| Texto completo | |
| Autor(es): |
Pereira, Paula Natalia
;
Charles Smith, James Andrew
;
Mercier, Helenice
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | PHYSIOLOGIA PLANTARUM; v. 160, n. 4, p. 361-372, AUG 2017. |
| Citações Web of Science: | 4 |
| Resumo | |
Among species that perform CAM photosynthesis, members of the genus Kalanchoe have been studied frequently to investigate the effect of environmental factors on the magnitude of CAM activity. In particular, different nitrogen sources have been shown to influence the rate of nocturnal CO2 fixation and organic-acid accumulation in several species of Kalanchoe. However, there has been little investigation of the interrelationship between nitrogen source (nitrate versus ammonium), concentration and the activity of the vacuolar proton pumps responsible for driving nocturnal organic-acid accumulation in these species. In the present study with Kalanchoe laxiflora and Kalanchoe delagoensis cultivated on different nitrogen sources, both species were found to show highest total nocturnal organic-acid accumulation and highest rates of ATP- and PPi-dependent vacuolar proton transport on 2.5 mM nitrate, whereas plants cultivated on 5.0 mM ammonium showed the lowest values. In both species malate was the principal organic-acid accumulated during the night, but the second-most accumulated organic-acid was fumarate for K. laxiflora and citrate for K. delagoensis. Higher ATP- and PPi-dependent vacuolar proton transport rates and greater nocturnal acid accumulation were observed in K. delagoensis compared with K. laxiflora. These results show that the effect of nitrogen source on CAM activity in Kalanchoe species is reflected in corresponding differences in activity of the tonoplast proton pumps responsible for driving sequestration of these acids in the vacuole of CAM-performing cells. (AU) | |
| Processo FAPESP: | 11/50637-0 - Competência para a expressão do metabolismo ácido das crassuláceas (CAM) em bromélia epífita: sinalização, modulação da expressão, perfil transcricional e interação com o metabolismo de nitrogênio |
| Beneficiário: | Helenice Mercier |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |