Effects of Garlic Bulb Aqueous Extract on Cucumber Seedlings, Soil Microbial Counts, and Enzyme Activities

Abstract

The effects of the aqueous extract of garlic bulbs on cucumber seed germination, seedling growth, soil microbial counts, and soil enzyme activities were investigated using a bioassay test and a pot experiment. Garlic bulb extracts impacted cucumber seed germination and seedling growth but had no significant effects at low concentration. Polyphenol oxidase, saccharase, urease, and catalase activities were increased significantly at all concentrations of aqueous extract tested in the soil. Bacterial counts were increased by garlic bulb extract and trends of actinomycete counts were the same as for bacterial counts. Fungal counts were significantly depressed with increasing concentration of garlic bulb extract. Polyphenol oxidase activity showed significant positive correlations with catalase, saccharase, and urease activities and counts of actinomycetes and a significant negative correlation with fungal counts. The results indicate that garlic may be effective in reducing some obstacles of continuous cropping through its potential effects in appropriate culture systems.

Keywords:

• Continuous cropping
• cucumber
• enzymes
• garlic bulbs extract
• microbes

Acknowledgments

This work was funded by the Natural Science Foundation of Beijing (6091001 and 6972014) and the Chinese National Science and Technology Support Plan (Project 2011BAD12B03).