ЭлБиб

ACTIVITY OF PHOTOSYNTHETIC APPARATUS OF DACTYLIS

GLOMERATA AS A FUNCTION OF LEAD BIOAVAILABILITY

IN CONTAMINATED SOIL

Pampura T.V., Kreslavski V.D.

Institute of Physicochemical and Biological Problems in Soil Science,

Pushchino, Russia, +7(0967) 73 38 30,

Institute of Basic Biological Problems RAS, Pushchino, Russia,

+7 (0967) 73 36 01,

Introduction. Lead toxicity with respect to plants is partially

related to its negative effect on the activity of photosynthetic apparatus.

This effect can be explained by oxidizing destruction of chloroplasts,

metal binding by proteins of photosynthetic membranes, and also

indirectly by the reduction of plant water potential due to metal-induced

water stress. It is recognized that lead toxic effect is dependent on metal

bioavailability rather then on its total content in soil. The most

significant uptake route of metals to plants is via the soil solution in the

form of dissolved metals and especially free metal ions (Lofts et al.,

2004. However we do not know any experimental work where the

toxic metal effect on the activity of photosynthetic apparatus would be

investigated in relation with metal bioavailability in soils. Furthermore,

mostly the short-term (no longer then during one vegetation period)

experiments were carried out to study metal effect on photosynthesis

(Seregin and Ivanov, 2001). The aim of our work was to study the

activity of photosynthetic apparatus as a function of bioavailable metal

content in soil (metal concentration in soil solution) in the field

experiment during 3 vegetation periods.

Methods.

Dactylis glomerata L.

was selected as a widely spread

dominant plant of natural meadow populations in Western Europe and

European part of Russia. Long-term field experiment was started in the

end of August 2001 at the experimental plot of IPBPSS. Plastic

containers 20-30-40 cm (without bottom) were filled with Luvisols

heavy loam soil, collected from humic horizon in the meadow of the

field experimental station of JPBPSS. Soil in containers was

contaminated with Pb in soluble (Pb(N03)2) and insoluble (РЬОг)

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