Removal of Zn, Pb and Cd ions from soil using cereals

Seeds of Vigna radiate, Phaseolus aconitifolius and Doliphous Biflorus were treated with growth regulator and planted on soil contaminated with salt of Zn, Pb, Cd, and some salt mixtures. It was shown that during 15 days of germination quantity of zinc in primary leaves of 1) Increased from to 243.75%in compression to control experiment’s and decreased in soil: 95.74 and 85.07 in upper layer 95.83 to 82.04, lower layer 85.72 to 72.74 mkg/kg correspondingly approximately the same was shown for Zn and other metals absorption of heavy metal by a plant was shown to be depended from growth stimulator pretreatment procedure and is connected with exudative activity of roots of a plant. Specify of the process of phytoextraction for each metal and for the type of plant are speculated thus, it was shown that stimulation of root exudative activity by pretreatment with a growth regulative may be successful in cleaning of soil.


soils (Rosenfeld and
. In this regard, California researchers developed and demonstrated the phytoremediation of Se under a variety of condition 's (Banuelos et al., 2002b;Zayed et al., 2000;Wu et al., 2000;Franken Berger and Karlsn, 1995;Lin et al., 2002).

MATERIAL AND METHODS
Soil experiment's: seeds of Vigna radiate, Phaseolus aconitifolius, Doliphous Biflorus were treated with strong water solution of FeSuc before planting in soil of black earth type and in the same soil, which was previously treated with solution of ZnSo4 (650 mg/kg of soil).Control experiment with and without Feso4 and salt of metals were done in the same condition.Zn, Pb and Cd in plant's and in soil were measured by ICP-AES method of spectrophotometer AAS-30 (Germany).Sterile experiments: Seeds of inbred lands.(Hybrid of 1) (Vigna radiate, 2) (Phaseolus aconitifolius, 3) Doliphous biflorus were germinated in vessels with sterile sand during 15 days with following collection of root exudates on digestion with Nitric acid.Amino acids of primary leaves exudates was performed on automatic amino acid analyzer AAA-339, CZECH.

RESULTS AND DISCUSSION
Optimum concentrations, conditions of pretreatment of seeds by solution FeSuc was experimentally selected and lead to increase an ability to germinate (energy of germination of treated seed was higher).It is very important fact in the case of highly contaminated soils were remediants may not germinate at all is possible to demonstrate the process of plant uptake of metal ions enhanced by application of the growth regulator in soil experiments shown in Table 1.
During growth of seeds of wild grasses in condition of soil experiments described about quantity of amino acid in primary leaves increased in the most of amino acid in primary leaves increased in the most of experiments under influence of FeSuc  2.
Application of the growth regulator was very effective in the process of absorption of metal ions; especially significant in the uptake of Zn was increased (Table 1).It is well known fact that wild cereals may accumulate Zn in quantities that exceeds the quantity of the metal in soil, i.e. biological coefficient of absorption (BCA) for Zn by some type of wild cereal plants was greater than 1 and reaches in some cases 1,8, -1,9 (Cabata -Pendias, 1986and Kostishin, 1995, Kulkarni et. al, 2006).On highly contaminated with Zn salts soil under influence FeSuc uptake of Zn by plant in our experiment N 2 increased in 2,5 times.Cd is the second and Pb is the third metal in ability to accumulate in plants.But their BCA is only 0, 66 and 0, 47 maximum and is highly dependant from type of soil, its pH and quantity of humic acids.Application of the growth regulator changes these value very much and made uptake of Cd more preferentially and Pb nearer to that of Zn.Even more, in this experiments absorption of Cd is more than Zn.Thus influence of FeSuc lead not only to increase of metal ions but also develop a mechanism that is not a same that is natural condition of the growth.It is impossible to explain these data only by activity of metalothioneins, but it seems to occur due to better ability of Cd and Pb to format complexes with amino acids.Amino acids have fictional group that can act as sides of interaction with heavy metal ions in soil.Wild cereals had more polyfuctional amino acids in the exudates a larger value of TD.During growing on sterile sand application of FeSuc lead to increase of total quantities of exudates amino acids in 1.5-2 times (Shtemenko, 2000).We guess that similar effect occurs in natural condition too.Over exudation of amino acids that is very important fact which, could explain altering of rhizospore by conditions of FeSuc application.As polyfuctional substances are exudates, as more intensive is the process of modification of rhizosphere by enhancing mobility and by bioavailability of metals (Salt, 1995).
The origin of amino acids in coming to soil from seeds during germination Is not almost clear even physiological role of this process is an object of discussion.One point view is that root exudation has an allelopathic role and that physiological function of a releasing pool is to have a place in ecological low (Grodzinsky, 1975) It is very interesting to note that, we found species of cereals, that differs so much in this process and are so active in the exudation of amino acids under influence of growth regulation.

CONCLUSION
Stimulation of growth by pre-treatment of cereal seeds with a synthetic substances lead to increase of amino acids exudation, changed mechanism of uptake of metal ions and clean the soil.Thus, phytoremediation hold greater potential specially, promising with elaboration of growth regulator application.