Root Porosity Changes in Salix nigra Cuttings in Response to Copper and Ultraviolet-B Radiation Exposure

• Published in: Water, air, and soil pollution air, and soil pollution, 2011-10, Vol.221 (1-4), p.99-105
• Main Authors: Baud, Donald R., Pezeshki, S. Reza
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Anoxia; Applied ecology; Aquatic habitats; Atmospheric Protection/Air Quality Control/Air Pollution; Bank stabilization; Biological and medical sciences; Biomass; Bioremediation; Climate Change/Climate Change Impacts; Copper; Cuttings; Earth and Environmental Science; Ecotoxicology, biological effects of pollution; Environment; Environmental monitoring; Erosion control; Fundamental and applied biological sciences. Psychology; General aspects; Hydrogeology; Hydroponics; Nuclear radiation; Plant growth; Porosity; Radiation measurement; Salix nigra; Soil Science & Conservation; Stream banks; Studies; Ultraviolet radiation; Water Quality/Water Pollution; Wetlands; Willow trees
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-011-0772-2

Cuttings of black willow ( Salix nigra ), a naturally occurring wetland species, are used for restoration and streambank stabilization. As an adaptation to their wetland habitat, this species develops aerenchyma tissue to avoid root anoxia. To determine the effects of combined copper and ultraviolet-B radiation exposure on aerenchyma tissue (measured as root porosity), black willow cuttings were grown hydroponically and exposed to three ultraviolet-B (UV-B) intensities and three Cu concentrations in a completely randomized 3 × 3 factorial design. While both UV-B ( F 2,42  = 11.45; p  = 0.0001) and Cu ( F 2,42  = 6.14; p  = 0.0046) exposure increased root porosity, total biomass decreased in response to both UV-B ( F 2,43  = 3.36; p  = 0.0441) and to Cu ( F 2,43  = 4.03; p  = 0.0249). Root biomass decreased only in response to Cu ( F 2,41  = 3.41; p  = 0.0427) resulting in a decrease in the root/shoot ratio ( F 2,42  = 3.5; p  = 0.0393). Copper exposure also resulted in a decrease in the number of leaves/shoot ( F 2,42  = 7.03; P  = 0.0023). No UV-B and Cu interaction was found. While the present research indicates the negative effects of Cu contamination and elevated UV-B intensities on S. nigra , it also points out potential mechanisms that S. nigra uses to alleviate these stresses.