Table 3. Results (degrees of freedom, F- and P-values) of linear mixed effects model among standardized precipitation-evapotranspiration index (SPEI) and leaf morphological, physiological and anatomical traits in five plant functional types (PFTs) along the large-scale aridity gradient in northeast of China.

PFTs	LMA	LT	VaD	VeD	AVe/AVa	SD	SI	RWC	Pr	SS
Trees
df	6	6	6	6	6	6	6	6	6	6
F	30.23	2.79	3.19	4.17	3.93	4.53	1.52	5.78	4.52	17.35
P	<0.001	0.197	0.081	0.069	0.111	0.051	0.213	0.031	0.048	<0.001
Shrubs
df	8	8	8	8	8	8	8	8	8	8
F	14.57	29.49	21.67	23.97	141.28	8.19	11.60	1.59	62.40	58.97
P	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	0.177	<0.001	<0.001
Perennial grasses
df	8	8	8	8	8	8	8	8	8	8
F	42.69	7.39	1.94	10.65	35.88	43.46	10.29	5.55	53.76	1.24
P	<0.001	<0.001	0.065	<0.001	<0.001	<0.001	<0.001	0.002	<0.001	0.291
Annual grasses
df	8	8	8	8	8	8	8	8	8	8
F	4.34	0.197	4.18	3.29	3.08	3.67	1.24	16.09	45.72	0.43
P	0.060	0.977	0.071	0.125	0.133	0.079	0.231	<0.001	<0.001	0.857
Perennial forbs
df	6	6	6	6	6	6	6	6	6	6
F	3.62	2.01	9.18	18.20	24.96	4.03	1.19	1.87	2.36	5.15
P	0.074	0.080	<0.001	<0.001	<0.001	0.088	0.329	0.119	0.052	0.047

Fixed factor: SPEI; random factors: spatial structure, soil type. 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, relative water content; Pr, proline content; SS, soluble sugar content.