Yuliana Markovska

Physiological Changes in Higher Poikilohydric Plants - Haberlea Rhodopensis Friv. and Ramonda Serbica Pan<c. during Drought and Rewatering at Different Light Regimes

Summary A comparative physiological characterization of the transitions biosis-anabiosis-biosis in the poikilohydrous higher polants Haberlea rhodopensis Friv. and Ramonda serbica Panc. (Gesneriaceae) is made, analyzing the changes in the rates of net photosynthesis, transpiration and stomatal resistance under light conditions, close to the natural (65.μmol · m −2 · s −1 ), and in the dark. The role of light in the physiological processes during these transitions is discussed.

Lipid and sterol changes in leaves of Haberlea rhodopensi and Ramonda serbica at transition from biosis into anabiosis and vice versa caused by water stress

Abstract The lipid and sterol composition of leaves of Haberlea rhodopensis and Ramonda serbica and their changes at different water deficits and restoration from anabiosis in light and dark were investigated. Lipid and sterol composition changes more drastically at 50% water deficit, while at 87% water deficit (air-dried plant) it is similar to that of fresh plants. This is an indication that there is almost full adaptation of the investigated plants in the stage of anabiosis. The restoration in light leads to lipid and sterol composition similar to that of the fresh plants, while restoration in dark leads to a composition similar to that of half-dried plants.

Effects of salinity on the photosynthetic apparatus of two Paulownia lines

The effects of soil salinity on the functional activity of photosynthetic apparatus and pigment composition of two Paulownia lines (Paulownia tomentosa x fortunei and Paulownia elongata x elongata) were investigated. PAM chlorophyll fluorescence measurements revealed that salinity leads to: (i) an increase of the photochemical quenching coefficient (qP) and the linear electron transport rate (ETR) in both lines of Paulownia, while the maximum quantum yield of the primary photochemistry of PSII in the dark adapted state (Fv/Fm) was unaffected; (ii) improved the efficiency of the photochemical energy conversion (ФPSII); (iii) an impact on the chlorophyll fluorescence decrease ratio (RFd), which correlates to the net CO2 assimilation rate; (iv) an impact on [Formula: see text] reoxidation. The analysis of the kinetics of P700(+) reduction upon turning off far-red irradiation revealed that salinization lead to a delay of the cyclic electron transport around PSI in both studied lines as the effect on this process is more pronounced in P. tomentosa x fortunei than in (in comparison with) P. elongata x elongata. The present experimental results suggested high salt tolerance of the studied lines Paulownia, but P. tomentosa x fortunei is more tolerant to salinity than P. elongata x elongata. Molecular mechanisms involved in the Paulownia response to the soil salinity are discussed.

Antioxidant capacity of sage grown on heavy metal-polluted soil

Oxidative stress response and essential oil composition of sage (Salvia officinalis L.), grown on industrially polluted soil were studied. Sage plants were grown on the soil polluted with Cd, Cu, Pb, Zn, and non-polluted control soil. One-year-old sage possessed a high potential for heavy metal accumulation mainly in the roots. Heavy metal pollution resulted in root and shoot dry biomass inhibition. The increased levels of hydrogen peroxide and MDA showed that the heavy metal uptake caused oxidative stress. The increase towards the control was observed in the levels of glutathione, ascorbate, dehydroascorbate, catalase, dehydroascorbate reductase, and glutathione peroxidase. Weak activities of the most enzymes of the ascorbate-glutathione cycle allowed to suppose that H2O2 neutralization is rather non-enzymatic than enzymatic process. Observed decline in α- and β-thujones and elevated camphor content in the sage leaves did not indicate a deterioration of the essential oil quality. Sage grown on heavy metal-polluted soil successfully accumulated cadmium, lead, and zinc, which is resulted in plant biomass inhibition, but essential oil yield and quality was not declined.

Effect of high light intensity on the photosynthetic apparatus of two hybrid lines of Paulownia grown on soils with different salinity

The objective of this investigation was to evaluate the simultaneous action of light stress and salinity. Pulse amplitude modulated chlorophyll fluorescence, P700 redox state, and pigment analysis were used to assess the impact of high light intensity on Paulownia tomentosa × fortunei and Paulownia elongata × elongata grown on soils with different salinity. It was found that light stress reduced the amount of pigments and the efficiency of photochemical energy conversion, inhibited the maximum and the effective quantum yields of PSII photochemistry, decreased photochemical quenching and photosynthetic rate. Data also showed influence on the primary quinone acceptor (QA) reoxidation, which led to the restriction of the electron flow from QA to plastoquinone and stimulation of the cyclic electron flow. The possible reasons for the increased effects of the light stress under conditions of high salt concentration in soil for Paulownia tomentosa × fortunei are discussed.

EDTA reduces heavy metal impacts on Tribulus terrestris photosynthesis and antioxidants

The effects of EDTA application to heavy metal-polluted soil on phytoextraction of heavy metals, leaf anatomy, gas exchange parameters, enzyme activities of C4 carbon cycle, antioxidant defense, and active compounds of Tribulus terrestris L. were evaluated. The addition of EDTA to the soil polluted with Cd and Pb markedly increased dry weight and Pb, Zn, and Cd contents in shoots. Plants responded to the action of EDTA by an increased stomatal conductance, photosynthetic and transpiration rates, water use efficiency, chlorophyll and carotenoid contents. The activities of C4 carbon cycle enzymes simultaneously increased, thus concentrating CO2 for enhanced CO2 assimilation and providing NADPH for the antioxidant system. Antioxidants, such as ascorbate, reduced glutathione, and flavonoids, increased more in the shoots of T. terrestris after the addition of EDTA. The activities of guaiacol peroxidase, catalase, and the enzymes of the ascorbate-glutathione cycle enhanced significantly in the presence of EDTA. Increased activities of antioxidant enzymes suggest that they have some additive functions in the mechanism of metal tolerance. EDTA application lowered the activity of phenylalanine ammonia-lyase and the content of total phenols, MDA, hydrogen peroxide, dehydroascorbate, and lipid-soluble antioxidant capacity expressed as α-tocopherol. Increased levels of total radical-scavenging activity are in correspondence with the activity of water-soluble antioxidant compounds in T. terrestris tissues. The content of furostanol saponins protodioscin, prototribestin, and rutin increased as a result of EDTA addition. The results obtained allowed us to assume that applied EDTA reduced a negative heavy metal impact on puncture vine photosynthesis and antioxidant potential.

Physiological Response of Foliar Fertilized Matricaria recutita L. Grown on Industrially Polluted Soil

Essential oil quality, quantity, and antioxidant capacity of foliar fertilized Matricaria recutita L., grown on industrially polluted with cadmium (Cd) and lead (Pb) soil were studied. The polluted field is near the waste depository of ferrous metallurgical combine “Kremikovci”. Content of Cd and Pb in the soil exceeded permissible concentrations 4.6 and 2.0 times, respectively. The presence of high levels of heavy metals in the soil resulted in retained plant growth. In M. recutita grown on industrially polluted soil, a decrease of root and shoot dry biomass and reduction of number of lateral steams was observed. Otherwise, the number and biomass of flowers per plant increased. Antioxidant defense in the foliar fertilized plants grown on industrially polluted soil could due mainly to increased levels of peroxidases with substrates ascorbate, glutathione, guaiacol, and hydrogen peroxide. Enhanced levels of Cd and Pb in soil did not influence essential oil yield and quality of chamomile.