The induction of chlorophyll fluorescence in the leaves of maize under conditions of contamination with heavy metals

Abstract

Photoinduction chlorophyll fluorescence is a modern informative method of determining the effect of heavy metals on the physiological state agrocenosis corn without damaging the plants. Changes in any link of photosynthesis result in the change of Kautsky curve type. This allows to diagnose the present state of the photosynthetic apparatus of plants under the influence of the heavy metals. During the experience we marked differences between of fluorescence of chlorophyll leaves of corn. in areas of control and ecotypes, which are contaminated with heavy metals. The peculiarity of curves forming is determined by basic kinetic parameters, that are associated with the activities of photosynthetic apparatus.Excessive accumulation of lead, zinc, cadmium in soil is accompanied by disturbances in the photosynthetic apparatus in leaves of maize both in the initial phase of development (3–4 leaves), and during the formation of maize panicle. The value of the basic parameters such as the background fluorescence (Fo), maximum fluorescence (Fm), stationary fluorescence (Fst) shows a decrease of primary processes of photosynthesis and violation of coherence reactions of the Calvin cycle. Kautsky curve, which is obtained in the variant with a 100-fold excess background had much lower peaks amplitude than others.