Surface charge on isolated maize-coleoptile amyloplasts |
| |
Authors: | F. D. Sack D. A. Priestley A. C. Leopold |
| |
Affiliation: | 1. Boyce Thompson Institute for Plant Research, Cornell University, 14853, Ithaca, NY, USA
|
| |
Abstract: | Whole amyloplasts were isolated from Zea mays L. coleoptiles. Electron microscopy confirmed that their envelopes consisted of two intact membranes. Their surface charge was quantified through electrokinetic measurements employing a vertically oriented cataphoresis cell. Amyloplasts from coleoptiles of different ages (5–9 d) and degree of exposure to light (0–9 d) all had negative zeta potentials (mean of -19.4 mV). Isolated starch granules had comparable values. The net negative surface charge was confirmed ultrastructurally by the binding of cationised ferritin to both amyloplasts and starch grains. Cationised ferritin tagged with a fluorescent label (fluorescein isothiocyanate) showed binding to some amyloplasts but not to starch grains. These results are discussed in the context of a hypothesized role for statolith charge in plant graviperception. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |