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Cereals, which belong to the Poaceae family, are the most economically important group of plants. Among abiotic stresses, temperature stresses are a serious and at the same time unpredictable problem for plant production. Both frost (in the case of winter cereals) and high temperatures in summer (especially combined with a water deficit in the soil) can result in significant yield losses. Plants have developed various adaptive mechanisms that have enabled them to survive periods of extreme temperatures. The processes of acclimation to low and high temperatures are controlled, among others, by phytohormones. The current review is devoted to the role of brassinosteroids (BR) in cereal acclimation to temperature stress with special attention being paid to the impact of BR on photosynthesis and the membrane properties. In cereals, the exogenous application of BR increases frost tolerance (winter rye, winter wheat), tolerance to cold (maize) and tolerance to a high temperature (rice). Disturbances in BR biosynthesis and signaling are accompanied by a decrease in frost tolerance but unexpectedly an improvement of tolerance to high temperature (barley). BR exogenous treatment increases the efficiency of the photosynthetic light reactions under various temperature conditions (winter rye, barley, rice), but interestingly, BR mutants with disturbances in BR biosynthesis are also characterized by an increased efficiency of PSII (barley). BR regulate the sugar metabolism including an increase in the sugar content, which is of key importance for acclimation, especially to low temperatures (winter rye, barley, maize). BR either participate in the temperature-dependent regulation of fatty acid biosynthesis or control the processes that are responsible for the transport or incorporation of the fatty acids into the membranes, which influences membrane fluidity (and subsequently the tolerance to high/low temperatures) (barley). BR may be one of the players, along with gibberellins or ABA, in acquiring tolerance to temperature stress in cereals (particularly important for the acclimation of cereals to low temperature).

The aim of the current work was to characterize disturbances in the hormonal balance and changes in the accumulation of the protective heat shock proteins (HSP) as a result of deacclimation in a few cultivars of oilseed rape. Samples for both analyses were collected from plants that had not been acclimated (before cold acclimation—control), cold acclimated (at 4 °C d/n, three weeks) and then deacclimated at 16/9 °C d/n (one week). The tested hormones included abscisic acid, jasmonic acid, salicylic acid, gibberellins, auxins and cytokinins (including their precursors, intermediates and conjugates). Unambiguous results were obtained for a stress hormone, abscisic acid, whose concentration increased in the leaves of all of the tested cultivars during cold acclimation while it strongly decreased during deacclimation. Deacclimation resulted also in an elevated level of the typical growth hormones. As a result of cold acclimation, the accumulation of protective proteins such as cytoplasmic HSP70 and HSP90 increased in three of the four tested cultivars. The HSP content most often decreased in the deacclimated plants compared to the cold-acclimated plants. The hormonal and protein changes are discussed relative to the frost tolerance changes of the tested cultivar.

The objective of this study was to answer the question of how the deacclimation process affects frost tolerance, photosynthetic efficiency, brassinosteroid (BR) homeostasis and BRI1 expression of winter oilseed rape. A comparative study was conducted on cultivars with different agronomic and physiological traits. The deacclimation process can occur when there are periods of higher temperatures, particularly in the late autumn or winter. This interrupts the process of the acclimation (hardening) of winter crops to low temperatures, thus reducing their frost tolerance and becoming a serious problem for agriculture. The experimental model included plants that were non-acclimated, cold acclimated (at 4 °C) and deacclimated (at 16 °C/9 °C, one week). We found that deacclimation tolerance (maintaining a high frost tolerance despite warm deacclimating periods) was a cultivar-dependent trait. Some of the cultivars developed a high frost tolerance after cold acclimation and maintained it after deacclimation. However, there were also cultivars that had a high frost tolerance after cold acclimation but lost some of it after deacclimation (the cultivars that were more susceptible to deacclimation). Deacclimation reversed the changes in the photosystem efficiency that had been induced by cold acclimation, and therefore, measuring the different signals associated with photosynthetic efficiency (based on prompt and delayed chlorophyll fluorescence) of plants could be a sensitive tool for monitoring the deacclimation process (and possible changes in frost tolerance) in oilseed rape. Higher levels of BR were characteristic of the better frost-tolerant cultivars in both the cold-acclimated and deacclimated plants. The relative expression of the BRI1 transcript (encoding the BR-receptor protein) was lower after cold acclimation and remained low in the more frost-tolerant cultivars after deacclimation. The role of brassinosteroids in oilseed rape acclimation/deacclimation is briefly discussed.

