Fig. 6: Communication between leaves and hypocotyls is responsible for AR initiation.
From: AUREA maintains the balance between chlorophyll synthesis and adventitious root formation in tomato
a–d Different types of grafting combinations. rf/WT represents that scion of rf was grafted onto the WT stock, and the same designation rule applies to WT/WT, WT/rf, and rf/rf. The yellow boxes indicate the hypocotyl section that is enlarged in the corresponding insets. The yellow arrows indicate adventitious roots (c). Bar = 1 cm. e Quantification of ARs in different types of grafting. Error bars represent SE (n = 5). f Hypocotyl HO-1 activity in different types of grafting. Error bars represent SE (n = 5). g Schematic diagram of the AU–(HO-1)–heme–CO pathway in adventitious root formation. Loss of function of AU potentially leads to massive accumulation of heme in leaves and enhances HO-1 activity in the hypocotyl. The overaccumulated heme fluxes from the leaves to hypocotyls, where it is decomposed by HO-1. Through CO production, extra heme promotes the formation of adventitious roots in stems
