Pollen tube cell volume changes rapidly in response to perturbation of the extracellular osmotic potential. This report shows that specific phospholipid signals are differentially stimulated or attenuated during osmotic perturbations. Hypo-osmotic stress induces rapid increases in phosphatidic acid (PA). This response occurs starting at the addition of 25% (v/v) water to the pollen tube cultures and peaks at 100% (v/v) water. Increased levels of PA were detected within 30 s and reached maximum by 15 to 30 min after treatment. The pollen tube apical region undergoes a 46% increase in cell volume after addition of 100% water (v/v), and there is an average 7-fold increase in PA. This PA increase appears to be generated by phospholipase D because concurrent transphosphatidylation of n-butanol results in an average 8-fold increase in phosphatidylbutanol. Hypo-osmotic stress also induces an average 2-fold decrease in phosphatidylinositol phosphate; however, there are no detectable changes in the levels of phosphatidylinositol bisphosphates. In contrast, salt-induced hyperosmotic stress from 50 to 400 mm NaCl inhibits phospholipase D activity, reduces the levels of PA, and induces increases in the levels of phosphatidylinositol bisphosphate isomers. The pollen tube apical region undergoes a 41% decrease in cell volume at 400 mm NaCl, and there is an average 2-fold increase in phosphatidylinositol 3,5-bisphosphate and 1.4-fold increase in phosphatidylinositol 4,5-bisphosphate. The phosphatidylinositol 3,5-bisphosphate increase is detected within 30 s and reaches maximum by 15 to 30 min after treatment. In summary, these results demonstrate that hypo-osmotic versus hyperosmotic perturbation and the resultant cell swelling or shrinking differentially activate specific phospholipid signaling pathways in tobacco (Nicotiana tabacum) pollen tubes.

• MeSH
• chlorid sodný farmakologie   MeSH
• fosfatidylinositol-4,5-difosfát biosyntéza   MeSH
• fosfatidylinositolfosfáty biosyntéza   MeSH
• fosfolipasa D účinky léků   metabolismus   MeSH
• fosfolipidy metabolismus   MeSH
• květy růst a vývoj   metabolismus   MeSH
• kyseliny fosfatidové biosyntéza   MeSH
• osmotický tlak účinky léků   MeSH
• signální transdukce účinky léků   fyziologie   MeSH
• tabák růst a vývoj   metabolismus   MeSH
• voda farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorid sodný MeSH
• fosfatidylinositol-4,5-difosfát MeSH
• fosfatidylinositolfosfáty MeSH
• fosfolipasa D MeSH
• fosfolipidy MeSH
• kyseliny fosfatidové MeSH
• phosphatidylinositol 3,5-diphosphate MeSH Prohlížeč
• voda MeSH