Compartmention of assimilate fluxes in leaves. II. Apoplastic sugar levels in leaves of plants with different companion cell types. - Voitsekhovskaja, ,O..V.,.; Pakhomova, ,M..V.,.; Syutkina, ,A..V.,.; Gamalei, ,Y..V.,.; and Heber, ,U.. (Plant Biol., 2000)