Figure 4

Auxin response in DR5::GUS /WT grafted plants. A and B) Ungrafted DR5::GUS plants. Cotyledons were removed at 6 dag and plants were transferred 7 days after to medium without IAA (A) or to medium supplemented with 5 μm IAA (B) for 3 days, and stained for GUS activity. Note the increased staining in the hypocotyl of the plant treated with IAA (B). C and D) Grafted DR5/WT plant after 3 days in medium without IAA (C) or medium supplemented with 5 μm IAA (D). Note that, as treated ungrafted plants, IAA treated grafted plants show increased staining, especially in the hypocotyl (dotted box) compared to untreated plants. E) In these experiments, only the rootstock was in contact with the medium and hormone. The picture shows a grafted plant that was transferred to a plate containing medium supplemented with 5 μm IAA; the agar was cut and the plants were placed in such a way that only the WT rootstock is in contact with the medium and the DR5 scion does not have any contact with it. F and G) Hypocotyl region of grafted DR5/WT plants in plates without IAA (F) or with 5 μm IAA (G), where increased staining in the hypocotyl of the IAA treated grafted plants compared to the untreated plants can be observed. Yellow arrowheads point to the union site of the grafted plants.