[The structures of plant trophic tract: plastid stromules and cell wall plasmodesmata]

Plastid stromules and cell wall plasmodesmata are special structures of plant cell. They were discovered with time difference in one and half hundred years: stromules--at the beginning of XXI century, plasmodesmata--at the end of XIX century. The former and latter are, correspondingly, the intra- and intercellular fragments of endoplasmic reticulum which is a network for the photosynthate distribution along plant body. Discovery methods and history, structural similarity and differences, succession of functional interpretation are discussed. The origin of both is connected with photosynthesis and photosynthate export. Their tubular structure and transport function are similar. The impulsive mobility of both is under control of the acto-myosin cytoskeleton. Temperature regime of formation and functioning is also the same. Photosynthesis is possible at 0 °C and even below. The structures of exporting network, stromules and plasmodesmata, are not formed up to 10 °C, and the numbers of both increase sharply at temperature 20 °C due to increasing cytoskeleton plasticity. Structural and functional continuity of stromules and plasmodesmata are postulated as the mobile trophic tract of vascular plants.