Table 3.

Correlation matrix (Pearson correlation r) between poplar traits, enzymatic activities, and percentage mycorrhizal colonization

	%	Chl	DW stem	DW roots	LMA	M Xyl	M Glr	M Nag	M Cel	M Gls	M Pho	M Lac	NM Xyl	NM Glr	NM Nag	NM Cel	NM Gls	NM Pho
	1	−0.09	0.20	0.20	0.06	0.22	0.14	0.13	0.07	0.13	0.04	0.05	0.05	0.13	0.02	−0.02	0.06	0.13
Chl		1	−0.12	−0.12	−0.01	–0.19	−0.01	−0.07	–0.18	–0.18	−0.05	0.01	−0.00	0.02	0.08	0.08	0.00	0.11
DW stem			1	0.42	–0.28	−0.05	−0.04	0.04	−0.07	−0.13	−0.02	−0.01	−0.01	0.09	0.12	0.00	−0.02	0.01
DW roots				1	–0.20	0.05	0.04	0.06	−0.01	0.02	−0.03	0.06	−0.07	0.00	−0.09	−0.09	−0.10	−0.02
LMA					1	0.14	0.09	0.14	0.06	0.10	0.12	0.13	−0.08	−0.13	−0.04	−0.07	−0.06	0.04
M Xyl						1	0.12	0.41	0.64	0.56	0.25	0.25	0.07	0.02	−0.03	0.11	−0.03	0.09
M Glr							1	0.27	0.18	0.15	0.30	0.15	0.01	0.07	−0.12	−0.13	−0.07	0.15
M Nag								1	0.35	0.33	0.47	0.31	−0.11	−0.08	−0.04	−0.01	–0.19	0.32
M Cel									1	0.69	0.22	0.16	0.06	−0.04	0.02	0.05	−0.06	0.05
M Gls										1	0.25	0.27	0.01	−0.05	−0.07	0.06	−0.05	0.09
M Pho											1	0.29	0.01	0.08	−0.01	0.02	0.01	0.36
M Lac												1	−0.12	−0.05	−0.14	−0.06	−0.10	0.21
NM Xyl													1	0.47	0.27	0.43	0.35	−0.03
NM Glr														1	0.25	0.39	0.29	0.04
NM Nag															1	0.24	0.31	−0.03
NM Cel																1	0.28	−0.03
NM Gls																	1	0.07
NM Pho																		1

Abbreviations: %, percentage mycorrhizal colonization; Chl, chlorophyll (g m⁻²); DW, dry weight (g); LMA, keaf maximum area (m²); M, mycorrhizal root tips; NM, non-mycorrhizal root tips; Pho, acid phosphatase; Nag, N-acetylglucosaminidase; Gls, β-glucosidase; Cel, cellobiohydrolase; Xyl, β-xylosidase; Lac, laccase; Glr, β-glucuronidase.

Correlation is significant for P <0.01 (values in bold).