Within-plant relationships among wounding, jasmonic acid, and nicotine implications for defence in Nicotiana sylvestris.

In Nicotiana sylvestris Spegazzini and Comes (Solanaceae), we examined the relationships among wounding, endogenous leaf jasmonic acid (JA) pools, and whole-plain (WP) nicotine accumulation over a range of wounding intensities and spatial distributions, in order to explore optimal defence (OD) theory predictions. We quantitatively wounded one or four leaves and then quantified: (1) JA in damaged and undamaged leaves 90 min after wounding; (2) WP nicotine concentration after 5 d (the times when JA and nicotine attain the largest wound-induced concentrations). We find: (1) statistically significant, positive relationships on a leaf-by-leaf basis among the number of leaf punctures, endogenous leaf JA, and WP nicotine accumulation; (2) that young, undamaged leaves have a higher concentration of JA than do older, undamaged leaves, and produce a greater amount of JA per puncture than older leaves, but that all leaves have the same JA content (ng JA per leaf); and (3) that a damaged leaf produces less JA when other leaves in the canopy are wounded than when it is the onh wounded leaf in the canopy, but that when it is the only wounded leaf, the phylotactically adjacent, undamaged leaves do not increase their JA concentrations.