Unraveling the role of sulfide tolerance and iron accumulation in the invasive potential of Spartina alterniflora

Abstract

Spartina alterniflora is an invasive plant widely distributed in coastal areas of China, and the invasion has caused the accumulation of soil sulfur contents, while sulfide can accumulate to phytotoxic levels. It has been verified that S. alterniflora is more tolerant to sulfide than Scirpus mariqueter. Therefore, sulfide may be may play a significant role in S. alterniflora invasion, but the specific mechanism by which S. alterniflora tolerates sulfides in soil during the invasion process awaits further investigation. Through experiments with situ rhizoboxes in the Jiuduansha Wetland, we conducted field investigations to analyze soil sulfur (sulfate and sulfide) content, iron (Fe(II) and Fe(III)) content, and physicochemical properties. Meanwhile, the effect of roots on soil bacterial communities and sulfur cycle-related microorganisms was investigated. The soil sulfide content in S. alterniflora was 2.4 times higher, and sulfate content was 1.7 times higher than those in S. mariqueter. In the rhizoboxes of S. alterniflora, the contents of soil sulfide in the rhizosphere soil were significantly lower than that in bulk soil. The iron contents in the rhizosphere of S. alterniflora were 6 times higher than that in S. mariqueter. In conclusion, the S. alterniflora may gain an advantage in the invasion process by oxidizing the sulfide through radial oxygen loss and by enriching iron to mitigate high sulfide concentrations in the rhizosphere.