Development of Enzymes Involved in Photosynthetic Carbon Assimilation in Greening Seedlings of Maize (Zea mays) 1
AUTOR(ES)
Kobayashi, Hirokazu
RESUMO
Upon illumination of dark-grown maize seedlings (5 days old) with incandescent light, there occurred a nearly simultaneous increase, after a certain lag period, in the activities of enzymes engaged in the C4 pathway and the Calvin-Benson cycle. The light-induced biosynthesis of chlorophyll (a and b) precedes the increase in enzyme activities and proceeds without lag phase. A diphasic feature in the elevation of enzyme activities as a function of the intensities of light provided was observed; the increase in enzyme activities was enhanced by light intensities greater than 103 ergs per square centimeter per second in comparison with light of lower intensities. Under light intensities greater than 103 ergs per square centimeter per second, the simultaneous addition of levulinic acid, which inhibited chlorophyll formation, markedly reduced the increase of enzyme activities. However, neither the diphasic light effect nor the inhibitory effect of levulinic acid was observed with ribulose-1,5-bisphosphate carboxylase. The enzyme activities in the dark-grown maize seedlings were enhanced by a brief irradiation with the red light and the red light effect was reversed by the following far red light treatment. The red light-induced increase in the enzyme activities did not accompany chlorophyll synthesis, and was completely inhibited by cycloheximide, indicating that enzyme synthesis rather than activation might be involved. Light may play a dual role in enzyme induction; one is as an energy source through the photosystems at high intensities and the other is presumably as a signal mediated by phytochrome at low intensities.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=440297Documentos Relacionados
- Development of Photosystem I and Photosystem II Activities in Leaves of Light-grown Maize (Zea mays) 1
- Prepared homoeopathic in corn seeds (Zea mays)
- Variabilidade genética em populações de teosinto (Zea mays subsp. mexicana) visando a contribuição para o melhoramento genético do milho (Zea mays subsp. mays)
- Genetic analysis of fumonisin production and virulence of Gibberella fujikuroi mating population A (Fusarium moniliforme) on maize (Zea mays) seedlings.
- Concentration and Translocation of Nitrogen Compounds in the Corn Plant (Zea Mays) During Grain Development1