Laboratory “Photosynthesis – Activity and Regulation”


Professor Violeta Velikova, DrSc

Bldg. 21, Office 109
Phone: +359-2-9792683


We conduct targeted fundamental research oriented towards possibilities for long-term practical applications. The objectives of our studies perfectly fit the main broad lines of research addressed in the Horizon Europe framework program of the European Commission (EC), specifically dealing with Food, Bioeconomy, Natural Resources, Agriculture and Environment. They are directly related to the societal challenges defined in the National Strategy for Research Development in the Republic of Bulgaria 2017-2030, in particular: “improving the quality of life – food, health, biodiversity, environmental protection, urban environment, transport”, “increasing the competitiveness and productivity of the economy” and “efficient utilization of natural resources”.

The structural organization and the mechanisms of functioning of the photosynthetic apparatus in response to different environmental stresses (high and low temperatures, increased CO2 concentration, drought, salinity, heavy metals, UV-radiation) with a focus on the mechanisms of adaptation and defense, represent the major field of research in the Department of Photosynthesis – activity and regulation. Investigations have been conducted on the impact of changing climatic factors on primary and secondary plant metabolism. The physiological role of volatile and non-volatile isoprenoids, lipid and fatty acid composition, as well as other metabolites involved in plant defense are also studied. We are applying modern imaging techniques like chlorophyll fluorescence and thermal imaging, photosynthetic gas exchange, thermoluminescence, PCR and qPCR, SDS – PAGE, Blue Native PAGE, Western blot, analyses of various markers of oxidative stress and activity of antioxidant defense system.

Physiological phenotyping. Primary and secondary plant metabolism under climate changes

Our research efforts are focused on the impact of changing climatic factors and anthropogenic pollution on photosynthesis. Based on analyses of CO2 and H2O exchange and chlorophyll fluorescence parameters we study the limiting steps leading to decreased photosynthetic productivity under adverse conditions. Our research group is also studying phenotypic differences between plant populations from contrasting environments for identification of putative stress-responsive metabolites and on the understanding mechanisms of plant adaptation to stress conditions. In parallel with the primary metabolism we study the changes in the secondary metabolism of plants with a focus on biogenic volatile organic compounds. Exploring the relationship biogenic emissions – environment we aim at selecting the most environmentally friendly plant species to be used for landscape architecture and afforestation of areas with different levels of pollution, which in turn is related to air quality.

Sustainable plant development in changing environment

We explore different high-tech and innovative approaches for increasing the quality and quantity of plant production. Through innovative technology (e.g. LED) we aim to develop more sustainable plant genotypes with increased levels of natural secondary metabolites, which are an important raw material for the food and pharmaceutical industries. The focus of our research is also on the application of innovative agrotechnical substances by the group of biostimulants (plant protein hydrolysates) and nanomaterials (carbon nanotubes, biocompatible polymer nanoparticles and magnetite), their physiological effects and the possibilities for overcoming adverse abiotic factors. A wide range of research methods are applying, including modern imaging methodologies (fluorescence and thermal imaging) widely used in plant phenotyping.

Mechanisms of desiccation tolerance of plants under changing environmental conditions

The resurrection plant Haberlea rhodopensis Friv. (Gesneriaceae) is used as a model system for elucidation of the mechanisms of desiccation tolerance under changing environmental conditions.  We investigate the acclimation mechanisms at different levels of organization of the photosynthetic apparatus (whole leaf, isolated chloroplasts) using physiological, biophysical and biochemical approaches. Special attention is focused on the relationship between the extent of stress treatment and the level of some stress markers, on the structure and functionality of the photosynthetic apparatus, activity of antioxidant defense system, the synthesis of stress-induced proteins (HSPs, Dehydrins, ELIPs), the changes in pigment-protein complexes, the main PSI and PSII proteins, and the expression of specific genes upon stress treatments.

Primary photosynthetic reactions, abiotic stress and the role of biologically active substances (polyamines, salicylic acid, ABA, nitric oxide)

Our efforts are emphasized on the interrelation between structural organization and functional activity of the photosynthetic apparatus, regulation of photosynthetic electron and proton transport under optimal and stress conditions (drought, including extreme drought, salinity, changes in the light spectral composition, UV-B radiation effects, heavy metal pollution, etc.). Different crops and medicinal plants of great economic importance as well as plants and microalgae tolerant to a certain type of abiotic stress have been used as model systems. The effects of some biologically active compounds (polyamines, salicylic acid, ABA and nitric oxide) in the process of adaptation of crop plants to abiotic stresses are also studied. Various biophysical and biochemical approaches have been applied in our research, including chlorophyll fluorescence, thermoluminescence, redox kinetics of Р700, oxygen evolution, pigment content, changes in some enzymatic and non-enzymatic components of plant antioxidant defense system.

Research Projects

More Significant Research Achievements

Scientific Publications

Research Team

Violeta Velikova – Professor, DrSc
Office 109, lab. 215
Tel. (+359 2) 979 26 83; (+359 2) 979 26 04
ORCID ID: 0000-0002-3058-919X
ResearcherID: J-8849-2016
Research Gate: Violeta Velikova
Professional interests: Agronanothechnology, plant stress physiology, phenotyping, biogenic volatile organic compounds, photosynthesis, chlorophyll fluorescence, metabolomics, proteomics, oxidative stress.
Katya Georgieva – Professor, PhD
Office 205, Lab. 116
Тел. (+359 2) 979 26-20, (+359 2) 979 26-88
ORCID: 0000-0002-5509-3801
Research Gate: Katya_Georgieva
Professional interests: Abiotic stress, acclimation, resurrection plants, photosynthesis, chlorophyll fluorescence, antioxidant enzymes, stress-induced proteins, gene expression.
Violeta Peeva – Assistant Professor, PhD

Office 305, lab. 328
Tel. (+359 2) 979 26-36, (+359 2) 979 36-82
Professional interests: Photosynthesis, photosynthetic electron transport, thermoluminescence, oxygen evolution, abiotic stress, effects on photosynthetic processes, biochemical and biophysical stress markers.

Liliana Brankova – Assistant Professor, PhD

Office 305, lab. 215
Tel. (+359 2) 979 26 36, (+359 2) 979 26-04
Professional interests: Bioremediation, stress, plant defense system.

Gergana Mihailova – Assistant Professor, PhD

Office 305, Lab. 116
Tel. (+359 2) 979 26 36, (+359 2) 979 26 88

ORCID: 0000-0001-6006-6720
ResearcherID: AAE-2856-2021
ResearchGate: Gergana_Mihailova
Professional interests: Photosynthesis, chlorophyll fluorescence, resurrection plants, abiotic stress, protective mechanisms, antioxidant system, gene expression, protein synthesis.

Dilyana Doneva – Assistant Professor, PhD

Lab. 302
Tel. (+359 2) 979 26-33
Professional interests: Photosynthetic gas exchange, oxidative stress, antioxidant enzymes, light quality effects on plant growth and development.

Vladimir Aleksandrov – Assistant Professor, PhD

Lab. 304
Tel. (+359 2) 979 26 33
ORCID ID: 0000-0003-0441-5644
Research Gate: Vladimir_Aleksandrov
Professional interests: Phenotyping, photosynthesis, chlorophyll fluorescence, abiotic stress, photobiophysics, mathematical models of biological systems, nanobiology, bioinformatics.

Daniel Ilkov – MSc

Lab. #304
Tel. (+359 2) 979 26 33

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