Figure 3: Effect of pH on PA-induced root abscission in A. pinnata. Root abscission is represented as % of the initial number of roots. Assays were conducted in (a) neutral phosphate buffer in the presence of 2 mM spermine at pH 9 and pH 7 () and 2 mM spermine tetrahydrochloride (Spm·4HCl) at pH 6.8 (), (b) neutral phosphate buffer in the presence of 2 mM spermidine at pH 8.3 () and pH 7 (), and (c) 10 mM potassium phosphate solution pH 4, 5, 6, 7, 8 (), 9 and 10 (). Hydrochloric acid was used to adjust the pH. In (c), since the results were identical, four representative data (pH 4, 6, 8, and 10) are shown for simplification. Standard error bars are only shown where larger than the symbols used.