Table 2. Growth, photosynthetic parameters, the content of free radical, enzyme activity and osmotic adjustment matter content of C. annuum and G.max under extreme drought.
| Plant system | C. annuum | G. max | ||
|---|---|---|---|---|
| Parameters | Control | Drought | Control | Drought |
| Height (cm) | 25.67 ± 0.35A | 25.00 ± 1.20A | 29.93 ± 0.98A | 27.80 ± 3.12A |
| Crown diameter (cm) | 27.44 ± 1.06A | 19.22 ± 3.29A | 25.44 ± 2.26A | 24.33 ± 3.36A |
| Chl a (mg/g) | 4.32 ± 0.39B | 4.64 ± 0.03B | 6.59 ± 0.48A | 5.82 ± 0.19A |
| Chl b (mg/g) | 2.23 ± 0.23A | 2.36 ± 0.10A | 2.67 ± 0.18A | 2.54 ± 0.14A |
| Car (mg/g) | 1.64 ± 0.25B | 2.04 ± 0.12B | 2.77 ± 0.06A | 1.98 ± 0.06B |
| LRWC (%) | 89.41 ± 0.03A | 81.86 ± 0.05A | 49.05 ± 9.84B | 55.38 ± 5.09B |
| Pn (µmol m−2s−1) | 16.04 ± 0.68A | 16.68 ± 1.21A | 14.26 ± 1.48A | 12.63 ± 1.43A |
| Ci(µmol mol−1) | 307.56 ± 16.04A | 297.69 ± 11.36A | 309.62 ± 10.38A | 306.20 ± 7.25A |
| Gs (mol m−2s−1) | 0.37 ± 0.05A | 0.51 ± 0.09A | 0.48 ± 0.01A | 0.37 ± 0.01A |
| Tr (mmol m−2 s−1) | 2.99 ± 0.94A | 4.03 ± 0.62A | 3.99 ± 0.51A | 3.71 ± 0.43A |
| WUEintr (µmol mol−1) | 4.30 ± 0.49A | 3.80 ± 0.34A | 4.34 ± 0.43A | 3.18 ± 0.51A |
| H2O2content (µmol g−1 FW) | 126.36 ± 16.89B | 265.28 ± 40.96A | 53.94 ± 17.20B | 77.40 ± 5.31B |
| O2− producing rate (nmol min−1 g−1 FW) | 0.03 ± 0.005A | 0.03 ± 0.025A | 0.052 ± 0.019A | 0.039 ± 0.009A |
| MDA content (µmol g−1 FW) | 8.50 ± 1.11B | 12.79 ± 0.32B | 12.28 ± 1.38B | 20.32 ± 2.23A |
| SOD activity (nmol mg−1 protein min−1) | 22.79 ± 1.43A | 23.16 ± 0.77A | 30.21 ± 5.49A | 26.41 ± 3.53A |
| CAT activity (nmol mg−1 protein min−1) | 0.008 ± 0.003B | 0.024 ± 0.003B | 0.085 ± 0.007A | 0.095 ± 0.027A |
| Soluble sugar (mg g−1 DW) | 0.63 ± 0.05A | 0.56 ± 0.11A | 1.18 ± 0.37A | 0.79 ± 0.06A |
| Soluble protein (mg g−1 DW) | 31.57 ± 1.16A | 31.23 ± 0.33A | 26.32 ± 4.98A | 26.03 ± 3.54A |
| Proline (µg g−1 DW) | 0.04 ± 0.004A | 0.04 ± 0.002A | 0.04 ± 0.005A | 0.03 ± 0.003A |
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. ANOVA was used to assess the effects of extreme drought on plant physiology properties.
*
P < 0.05.
**
P < 0.01.
***
P < 0.001
ns
non-significant (P >0.05).