*4.8. Statistical Analysis*

The statistical analyses were performed using SPSS 13.0 (IBM, Armonk, NY, USA). The significant differences between control and experimental groups that were treated with green garlic was tested by one-way ANOVA followed by Tukey s test. The significant differences between DADS treatment and control was determined by a t-test, with \* *p* values < 0.05 and \*\* *p* values < 0.01, respectively.

#### **5. Conclusions**

This study's results showed that diallyl disulfide (DADS) is the main allelochemical of green garlic volatiles and it is released naturally at a level of approximately 0.08 mg/g green garlic. Green garlic volatiles and DADS showed obvious concentration effects. They both can reduce O2 − and they increase the accumulation of H2O2 by decreasing the expression of *CscAPX, CsGPX, CsCAT* and *CsPOD*, which may increase the disease resistance of cucumber. We will continue to study the effect of green garlic volatiles on cucumber disease resistance in the future.

**Supplementary Materials:** The following are available online. Figure S1: Plant growth and experimental design; Figure S2: Process of collection and identification of main allelochemicals of green garlic volatiles by GC/MS; Table S1: Total 17 compounds of green garlic volatile compounds of cutting segments (in sealed desiccator); Table S2: Total 42 compounds of whole green garlic (in sealed desiccator); Table S3: The green garlic weight and DADS concentration of different treatments.

**Author Contributions:** Formal analysis, F.Y. and X.L.; Funding acquisition, Z.C.; Investigation, H.W., R.D. and H.Y.; Methodology, F.Y., X.L. and H.W.; Project administration, Z.C.; Resources, Z.C.; Writing – original draft, F.Y.; Writing – review & editing, F.Y., X.L., H.W., R.D., H.Y. and Z.C.

**Funding:** This research was funded by the National Natural Science Foundation of China (No. 31772293).

**Acknowledgments:** We thanks to key laboratory of Northwest A&F University. Thanks to Yupeng Pan, Cheng F., Liu HQ and Muhamad A. give valuable advices on the revision.

**Conflicts of Interest:** The authors declare no conflict of interest.

### **References**


**Sample Availability:** Samples of the compounds are not available from the authors.

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