Bean (Phaseolus vulgaris L. cv. Berbukskaya) seedlings were pre-treated with choline compounds, 19 mM 2-ethyltrimethylammonium chloride (Ch) or 1.6 mM 2-chloroethyltrimethylammonium chloride (CCh), during 24 h, then after 6 d the excised primary leaves were exposed to UV-B and high temperature stress. Chlorophyll (Chl) fluorescence, delayed light emission, accumulation of photosynthetic pigments, contents of thiobarbituric acid reactive substances, and activities of the active oxygen detoxifying enzymes (superoxide dismutase, ascorbate peroxidase, and glutathione reductase) were examined. Pre-treatment of plants with Ch or CCh enhanced the resistance of photosystem 2 (PS2) photochemistry to UV-B and heat injuries. The higher stress resistance can be explained by the increased activity of the detoxifying enzymes. The increased content of UV-B-absorbing pigments may also contribute to the enhanced resistance of choline-treated plants to UV-B radiation. and V. D. Kreslavski ... [et al.].
The effects of 2-chloroethyltrimethylammonium chloride (CCh), 2-ethyltrimethylammonium chloride (Ch), and acetylcholine chloride (ACh) at concentrations of 1 µM - 5 mM and of red radiation (R) pulse on growth, greening, and formation of the photosynthetic apparatus in etiolated wheat seedlings (Triticum aestivum L. cv. Moskovskaya-35) were examined. A short-term application of cholines and R pulse stimulated the first leaf growth and its appearance from coleoptile, and inhibited the coleoptile growth. The effects of cholines were observed during 96 h after the treatment of 4-d-old seedlings and depended on the type and the concentration of cholines. CCh, Ch, and R were also stimulators of greening and increased the photosynthetic activity, whereas ACh did not influence the process of greening. Joint effects of R with cholines on the growth and photomorphogenesis were greater than the individual ones, whereas far-red (FR) radiation decreased the influence of cholines. Thus phytochrome may modify the effects of cholines in the processes of growth and greening. and E. F. Kobzar, V. D. Kreslavskiï, E. N. Muzafarov.