Figure 1.
Dehydration Stimulates PLD Activity.
(A) Leaf discs from C. plantagineum were prelabeled with 32Pi for 16 hr, removed from the labeling buffer, and dried for the times indicated. To measure PLD activity, we again incubated them in buffer that included <0.75% n-butanol (ButOH). After 5 min of vacuum infiltration, the discs were incubated for 25 min at room temperature.
(B) Autoradiography of a TLC plate with the separated phospholipids extracted from one leaf disc, showing the extent of PtdButOH and PtdOH formation in response to dehydration. The positions of PtdButOH and PtdOH are indicated. C, control disc.
(C) Quantification of PtdButOH and PtdOH by using a PhosphorImager. The amount of each phospholipid is expressed as fold stimulation relative to that in the control. The horizontal lines in the graph indicate the amount of PtdButOH (top) and PtdOH (bottom) measured in the control discs. The values are means of two independent experiments. The error bars indicate the standard deviations.
(D) Leaf discs of C. plantagineum were treated as described in (A) but were sampled after different durations of dehydration.
(E) Autoradiography of the TLC plate after separation of the phospholipids (cf. [B]).
(F) Quantification of PtdButOH and PtdOH by using a PhosphorImager (cf. [C]).