Effect of Low Light on Photosynthetic Performance of Tomato Plants-Ailsa Craig and Carotenoid Mutant .

The effects of a five-day treatment with low light intensity on tomato plants-Ailsa Craig and mutant-at normal and low temperatures and after recovery for three days under control conditions were investigated. The tomato, which has orange fruits, yellowish young leaves, and pale blossoms, accumulates prolycopene rather than all- lycopene. We investigated the impact of low light at normal and low temperatures on the functioning and effectiveness of photosynthetic apparatuses of both plants.

Antioxidative Defense, Suppressed Nitric Oxide Accumulation, and Synthesis of Protective Proteins in Roots and Leaves Contribute to the Desiccation Tolerance of the Resurrection Plant .

The desiccation tolerance of plants relies on defense mechanisms that enable the protection of macromolecules, biological structures, and metabolism. Although the defense of leaf tissues exposed to solar irradiation is challenging, mechanisms that protect the viability of the roots, yet largely unexplored, are equally important for survival. Although the photosynthetic apparatus in leaves contributes to the generation of oxidative stress under drought stress, we hypothesized that oxidative stress and thus antioxidative defense is also predominant in the roots.

The Role of Alternative Electron Pathways for Effectiveness of Photosynthetic Performance of , Wt and , under Low Temperature and High Light Intensity.

A recent investigation has suggested that the enhanced capacity for PSI-dependent cyclic electron flow (CEF) and PSI-dependent energy quenching that is related to chloroplast structural changes may explain the lower susceptibility of to combined stresses-a low temperature and a high light intensity. The possible involvement of alternative electron transport pathways, proton gradient regulator 5 (PGR5)-dependent CEF and plastid terminal oxidase (PTOX)-mediated electron transfer to oxygen in the response of plants-wild type (wt) and -to treatment with these two stressors was assessed by using specific electron transport inhibitors. Re-reduction kinetics of P indicated that the capacity for CEF was higher in when this was compared to wt.

Reactivation of the Photosynthetic Apparatus of Resurrection Plant during the Early Phase of Recovery from Drought- and Freezing-Induced Desiccation.

is a unique desiccation-tolerant angiosperm that also survives winter frost. As, upon freezing temperatures, desiccates, the taxon is proposed to survive low temperature stress using its desiccation tolerance mechanisms. To reveal the validity of this hypothesis, we analyzed the structural alterations and organization of photosynthetic apparatus during the first hours of recovery after drought- and freezing-induced desiccation.

The role of antioxidant defense in freezing tolerance of resurrection plant .

Unlabelled: Friv. is unique with its ability to survive two extreme environmental stresses-desiccation to air-dry state and subzero temperatures. In contrast to desiccation tolerance, the mechanisms of freezing tolerance of resurrection plants are scarcely investigated.

Low temperature and high light dependent dynamic photoprotective strategies in Arabidopsis thaliana.

Arabidopsis thaliana has been recognized as a chilling tolerant species based on analysis of resistance to low temperature stress, however, the mechanisms involved in this tolerance are not yet clarified. The low temperature-induced effects are exacerbated when plants are exposed to low temperatures in the presence of high light irradiance but the experimental data on the impact of light intensity during cold stress and its influence during recovery from stress are rather limited. The main objective of this study was to re-examine the photosynthetic responses of A.

Acquired tolerance of the photosynthetic apparatus to photoinhibition as a result of growing Solanum lycopersicum at moderately higher temperature and light intensity.

The kinetics of photoinhibition in detached leaves from tomato plants (Solanium lycopersicum L. cv. M82) grown for 6 days under different combinations of optimal and moderately high temperature and optimal and high light intensity were studied.

Differential temperature effects on dissipation of excess light energy and energy partitioning in lut2 mutant of Arabidopsis thaliana under photoinhibitory conditions.

The high-light-induced alterations in photosynthetic performance of photosystem II (PSII) and photosystem I (PSI) as well as effectiveness of dissipation of excessive absorbed light during illumination for different periods of time at room (22 °C) and low (8-10 °C) temperature of leaves of Arabidopsis thaliana, wt and lut2, were followed with the aim of unraveling the role of lutein in the process of photoinhibition. Photosynthetic parameters of PSII and PSI were determined on whole leaves by PAM fluorometer and oxygen evolving activity-by a Clark-type electrode. In thylakoid membranes, isolated from non-illuminated and illuminated for 4.

Valorization of a plant β-amylase: Immobilization and dataset on the kinetic process.

The data presented in this article are related to the research article titled "Immobilization nd topochemical mechanism of a new β-amylase extracted from Pergularia tomentosa" (Lahmar et al., 2017) [1]. This article documented information on the determination of the molecular weight of the β-amylase, the method of its immobilization and a comparison of the kinetic mechanism between the free and the immobilized forms by a mathematical method.

Heat stress-induced effects of photosystem I: an overview of structural and functional responses.

Temperature is one of the main factors controlling the formation, development, and functional performance of the photosynthetic apparatus in all photoautotrophs (green plants, algae, and cyanobacteria) on Earth. The projected climate change scenarios predict increases in air temperature across Earth's biomes ranging from moderate (3-4 °C) to extreme (6-8 °C) by the year 2100 (IPCC in Climate change 2007: The physical science basis: summery for policymakers, IPCC WG1 Fourth Assessment Report 2007; Climate change 2014: Mitigation of Climate Change, IPCC WG3 Fifth Assessment Report 2014). In some areas, especially of the Northern hemisphere, even more extreme warm seasonal temperatures may occur, which possibly will cause significant negative effects on the development, growth, and yield of important agricultural crops.

Tomato plants acclimate better to elevated temperature and high light than to treatment with each factor separately.