The objective of this study was to answer the question of how the deacclimation process affects frost tolerance, photosynthetic efficiency, brassinosteroid (BR) homeostasis and

Although the only known steroid hormones in plants are brassinosteroids, interestingly, mammalian steroid hormones such as androgens or estrogens are also part of the plant metabolic profile. This presented review is focused on the progress that has been made in this matter during the last two decades. The presence of testosterone, 17β-estradiol, and other androgens/estrogens in plants (particularly those that can be measured using more advanced techniques) is described. The physiological activity of androgens and estrogens, especially in plants’ stress response, are discussed, together with some possible mechanisms of their action. The current knowledge indicates that although androgens and estrogens do not have the status of hormones in plants, they are physiologically active and can serve as regulators that support the activity of classic hormones in (1) regulating the various processes connected with plant growth and development and (2) the interaction of plants with their environment.

Background In earlier studies [1], we indicated that applying brassinosteroids (BRs) to lipids that had been isolated from plants altered the physicochemical properties of the monolayers. A continuation of these dependencies using the defined model lipid systems is presented in this paper. The influence of homocastasterone (HCS) and castasterone (CS) (BRs for which the increase in concentration were characteristic of plants grown at low temperatures) on the membrane properties of their polar and the hydrophobic parts were studied. Results Changes in the electrokinetic potential indicate that both BRs decreased the negative charge of the surface, which is an important factor in modifying the contacts with the polar substances. This property of BRs has not yet been described. The studies of the interactions that occur in the hydrophobic part of the membrane were investigated using the EPR methods and Langmuir techniques. The physicochemical parameters of the lipid structure were determined, and the excess of Gibbs free energy was calculated. Conclusion We conclude that examined BRs modify both the hydrophilic and hydrophobic properties of the membranes, but to a greater extent HCS. The consequence of these changes may be the attempt to maintain the stability of the membranes in stressful temperature conditions and / or to the possibility of adsorption of other substances on membranes surfaces. The change of plant metabolism towards increasing the amount of BR, mainly HCS (under cooling) may by an important factor for maintaining optimal structural properties of membranes and their functionality despite temperature changes.

A rapid increase of ozone concentration up to the phytotoxic level is currently observed in the tropical forests. However, the effect of elevated concentration of O3 on tropical ferns and epiphytes has not yet been described and mechanisms of tolerance remain unknown. The aim of this study was to determine the physiological response of the epiphytic fern Platycerium bifurcatum to a high concentration of ozone (150 ppb). In particular, changes in the course of photosynthesis and the pigment composition of sporotrophophyll leaves were taken into account. P. bifurcatum showed high resistance to the 4-week ozone stress. The effect of ozone was an initial decrease in net photosynthesis and reduction in transpiration. Ozone tolerance mechanisms are associated with the closure of stomata and the synthesis of carotenoids and flavonoids. We found that brassinosteroids play an important role in the resistance of P. bifurcatum to ozone. In response to ozone stress an increase in 28-homocastasterone content was observed.

Ten doubled haploid (DH) lines of winter barley with an increased range of freezing/drought tolerance were used to identify phytohormones involved in plant stress acclimation. Cold hardening and drought stress were applied at the most critical stages of plant development on young seedlings and heading plants, respectively. The level of the phytohormones was significantly higher at heading, more than 5-fold in respect of salicylic acid (SA) and total brassinosteroids (BRs) and 1.7-fold in the case of abscisic acid (ABA). Moreover, the spectrum of detectable BRs increased from one—homocastasterone (HCS)—found in seedlings to four BRs identified in heading plants [HCS, castasterone (CS), teasterone and dolicholide], with the last one detected for the first time in cereal species. To some extent freezing tolerance seems to be determined by native hormonal status as control seedlings of tolerant DH lines contained 1.4- and 2.3-fold lower amount of ABA and HCS and 2.3-fold higher amount of SA in comparison to freezing-sensitive ones. Such dependency was not observed in heading plants as significant variation in CS content was the only detected difference. Under stress treatments, tolerant DH lines accumulated significantly lower (75–81%) amount of ABA, which probably reflected lower stress intensity resulting from another defence strategy. In contrast, stress-induced significant almost 2-fold increase in HCS/CS and 2–3-fold decrease in SA content specific for tolerant DH lines of barley suggest the involvement of these molecules in freezing/drought defence. Detected correlations suggest their interaction with nonspecific peroxidase and low molecular weight antioxidants.

