Effect of different storage conditions on the viability of Eupatorium adenophora seeds

Eupatorium adenophora is a widely distributed quarantine invasive weed in southwestern China, and the study of its seed survival in soil is essential for further clarifying its invasion mechanism and comprehensive control. In this study, we monitored the survival rate of E. adenophora seeds under different soil temperatures, humidity, depth, pH, salt stress, and drought stress conditions through indoor incubation tests for 6 months. The results showed that storage temperature, storage humidity, and storage time had significant effects (P < 0.01) on the viability of E. adenophora seeds, and there was a strong interaction effect. The seed viability of E. adenophora showed a decreasing trend with the increase of storage time, and after 6 months of storage, the seed viability of E. adenophora under high temperature (30 ℃) and high humidity (80% humidity) was as high as 82.22%, whereas seed viability under high temperature (30 ℃) and low humidity (20% humidity) was less than 3%. Seed viability increased with the increase of burial depth, and after 6 months of storage, the viability of E. adenophora seeds on the soil surface decreased to 60%, while the viability of seeds buried at 8 cm depth was as high as 92.22%. The survival rate of E. adenophora seeds stored in soil at pH 7 for 6 months was 88.9%, while the survival rate of E. adenophora seeds was reduced to approximately 70% when stored in pH 4 and 10 environments. Furthermore, E. adenophora seeds were tolerant to NaCl stress (240 mmol·L⁻¹) and drought stress (PEG-0.6 MPa), and the survival rate was still higher than 60% and 75%, respectively, after 6 months of storage. As such, strong adaptability of the seeds to the soil environment may be a reason for its successful invasion and becoming a dominant population in the southwestern part of China. Appropriate no-tillage or less tillage can help reduce the density of the seed bank of the soil of E. adenophora.