Table 2.

Correlation coefficients (r) among the photosynthetic traits, morphology indexes, and root physiological parameters for the pine seedlings of families Nos. 35 and 79, which were exposed to the SAR at pH of 5.6, 4.5, 3.5, and 2.5.

Variables	Chl. a/b	RPRPM	OA	MA	CA
Chl. a	− 0.726*	− 0.865**	− 0.551	− 0.099	0.052
Chl. b	− 0.959**	− 0.966**	− 0.693	0.021	0.087
Chl. a + b	− 0.899**	− 0.959**	− 0.661	− 0.026	0.076
Chl. a/b	1	0.928**	0.650	− 0.172	− 0.170
RPRPM	0.928**	1	0.798*	0.077	0.046
RL	− 0.935**	− 0.982**	− 0.726*	0.027	0.049
SL	− 0.936**	− 0.966**	− 0.709*	0.063	0.071
RDW	− 0.931**	− 0.958**	− 0.698	− 0.012	0.009
PLRN	− 0.946**	− 0.943**	− 0.584	0.242	0.286
OA	0.650	0.798*	1	0.529	0.570
MA	− 0.172	0.077	0.529	1	0.959**
CA	− 0.170	0.046	0.570	0.959**	1
RpH	− 0.860**	− 0.943**	− 0.924**	− 0.280	− 0.291
NRpH	− 0.836**	− 0.929**	− 0.948**	− 0.331	− 0.342

**, and * = significant at 0.01 and 0.05 levels, respectively. The underlined data indicates a significant negative correlation between the two indicators.

Chl. a chlorophyll a, Chl. b chlorophyll b, Chl. a + b chlorophyll a + b, Chl. a/b chlorophyll a/b, RPRMP relative permeability of plasma membrane, RL root length, SL shoot length, RDW root dry weight, PLRN primary lateral root number, OA oxalic acid, MA malic acid, CA citric acid, RpH rhizosphere pH, NRpH non-rhizosphere pH. The abbreviations above are the same as the following.