Brassinosteroids (BR) are steroid phytohormones that are involved in the growth and stress response in plants, but the precise mechanisms of their action are still being discovered. In our study we have used BR-deficient barley mutants 522DK and BW084 (which carry missense mutations in the HvDWARF and HvCPD genes, respectively). We have also used a BR-signalling mutant that harbors missense substitutions in the HvBRI1 gene. Our aim was (1) to find out if the content of phytohormones in the mutants grown at 20 °C is different than in the wild types and whether/how the content of phytohormones changes after plant acclimation at temperatures of 5 °C and 27 °C?, (2) to characterise the effectiveness of the light reactions of photosynthesis of the barley mutants in comparison to wild types at various temperatures, and (3) to verify the impact of mutations on the tolerance of barley to high and low temperatures. Hormonal characteristics of the BR mutants of barley show the complexity of the interactions between BR and other plant hormones that are additionally modified by temperature and possibly by other factors. The results suggest the participation of BR in auxin catabolism. Further, BR appears to play a role in maintaining the ABA–ABAGlc balance. As for the gibberellin content in plants at a temperature of 20 °C, more in-depth studies will be required to explain the contradictory effects regarding the accumulation of GA3, GA4 and GA5, which appears to be dependent on the type of mutation and connected to the BR level. A fast-kinetic chlorophyll a fluorescence analysis has revealed that the mutants had lower values of energy absorption than the wild types, but the values of the energy transferred via the electron-transport chain was maintained at the wild-type level. We presumed that BR are involved in regulating plant acclimation to extreme (low/high) temperatures, thus the BR-deficient and BR-signalling mutants should be less tolerant to low/high temperatures when compared to the wild types. Unexpectedly, all of the mutants showed a higher tolerance to high temperatures than the wild types. The BW084 and BW312 mutants were less tolerant to frost than the wild type, but 522DK had a similar frost tolerance as the reference wild-type cultivar.

Ecdysteroids (ECs) are steroid hormones originally found in the animal kingdom where they function as insect molting hormones. Interestingly, a relatively high number of these substances can also be formed in plant cells. Moreover, ECs have certain regulatory effects on plant physiology, but their role in plants still requires further study. One of the main aims of the present study was to verify a hypothesis that fenarimol, an inhibitor of the biosynthesis of ECs in the animal kingdom, also affects the content of endogenous ECs in plants using winter wheat Triticum aestivum L. as a model plant. The levels of endogenous ECs in winter wheat, including the estimation of their changes during a course of different temperature treatments, have been determined using a sensitive analytical method based on UHPLC-MS/MS. Under our experimental conditions, four substances of EC character were detected in the tissue of interest in amounts ranging from less than 1 to over 200 pg·g−1 FW: 20-hydroxyecdysone, polypodine B, turkesterone, and isovitexirone. Among them, turkesterone was observed to be the most abundant EC and accumulated mainly in the crowns and leaves of wheat. Importantly, the level of ECs was observed to be dependent on the age of the plants, as well as on growth conditions (especially temperature). Fenarimol, an inhibitor of a cytochrome P450 monooxygenase, was shown to significantly decrease the level of naturally occurring ECs in experimental plants, which may indicate its potential use in studies related to the biosynthesis and physiological function of these substances in plants.

Climate changes, which result in the occurrence of periods with relatively high temperatures during the winter, can lead to the deacclimation of cold-hardened plants and cause problems with their winter survival. The aim of these studies was to investigate the physiological changes (photosynthesis and water relations including aquaporin expression) that accompany deacclimation process in the economically important winter oilseed rape plants. The effect of deacclimation on frost tolerance was also estimated for two tested cultivars: semi-dwarf and plants of a normal height. After cold acclimation at 4 &deg, C (compared to the unacclimated control) the typical changes that accompany cold acclimation such as an increase in the content of water-soluble sugars or a lower water content in the leaves, which lead to an increased frost tolerance, were observed. Deacclimation partially or completely reversed these changes, which resulted in a decreased frost tolerance that was accompanied by a decrease in the content of sugars and an increase of the osmotic potential. The chemical composition of the leaves, which was measured using FT-Raman spectroscopy also clearly confirmed the metabolic differences between the cold-acclimated and deacclimated plants. The plants were significantly different in regard to the content of the various pigments as well as fatty acids and polysaccharides. The phenomenon of a deacclimation-induced decrease in aquaporin PIP1 accumulation, which was accompanied by unchanged PIP1 transcript accumulation, will be discussed in the aspects of the water relations and decreased frost tolerance in deacclimated plants.

