Assessment of Siberian Stone Pine Viability in the Introuced Plantations of Middle Volga Region

Abstract

Introduction. Many researches show successful growth of  Siberian stone pine  in various ecological conditions of the region, but the criteria to select sustainable  adapted biotypes are lack of study. The goal of the research is to assess  the vital condition of  Siberian stone pine  (Pinus sibirika Du Tour) in the Middle Volga Region plantations by biometric and bioelectric  figures and to determine their informational content for selection the sustainable and  productive biotypes. Siberian stone pine  plantations of Middle Volga Region were chosen to be the object of the research. Methods. A high-resistance millivoltmeter of continuous current with platinum electrodes (Ekstra-999) was used to measure bioelectric potential. The impedance of over cambium complex of tissues was measured with Ц 4314 apparatus  on a frequency of 500 Hz using a transducer  of ЭВ–2К electronic moisture meter. Distance between the electrodes is 20,0 mm, length of active part of electrodes is 10,0 mm, diameter is 1,0 mm. The measurement was taken in the middle of  vegetation period from the shady side at 1,3 m height. Results. The top ranking trees of Siberian stone pine  are of high bioelectric potential (186,3±11,6 mV) and are of high content of general chlorophyll in the needles (3,15 ±0,08 mg/g of dry weight). The values of the weakened trees are twice lower. The impedance of over cambium complex of tissues of healthy trees of Siberian stone pine is of optimum parameters (15…25 kiloohm), weakened trees show higher figures  (47,9±3,8), which is the evidence of  disorder of water regime. It was determined that weakened trees showed  the decrease of activity of  catalase in the needles, the increase of osmotic potential and the increase of impedance of over cambium complex of tissues. Seed generation of the local  reproduction of top ranking trees has an intensive growth: the medium height of 7-year trees is  75,2±2,1 cm. Conclusion. The existing plantations of  Siberian stone pine  are the source of valuable genebank to establish plantations and develop landscape gardening. An express diagnosis of vital condition by the value of  bioelectric potential, impedance of over cambium complex of tissues and  osmotic pressure of cellular fluid of needles  give the possibility to select the trees, which are sustainable to  the changes of environment and  adapted to water regimes of biotopes. It is particularly important for Middle Volga, where drought periodically takes place.