Figure 4.

Structure-activity relationships of glucans in eliciting PAL activity in tobacco cells. The glucan fractions included: laminarin (Lam), laminarin oligomers, namely laminaripentaose through laminaribiose (referred to as pentaG through diG); a mycelial, cell wall extract from P. sojae (Psg) obtained as described by Ayers et al. (1976b); and the β-1,6–1,3 glucan heptasaccharide (HeptaG) purified from the latter glucan fraction (Sharp et al., 1984a, 1984b). The structures of the β-1,6–1,3 heptaglucan and the laminarin DP5 are represented. The induction of PAL activity was measured 4 h after the addition of glucans, applied at 50 μg mL⁻¹. Representative data from 1 of 2 replicates are presented.