Figure 4.
Casparian strip formation in mir528a, mir528b, and mir528a/b loss-of-function mutants.
(A) ZmmiR528 levels in the WT and in mir528a, mir528b, and mir528a/b loss-of-function mutants as indicated by small RNA northern blots. Numbers below each lane indicate relative expression. U6 RNA was probed as a loading control.
(B) Effects of N supply on Casparian strip formation in mir528a, mir528b, and mir528a/b loss-of-function mutants grown in a hydroponic solution containing 8 mM NO3−-N for 3 days. The area 1.0–1.5 cm from the root apex was sampled, stained with berberine hemisulfate, and assessed for Casparian strip formation. Casparian strips are indicated by red arrowheads. Numbers below the photographs indicate the percentage of root tips with Casparian strips (% and number of roots that formed Casparian strips/total root number). Scale bars represent 50 μm.
(C) Fluorescence signal ratio of Casparian strips to xylem vessels. Values are means ± SEM. Means with the same letter are not significantly different at P < 0.05 according to the LSD test.