FLUORIDE INFLUENCE ON THE GROWTH, MORPHOLOGICAL AND BIOCHEMICAL PARAMETERS, AND ELEMENTAL COMPOSITION OF TRITICUM AESTIVUM L. IN A MODEL EXPERIMENT

Anthropogenic pollution of the environment by fluoride (F) can lead to abnormality symptoms in some species of plants even at relatively low impact levels. Currently, an active accumulation of data on the effect of F on plant functions take place. The purpose of the present work was complex investigation of influence of different F concentrations in soil on growth, morphological and biochemical parameters and elemental composition of the wheat plants (Triticum aestivum L.). Seed germination, survivorship rate, external appearance, length and thickness of leaf blade, chlorophyll, electrolyte leakage, catalase and acid phosphatase activity and elemental composition (As, Ba, Ca, Cd, Co, Cr, F, Fe, K, Mg, Na, Ni, Pb, Se, Sr, Ti, V, Y, Zn and rare-earth elements) were studied at different levels of F in soil in range of 100 - 7600 mg/kg. Methods of spectrophotometry, conductometry, inductively coupled plasma mass-spectrometry and atomic absorption spectrometry were used. The most sensitive biochemical markers for estimation of the plant F stress were found to be electrolyte leakage and acid phosphatase activity. Noticeable change of these parameters started at F soil concentration of 600 and 1100 mg/kg respectively. Concentration of Mg, Ca and Sr in the plants was established to decrease at increasing F in soil. Distribution of concentration Al, As, Ba, Co, Cr, Fe, K, Ni, Pb, Sb, Th, Ti, V, Y, and light rare-earth elements was described by curve with maxima at 1100 mg/kg; maximum concentration of Fe, K, and Ni was observed at 2100 mg/kg of F in soil. Possible 3-stage's scheme for the development F stress in wheat plant was suggested. Both the decrease of the F bioaccumulation factor, electrolyte leakage, acid phosphatase activity and the increase of the content of molybdenum that is a component of plant enzymes catalyzing key stages of nitrogen, carbon, and sulfur metabolism at high F soil levels could be parts of adaptation mechanism of the wheat plants (Triticum aestivum L.) to F stress.