Herbicide effects on Typha latifolia (Linneaus) germination and root and shoot development

Aqueous 7-d germination and growth experiments were performed to compare re sponses of T. latifolia to exposures of atrazine (2-chloro-4-ethylamino-6-i sopropylamine-s-triazine) and paraquat dichloride (1,1'-dimethyl-4,4'-bipyr idinium dichloride). T, latifolia seed germination was < 50% in concentrati ons greater than or equal to 1.0 mg/L of paraquat dichloride. No observed e ffect concentration (NOEC) and lowest observed effect concentration (LOEC) for paraquat and root growth were 0.001 and 0.01 mg/L, respectively, while NOEC and LOEC for paraquat and shoot growth were 0.01 and 0.1 mg/L, respect ively following 7-d exposures. Greater than 72% of seeds germinated in each concentration up to 30 mg/L atrazine. After 7-d exposure, NOEC and LOEC fo r atrazine and root growth were 0.1 and 1.0 mg/L, while atrazine and shoot growth NOEC and LOEC values were 15 and 30 mg/L, respectively. This researc h provides data concerning relative sensitivity of T. latifolia seedlings t o the herbicides atrazine and paraquat, as well as the potential use of T. latifolia as a representative plant test species. (C) 1999 Elsevier Science Ltd. All rights reserved.