“…BLEDSOE et aI., 1949;BIDDULPH, 1951BIDDULPH, , 1954SWANSON and WHITNEY, 1953;ZIEGLER, , 1963aBUKOVAC et aI., 1956;BIDDULPH et aI., 1958;ANSIAUX, 1958ANSIAUX, , 1959WELLS and METZ, 1963;LEVI, 1967LEVI, , 1968BAKER, 1969). high Ca2+ concentration in the surroundings of the sieve tubes, Ca2+ can enter the sieve tubes (MILLIKAN and HANGER, 1969;RINGOET et aI., 1967RINGOET et aI., , 1968 and is then translocated like the other constituents in the lumen of the sieve tubes (WIER SUM et aI., 1971). Under certain circumstances, e.g.…”