Page 222 - Plant-Based Remediation Processes

214 M. Griga and M. Bjelkova ´

Gaudchau and Schneider 1996; Schneider et al. 1996; Schneider and Marquard
1996; Cieslinski et al. 1996; Li et al. 1997; Becher et al. 1997; Kokurin and Yagodin
1997; Grant et al. 2000; Hocking and McLaughlin 2000; Bjelkova et al. 2001;
Lukipudis 2001). By comparing 20 flax genotypes, Bo ¨hm et al. (1992) found that
only seven tested cvs responded sensitively to Cd content changes in the soil; all
other genotypes behaved independently, thus the Cd concentration in the stem
could not be simply derived from the soil Cd content. Gaudchau and Schneider
(1996) and Schneider and Marquard (1996) reported significant genotype
differences in Cd accumulation of linseed—cv. Marigold accumulated more Cd
in the seeds, while cv. McGregor retained significantly more Cd in roots. Increasing
of soil Cd concentration (0.12, 0.72 and 1.3 mg Cd kg 1 soil) surprisingly resulted
in increased Cd transport to seeds and in decreased Cd retaining by roots.
According to authors, great differences in Cd content in particular plant organs
are predetermined by genetically based different distribution in plants (i.e. different
1
translocation and accumulation in seeds). Thus, at concentration 0.12 mg Cd kg
soil, cv. McGregor retained 92 % uptaken Cd in root and stem and only 8 % was
transported to the seeds, while in cv. Marigold there are quite different relations:
61 % uptaken Cd was retained by root and stem and 39 % was translocated to the
seeds. Similar conclusions (cv. McGregor accumulates very low seed Cd
concentrations) were done by Becher et al. (1997). Some authors (Helal et al.
1991; Cieslinski et al. 1996; Becher et al. 1997) supported the idea that genotype
differences are a result of different Cd redistribution within shoots and not of Cd
uptake and translocation from roots to shoots. Becher et al. (1997) stated that
genotype differences were restricted to Cd and were no general phenomenon of
supply of generative organs with micronutrients (e.g. Zn, Cu).
The most complex and detailed study of L. usitatissimum L. as related to Cd,
covering 4-year field-simulated experiment, broad range of soil Cd concentrations
(10 to 1,000 mg Cd kg 1 soil), both technological L. usitatissimum types—flax and
linseed, ten commercial flax/linseed cultivars and four analysed plant organs has
been recently published by Bjelkova ´ et al. (2011a, b). The most Cd was accumulated
by roots, followed by shoots, while reproductive parts (capsules and seeds) played
comparably smaller role. The increasing soil Cd concentration resulted in increasing
Cd accumulation by roots, while transport to above-ground plant parts was progres-
sively inhibited. Even high soil Cd concentrations (1,000 mg Cd kg 1 soil) had not
dramatic negative effect on plant growth and development. Cultivar differences as
well as the differences between both technological Linum types have been found in
Cd accumulation (flax being better Cd accumulator than linseed). Nevertheless, the
recorded variation between technological types and within cultivars was in multiples
of Cd values (units of mg Cd kg 1 DW), not in orders of magnitude as needed for
highly efficient phytoextraction. A significant year-to-year effect on plant growth/
development resulting in high variation in Cd accumulation was observed. Flax cv.
Jitka exhibited good transport of Cd from roots to above-ground parts, while flax cv.
Merkur showed high retention of Cd in roots. Further, the contrasting cultivars in
total Cd accumulation (high accumulating flax cv. Jitka versus low accumulating
linseed cv. Jupiter) were selected.