Abstract: | To study the kinetics of synthesis, wall-binding and degradationof xyloglucan, we incubated suspension-cultured rose cells for0524 h in L-1-3H]arabinose. >95% of the 3H]arabinosewas taken up within 2 h. UDP-Pentoses were maximally labelledwithin 05 h and had lost most of their 3H by 2 h afterthe addition of 3H]arabinose. Therefore, the 24 h experimentresembled a pulse-chase rgime. The 3H]xyloglucan formed wasfractionated into four cellular pools detergent-extractable(interpreted as cytoplasmic), and guanidinium thiocyanate-,06 M NaOH- and 60 M NaOH-extractable (interpreted as progressivelymore firmly wall-bound)]; soluble extracellular xyloglucan wascollected as a fifth pool. All five pools of xyloglucan hadstarted accumulating 3H at their respective maximal rates by |