Influence of lead salts on some morphological and physiological parameters of filamentous cyanobacteria

A R Galperina,O B Soprunova

doi:10.15421/011834

Abstract

In the conditions of a model laboratory experiment the influence of lead salts (an acetate and nitrate) on morphological and physiological parameters of filamentous cyanobacteria was studied. During the experiment we estimated features of formation of biomass, structure of trichomes, form and the size of cells, content of chlorophyll a, carotenoids and phycobiliproteins. It is noted that in the presence of lead acetate of up to 5 maximum allowable concentrations there is a formation of a biomass in the form of attached and free films, and presence of a nitrate form of lead at the same concentration promotes formation of filaments, fixed from one side. At the same time, the increase of concentration of both acetate, and nitrate forms of lead promotes formation of rarefied films of one layer multidirectional trichomes; to disintegration of trichomes on the fragments and separate cells united by an external mucilaginous envelope. Content of lead acetate in concentration of 15 times the maximum allowable concentration, and lead nitrate at 10 times the maximum allowable concentration leads to formation of abnormally long cells up to 10.0–10.5 µm long. It is established that lead acetate has a stimulating effect on formation of a biomass and synthesis of photosynthetic pigments. The biomass growth of up to 223.7% of the control was observed at concentration up to 15 times the maximum allowable concentration inclusive. The content of chlorophyll a grew by 30.6%, carotenoids – by 24.0% at one maximum allowable concentration. Lead nitrate stimulates a biomass gain much more weakly – up to 70.0% at 5 times the maximum allowable concentration and also has the expressed inhibiting effect on synthesis of photosynthetic pigments. Depression of concentration of chlorophyll a and carotenoids by 38.8% and 79.4% respectively was observed already at one maximum allowable concentration. The stimulating effect of lead acetate is noted on synthesis of phycocyanin (by 94.0%) and allophycocyanin (by 120.0%) in concentration up to 5 times the maximum allowable concentration; the stimulating effect of lead nitrate was observed on synthesis of phycocyanin (by 64.7%) in concentration up to 5 times the maximum allowable concentration and on synthesis of allophycocyanin (up to 140.0%) and on phycoerythrin (up to 228.0%) at concentration up to 10 times the maximum allowable concentration. Comparison of influence of various lead salts on filamentous cyanobacteria revealed a more expressed inhibiting effect of the nitrate form of lead in comparison with acetate.

Highlights

One of the most significant sources of the environmental pollution is salts of lead
We observed that presence of lead of up to 5 MPC did not inhibit the development of cyanobacteria
Μm lead acetate lead nitrate length of cells width of cells length of cells width of cells

Summary

Introduction

One of the most significant sources of the environmental pollution is salts of lead. Annually, around 3.5 Mt of lead is released into the environment, and if we take into account the re-extraction of lead from wastes, the production of lead is 4.1 Mt. Cyanobacteria are promising objects to apply for cleaning discharge water from compounds of heavy metals in general, and lead in particular, one of the most significant functions of which is the capacity of bioaccumulation and detoxication of heavy metals (Abdullah & Loo, 2006) Their response reactions (sizes, morphology, ultrastructure of the cells and physiologicbiochemical features) to the impact of anthropogenic factors are the fastest and can be representative indicators of the condition of aquatic and soil ecosystems (Bekasova et al, 2002; Tay et al, 2003; Dubey et al, 2011; Shilpi et al, 2014; Fokina et al, 2015; Fokina et al, 2017). Different anions are able to reduce or strengthen toxic effects of the heavy metal (Temraleeva & Pinskii, 2010; Vijayakumar, 2012; Bilal et al, 2018)

Objectives

Methods

Results

Discussion

Conclusion