Honors Students' Abstracts
Effects of Cadium Intake on Green Lynx Spiders Peucetia viridians (Aranae, Oxyopide)
Austin Nguyen, Bree Aguinaldo, Theresa Graebener
The effects of heavy metals and other human contaminants have become an important consideration for environmental restoration and conservation. The effects of cadmium on growth and photosynthetic acclimation rates were investigated in the radish plant Raphanus sativus L. Plants were raised post-germination on nutrient solutions containing various concentrations of cadmium (0, 10, 20 μM CdCl2) in sand culture. Plant height was measured throughout growth. Cadmium-treated plants were observed to have stunted growth rates in early exposure to cadmium, with higher growth in later vegetative stages. Leaf areas, measured at 20 days post-germination, were insignificantly largest in the lower cadmium concentration, likely due to a biostimulatory phenomenon, hormesis. Cadmium contents in the root and shoot systems were analyzed by mass spectrometry to investigate accumulation and transport of this heavy metal. Light response curves of plants from each cadmium concentration showed a decreased photosynthetic saturation as cadmium exposure increased. Cadmium was observed to significantly reduce photosynthetic acclimation rates in both concentrations of cadmium versus the controls by fourfold in the first change of light conditions from 600 to 400 μmol/m2s, and twofold in the second transition from 400 to 200 μmol/m2s. This reduction of acclimation may have detrimental effects on survival of plants in variable environmental conditions.