Cytokinins in shoot apices of Brassica napus plants during vernalization

0375184 - ÚEB 2012 RIV IE eng J - Journal Article
Tarkowská, Danuše - Filek, M. - Biesaga-Koscielniak, J. - Marcinska, I. - Macháčková, Ivana - Krekule, Jan - Strnad, Miroslav
Cytokinins in shoot apices of Brassica napus plants during vernalization.
Plant Science. Roč. 187, č. 1 (2012), s. 105-112. ISSN 0168-9452. E-ISSN 1873-2259
R&D Projects: GA AV ČR KAN200380801; GA MŠMT ED0007/01/01
Keywords : Cytokinins * Vernalization * Winter rape * Flowering
Subject RIV: EF - Botanics
Impact factor: 2.922, year: 2012

The putative role of cytokinins in processes leading to reproductive development of plants was investigated by analysing the shoot apical parts of a winter cultivar of oilseed rape (Brassica napus L. var. oleifera, cv. Górczański). The endogenous cytokinin levels were measured by liquid chromatography–tandem mass spectrometry (LC–MS) in the shoot apices of vegetative plants (grown at 20/17 °C with a 16/8 h day/night regime) and vernalized plants (56 days at 5/2 °C with a 16/8 h photoperiod) at different times during floral transition. During vernalization, the content of all isoprenoid cytokinins increased significantly, coinciding well with the onset of the early stages of reproductive development. Cytokinin levels reached their maxima when most of the plants became irreversibly reproductive (after 42 days of cold treatment). cis-Zeatin riboside (unequivocally identified by quadrupole-time-of-flight MS) accounted for ca. 87–89% of the total isoprenoid cytokinin content in control and vernalized plants, whilst N6-isopentenyladenosine (6% in control and 8% in vernalized plants) and cis-zeatin (2% in control and 1% in vernalized plants) were the next most abundant cytokinins. In the post-vernalization period, endogenous cytokinin levels decreased, but remained significantly higher in the reproductive plants than in the vegetative controls. These results suggest that cytokinins, especially those of the cis-zeatin type, are involved in vernalization-induced reproductive development of B. napus.
Permanent Link: http://hdl.handle.net/11104/0207916