Sucrose Transport in Isolated Immature Barley Embryos |
| |
Authors: | CAMERON-MILLS V; DUFFUS C M |
| |
Institution: | Department of Agricultural Biochemistry, Edinburgh School of Agriculture, University of Edinburgh West Mains Road, Edinburgh EH9 3JG |
| |
Abstract: | Techniques have been devised to select immature barley embryosat various stages in their development, and to study their accumulationof sucrose in vitro. Isolated embryos accumulate sucrose overa period of several hours of which some 80 per cent is conservedas a pool of free sucrose and the remainder utilized in macromolecularsynthesis. The rate of sucrose uptake increases with embryodevelopment, however the specific activity of uptake remainsconstant, indicating that the transport processes are fullyoperative early in embryogenesis. From the kinetics of sucroseuptake it is deduced that facilitated transport predominatesat sucrose concentrations of 50 mM, while at higher concentrationspassive diffusion makes an increasing contribution to sucroseaccumulation. The substrate specificity and the sensitivityof sucrose transport to uncoupling agents, in addition to thestability of the pool of accumulated sucrose, are all indicativeof active transport playing a major role in the sucrose assimilationof developing barley embryos. Hordeum distichum (L.) Lam, barley, embryo, sucrose transport |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|