A Preliminary Study on Allelopathy and Potential Allelochemicals of Root Exudates from Solanum rostratum Dunal

Aims: In order to understand the role of allelopathy in invasion success, effects of root exudates from Solanum rostratum Dunal on germination and primary growth of wheat and cabbage seeds were studied by vitro bioassay. These results indicated the allelopathy of root exudates and would be helpful for understanding Solanum rostratum Dunal invasion. Study Design: The roots were washed clean for three times with distilled water before they were gathered in a big bucket. The container was filled with distilled water, enough to submerge the roots, and air was aerated constantly with an air pump. The water extract was collected per 24 hs and for four times totally. The water extract from Solanum rostratum was concentrated with a rotary evaporator at 40°C and deposited in a refrigerator at 4°C. All the root exudates were pooled around 1500 mL, and the fresh weight of Solanum rostratum used for exudates collection was 1208 g, the exudate concentration was then marked as 0.8g f w/mL. Place and Duration of Study: Solanum rostratum was grown in the greenhouse on April 15th, 2019, its seeds were collected from the invaded fields in Chaoyang city (Liaoning province, China). Methodology: Petri dish bioassay was applied to test the effects of root exudates of Solanum rostratum on the seeds of wheat and Chinese cabbage. For test of allelochemicals exudated through the root, The compounds in organic fraction of root exudates analysed by GC-MS. Results: These results indicated the allelopathy of root exudates and would be helpful for understanding Solanum rostratum Dunal invasion. Conclusion: Root exudates of Solanum rostratum contained some allelochemicals, which could inhibit the germination and radicle growth of wheat and Chinese cabbage, though the effects of root exudates on shoot growth are different, with a stimulation on Chinese cabbage while a inhibition on wheat. The difference indicated a selectivity of allelopathy effect of root exudates from Solanum rostratum Dunal.