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Endogenous cytokinin accumulation and cytokinin oxidase activity during shoot organogenesis of Petunia hybrida
Author(s) -
Auer Carol A.,
Motyka Václav,
Březinová Alena,
Kamínek Miroslav
Publication year - 1999
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1999.105121.x
Subject(s) - cytokinin , petunia , zeatin , biology , shoot , explant culture , organogenesis , botany , oxidase test , riboside , auxin , biochemistry , enzyme , gene , in vitro
Changes in endogenous cytokinin content and cytokinin oxidase activity were characterized in leaf explants from two Petunia hybrida Vilm. genetic lines which differed in their shoot organogenic response to exogenous N 6 ‐benzyladenine (BA). Endogenous cytokinin content in leaf explants of the highly shoot organogenic line, St40, increased 1.7‐fold during the shoot induction phase (days 6–10) and had an additional 2.6‐fold cytokinin increase correlated with the shift from induction to the shoot development phase. The cytokinins isopentenyl adenine (iP) and isopentenyl adenosine (iPAR) increased, while the cytokinins zeatin, zeatin riboside and dihydrozeatin remained at consistently low levels. In contrast, isoprenoid cytokinins did not accumulate in petunia TLV1 leaf explants which were incapable of shoot induction during 12 days of culture with BA. Cytokinin oxidase activity continuously increased in leaf explants of both petunia genotypes in response to BA, with a larger increase in St40. These results suggest that the differences in organogenic response in the two petunia genotypes may be the result of differences in BA uptake and metabolism which subsequently affects the accumulation of isoprenoid cytokinins and the activity of cytokinin oxidase in the early stages of shoot development.