SELECTION OF COLD-TOLERANT PLANTS FOR GROWTH IN SOILS CONTAMINATED WITH ORGANICS

A mixture of organic chemicals (MOC) containing equal molar amounts of benzoic acid, hexadecane, 2,2-dimethyl 4,n-propyl-benzene, phenanthre ne, pyrene, and either cycloheptane or cis-decahydronaphthalene (cis-d ecalin) was applied to soil at rates of 0 to 8000 mg/kg. In a plant-sc reening experiment, growth responses of four legume and five nonlegume species were determined at 10 and 25 degrees C. The MOC applied at 20 00 mg/kg reduced the growth of several species without resulting in si gnificant seedling death. At 10 degrees C, the growth of alpine bluegr ass (Pea alpina L.) in the 1000 and 2000 mg/kg treatments of soil incr eased by more than 185%. In a plant growth response experiment, alpine bluegrass and alfalfa (Medicago sativa L.) were grown in soil that ha d been contaminated at rates of 0 and 2000 mg/kg. At 14 weeks, the sho ot and root dry weights of alfalfa were 97% lower in the contaminated soil, while the shoot dry weight, root dry weight, and root length of alpine bluegrass were 135, 235, and 268% higher, respectively. Except for pyrene, <23% of the compounds comprising the MOC remained in the s oil after 4 weeks and <5% after 14 weeks. The disappearance of the MOC was not significantly influenced by the presence of alfalfa or alpine bluegrass.