Source-sink relationship and photosynthesis in the horn-shaped gall and its host plant Copaifera langsdorffii Desf. (Fabaceae)

► The galls on Copaifera langsdorffii are a sink of photoassimilates. ► The polysaccharides and soluble sugars contents were higher in galls. ► Nitrogen and chlorophyll contents are related to the low photosynthetic activity. ► Photosynthesis in gall tissues could provide oxygen to the structure.