EXPORT OF SOLUBLE SUGARS AND INCREASE IN MEMBRANE-PERMEABILITY OF GLADIOLUS FLORETS DURING SENESCENCE

Export of soluble sugar, changes in all membrane permeability, and pro duction rate of ethylene in the perianths of the lower florets on the gladiolus spikes were determined as related to physiological events af fecting the wilting of perianths after they were fully unfolded. 1. Pe rianths appeared to be wilting between 2 and 3 days after unfolding fu lly (DAU). Concurrent with the onset of wilting, perianths rapidly dec reased in fresh and dry weights. 2. Between 1 and 2 DAU, one day befor e perianths started to wilt, total soluble sugar contents began to dec rease. Between 2 and 3 DAU, the largest loss of total soluble sugars o ccurred, most of which was possibly due to export from perianths to ot her parts. Concurrent with the export of sugars, an increase in leakag e of ions from perianth tissues was observed. 3. Rates in ethylene pro duction of perianths did not show a significant change in relation to the time of wilting. Depletion of sugars was discussed as related to t he disintegration of membranes, which could cause perianths to wilt.