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Phenols, proline and low-molecular thiol levels in pea (Pisum sativum) plants respond differently toward prolonged exposure to ultraviolet-B and ultraviolet-C radiations

100%

Katerova Z., Ivanov S., Mapelli S., Alexieva V.

Acta Physiologiae Plantarum

2009

tom 31

nr 1

Pea (Pisum sativum L.) seedlings were exposed to low, moderate, and high regimes of ultraviolet-B (UVB) (ld-B 4.4, md-B 13.3, and hd-B 26.5 kJ m⁻² day⁻¹), or ultraviolet-C (UV-C) (ld-C 0.1, md-C 0.3, and hd-C 0.6 kJ m⁻² day⁻¹) radiations. Concentrations of total phenols, free proline, and low-molecular thiol groups were determined in the last formed (young) and older leaves after irradiation for 7, 10 or 14 consecutive days. Shoot length and weight did not change markedly after 14 days of ld-B and ld-C, but reduced substantially after moderate and high regimes of both UV-B and UV-C. Proline decreased upon high doses of irradiation, while in ld-B treated plants, by contrast, an increase was observed. The reduction in total phenols and thiols was stronger after hd-B than after hd-C irradiations, although an induction was found in ld-B treated plants. In contrast to ld-B, ld-C regime led mainly to reductions or insignificant changes in proline, phenols, and thiols. Therefore, the stress-protection mechanisms are different between low UV-B and UV-C irradiation regimes in regard to proline, phenols, and thiols.

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

76%

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.

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

63%

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.

Ograniczanie wyników

3 Acta Physiologiae Plantarum

3 Alexieva V.

2 Hall M.

2 Karanov E.

2 Smith A.

2 Todorova D.

2 Vaseva-Gemisheva I.

1 Genkov T.

1 Ivanov S.

1 Katerova Z.

1 Mapelli S.

1 Petrov P.

1 Stoynova-Bakalova E.

1 2009

1 2006

1 2005

Wyniki wyszukiwania

Phenols, proline and low-molecular thiol levels in pea (Pisum sativum) plants respond differently toward prolonged exposure to ultraviolet-B and ultraviolet-C radiations

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

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