Fig. 4

Visualization of labeled choline phospholipids in tissues from reproductive plants. Arabidopsis plants were grown for 6 weeks on agar media containing 200 µM propargylcholine. a–j Light and a′–j′ fluorescence matching light images are shown after performing click chemistry with fluorescein azide (green) (a, b, e–j) or Alexa Fluor 594 azide (red) (c, d). a Leaf epidermis reveals brightly fluorescing guard cells. b Magnification of guard cells on leaves. c The 0 μM propargylcholine control shows little or no background fluorescence (red) from the leaf epidermis after the Alexa Fluor 594 azide reaction. In contrast, d the epidermis from plants grown in on media containing propargylcholine display a strong fluorescence signal in guard cells, similar to that seen in b. e, f Root and e, f stem tissues exhibit fluorescence at cell peripheries and within cells. h Root hairs exhibit fluorescence (arrows). i, j Cryosections of mature seeds harvested at 7 weeks. i The seed endosperm exhibits a strong fluorescence signal. j Mucilage secretory cells of the seed coat exhibit fluorescence at the boundaries of the columella (arrows)