US EPA

1510455 

Journal Article 

Effects of dichromate on growth and root system architecture of Arabidopsis thaliana seedlings 

Castro, RO; Trujillo, MM; Bucio, JL; Cervantes, C; Dubrovsky, J 

2007 

1 

Plant Science
ISSN: 0168-9452
EISSN: 1873-2259 

172 

4 

684-691 

10.1016/j.plantsci.2006.11.004 

WOS:000245340400002 

The hexavalent form of chromium [Cr(VI)] is toxic for most
organisms; however, very little information is available regarding the effects of this metal on
plant morphogenesis. In this work, we investigated the effects of Cr(VI) on the growth and
development of Arabidopsis thaliana, a species widely used as a model for studying the diverse
physiological and cellular processes in plants. Elongation of root hairs and biomass production
were stimulated by relatively low concentrations (100 mu M) of Cr(VI) as potassium dichromate.
Concentrations of Cr(VI) greater than 200 mu M were toxic to plants as revealed both by arrested
growth of roots and shoots and the development of chlorosis in leaves. At 200 mu M the primary
root growth was totally inhibited but the plants continued their growth manifesting different
alterations in root development. These alterations correlated with changes in mitotic activity
and in cellular expansion. The analyses of A. thaliana transgenic plants that express the auxin-
inducible marker DR5:uidA, and the response of the auxin-resistant mutants axr2 and aux1-7 to
dichromate suggest that auxins do not participate as mediators in the cellular and physiological
responses to this metal. The primary root growth inhibition by 200 mu M dichromate was alleviated
by more than 70% by increasing the sulfate, phosphate or nitrate concentration in the media,
which suggests a relation of dichromate with these mineral nutrients. (c) 2006 Elsevier Ireland
Ltd. All rights reserved. 

Arabidopsis thaliana; hexavalent chromium; root architecture; development; mineral nutrients