Mýtinová Z, Motyka V, Haisel D, Gaudinová A, Lubovská Z, Wilhelmová N
BIOLOGIA PLANTARUM
54:
461-470,
2010
Keywords:
abiotic stress; abscisic acid; antioxidative enzymes; cytokinin; cytokinin oxidase/dehydrogenase; drought; salinity; zinc
Abstract:
The responses of antioxidant enzymes (AOE) ascorbate peroxidase (APX), glutathione reductase (GR), superoxide
dismutase (SOD), and catalase (CAT) in soluble protein extracts from leaves and roots of tobacco (Nicotiana tabacum L.
cv. Samsun NN) plants to the drought stress, salinity and enhanced zinc concentration were investigated. The studied
tobacco included wild-type (WT) and transgenic plants harbouring the cytokinin oxidase/dehydrogenase (CKX) gene under
control of 35S promoter from Arabidopsis thaliana (AtCKX2). The transgenic plants exhibited highly enhanced CKX
activity and decreased contents of cytokinins and abscisic acid in both leaves and roots, altered phenotype, retarded
growth, and postponed senescence onset. Moreover, an enhanced photoprotection was found in leaves of AtCKX2 tobacco
previously. Under control conditions, the AtCKX2 plants exhibited noticeably higher activity of GR in leaves and APX
and SOD in roots. The AOE responses to the stresses differed between AtCKX2 and WT plants as well as between leaves
and roots within individual plants. The stress conditions induced the opposite effects on CAT activity in leaves: it always
decreased upon stresses in WT while increased in AtCKX2 plants. On the contrary, the SOD activity enhanced in WT but
declined in AtCKX2 leaves. In roots, the APX activity prevailingly increased in WT while mainly decreased in AtCKX2 in
response to the stresses. Both WT and AtCKX2 leaves as well as roots exhibited elevated abscisic acid concentration and
increased CKX activity under all stress conditions while endogenous CKs and IAA levels were not much affected by stress
treatments in either WT or transgenic plants.
Fulltext: contact IEB authors
IEB authors: Alena Gaudinová,
Daniel Haisel,
Zuzana Lubovská,
Václav Motyka,
Naďa Wilhelmová