title: Influence of diesel contamination in soil on growth and dry matter partitioning of Lactuca sativa and Ipomoea batatas.
abstract: Phytotoxic effect of diesel contaminated soil was investigated on growth and dry matter partitioning in Lactuca sativa and Ipomoea batatas in greenhouse pot experiment at two concentration range (0-30 ml and 0-6 ml diesel kg(-1) soil) for 14 weeks. The results indicated thatwhole plant biomass, stem length, root length, number of leaves and leaf chlorophyll in two plants were negatively correlated with increasing diesel concentrations. The critical concentration of diesel associated with 10% decrease in plant growth was 0.33 ml for lettuce and 1.50 ml for sweet potato. Thus, growth of lettuce in diesel contaminated soil was more sensitive than sweet potato. The pattern of dry matter partitioning between root and shoot in both plants were similar. In 0-6 ml diesel contamination range, allocation of dry matter to shoot system was favoured resulting in high shoot: root ratio of 4.54 and 12.91 for lettuce and sweet potato respectively. However, in 0-30 ml diesel contamination range, allocation of dry matter to root was favoured, which may have been an adaptive mechanism in which the root system was used for storage in addition to increasing the capacity for foraging for mineral nutrients and water. Although lettuce accumulated more metals in its tissue than sweet potato, the tissue mineral nutrients in both species did not vary to great extent. The critical diesel concentration for toxicity suggested that the cause of mortality and poor growth of sweet potato and lettuce grown in diesel contaminated soil was due to presence of hydrocarbons in diesel.
authors.forename: Kayode
authors.initials: K
authors.lastname: Fatokun
authors.forename: Godfrey Elijah
authors.initials: GE
authors.lastname: Zharare
mesh_terms: D004305:Dose-Response Relationship, Drug; D005742:Gasoline / Q000032:analysis / Q000633:toxicity*; D027723:Ipomoea batatas / Q000737:chemistry / Q000633:toxicity*; D018545:Lactuca / Q000187:drug effects*; D012989:Soil Pollutants / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*
chemical_list: D005742:Gasoline; D012989:Soil Pollutants