Table 1. Heavy metals content in plants and MCL for their vegetable forages.
|
Substance |
HM content in plants, mg/kg |
MCL in vegetable forages of natural humidity, mg/kg |
|||
|
Non-treated with SA |
Treated with SA |
||||
|
смесь Кноппа |
Knop´s mixture + Pb, Hg, Cd |
Knop´s mixture
|
Knop´s mixture + Pb, Hg, Cd |
||
|
Cadmium |
<0,004 |
0,42 |
<0,004 |
0,10 |
0,3 |
|
Lead |
<0,012 |
8,52 |
<0,012 |
2,26 |
5,0 |
|
Nickel |
0,058 |
12,32 |
0,058 |
1,17 |
3,0 |
Cultivated plants intensively absorb special substances form the soil solution. The pea family plants can accumulate a considerable amount of metals, the dangerous for animal bodies heavy metals (HM) (with the density of 5 g/cm3) among them. Taking into account a regular increase of not used in the metabolic process substances´ concentration, a health hazard for people or animals making use of such contaminated products can emerge in the following food links [2].
In connection with the abovementioned the laboratory research on the study of physiological growth and the ability to toxic metals accumulation by the pea plants´ organs at the pre-sowing treatment of the seeds with salicylic acid (SA) with the concentration of 2·10-8 М [1] was carried out. The investigations of heavy metals´- Pb, Ni, Cd - content were carried out in the accredited by the scientific research testing laboratory of the Orel State Agrarian University according to standard practice [3]. The valuation of the physiological state of the plants was performed visually. For the heavy metal standard the limits of their concentrations promoting normal regulation of functions in plants are taken.
Pic. Development of pea plants against the background of heavy metals:
1 - non-treated with SA; 2 - treated with SA.
The studied plants varied in their ability to accumulate heavy metals. At the pre-treatment with SA the toxic metals accumulation in the quantities not exceeding the MCL (maximum concentration limit) was registered in the tissues. At that nickel was accumulated in the maximal concentrations, and cadmium - in the minimal ones. In the nutrient solution with a high concentration of HM the non-treated plants accumulated the metals in the concentrations considerably exceeding the MCL. The data of the table show that the lead content in this variant exceeded the norm 1,7 times, and nickel - 4,1 times. As the results of visual observations testify, a high HM concentration in the nutrient mixture without the plants´ pre-stimulation with super-low SA dosages leads to the inhibition of growth processes (pic.).According to the analysis results the plants grow better and accumulate a less amount of HM when using super-low dosages of endogenous stimulants of nonspecific resistance, which salicylic acid is referred to. This method allows obtaining the environmentally sound forage crop at a high technogenous load.
References:
- Gorbatenko I.Yu. Super-low dosages of biologically active substances and perspectives of their use / Gorbatenko I.Yu. // PH of RAS - Biology - 1997 - № 1 - pp. 107-110.
- Zudilin S.N. Heavy metals accumulation by herbs / Zudilin S.N., Tolpekin A.A. // Forage production - 2005 - № 9 - pp. 30-32.
- Kovalsky V.V. Methods of trace substance defining in organs and tissues of animals, plants and soils / Kovalsky V.V., Gololobov A.V. - M.: Kolos (Spike), 1979 - p. 272.
The article is admitted to the International Scientific Conference "Ecosystem exploitation and environment protection", China (Beijing), 26 November - 4 December, 2007, came to the editorial office on 09.11.07.