С. 25–36 UDC 581.176:581.19: 577.164.2 THE CHANGES IN REDOX STATUS OF ASCORBATE IN STEM TISSUE CELLS DURING SCOTS PINE GROWTH G. F. Antonova, V. V. Stasova, N. V. Astrakhantseva Federal Research Center Krasnoyarsk Scientific Center, Russian Academy of Sciences, Siberian Branch, Solitary Unit V. N. Sukachev Institute of Forest, Russian Academy of Sciences, Siberian Branch Akademgorodok, 50/28, Krasnoyarsk, 660036 Russian Federation E-mail: antonova_cell@mail.ru, vistasova@mail.ru, astr_nat@mail.ru Received 03.03.2016 г. <...> The contents of ascorbate (AsA) and dehydroascorbate (DHA) and their ratio, showing cellular redox state of AsA, were studied in the cells of the separate tissues at different levels of Pinus sylvestris L. stem during early- and latewood formation. <...> Morphological status of the cells in the tissues and the content of soluble carbohydrates were also estimated. <...> The content of AsA and AsA/DHA ratio in the cells of non-conducting phloem along the stem were higher than in mature xylem and less during earlywood than latewood formation. <...> The cells of conducting phloem and forming xylem, as the principal tissues taking part in annual ring wood formation, differed in the content of acids in the course of early and late xylem formation. <...> The AsA/DHA of conducting phloem during earlywood formation was greatest below the stem and diminished to the top of the tree, while in the course of latewood development it was similar at all levels. <...> In forming xylem AsA/DHA increased to the top of tree during the early xylem formation and decreased in late xylem that indicates the differences in oxidation-reduction reactions into the cells of two type of forming wood. <...> Keywords: Pinus sylvestris L., levels of stem, non-contacting phloem, conducting phloem, forming xylem, mature xylem, ascorbate/dehydroascorbate ratio. <...> How to cite: Antonova G. F., Stasova V. V., Astrakhantseva N. V. The changes in redox status of ascorbate in stem tissue cells during Scots pine tree growth // Sibirskij Lesnoj Zurnal (Siberian Journal of Forest Science). 2017. <...> DOI: 10.15372/SJFS20170103 INTRODUCTION The growth and development of the plants are accompanied by the production of reactive oxygen species (ROS) such as superoxide oxygen anion radicals, hydrogen peroxide and hydroxyl radical in the course of normal development or as the response to abiotic and biotic factors (temperature, drought, wounding, pollution) (Smirnoff, 1993 <...>