Diurnal Fluctuations in Ethylene Formation in Chenopodium rubrum.
AUTOR(ES)
Machackova, I.
RESUMO
Ethylene formation was studied in 5- to 6-d-old Chenopodium rubrum seedlings under the following light regimes: continuous light (CL), continuous darkness (CD), and alternating light/darkness (12 h of each). No significant regular oscillations in ethylene formation were found in either the CL or CD groups. In the light/dark regime, pronounced diurnal fluctuations in ethylene formation were observed. Activity of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase was transiently increased on transfer from light to dark and vice versa. In CL, ACC oxidase activity did not change significantly, whereas in CD, it decreased continuously after the initial increase. The in vivo levels of ACC and N-malonyl-ACC (MACC) were constant for the first few hours of darkness, then decreased dramatically, but increased again in the light. In constant darkness, the level of ACC displayed endogenous rhythm, with minimum values at h 12 and 44, and a maximum value at h 32 to 36. The level of MACC in both shoots and roots decreased in the CD group until h 12, and then remained constant until h 30 before decreasing continuously. We conclude that the photoperiodic regime affects both ACC and MACC levels, as well as the conversion of ACC to ethylene. Correlation of the described changes in ethylene formation to photoperiodic flower induction is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=158219Documentos Relacionados
- Immunocytochemical ultrastructural analysis of chromatophore membrane formation in Rhodospirillum rubrum.
- Carbon monoxide dehydrogenase from Rhodospirillum rubrum.
- Identification and Preliminary Characterization of a Ca2+- Dependent High-Affinity Binding Site for Inositol-1,4,5-Trisphosphate from Chenopodium rubrum.
- Identification of an alternative nitrogenase system in Rhodospirillum rubrum.
- Carbon monoxide-dependent growth of Rhodospirillum rubrum.