In Vitro Sugar Transport in Zea mays L. Kernels 1: II. Characteristics of Sugar Absorption and Metabolism by Isolated Developing Embryos
AUTOR(ES)
Griffith, Stephen M.
RESUMO
In vitro sugar transport into developing isolated maize embryos was studied. Embryo fresh and dry weight increased concomitantly with endogenous sucrose concentration and glucose uptake throughout development. However, endogenous glucose and fructose concentration and sucrose uptake remained constant. The uptake kinetics of radiolabeled sucrose, glucose, and fructose showed a biphasic dependence on exogenous substrate concentration. Hexose uptake was four to six times greater than sucrose uptake throughout development. Carbonylcyanide-m-chlorophenylhydrazone and dinitrophenol inhibited sucrose and glucose uptake significantly, but 3-O-methyl glucose uptake was less affected. The uptake of 1 millimolar sucrose was strongly pH dependent while glucose was not. Glucose and fructose were readily converted to sucrose and insoluble products soon after absorption into the embryo. Thus, sucrose accumulated, while glucose pools remained low. Based on the findings of this and other studies a model for sugar transport in the developing maize kernel is presented.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1056605Documentos Relacionados
- In Vitro Sugar Transport in Zea mays L. Kernels 1: I. Characteristics of Sugar Absorption and Metabolism by Developing Maize Endosperm
- Sterol Accumulation and Composition in Developing Zea mays L. Kernels 1
- Abscisic Acid Biosynthesis in Isolated Embryos of Zea mays L. 1
- Concentration and Metabolic Turnover of Indoles in Germinating Kernels of Zea mays L. 1
- Acetolactate Synthase Activity in Developing Maize (Zea mays L.) Kernels
