Allelopathic effect of microalgae on winter wheat plants

Abstract

The results of the study of the allelopathic activity of the culture medium of two species of green and charophyte microalgae (Chlorella vulgaris Beijer. and Interfillum terricola (J.B.Petersen) Mikhailyuk et al.) to winter wheat (Triticum aestivum L.) in model pot experiments with the aim to discover of physiological mechanisms of allelopathy and finding effective and safe compounds with growth-promoting effects. The microalgae culture medium was applied in a rate of 1; 3 and 10 mL per a pot (250 mL) filled with sifted and sterilized gray podzolic soil, before sowing wheat seeds. Test plants were grown in a phytochamber under controlled conditions of light intensity, temperature and soil moisture. The number of germinated seeds was recorded from the 2nd to the 8th day after sowing. The vitality of winter wheat was evaluated at the end of the experiments using morphometric characteristics of growth (height of aboveground parts, leaf surface area, length of root system, number of lateral roots; dry matter mass of aboveground parts and roots) and content of photosynthetic pigments in leaves. At the end of the experiment, the indicators of electrical conductivity, redox potential, pH and content of nutrients in the soil were determined. The positive effect of microalgae on seed germination, growth and photosynthetic apparatus of T. aestivum plants was established. Culture medium of C. vulgaris showed a higher stimulating effect on seed germination and growth of wheat seedlings than I. terricola. The positive effect of microalgae on the photosynthetic activity of wheat and the content of organic carbon in the soil indicates the possibility of developing of biofertilizers based on them in order to improve the structural and functional organization of agroecosystems. The obtained results confirmed the prospects of C. vulgaris as a biofertilizer in crops. The allelopathic effect of I. terricola on vascular plants has been studied for the first time. The important role of indirect allelopathic mechanisms in the interactions between the studied species of microalgae and vascular plants has been established.