Table 2. Partial correlations between standardized precipitation-evapotranspiration index (SPEI) and leaf morphological, physiological and anatomical traits in five plant functional types along the large-scale aridity gradient in northeast China while controlling the effects of spatial structure and soil type.

		Tr	Sh	Pg	Ag	Pf
LMA	SPEI	0.515**	−0.241	−0.498**	−0.291	−0.127
LT	SPEI	−0.278	−0.501**	−0.307*	0.076	−0.298*
VaD	SPEI	−0.284	0.286	0.094	−0.015	−0.094
VeD	SPEI	−0.026	0.373**	0.374**	0.047	0.316*
AVe/AVa	SPEI	−0.291	0.224	0.344**	0.202	0.308*
SD	SPEI	0.289	0.116	0.083	−0.017	0.208
SI	SPEI	0.253	0.425**	0.307*	−0.032	0.172
RWC	SPEI	−0.274	0.131	0.275	0.281	0.164
Pr	SPEI	0.344*	−0.517**	−0.521**	−0.587**	0.101
SS	SPEI	−0.330*	0.504**	−0.031	−0.094	0.073

Dependent variables: LMA, leaf mass per area; LT, leaf thickness; VaD, vascular diameter; VeD, vessel diameter; A_Ve/A_Va, ratio of vessel area to vascular area; SD, stomatal density; SI, stomatal index; RWC, leaf relative water content; Pr, proline content; SS, soluble sugar content. Tr, temperate cold-deciduous broad-leaved tree; Sh, temperate cold-deciduous low or high shrub; Pg, perennial grass; Ag, annual grass; Pf, perennial forb. Negative values refer to negative relationships between the examined dependent variables and SPEI. *P < 0.05, **P < 0.01.