Chromatin-associated ornithine decarboxylase at early stages of growth and differentiation of etiolated mono- and dicotyledonous plants

Ornithine decarboxylase (ODC) of barley, corn, bean and pea plants was associated with chromatin at early stages of growth. In corn, bean and pea plants the chromatin of roots possessed ODC with the highest specific activity of 30–65 units per mg protein. After 200 h of growth ODC activity of chromatin declined, while ODC activity of cytosol increased linearly to 4–19 units per mg protein. ODC activity of either chromatin or cytosol of shoots in the above mentioned plants was usually low, 1–2 units per mg protein and only at the beginning of shoot growth (96 h) did pea chromatin have high ODC activity (14 units per mg protein). In these plants ODC was tightly bound to chromatin and could not be extracted with different concentrations of NaCl (0.1–1.0 M) or non-ionic detergent (Triton X100, Tween 20) but could be extracted by freezing and thawing with satisfactory recovery.