Real Time Studies of Carbon- 11 Translocation in Moonflower: III. FURTHER EXPERIMENTS ON THE EFFECTS OF A NITROGEN ATMOSPHERE, WATER STRESS, AND CHILLING; AND A QUALITATIVE THEORY OF STEM TRANSLOCATION

Translocation of naturally loaded carbon- 11 is studied in themoonflower Ipomoea alba L. and data are presented to show that:(i) source leaf export is momentarily inhibited by a suddenlyapplied water stress; (ii) pathway translocation appears toproceed by a MÜnch-like mechanism, but in a porous mediumrather than in an array of parallel, only slightly leaky pipes;and (iii) sink unloading seems to proceed normally in a nitrogenatmosphere. A qualitative model which incorporates these findingsis presented.