Long-term Effects of Ionising Irradiation and
Phytohormone Treatment of Seabuckthorn Seeds
Skuridin G.M., Lbova M.I., Solonenko L.P., and Privalov G.F.
(Institute of Cytology and Genetics SD RAN, Novosibirsk, Russia)
Abstract:
Germinating seeds of seabuckthorn were treated with gamma irradiation (GI), alpha-
naphtalene acetic acid (NAA) and gibberellic acid (GA3). The long-term effects were expressed in
changes of growth (plant height), development (duration of vegetative period) and in fruit pulp
composition (ascorbic acid, total lipids and total carotenoid content). It was established that GI, GA3
and NAA are able to change correlations between valuable characteristics of adult plants. The index
of vegetative period duration (VPI) is offered for quantitative estimation. The possibility of early
treatment application to evaluate various kinds of biological variability (genotype, ecological and
dynamic) is discussed.
Key words:
seabuckthorn, chemical composition, growth and development, correlation, long-term
effects, ionising irradiation, phytohormones
1. Introduction
It had been established earlier that treatments of germinating seeds with acute ionizing gamma
irradiation (GI) and phytohormones: alpha-naphtalene-acetic acid (NAA) and gibberellic acid (GA3)
lead to significant changes in seedling growth rate at the initial stages of development. The study of
seedling growth correlation by evaluation of linear correlation between germinal roots and hypocotyles
demonstrated the strong dependence on experimental conditions (Skuridin et al. 1993). The decrease
of correlation value indicated serious upset of growth processes in treated plants. The results of
previous work demonstrated the long-term effects of experimental treatments applied to seabuckthorn
seeds. For example, gamma irradiation and phytohormone treatment led to changes in chemical
composition of fruits (Privalov et al. 1971, Privalov et al. 1977). It was important to clarify the long-
term effects of these agents on characteristics of plant growth, development and correlative links as
well. The tasks of the present study, therefore, were to investigate long-term effects on the following
characteristics:
1 Plant height
2 Duration of vegetative period
3 Chemical composition of fruit pulp
4 Correlation between characteristics
2. Materials and Methods
2.1. Plants raised from seedlings described were used (Skuridin et al. 1993). Seabuckthorn seeds
(var. Ziryanka) after 24 h soaking in distilled water were exposed to acute irradiation at a dosage of
10-25 kR or with 0.01% phytohormones GA3 and NAA dissolved in 0.001 M phosphate buffer (pH
6.95) for 24 h. Control seeds were soaked in phosphate buffer only. After 3 weeks of cultivation about
25% of well-developed seedlings but with restricted growth from each group were selected for further
growth and observation in the field.
2.2. The plant height was measured in September at the end of the vegetation period, and each
mean value of the experimental groups was related to the mean of the control group.
2.3. The duration of vegetative period was determined after fruit harvesting from adult 8-year-old
plants. We used three degrees of this parameter: "E" (early defoliation), if more than half of the tree's
leaves had fallen down; "M" (medium defoliation), if about half of the tree's leaves had fallen down,
and "L" (late defoliation), if a majority of leaves remained on the branches. For a quantitative
estimation of this characteristic the index of vegetative period (VPI) was introduced:
