663 TISSUE AND BIOCHEMICAL BARRIERS OF SUGAR BEET (BETA VULGARIS L. provar. altissima Doell.) PERICARP Oksana Klyachenko* 1 , Artur Likhanov 1 , Volodymyr Grakhov 2 Address(es): doctor of agricultural sciences, Oksana Klyachenko, 1 National University of Life and Environmental Sciences of Ukraine, Department of Ecobiotechnology and biodiversity, Heroiv Oborony Str, 15, 03041, Kyiv, Ukraine, +380445278517 2 M. M. Gryshko national botanical garden of Ukraine, Timiryazevskaya str, 1, 01014, Kyiv, Ukraine, +380442854036 *Corresponding author: klyachenko@ukr.net ABSTRACT Keywords: sugar beet, pericarp, phenolic compounds, biological activity, inhibitors, dormancy INTRODUCTION Seed viability saving of flowering plants during germination provided defence mechanisms (Adkins et al., 2002; Coumans et al., 1976), the most important of which are based on peculiarities of the structure of covering and mechanical tissues of the seeds, fruits and stems. (Takhtajan, 1991). One of the universal mechanisms that activate defence responses in plants to various fungal, bacterial, viral infections and insects as well as dormancy state control of seeds are thick endocarp cells, tannin and crystal-cells (Barnabas et al., 1990). Electron microscopic studies have revealed close relationship of crystal-cells and sclereids in the process of histogenesis (Klyachenko et al., 2013), conjugated to lignification of cell walls (Gorshkova, 2007). Biologically active substances play an important role in the regulation of seed germination, growth and development of seedlings, hormones same how abscisic acid, ethylene (Adkins et al., 2002, Hermann et al., 2007), polyphenols (hydroxycinnamic acids, flavonoids, tannins, flavolignans) (Blazhey et al., 1977, Chiji et al., 1980; Buer et al., 2010) coumarin (Adkins et al., 2002) and saponins (Vasilyeva et al., 2000; Abid Ali Khan et al., 2012) are especially important. It was shown that highly active compounds can significantly affect germination of sugar beet seeds (Beta vulgaris L. provar. altissima Doell.), located mainly in the pericarp (Chiji et al., 1980), and especially in the mesocarp tissues (Inoue et al., 1975). Pericarps of sugar beet fruits are formed from the ovary walls, which are in the process of embryo formation, differentiate with formation of different tissue structures: exo-, meso- and endocarp (Takhtajan, 1991), functions of which are due to peculiarities of the anatomical structure, chemical nature and distribution of metabolites. The most of seed germination inhibitors are polar compounds, which include abscisic (ABA) (Coumans et al., 1976) and oxalic acids (Hermann et al., 2007), oxalates, sodium nitrate (Juntilla, 1976) and phenol carbonic acids (Morris et al., 1984). In the fruit of sugar beet there were detected hydroxycinnamic and hydroxybenzoic acids, protocatechuic and lilac aldehydes (Chiji et al., 1980), cis- 4-cyclohexane-1,2-dicarboximide (Bewley D. et al., 1980) and 1-amino-1- cyclopropane carboxylic acid (key water soluble agent for maintaining of the dormancy state) (Coumans et al., 1976). The most active inhibitors, according to some authors, are abscisic acid and coumarin which contained in fruit pericarps (Kovalev et al., 2003). It was shown that the chemical compound from sugar beet pericarps can slow germination of seeds in many plant species (Juntilla, 1976). To the semi-polar inhibitors of beets flavonoids, bisalkaloids and isoindole compounds are belong. Despite the fact that the main potential inhibitors of germination of sugar beet seeds are well known (Barnabas et al., 1990, Morris et al., 1984), concerning the mechanisms of seed germination regulation of sugar beet, insufficient and extremely contradictory information in the literature are presented. In this paper the results of research in the regulatory role of pericarp in seeds germination and formation of biochemical barriers of pericarp in different genotypes of sugar beet are represented. MATERIAL AND METHODS Two varieties of sugar beet Belotserkovskaya single seed 45 (BTS 45), Yaltushkovskaya single seed 64 (YlS 64) and 8 di- and triploid sterile hybrids on the basis of domestic and foreign selection: Ukrainskaya MS 70 (UkMS 70) and Ukrainskaya MS 72 (UkMS 72), Belotserkovskaya MS 57 (BTSMS 57), Ivanovskaya MS 33 (IvMS 33), Yaltushkovskaya MS 72 (YlMS 72), Uladovo- Verhnyachskaya MS 37 (UVMS 37) and Uladovo-Veselopodolianskaya MS 84 (UVMS 84), Alexandria. The polar compounds from pericarps were extracted with bidistilled water at 40°C during 24 hours (in the ratio 1:10). The biological activity of the extracts was evaluated on the test object, using for this purpose pure cultures of Chlorella vulgaris 106 and Erwinia aroideae. Clean test cultures were plated on solid agar culture media. Aqueous extracts of fruits from examined genotype were added in amount of 30 mcl in prearranged holes 6 mm in diameter, and then test cultures were grown in incubator at a regulated temperature + 25°C. The biological activity of the extracted substance was evaluated according to the suppressed zone in the test culture on 5th, 7th and 12th day. Allelopathic potential (phytotoxicity) of water extracts was determined by the strength of the biologically active compounds influence on growth of radish sprouts’ roots (Krasniy variety with white tip) (Grodzinsky, 1973). Secondary metabolite profiling was performed by DAD-RP-HPLC on Agilent 1100 system using 2-eluent scheme (eluent A = 0,05 M aqueous solution of H3PO4; B = acetonitrile), column – Agilent Poroshell® 120, 2.7 μm, 2.1 × 150 mm, temperature control 20°C, sample volume 5 μl, flow rate 0.2 ml/min, analysis time up to 80 min, elution profile – wide range linear gradient from 0% B in A to 100% B in 30 min, then isocratic B with flow accelerated up to 0.6 ml/min and column temperature increased up to 40°C. Wavelength detection at 206, 254, 300, 350 and 450 nm was used to determine the most organic compounds (including terpenoids), most of substances with aromatic structure in molecule, phenylpropanoids (mainly cinnamic acids), flavonoids (flavones and flavonols), Shown that various pericarp of sugar beet hybrids contain a substantial amount of phenolic compounds which are represented by hydroxycinnamic acids, flavonoids and coumarins. Contained in the fruits of sugar beet triterpenoid saponins enhance the action of phenolic substances, creating complex system of protection of beet sprouts from the negative impact of biotic factors. The model of the functioning of biochemical regulation of seed germination and the formation around the pericarp phytoactive areas, performing the function of the protection system of seedlings from potential competitors and pathogens. A complex reaction of biological activity for water extracts of pericarp in relation to dicotyledonous plants, algae and root rots was established in the experimental data. This test can be used in the selection of sugar beet as a marker of potential resistance of genotypes to fungal and bacterial infections at the stage of seed germination. ARTICLE INFO Received 26. 3. 2018 Revised 28. 5. 2018 Accepted 11. 6. 2018 Published 1. 8. 2018 Regular article doi: 10.15414/jmbfs.2018.8.1.663-667