Revista Chilena de Historia Natural 86 (2): 207-219, 2013
RESEARCH ARTICLE
Morphogenic responses of the roots of Arabidopsis thaliana
(Magnoliophyta: Brassicales) to Cr(VI) stress
The growth response of roots to stress conditions is a strategy that allows the
plant to either avoid the adverse conditions or to adapt to them. Human activities have resulted in the accumulation of
some metals from certain concentrations have an adverse effect on plant growth. Among these, Chromium (Cr) is a serious
pollution caused by metal processing industries and leather tanning. To understand in detail the response of roots Cr(VI)
stress, it was used an in vitro system with Arabidopsis thaliana utilizing three experimental conditions. (A) Plants
germinated and grown for 6 days, without lateral roots, were transferred to media with different concentrations of Cr(VI).
This allowed the evaluation as affecting the growth of the primary root to move quickly from MS medium to MS medium
with Cr(VI) and the extent to which stimulated or inhibited the formation and growth of new lateral roots. (B) Plants
germinated and grown for 8 days, with lateral roots, transferred to media with different concentrations of Cr(VI). This
condition allowed us to evaluate how they affected the growth of primary roots and lateral roots previously formed to move
quickly from MS medium to media supplemented with Cr(VI). In addition, it was possible to compare how new lateral roots
behave. (C) Seeds germinated directly on MS medium with Cr(VI) diffusion, which allowed us to determine how they
affected the growth of primary and lateral roots gradually passing from one medium to another MS supplemented with
Cr(VI). The results obtained showed that (a) stress tolerance was greater when plants were grown in a gradient from low to
high concentration of Cr(VI), (b) the plants were more tolerant to stress with further development of these, and (c) lateral
roots formed when the plant was in the medium with the metal, were always more tolerant than the primary root and lateral
roots previously formed.
Key words:
chromium, development, plant, root.
