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Cytokinin oxidase-dehydrogenase [CKX] activity in wild and ethylene-insensitive mutant eti5 type of Arabidopsis thaliana [L.] Heynh plants and the effect of cytokinin N1-[2-chloro-4-pyridyl]-N3-phenylurea on enzymatic activity and leaf morphology

100%

Todorova D., Vaseva-Gemisheva I., Petrov P., Stoynova-Bakalova E., Alexieva V., Karanov E., Smith A., Hall M.

Acta Physiologiae Plantarum

2006

tom 28

nr 6

The specific activity of cytokinin oxidase/dehydrogenase (EC 1.5.99.12) (CKX) was determined in leaves of wild type (wt) and ethylene-insensitive mutant (eti5) of Arabidopsis thaliana (L.) Heynh plants. Comparative studies showed that this mutation has lower basal CKX activity than wt. Application of 4PU-30 (N1-(2-chloro-4-pyridyl)-N2-phenylurea) resulted in decreased CKX activity in both wt and mutant plants. The treatment increased leaf blade thickness and the volume of chlorophyll-containing cells per unit leaf area in wt but these changes were not observed in the eti5 mutant. The reduction in chlorophyll “a” and “b”, as well as in carotenoids content in the treated wt tissues resulting from altered leaf morphology was not detected in eti5 plants.

Effect of temperature stress on the endogenous cytokinin content in Arabidopsis thaliana [L.] Heynh plants

80%

Todorova D., Genkov T., Vaseva-Gemisheva I., Alexieva V., Karanov E., Smith A., Hall M.

Acta Physiologiae Plantarum

2005

tom 27

nr 1

The levels of three endogenous cytokinin equivalents: zeatin (Z), iso-pentenyladenine (iP) and dihydrozeatin (dZ) in two Arabidopsis thaliana (L.) Heynh genotypes - wild type (wt) and ethylene-insensitive mutant (eti5), were compared using enzyme immunoassay (ELISA). Cytokinin content was measured after exposure to low (4 °C for 24 h in darkness) or high temperature (38 °C for 24 h in darkness). Measurements were performed immediately and 24, 48 and 120 h after treatments. It was found that at normal growth conditions eti5 plants contained more endogenous cytokinins compared to the wild type. At both temperature treatments mutant plants had decreased total cytokinin levels. Wild-type plants treated with high temperature (HT) exhibited reduced total cytokinins (with the exception of rates at 48 h), while low temperature (LT) treatment resulted in elevated total amount of the studied equivalents (except at 24 h). The obtained results suggested that HT had greater effect on cytokinin levels than LT since it caused more profound changes in the total content. We assume that this was due to the natural chilling tolerance of Arabidopsis plants.

Ograniczanie wyników

2 Acta Physiologiae Plantarum

2 Alexieva V.

2 Hall M.

2 Karanov E.

2 Smith A.

2 Todorova D.

2 Vaseva-Gemisheva I.

1 Genkov T.

1 Petrov P.

1 Stoynova-Bakalova E.

1 2006

1 2005

Wyniki wyszukiwania

Cytokinin oxidase-dehydrogenase [CKX] activity in wild and ethylene-insensitive mutant eti5 type of Arabidopsis thaliana [L.] Heynh plants and the effect of cytokinin N1-[2-chloro-4-pyridyl]-N3-phenylurea on enzymatic activity and leaf morphology

Effect of temperature stress on the endogenous cytokinin content in Arabidopsis thaliana [L.] Heynh plants