Table 1. Growth, photosynthetic parameters and osmotic adjustment matter content of of Z. bungeanum under extreme drought.

Plant system	Z		Z-C		Z-G
Parameters	Control	Drought	Control	Drought	Control	Drought	System	Drought	System* Drought
Height (cm)	161.50 ± 3.75A	158.50 ± 5.48A	180.00 ± 15.31A	149.00 ± 28.29A	158.00 ± 27.51A	136.00 ± 24.76A	ns	ns	ns
Crown diameter (cm)	100.67 ± 5.36A	40.00 ± 3.46C	100.67 ± 9.82A	68.33 ± 15.25C	110.78 ± 1.15A	61.67 ± 15.34B	ns	***	ns
Chl a (mg/g)	4.86 ± 0.47A	3.92 ± 0.00A	4.69 ± 0.10A	4.21 ± 0.31A	4.97 ± 0.36A	4.37 ± 0.18A	ns	*	ns
Chl b (mg/g)	2.25 ± 0.06A	2.19 ± 0.29A	2.86 ± 0.22A	2.86 ± 0.10A	1.70 ± 0.30A	1.78 ± 0.13A	**	ns	ns
Car (mg/g)	1.73 ± 0.12A	1.92 ± 0.14A	1.91 ± 0.22A	2.03 ± 0.14A	1.90 ± 0.04A	1.90 ± 0.04A	ns	ns	ns
LRWC (%)	86.15 ± 2.08A	74.74 ± 1.61AB	66.59 ± 5.85BC	62.24 ± 5.74C	85.65 ± 1.78A	84.50 ± 2.04A	**	ns	*
Pn (µmol m−2s−1)	15.36 ± 0.03AB	12.75 ± 0.83C	16.39 ± 0.01A	13.71 ± 1.08BC	13.93 ± 0.87BC	11.77 ± 0.81C	*	**	ns
Ci(µmol mol−1)	305.06 ± 5.47A	291.73 ± 10.92A	301.20 ± 17.65A	295.94 ± 5.76A	302.40 ± 10.86A	289.45 ± 3.88A	ns	ns	ns
Gs (mol m−2s−1)	0.34 ± 0.02AB	0.31 ± 0.04AB	0.31 ± 0.01AB	0.29 ± 0.01B	0.37 ± 0.03A	0.35 ± 0.00AB	*	ns	ns
Tr (mmol m−2 s−1)	3.55 ± 0.18AB	2.35 ± 0.16D	3.70 ± 0.03A	2.79 ± 0.10C	3.12 ± 0.07BC	2.86 ± 0.21C	ns	***	ns
WUEintr (µmol mol−1)	4.35 ± 0.23B	5.41 ± 0.03A	4.43 ± 0.04AB	4.96 ± 0.57AB	4.47 ± 0.33AB	4.14 ± 0.27B	ns	ns	ns
Ls	0.77 ± 0.01B	0.86 ± 0.02A	0.73 ± 0.01B	0.85 ± 0.03A	0.78 ± 0.01B	0.89 ± 0.03A	ns	***	ns
Soluble sugar (mg g−1 DW)	0.56 ± 0.02B	0.86 ± 0.13AB	0.90 ± 0.13AB	0.90 ± 0.10AB	1.05 ± 0.00AB	1.35 ± 0.31A	*	ns	ns
Soluble protein (mg g−1 DW)	23.43 ± 1.34B	21.40 ± 0.20B	30.80 ± 0.78A	24.75 ± 0.35B	24.70 ± 2.51B	11.25 ± 0.46C	***	***	**
Proline (µg g−1 DW)	0.28 ± 0.01A	0.26 ± 0.01AB	0.26 ± 0.00AB	0.27 ± 0.00A	0.25 ± 1.15B	0.26 ± 0.01AB	ns	ns	*

Notes.

“Z-G” denotes Z. bungeanum intercropping with G. max, “Z-C” denotes Z. bungeanum intercropping with C. annuum, and “Z” denotes the Z. bungeanum monoculture. Different uppercase letters indicate significant differences among all treatments. Two-way ANOVA was used to test the effects of planting systems and extreme drought on the growth and pigment contents.

^*P < 0.05.

^**P < 0.01.

^***P < 0.001.

^nsnon-significant (P > 0.05).