Cadmium uptake from solution by plants and its transport from roots to shoots

Abstract

The uptake of c a d m i u m by the roots of plants, and its transport to shoots was examined using solution culture. U p t a k e by the roots of perennial ryegrass over a period of 4 hours from an aqueous solution containing 0.25 p p m c a d m i u m as CdC12 was (i) enhanced by killing the roots and (ii) depressed when Ca 2÷, Mn 2* or Zn 2+ were added to the solution. The distribution of c a d m i u m between the roots and shoots of 23 species was examined at 4 days after a single, 3-day exposure to a nutrient solution containing 0.01 p p m added Cd. I n all except 3 species, i.e. kale, lettuce and watercress, more t h a n 50 per cent of t h a t taken up was retained in the roots. The concentration in the roots was always greater t h a n in the shoots, and in fibrous roots of fodder beet, parsnip, carrot and radish it was greater t h a n in the swollen storage roots. W h e n perennial ryegrass was similarly exposed to solutions containing 0.01, 0.05, and 0.25 p p m added cadmium, uptake, as measured at 3 days after adding cadmium, increased with increasing rates of addition, b u t the proportion retained in the roots was constant (approximately 88 per cent). There was no further transport from roots to shoots during the next 21 days, with the result t h a t the concentration in the shoots decreased progressively with increasing growth. I t is concluded t h a t although the roots of several species can take up large quantities of c a d m i u m from solution there are mechanisms which m a y restrict the m o v e m e n t of c a d m i u m through plants, and thus to animals.

The Effect of EDTA on Maize Seedlings Response to Cd-Induced Stress

“…Retention of Cd in roots is considered as a mechanism of metal tolerance and it is a common phenomenon in many plant species (Jarvis et al, 1976;Jastrow and Koeppe, 1980;Hardiman and Jacoby, 1984;Greger and Lindberg, 1986) includ ing maize (Florijn and Van Beusichem, 1993; Lozano-Rodriguez et al, 1997). In our studies roots accumulated 7 9 -9 4 % of the metal taken up (Fig.…”

Cadmium accumulation in crops

“…Distribution of Cd in the plant differs depending on the plant species and growing conditions (Williams and David 1973;Jarvis et al 1976;Cataldo et al 1981;Mullins et al 1986;Jackson and Alloway 1992;Choudhary et al 1994;Yang et al 1995). Concentration of Cd in the aboveground portion of plant species did not necessarily follow the same pattern as concentration in the root (Pettersson 1977).…”

“…Detailed kinetic analysis suggested competitive inhibition of Cd absorption and transport by these elements, which Cataldo et al (1983) interpreted as indicating a common transport site or process for Cd, Cu, Fe, Zn and possibly Mn. The uptake of Cd by roots of perennial ryegrass exposed to 9 × 10 -8 M Cd for 3 d was depressed by the addition of Ca, Mn, and Zn (Jarvis et al 1976). Other studies at higher, usually toxic, concentrations of Cd also indicate antagonism between Cd and Cu, Fe, Mn and Zn (Thys et al 1991;Jalil et al 1994b;Gussarsson et al 1995).…”

Nitrogen, phosphorus and zinc management effects on grain yield and cadmium concentration in two cultivars of durum wheat

“…Zinc applications can increase (Williams and David 1976) or decrease (Jarvis et al 1976;Abdel-Sabour et al 1988;Choudhary et al 1994;Grant and Bailey 1997) Cd accumulation in crops. Zinc and Cd are both divalent cations and may compete for binding sites in the soil system (Christensen 1984) and for uptake and translocation by the plant (Cataldo et al 1983;McKenna et al 1993).…”