Tolerance to deacclimation is an important physiological feature in plants in the face of global warming, which is resulting in incidents of increases in winter temperatures. The aim of the work was to explore how disturbances in the signalling and synthesis of brassinosteroids (BR) influence the deacclimation tolerance of barley. One group of mutants and their reference cultivars (Bowman and Delisa) was cold-acclimated, deacclimated and then tested for frost tolerance at − 12 °C. After cold acclimation, the second group of plants was additionally exposed to frost (− 6 °C) and then, deacclimated and tested for frost tolerance at − 12 °C. The deacclimated brassinosteroid mutants were characterised by an increased tolerance to frost, and consequently, had a higher tolerance to deacclimation than their wild-type cultivars. The mechanism of this phenomenon may be partly explained by analysing the hormonal homeostasis in the crowns. For all of the tested plants, a characteristic feature of the response to the deacclimation phase was an increase in the growth-promoting hormones and abscisic acid compared to the cold acclimation phase. The increase was greater in the BR-deficient (BW084) and BR-insensitive (BW312) mutants compared to the Bowman reference cultivar. Mutant 522DK was characterised by a lower accumulation of total cytokinins and gibberellins as well as an enhanced auxin deactivation compared to the Delisa. In the second group, when the plants were exposed to a temperature of − 6 °C before deacclimation, the hormonal homeostasis was further altered in both the mutants and reference cultivars, but all of the mutants had a higher frost tolerance than the wild types.

(1) Background: The study characterized barley mutants with brassinosteroid (BR) biosynthesis and signaling disturbances in terms of the physicochemical/structural properties of membranes to enrich the knowledge about the role of brassinosteroids for lipid metabolism and membrane functioning. (2) Methods: The Langmuir method was used to investigate the properties of the physicochemical membranes. Langmuir monolayers were formed from the lipid fractions isolated from the plants growing at 20 &deg, C and then acclimated at 5 &deg, C or 27 &deg, C. The fatty acid composition of the lipids was estimated using gas chromatography. (3) Results: The BR-biosynthesis and BR-signaling mutants of barley were characterized by a temperature-dependent altered molar percentage of fatty acids (from 14:0 to 20:1) in their galactolipid and phospholipid fractions in comparison to wild-type (WT). For example, the mutants had a lower molar percentage of 18:3 in the phospholipid (PL) fraction. The same regularity was observed at 5 &deg, C. It resulted in altered physicochemical parameters of the membranes (Alim, &pi, coll, Cs&minus, 1). (4) Conclusions: BR may be involved in regulating fatty acid biosynthesis or their transport/incorporation into the cell membranes. Mutants had altered physicochemical parameters of their membranes, compared to the WT, which suggests that BR may have a multidirectional impact on the membrane-dependent physiological processes.

(1) Background: The study characterized barley mutants with brassinosteroid (BR) biosynthesis and signaling disturbances in terms of the physicochemical/structural properties of membranes to enrich the knowledge about the role of brassinosteroids for lipid metabolism and membrane functioning. (2) Methods: The Langmuir method was used to investigate the properties of the physicochemical membranes. Langmuir monolayers were formed from the lipid fractions isolated from the plants growing at 20 °C and then acclimated at 5 °C or 27 °C. The fatty acid composition of the lipids was estimated using gas chromatography. (3) Results: The BR-biosynthesis and BR-signaling mutants of barley were characterized by a temperature-dependent altered molar percentage of fatty acids (from 14:0 to 20:1) in their galactolipid and phospholipid fractions in comparison to wild-type (WT). For example, the mutants had a lower molar percentage of 18:3 in the phospholipid (PL) fraction. The same regularity was observed at 5 °C. It resulted in altered physicochemical parameters of the membranes (Alim, πcoll, Cs−1). (4) Conclusions: BR may be involved in regulating fatty acid biosynthesis or their transport/incorporation into the cell membranes. Mutants had altered physicochemical parameters of their membranes, compared to the WT, which suggests that BR may have a multidirectional impact on the membrane-dependent physiological processes.

