Figure 1.

Polyamines trigger the formation of PIP₂ in Arabidopsis seedlings.

³²P_i‐pre‐labelled seedlings were treated for 30 min with 60 µm of putrescine (Put), spermidine (Spd) or spermine (Spm), or with buffer alone (control, Ctrl), after which their lipids were extracted, separated by thin‐layer chromatography and visualised by autoradiography.

(a) Autoradiograph of typical TLC, containing three samples per treatment. Abbreviations: PA, phosphatidic acid; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; PI, phosphatidylinositol; PIP, phosphatidylinositol phosphate; PIP₂, phosphatidylinositol 4,5‐bisphosphate. (b) Quantified ³²P‐PIP₂ response after 30 min treatment with Put, Spd, Spm, diaminopropane (Dap) or thermospermine (tSpm) at the indicated concentrations, calculated as fold increase compared with control. Data are presented as the mean ± SD (n = 6). (c) Dose–response with Spm for 30 min and (d) time‐course with 60 µm Spm or buffer alone, showing the percentage of ³²P‐PIP₂ with respect to the total of ³²P‐labelled phospholipids. In all cases, data are presented as the mean ± SD (n = 6).