Inhibition of pollen-tube growth and protein secretion by the monovalent ionophore monensin

✍ Scribed by Speranza, A. ;Calzoni, G.L.

• Publisher: Springer
• Year: 1992
• Tongue: English
• Weight: 796 KB
• Volume: 5
• Category: Article
• ISSN: 0934-0882
• DOI: 10.1007/bf00189817

✦ Synopsis

Apple pollen tubes grown in vitro in the presence of up to 1 gM monensin, which is known to slow down or stop vesicular traffic originating from the Golgi complex, were severely inhibited by the carboxylic ionophore. Monensin at concentrations as low as 5 nM significantly decreased the secretory release of protein into the extracellular space. During 2 h of germination in the presence of monensin, 3H-leucine incorporation into the membrane versus the soluble fraction increased with respect to the controls. These data seem to be consistent with an effective action of monensin on the secretory routes which, in pollen tubes, deliver products from the dictyosomes to the extending tip. The importance of monovalent cation homeostasis in the functioning of secretory paths, also in unique cells such as pollen tubes, emerges clearly from the present data.