Ultramorphometric study of the plastids in apical tuber cells of original and transgenic potato plants treated with ambiol

Abstract

Synthetic growth regulators capable of stimulating or inhibiting growth processes in plants in a concentration-dependent way and increasing the plant tolerance to stress conditions have long attracted the attention of researchers [1][2][3][4]. Much recent attention has been given to synthetic growth regulators with an antioxidant action, which strongly affect plant growth processes and the development of anti-stress responses [5][6][7]. Hence our interest in the antioxidant ambiol (2-methyl-4-dimethylaminomethyl-5-hydroxybenzimidazole dihydrochloride), first synthesized at the Institute of Biochemical Physics, Russian Academy of Sciences, which displays anti-stress properties and acts as a growth regulator [5,6,[8][9][10][11][12][13]. It is demonstrated that ambiol influences formation, growth, and development processes in plants [4,5,[14][15][16][17], the content of phytohormones in plant tissues, and activities of H + -ATPase in the plasmalemmata of potato tuber cells [9,[18][19][20][21]. Studies of the effects of individual antioxidants, particularly ionol [22,23] and ambiol [24], on the plant organism were initiated.Genetically transformed (transgenic) plants, e.g., potato plants carrying the gene coding for antimicrobial oligopeptides, so-called defensins, is a promising model for studying the mechanism of ambiol action. It is demonstrated that defensins are capable of protecting plants from phytopathogens [9,25], which is very important for increasing resistance and yield of potato plants.This work continues our research into mechanisms underlying the action of the antioxidant ambiol in original and defensin gene-transfected plants of potato cultivar Desire [9,15,16,18,19,24]. It was found earlier that ambiol was capable of regulating growth through either stimulation or inhibition of tuber germination of original and transgenic plants depending on the concentration [9]. It was interesting to evaluate the effect of ambiol at various concentrations on the plastids in apical tuber cells of original and transgenic potato plants, as the state of plastids in many respects reflected the functional state of apical meristematic cells under experimental conditions. The goal of the work was to study ultrastructural and morphometric characteristics of plastids in the cells of the central and axial meristems of tuber apices in original and transgenic potato cultivar Desire plants under normal conditions and after treatment with ambiol. MATERIAL AND METHODS Tuber apices of original and transgenic potato ( Solanum tuberosum L.) plants of the cultivar Desire at the stage of germination after forced dormancy were the object of this study. The potato plants were transformed at the All-Russia Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences [9]. Whole tubers of original and transgenic plants in a natural dormancy were soaked in ambiol solution for 20 h. The growth-regulating concentrations of ambiol (5 and 60 mg/l) [9] were used in the experiment. Original and transgenic potato tubers soaked ...