Early root structure and growth of Japanese barberry seedlings.

摘要

Japanese barberry (Berberis thunbergii DC.) is an invasive woody shrub that has invaded many different habitats throughout the northeast United States. Its ability to flourish under various environmental conditions gives it a tremendous competitive advantage when compared to indigenous flora. As a result, many indigenous plants are being displaced, ultimately causing changes in biodiversity and ecosystem function.;Since Japanese barberry is so prevalent under various environmental conditions I wanted to determine if Japanese barberry seedlings, first year plants, demonstrate different root growth patterns and structure based on local soil conditions. I also wanted to determine how early root development might contribute to invasiveness. My research was conducted at three locations in northeastern New Jersey, USA where all three locations were heavily invaded by Japanese barberry. I measured ten different soil components at each site to establish a soil chemistry and composition profile that I used as a baseline for comparing sites. I also wanted to determine if variations local soil chemistry and composition were possible contributors to root structure and development.;Results indicate that Japanese barberry seedling demonstrated very distinct growth patterns and structure at each site during their first year. The Upland and Stream Bed seedlings showed relatively linear growth with the Upland seedlings having much greater plant mass and complex root structure opposed to the Stream Bed seedlings, which appeared poorly developed. The Great Swamp seedlings demonstrated very limited change in plant mass and root growth from July to December. The Great Swamp soil lay in between the Upland and Stream Bed soils and therefore had moderate root complexity.;Although Japanese barberry seedlings demonstrate different growth patterns at each site there is no indication soil composition is a key factor in my results. However, the difference among the three sites in hydrology was quite apparent, and may be the most important factor. I conclude that although Japanese barberry seedlings are clearly capable of germinating and surviving the first growing season in saturated or wetland soils, the conditions of these soils may help these areas avoid dense infestations because root growth is impaired compared to upland soils.