Cadmium tolerance and accumulation by two species of Iris

Abstract

Seedlings of Iris lactea var. chinensis (Fisch.) Koidz. and I. tectorum Maxim. were subjected to 0-160 mg l(-1) Cd in hydroponic system and harvested after 42 days to determine effects on root and shoot dry mass. A subset of 16-day-old seedlings was exposed to 1000 mg l(-1) Cd to characterize sub-cellular localization of Cd in root cells. The Cd contents in the shoots of I. lactea var. chinensis reached 529 microg g(-1 )dry weight (dw) at 80 mg l(-1) Cd treatment and in the shoots of I. tectorum reached 232 microg g(-1) dw at 40 mg l(-1) Cd treatment, without showing signs of visible toxicity. The Cd contents in the shoots of both two test species exceeded 100 microg g(-1), the critical value of Cd hyperaccumulator. The indices of tolerance (ITs) of I. lactea var. chinensis were higher than those of I. tectorum under 10-160 mg l(-1)Cd stress. Sub-cellular localization of Cd in root cells was evaluated using transmission electron microscopy (TEM) and Cd deposits were found in the cell walls, in the cytoplasm and on the inner surface of xylem vessels in the root tip of I. lactea var. chinensis and I. tectorum. A few cells in the root tip of I. tectorum were necrotic. The results showed that the tolerance and accumulation of Cd by I. lactea var. chinensis were higher than those of I. tectorum, suggesting that I. lactea var. chinensis has potential application in phytoremediation.

Phytoremediation of Cadmium‐Contaminated Soil by Two Jerusalem Artichoke (Helianthus tuberosus L.) Genotypes

“…1), NY2 and NY5 growing in Cd-contaminated soil might employ the accumulation mechanism. This suggested that H. tuberosus genotypes NY2 and NY5 efficiently translocated Cd from roots to shoot and leaves, showing a Cd-phytoextraction potential, as in some other plant species [38,39]. Biomass production by NY2 and NY5 was not sharply decreased with an increase in Cd supply (in NY5 there was even an increase in biomass at 2.5 and Different letters within a column indicate the significant differences among the treatments ( p 0.05, n ¼ 6).…”

Heavy Metal Toxicity in Plants

“…Root elongation can be reduced by either the inhibition of root cell division and/or the decrease of cell expansion in the elongation zone (Fiskesjo 1997). Since inhibition of root elongation appears to be the first visible effect of metal toxicity, the root length can be used as an important tolerance index (Piechalak et al 2002;Belimov et al 2003;Odjegba and Fasidi 2004;Han et al 2007).…”

Cadmium Toxicity and Alleviating Effects of Exogenous Salicylic Acid in Iris hexagona

“…It has been reported that some species of the Iris genus, such as I. pseudacorus, I. tectorum and I. lacteal, are capable of accumulating high levels of Cd, as well as other toxic metals, in their shoots from the soil or hydroponic solution (Caldelas et al 2012;Han et al 2007). However, to our knowledge, the mechanisms of metal tolerance and accumulation in Iris genus plants are poorly understood.…”