The influence of two factors - high temperature and high light intensity, acting separately or simultaneously on the pigment composition, fluorescent characteristics, membrane integrity and synthesis of protective substances was investigated in tomato plants (Solanum lycopersicum cv. M 82). Moderate elevated temperatures (38/29 °C) were applied under optimum or high light intensity for 2 and 6 days and after that the plants are allowed to recover for 5 days at optimum conditions.

The Lack of Lutein Accelerates the Extent of Light-induced Bleaching of Photosynthetic Pigments in Thylakoid Membranes of Arabidopsis thaliana.

The high light-induced bleaching of photosynthetic pigments and the degradation of proteins of light-harvesting complexes of PSI and PSII were investigated in isolated thylakoid membranes of Arabidopsis thaliana, wt and lutein-deficient mutant lut2, with the aim of unraveling the role of lutein for the degree of bleaching and degradation. By the means of absorption spectroscopy and western blot analysis, we show that the lack of lutein leads to a higher extent of pigment photobleaching and protein degradation in mutant thylakoid membranes in comparison with wt. The highest extent of bleaching is suffered by chlorophyll a and carotenoids, while chlorophyll b is bleached in lut2 thylakoids during long periods at high illumination.

Comparison of thylakoid structure and organization in sun and shade Haberlea rhodopensis populations under desiccation and rehydration.

The resurrection plant, Haberlea rhodopensis can survive nearly total desiccation only in its usual low irradiation environment. However, populations with similar capacity to recover were discovered recently in several sunny habitats. To reveal what kind of morphological, structural and thylakoid-level alterations play a role in the acclimation of this low-light adapted species to high-light environment and how do they contribute to the desiccation tolerance mechanisms, the structure of the photosynthetic apparatus, the most sensitive component of the chlorophyll-retaining resurrection plants, was analyzed by transmission electron microscopy, steady state low-temperature fluorescence and two-dimensional Blue-Native/SDS PAGE under desiccation and rehydration.

UV-B response of greening barley seedlings.

The relationship between the greening stage of barley seedlings and their response to UV-B irradiation was studied. Etiolated barley seedlings ( Hordeum vulgare L., cv.

Response of isolated thylakoid membranes with altered fluidity to short term heat stress.

The effect of alterations of lipid phase order of thylakoid membranes on the thermosensitivity of photosystem I (PS I) and photosystem II (PS II) was studied. Plant sterols stigmasterol and cholesterol were applied to decrease the fluidity in isolated membranes. After sterol treatment, a decrease of the temperature of 50 % inhibition of PSII activity was observed.

Selective photobleaching of chlorophylls and carotenoids in photosystem I particles under high-light treatment.

Photosystem I particles (PSI-200) isolated from spinach leaves were studied by means of absorbance, 77K fluorescence and resonance Raman (RR) spectroscopy. The aim was to obtain better insight into the changes of the pigment spectral properties in those particles during prolonged exposure to high-light intensities and to reveal the involvement of these pigments in the photoprotection of the PSI. During prolonged exposure to high-light intensities of spinach PSI particles, a loss of a significant amount of photosynthetic pigments was observed.

Quality control of Photosystem II: cleavage and aggregation of heat-damaged D1 protein in spinach thylakoids.

Moderate heat stress (40 degrees C, 30 min) on spinach thylakoids induced cleavage of the D1 protein, producing an N-terminal 23-kDa fragment, a C-terminal 9-kDa fragment, and aggregation of the D1 protein. A homologue of Arabidopsis FtsH2 protease, which is responsible for degradation of the damaged D1 protein, was abundant in the stroma thylakoids. Two processes occurred in the thylakoids in response to heat stress: dephosphorylation of the D1 protein in the stroma thylakoids, and aggregation of the phosphorylated D1 protein in the grana.

Effect of membrane fluidity on photosynthetic oxygen production reactions.

The effect of changes of membrane fluidity on the oxygen evolving capability of isolated thylakoids was investigated. Alteration of the lipid phase fluidity was achieved by incorporation of the plant sterol stigmasterol. Incorporation of stigmasterol in the lipid bilayer of thylakoid membranes results in rigidization of the hydrophobic phase of thylakoid membranes and decreases the degree of packing of the lipid head groups.

High light-induced changes of 77 K fluorescence emission of pea thylakoid membranes with altered membrane fluidity.

The effect of lipid phase order of isolated thylakoid membranes on fluorescent characteristics of both photosystems during illumination with high light intensity at 22 degrees C and 4 degrees C was investigated. For artificial modification of membrane fluidity two membrane perturbing agents were applied-cholesterol and benzyl alcohol. 77 K fluorescence emission and excitation spectra of control, cholesterol- and benzyl alcohol-treated thylakoid membranes were analysed in order to determine the high light-induced changes of emission bands attributed to different chlorophyll-protein complexes-F 735, emitted by photosystem I-light-harvesting complex I; and F 685 and F 695, emitted by photosystem II-light-harvesting complex II.

Resonance Raman spectroscopy of carotenoids in Photosystem I particles.

Low-temperature resonance Raman (RR) spectroscopy was used for the first time to study the spectral properties, binding sites and composition of major carotenoids in spinach Photosystem I (PSI) particles. Excitation was provided by an argon ion laser at 457.9, 476.

Different kinetics of photoinactivation of photosystem I-mediated electron transport and P700 in isolated thylakoid membranes.

Photoinactivation kinetics of photosystem I (PSI)-mediated electron transport rate was compared to that of P700 content at room (22 degrees C) and low (4 degrees C) temperatures in isolated spinach thylakoid membranes. The high light treatment was carried out under aerobic and anaerobic conditions. At 22 degrees C the decrease of electron transport rate showed first order exponential kinetics.