VPI = (L-E) x 100%
N
Where:
E and L = the number of plants with early and late defoliation,
N = the total number of plants (N=E+M+L).
2.4. The chemical characteristics of fruit were determined by common analytical methods
(Solonenko and Skuridin 1983).
2.5. Linear correlation was calculated by generally accepted statistical method. To evaluate the
factor correlative pleiads we used an original FDC (Factor Data Correction) approach described in
Skuridin and Baginskaya (1998).
3. Results and Discussion
3.1. The comparison of mean plant height at the age of two, three, four and six years showed
gradual disappearance of marked differences between GI and control group. The identical decrease
of irradiation syndrome is well known (Grodzinsky 1989) and Eliseev (1979) had observed it in this
species. The growth stimulation effect of GA3 was weakened year by year as well, which coincides
with data in the literature (Muromtsev and Agnistikova (1973). On the contrary, the mean plant height
in the group with NAA treatment was below the control at all dates of observation, which indicates a
long-term growth retardant action of NAA (Table1). A long-term effect of growth stimulation by low
doses of GI (1,000-5,000 R) had been observed by Privalov and Shmeleva (1971).
3.2. The elongation of the vegetation period as an effect of ionising irradiation is known in annual
crops (Grodzinsky 1989). Our data show that the ionising irradiation resulted in an elongation of the
mean vegetation time of up to 8 years of woody plant cultivation. Treatment with GA3 essentially
increased the range of seabuckthorn plants of shortened vegetation period. It indicates long-term
effects of both GI and GA3 (Table 2). The NAA treatment did not affect this characteristic.
3.3. The exploration of chemical composition of fruits shows some long-term effects as well. The
mean sugar content in fruit pulp increased from 2.2% in the control to 2.8% when seabuckthorn seeds
of wild origin were exposed to GI at high doses of 50,000100,000 R as it had been shown by
Privalov and Solonenko (1977). The dose of 10,000 R is close to growth stimulation and did not affect
sugar content in 5-year-old plants, but it led to a 22% decrease of it in 11-year-old seabuckthorn
plants (Privalov et al. 1971). It seems to indicate that durable action can develop through latent
developmental period. The fact is of great interest for future investigation. The results of this
experiment show that GI and NAA led to a significant decrease of vitamin content: ascorbic acid 32%
and 29%, and total carotenoids 25% and 21%, respectively. The exposure with GI at a wide range of
doses (1,000-100,000 R) did not affect the fruit oil content Privalov et al. 1971, Privalov and
Solonenko 1977. A similar result was obtained in this experiment. The NAA application resulted in
reliable decrease of fruit oil content. The GA3 did not influence the chemical characteristics studied
(Table 2). The general comparison of stimulation and inhibition effects of GI according to the above
and literature data is presented in Table 3. Thus we can conclude that each agent tested led to long-
term effects in a certain but limited spectrum of characteristics. It is important to underline that all
these effects are developing within the initial seedling organism, including the fruit pulp composition
that is a mother plant tissue (hypanthium) (Trofimov 1976) and thus bears the mother's genome only.
3.4. As had been shown by our research, it is possible to determine correlation groups
("correlative pleiads" (Terent'ev 1959)) which arise by action of certain variability factors (Skuridin and
Baginskaya 1998). So, the presence of factor-specific correlation may serve as an indicator of
concrete factor action. Some results of calculation of marker correlation links are shown in Table 4.
The GI treatment weakens the correlation between dry matter and total sugar content, while GA3
and NAA slightly increase it. It was established that the correlation between these two characteristics
arises due to action of the genotype factor of the general biological variability factors (Skuridin and