Drought is a major factor limiting plant development and negatively affecting crop yield. It was reported that mutants defective in the brassinosteroid (BR) metabolism from several species, including barley (Hordeum vulgare), show improved tolerance to drought during the vegetative phase of growth. Hence, semi-dwarf barley mutants defective in the BR metabolism may be regarded as an alternative in breeding programs. Occurrence of drought during spike development has a profound effect on yield. Thus, determining reaction of the semi-dwarf, BR-deficient barley mutants to drought during the reproductive phase is crucial. This study was conducted on barley Near-Isogenic Lines defective in the BR metabolism and the reference &lsquo, Bowman&rsquo, cultivar. The experiments were performed under laboratory (optimal watering and drought) and field conditions. The following yield-related parameters were analyzed: total tillering, productive tillering, average grain weight per plant and per spike, as well as weight of 1000 seeds. Additionally, an analysis of chemical composition of grain was performed. The BR-insensitive BW312 line showed the highest values of the productive tillering and grain weight per plant under the drought conditions. Perturbations in the BR metabolism did not have any significant deteriorating effect on the contents of grain chemical ingredients.

The roles of endogenous brassinosteroids (BRs) in the modulation of reaction to drought and genetic regulation of this process are still obscure. In this study, a multidirectional analysis was performed on semi-dwarf barley (Hordeum vulgare) Near-Isogenic Lines (NILs) and the reference cultivar &ldquo, Bowman&rdquo, to get insights into various aspects of metabolic reaction to drought. The NILs are defective in BR biosynthesis or signaling and displayed an enhanced tolerance to drought. The BR metabolism perturbations affected the glucose and fructose accumulation under the control and stress conditions. The BR metabolism abnormalities negatively affected the sucrose accumulation as well. However, during drought, the BR-deficient NILs accumulated higher contents of sucrose than the &ldquo, cultivar. Under the control conditions, accumulation of transcripts encoding antioxidant enzymes ascorbate peroxidase (HvAPX) and superoxide dismutase (HvSOD) was BR-dependent. However, during drought, the accumulation of HvAPX transcript was BR-dependent, whereas accumulations of transcripts encoding catalase (HvCAT) and HvSOD were not affected by the BR metabolism perturbations. The obtained results reveal a significant role of BRs in regulation of the HvAPX and HvCAT enzymatic activities under control conditions and the HvAPX and HvSOD activities during physiological reactions to drought.

The integral parts of the cell membranes are the functional proteins, which are crucial for cell life. Among them, proton-pumping ATPase and aquaporins appear to be of particular importance. There is some knowledge about the effect of the temperature during plant growth, including stress-inducing temperatures, on the accumulation of the membrane proteins: plasma membrane H+-ATPase and aquaporins, but not much is known about the effect of the phytohormones (i.e. brassinosteroids (BR)) on control of accumulation of these proteins. The aim of our study was to answer the question of how a BR deficit and disturbances in the BR perception/signalling affect the accumulation of plasma membrane H+-ATPase (PM H+-ATPase), the aquaporin HvPIP1 transcript and protein in barley growing at 20 °C and during its acclimation at 5 °C and 27 °C. For the studies, the BR-deficient mutant 522DK (derived from the wild-type Delisa), the BR-deficient mutant BW084 and the BR-signalling mutant BW312 and their wild-type Bowman were used. Generally, temperature of growth was significant factor influencing on the level of the accumulation of the H+-ATPase and HvPIP1 transcript and the PM H+-ATPase and HvPIP1 protein in barley leaves. The level of the accumulation of the HvPIP1 transcript decreased at 5 °C (compared to 20 °C), but was higher at 27 °C than at 20 °C in the analyzed cultivars. In both cultivars the protein HvPIP1 was accumulated in the highest amounts at 27 °C. On the other hand, the barley mutants with a BR deficiency or with BR signalling disturbances were characterised by an altered accumulation level of PM H+-ATPase, the aquaporin HvPIP1 transcript and protein (compared to the wild types), which may suggest the involvement of brassinosteroids in regulating PM H+-ATPase and aquaporin HvPIP1 at the transcriptional and translational levels.

