Table 2. The effect of leaf age on chemical structural compositional similarity (CSCS) and Bray–Curtis similarity, controlling for jasmonic acid treatment, and on total ion intensity in control leaves.

Nonvolatile compounds were detected using LC-MS/MS; volatile compounds were detected using GC-MS. Significance refers to the proportion of 999 differences in chemical similarity between within-species and between-species sample pairs calculated for permuted datasets that were larger than the observed difference. For total ion intensity, we tested the hypothesis that total metabolomic ion intensity was greater in young than in mature leaves using a one-sided Wilcoxon rank sum test.

A. Nonvolatile compounds
	CSCS				Bray–Curtis similarity				Total Ion Intensity
Species	Within	Btwn	Δ	p	Within	Btwn	Δ	p	Young	Mature	Δ	p
I. cocleensis	0.34	0.15	0.19	0.010	0.24	0.11	0.13	0.010	4.70	12.14	−7.44	0.943
Pi. cordulatum	0.40	0.41	−0.00	0.471	0.27	0.25	0.01	0.300	2.09	2.88	−0.788	0.9
Pr. panamense	0.30	0.17	0.13	0.017	0.22	0.10	0.13	0.009	2.85	1.81	1.04	0.135
Ps. acuminata	0.38	0.30	0.08	0.013	0.23	0.16	0.07	0.004	67.85	8.18	59.67	0.057
Combined p#				<0.001				<0.001				0.602

Notes.

^#Combined p-values indicate the significance of the effect of leaf age over all species using the weighted Z-method.