Fig. 2.

(A) ESR spectra of treatments A and F from Fig. 1. The sextet signal corresponds to the naturally occurring manganese ions (Mn²⁺) with G-values lying between 1·8565 and 2·1619. The radical spectrum is a signal whose g-value of 2·0081 suggests that is a radical apparently derived from quinone (Nandi et al., 1997). (B) Mean amplitude of the ESR signals from Salix nigra seeds for treatments A–F (Fig. 1). Treatments with the same letters above columns are not significantly different at P = 0·05 according to Tukey's test.