Soil Bioassay 
Varied contaminants, moving into the ecosystem, can undergo different
transformations in it, strengthening in some cases their toxic action.
For this reason integrative estimation methods for the quality of the components
of the ecosystem have proven to be necessary. Research was conducted
on the basis of a multifactor stationary experiment in 11 TI polynomial
with different crop rotations. In the experiment the influence of
the following factors was studied: the fertility of the soil (A),
the system of fertilizers (B), and the system of crop protection (C).
The fertility of the soil, the system of fertilizers and the system of
crop protection were studied at doses 0, 1, 2 and 3. Base versions
were the following combinations:
As the objective of this work it was intended to study the inhibition
of chloroplast movements and the coefficient
of instantaneous growth as the tesed indices for contamination of the
soil, in the diverse variants of the multifactor experimental design.
To achieve the stated goal, statistical analysis was conducted to detect
the influence of each factor on the growth and development of Lemna
minor.
Inhibiting phototaxis of the chloroplasts of Lemna minor was investigated in different levels of the soil: 020, 2040 cm. The analysis of the response of phototaxis to the different experimental variations showed the reliable influence of each of the factors (fertility of soil, the system of fertilizers and the system of the protection of plants). The portion ofhe common variance of the fertility of soil composed 39,7%, the systems of fertilizers  30,7%, and the system of the protection of plants  30,7 %. Reliable differences in terms of the average value of the coefficient
of inhibition of phototaxis are noted between all versions with different
factors (Table 1).
On the fertility of soil a reliable difference is noted between variants 3, 0 and variants 2 and 1. Along the system of fertilizers the difference between the averages of variants 3, 0 (1 and 2). Along the system for protection of plants  variant 1 from variant 0 and variants 3 and 2. To investigate the joint influence of factors on inhibiting chloroplast phototaxis, we used different combinations of experimental variants:in the first case  000, 002, 022, 222, 220, 200, 202, 020, in the second case  111, 333, 331, 313, 133, 311, 131. The results of twofactor variance analysis testify about the significant influence of those interactions of the system of fertilizers and the plant protection system on the differences in the phototaxis for the first case (fraction/portion in the general/common dispersion it comprised 10,3%). For the second case a significant influence is discovered for the interactions of the fertility of soil and the system of fertilizers (53,2%). Threefactor variance analysis showed in the first case the reliable influence of interaction of all three factors. Fraction/portion in the general/common dispersion comprised 47,9%. In the work two levels of soil were studied: 020 cm and 2040 cm. Analysis of the test results showed the essential differences between the levels according to the index  inhibition of phototaxis. The portion in the general/common dispersion of the fertility of soil comprised 8,8%, the systems of fertilizers  17,5%, and the plant protection system  30,8%. On the average, for the index of the fertility of soil, a significant
difference is noted between versions 2, 0 and 3, 1; along the system of
fertilizers  between versions 2, 3 and 1, 0; and along the plant protection
system  versions 1 and 2 version 3 and 0 (tabl.2.)
The results of twofactor variance analysis testify to the significant influence of the fertility of the soil and the system of fertilizers on the differences in the phototaxis for the second case  53,2%. For the first case the significant influence of the factors is determined to be the fertility of soil and system of fertilizers (33,0%). Threefactor variance analysis showed in the first case the significant
influence of interaction of all three factors. Fraction/portion in
the general/common variance comprised 46,0 %.
The coefficient of instantaneous growth was investigated in diverse experimental variations, 000, 111, 222, 333, 002, 200, 220. First stage of testing  before the introduction of herbicides on sowings of winter wheat (April), the second stage  after the introduction of herbicides (May) and the last stage  at the moment of harvest (July). The precursor to the wheat crop  sunflower or corn. The appearance of new fronds was observed after a short lag phase, with the average doubling time for wet weight was in the range of 2  4 days. The coefficient of an instantaneous increase in the population (r) and
the doubling time of the number of fronds (t_{ of udv} ) were calculated
on the basis of the obtained results for the control and for each variant.
The calculation of these indices was carried out in the dynamics
with the analysis of soil samples. The analysis of data showed that
the doubling time of the population of duckweeds to treatment of the soil
was smallest in comparison with the data after processing and at the moment
of harvest. Common to the two predecessors is the fact that
after treatment we observed a suppression of the intensity of multiplication;
therefore doubling time increased to 14 days. In the observations
larger interest causes the response of soil after the introduction of the
herbicide and to the moment of harvest. First of all interaction
with the fertilizers and the level of fertility. Thus, in versions
022, 202  the negative effect of the pesticides was smoothed out (Fig.
1).
To sometimes obtain a direct response to the introduction of chemical preparations can be complicated by interaction of preparation with fertilizers either organic, or mineral (V.I.Tanskiy, et al., 1998; K. Fedke, 1985). The data we obtained made it possible to trace the dynamics of the response of the introduced preparations, in all versions with the chemical means of protection, where the inhibtion of the growth of the indicator plant was noted. Singlefactor analysis of variance showed the significant influence of each index on the rates of increase in the Lemna minor during the first stage. In the second stage the effect of differences on the fertility of the soil comprised 65,0 %, along the system of fertilizers and the system of the protection of plants  comprised 65,0%. Factors showed significant differences on the average for the coefficient of instantaneous increase in version 222 and versions 000, 111, 333. In the third stage the portion in the common variance of the fertility of soil comprised 42,9%, systems of fertilizers and system of the protection of plants  comprised 42,9%. A significant difference in terms of the average values of versions 000 and 111, versions 333 and 222 is noted. Analysis of variance showed the significant influence of the predecessor crop on the rates of increase in the Lemna minor. The portion of the general variance for the factor predecessor was small and comprised 11,1%. The portion in the general dispersion of the same factor during the analysis of the variability of the coefficient of growth is equal to 10,9%. No significant influence was seen for the fertility of the soil, system of fertilizers and system of plant protection, either separately or in interaction. Thus, data shwon on the sensitivity of duckweeds to diverse variants of soil samples make it possible to make the following conclusions:

MainBioassay ProceduresReaction to Heavy Metal Salts 
Êðàñíîäàð, 2002 