Plant-soil feedback of the invasive alien plant, Impatiens glandulifera
Impatiens glandulifera (Balsaminaceae: EPPO List of Invasive Alien Plants) is a widespread annual species alien to the EPPO region. Native to the Western Himalayas (Pakistan, India and Nepal), I. glandulifera was first introduced into the EPPO region (in the United Kingdom) in 1839. The species has the potential of forming dense monospecific stands which outcompete native plant species and their associated fauna. The present study set out to evaluate if I. glandulifera exhibits any form of plant-soil feedback by growing I. glandulifera plants in soil that had supported the species compared to plants grown in a control soil (I. glandulifera free). Plant growth parameters were measured throughout the experiment, along with the soil and foliar microbial community. Soil nutrients were also sampled. The results show that I. glandulifera plants grew larger and faster in soil previously conditioned by the species. Higher phosphate levels were found in conditioned soils. The percentage colonization of arbuscular mycorrhizal fungi (AMF) was lower in conditioned soil compared to the controls which suggests that I. glandulifera can alter AMF communities resulting in a positive feed-back mechanism. Interestingly, foliar endophytes showed a clear separation in plants grown in conditioned soils compared to the controls, with more endophyte species present in conditioned soils. In summary, I. glandulifera displayed a positive plant-soil feedback which extended beyond the soil microbial community to include the foliar endophytes.
Sources
Pattison Z, Rumble H, Tanner R, Jin L, Gange A (2016) Positive plant-soil feedbacks of the invasive Impatiens glandulifera and their effects on above-ground microbial communities. Weed Research, DOI: 10.1111/wre.12200