Department of Botany, Sri Venkateswara University, Tirupati-517502, India
*Present addresses: Plant Science Laboratories, Department of Bio-Sciences, Sri Krishnadevaraya University, Anantapur-515003.
**School of Life Sciences, University of Hyderabad, Golden Threshold, Hyderabad-500001, India.
Summary Studies of heavy metal tolerance of certain weed species indicated the presence of tolerant potentials in normal populations to Cu and Zn. At 0.6 ppm Cu and 4 ppm Zn in hydrated Ca (No2)3 solutions, four species showed Weh tolerant indices. The low reduction rates in biomass yields with high tissue metal concentrations confirmed the tolerant nature of these plants. However, the low tolerant indices and reduced biomass yields on Co or Ni enriched soils revealed the absence of Co-tolerance to Co and Ni.
