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1

Dynamics of the isoenzyme composition of peroxidase and pigments in the needles of the introduced species of Picea (L.) Karst. in the taiga zone (Karelia)

Автор: Kishchenko

The study was conducted at the Botanical Garden of Petrozavodsk State University (middle taiga sub-zone). The subjects of the study were an indigenous species (P. abies (L.) Karst.), and five introduced species (P. pungens Engelm. f. glauca Regel., P. pungens Engelm. f. viridis Regel., P. glauca (Mill.) Britt., P. omorica (Pane) Purk., P. mariana Britt., P. obovata Ledeb.). The study established high variability of the isoperoxidase spectrum in the Picea species needles during the circannual cycle. Molecular forms of peroxidase typical for growth and dormant periods were determined. Some Picea species were found to have isoenzymes appearing only during the deep dormant period. An increase in the heterogeneity of the needles isoperoxidase spectrum and appearance of molecular forms of the enzyme typical for the dormant period were observed in the indigenous and introduced Picea species in the course of adaptation to unfavorable winter conditions. The isoenzyme system rearrangement ensures plants tolerance to external factors and homeostasis regulation. The content of chlorophyll and carotenoids in the needles of the studied species undergoes significant seasonal changes and is largely determined by their biological characteristics. Pigments concentration naturally increases by the end of the vegetative period and decreases slightly in winter. The total number of pigments in the needles of the indigenous and introduced species is almost the same, indicating a similar rate of stock formation. By the dormant period, the ratio of chlorophylls to carotenoids increases and reaches approximately the same level in all Picea species. The Picea species introduced in Karelia adapt to low winter temperatures with the same physiological changes as the indigenous ones. These include changes in the isoenzyme composition of peroxidase, the dynamics of the pigments content in the needles, and the ratio of chlorophylls to carotenoids. Potential tolerance of the studied plant species to unfavorable environmental factors is affected by the extreme factor of tension that does not exceed the threshold value

2

Development of introduced species Malus Mill. (Rosaceae Adans.) in South Karelia

Автор: Kishchenko

This study contains findings of research carried out at the Botanical Garden of Petrozavodsk State University (South Karelia, central taiga subzone) in April – October in the period from 1986 to 2012. The subjects of the studies were introduced plants of three species of Malus Mill.: dwarf apple – Malus baccata (L.) Borkh., wild apple – Malus sylvestris Mill., and Niedzwetzky’s apple – Malus niedzwetzkyana Dieck. ex Koehne. Phenological observations were carried out once in 3 days by the N. Bulygin technique (1979). The phenophase was considered to have occurred if it was observed in at least 30% of the shoots of all specimens of the species under study. All samples were checked for compliance with the normal probability law. The correlation coefficients and differences between the mean values were verified to determine their reliability. Elementary statistics obtained demonstrate, among other things, that the experiment’s accuracy rate is fairly high (4–6%), while the variation coefficient is small (18–22%). It was found that M. baccata trees begin and end most of their phenophases approximately 5–10 days earlier than the other studied species. Furthermore, in the beginning and middle of the growing period, phonological phases of M. baccata proceed at colder weather compared to the other studied Malus species. At the end of the growing period, these differences among the species level off. Of all the studied climatic factors, air temperature has the most measurable positive influence on the development of Malus species in Karelia. Daily average air humidity and precipitation have a less prominent influence on еру phenophases of the studied Malus species. The course and strength of such influence depend on the peculiarities of the phenophase itself. All the studied introduced Malus species show a high degree of introduction prospect (82−93 points) and can be successfully used in Karelia for gardening and landscaping purposes.