The interactive effects of different sterilization levels and aqueous extracts from Alternanthera philoxeroides on the seed germination and seedling growth of Trifolium repens

Alternanthera philoxeroides Griseb is a worldwide weed and urgently needed to be controlled and removed, of which the allelopathy mechanism has gradually aroused people's extensive attention in recent years. To deeply understand its allelopathy mechanism, the seeds of Trifolium repens are subjected to the treatment groups of sterilization and aqueous extracts from A. philoxeroides. The results showed that sterilization and aqueous extracts from A. philoxeroides and their interactive effects had significant impacts on the seed germination, bud length and root length of T. repens. Under the condition of non-sterilization in soil, the underground aqueous extracts from A. philoxeroides had positive effects on T. repens and the aboveground ones had negative impacts. However, under the condition of sterilization in soil, both the underground aqueous extracts and the aboveground ones from A. philoxeroides had negative effects, but there were differences between the degree of their impacts. Compared to the aboveground ones, the effects of underground ones were more worse. Compared to the bud length as well, the root length was more vulnerable to the negative impacts of aqueous extracts from A. philoxeroides. In a word, there were some differences between the effects of the aqueous extracts from different parts of A. philoxeroides, and it was suggested that to study the allelopathy of A. philoxeroides, we should not only pay attention to the different parts of A. philoxeroides, but also to the external environment conditions, especially the microbes in the soil.