shoot axis tuber subterranean shoot axis tuber PO:0004547 tub&#233rculo subterr&#225neo (Spanish, exact) 地下塊茎 (Japanese, exact) PO_GIT:615 Functions in storage of photosynthate metabolites. This term should be used for tubers derived from branches, as found in Solanum spp. (e.g. potato) or Dioscorea spp. (e.g. yam) and other species. Use the term tuberous root tuber (PO:0025476) for tubers derived from roots, such as those found in Cassava, Ipomoea, or Hemerocallis. plant_anatomy A shoot axis tuber (PO:0004543) that develops below ground.