and snapdragon microspores developed into normal, fertile pollen when cultured in media T1 and AT3 at pH 7.0 and 25 degrees C for 6 and 8 days, respectively. First, pollen mitosis was asymmetric and mature pollen grains were filled with starch granules and germinated upon transfer to a germination medium. However, when tobacco and snapdragon microspores were cultured in media T1 and AT3, respectively, at pH 8.0-8.5 for 4-6 days at 25 degrees C, the frequency of symmetric division increased significantly with the formation two nuclei of equal size, and the gametophytic pathway was blocked, as seen by the lack of starch accumulation and the inhibition of pollen germination. The transfer of these microspores to embryogenesis medium AT3 at pH 6.5 resulted in the formation of multicellular structures in both species and, in tobacco, in the formation of embryos and plants. In order to understand the possible mechanisms of the action of high pH, sucrose metabolism was analysed in isolated microspores of tobacco cultured at various pH values. Invertase (EC 3.2.1.26) activity in microspores was maximal at pH 5.0 and strongly decreased at higher pH, leading to a slow-down of sucrose cleavage. At the same time the incorporation of (14)C-labelled sucrose from the medium into microspores was drastically reduced at high pH. These data suggest that isolated microspores are not able to metabolise carbohydrates at high pH and thus undergo starvation stress, which was shown earlier to block the gametophytic pathway and trigger sporophytic development.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
219
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
141-6
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Regulation of developmental pathways in cultured microspores of tobacco and snapdragon by medium pH.
pubmed:affiliation
Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Institute of Microbiology and Genetics, Dr. Bohrgasse 9/4, 1030, Vienna, Austria.
pubmed:publicationType
Journal Article