Membrane flow in plants: preparation and kinetics of labelling of plasma membranes from growing pollen tubes of tobacco |
| |
Authors: | Tetsuko Noguchi D J Morré |
| |
Institution: | (1) Department of Medicinal Chemistry, Purdue University, Hansen Life Sciences Research Building, 47907 West Lafayette, IN, USA;(2) Biological Laboratory, Nara Women's University, Nara |
| |
Abstract: | Summary Growing pollen tubes of tobacco germinated in suspension culture, were labelled with 3H]leucine and after varying times of chase with unlabelled leucine at 23, 16, or 4°C, were separated into plasma membrane-enriched and plasma membrane-depleted fractions by aqueous two-phase partition. At 23°C, the specific radioactivity of the plasma membrane increased with time to a maximum at 60 min. At 16°C and 4°C, labelling of the plasma membrane was respectively 40% and 10% that at 23°C. However, if labelling was at 23°C and subsequent transfer was at 4°C, plasma membrane labelling was much less affected and labelling of the plasma membrane was 60% that at 23°C. Additionally, quantitation of various morphological parameters revealed no accumulations of 50–70 nm transition vesicles in the space between endoplasmic reticulum and cis Golgi apparatus that might suggest formation of a low temperature compartment similar to those described for mammalian cells and tissues. Similarly, growth of pollen tubes was reduced but not blocked even at temperatures of 12°C. The results suggest that tube elongation is accompanied by a steady state flow of membranes to the cell surface that is relatively insensitive to interruption by low temperatures. Whereas leucine incorporation is reduced by low temperature even at 16°C, the flow pathway to the cell surface, including the endoplasmic reticulum to Golgi apparatus transfer step, as well as elongation growth does not exhibit a pronounced low temperature block in this tip growing system. |
| |
Keywords: | Pollen tube Endoplasmic reticulum Golgi apparatus Membrane biogenesis Plasma membrane (tobacco) |
本文献已被 SpringerLink 等数据库收录! |
|