The progressive contamination of food products by mycotoxins such as zearalenone (ZEN) has prompted the search for specific substances that can act as protectors against an accumulation of these toxins. This paper discusses the effect of selenium ions and 24-epibrassinolide (EBR) as non-organic and organic compounds that preserve human lymphoblastic cells U-937 under ZEN stressogenic conditions. Based on measurements of cell viability and a DAPI test, concentrations of ZEN at 30 μmol/l, Se at 2.5 μmol/l and EBR at 0.005 μmol/l were selected. The addition of both protectors resulted in an increase in the viability of ZEN-treated cells by about 16%. This effect was connected with a decrease in lipid peroxidation (a decrease in the malonyldialdehyde content) and the generation of reactive oxygen species, which were determined by a cellular ROS/superoxide detection assay and the SOD activity. The Se protection was observed as the blocking of the all excess ROS, while the EBR action was mainly concentrated on something other than the superoxide radical itself. The experiments on the model lipid membranes that mimic the environment of U-937 cells confirmed the affect of ZEN on the structure and physicochemical properties of human membranes. Although the presence of both Se and EBR reduced the effect of ZEN by blocking its interaction with a membrane, the action of Se was more evident.

The aim of study was to gain a deeper knowledge about local and systemic changes in photosynthetic processes and sugar production of pepper infected by Obuda pepper virus (ObPV) and Pepper mild mottle virus (PMMoV). PSII efficiency, reflectance, and gas exchange were measured 48 and/or 72 h after inoculation (hpi). Sugar accumulation was checked 72 hpi and 20 d after inoculation (as a systemic response). Inoculation of leaves with ObPV led to appearance of hypersensitive necrotic lesions (incompatible interaction), while PMMoV caused no visible symptoms (compatible interaction). ObPV (but not PMMoV) lowered Fv/Fm (from 0.827 to 0.148 at 72 hpi). Net photosynthesis decreased in ObPV-infected leaves. In ObPV-inoculated leaves, the accumulation of glucose, fructose, and glucose-6-phosphate was accompanied with lowered sucrose, maltoheptose, nystose, and trehalose contents. PMMoV inoculation increased the contents of glucose, maltose, and raffinose in the inoculated leaves, while glucose-6-phosphate accummulated in upper leaves.

Brassinosteroids (BRs) are plant hormones that were isolated for the first time in the 1970s. This group currently includes more than 70 compounds that differ in their structure and physiological activity. BRs are present in plants in a free form or in the form of conjugates. BRs are known as plant growth regulators, but they also play a role in the plant response to environmental stresses. In the case of plants that are exposed to low/high temperature, exogenous BRs can counteract growth inhibition and reduce biomass losses as well as increase plant survival. BRs show a multidirectional activity in regulating the metabolism of plants exposed to extreme temperatures. The following BRs actions can be distinguished: changes in membrane physicochemical properties, regulation of the expression of selected genes (including stress-responsive genes), as well as indirect effects on metabolism through other hormones or signalling molecules (such as hydrogen peroxide). This review summarizes the current knowledge about the effects of BRs on the physiological and biochemical processes that occur in plants during exposure to low or high temperatures.

The mechanism of action of brassinosteroids (BRs) in plant cells under stress has not been fully explained, despite ample evidence of their protective effects. The aim of this study was to investigate the significance of physicochemical properties of cell membranes during an interaction with BRs under stress conditions induced by a mycotoxin zearalenone (ZEA). Experiments were performed in in vitro cultures of wheat cells obtained from immature embryos of tolerant and sensitive genotypes. ZEA added to media (30 µM) accumulated in greater amounts in the cells of sensitive wheat, contrary to BRs, which accumulated in greater amounts by the tolerant genotype when added to media at 0.1 µM. Incorporation of 24-epibrassinolide (EBR) stimulated synthesis of casta- and homocastasterone, that is, endogenous BRs present in wheat cells, and enhanced the content of homocastasterone. When the cultures were supplemented with the mixture of ZEA and EBR, castasterone synthesis was stimulated to a higher degree in cells of the sensitive plant. EBR and ZEA added separately activated antioxidant enzyme systems in both genotypes but with preference for the sensitive one. In the cells treated with ZEA + EBR, the activation was close to that observed for EBR alone. The study discussed also the role of membrane permeability, electrokinetic potential changes, and structural properties of native (plasmalemma) and model (DOPC) monolayers in the mechanism of EBR-induced protection, including the possibility of replacing ZEA absorbed in the membrane lipid layers by BR molecules, independently of the activation of the antioxidant system.

Drought is one of the most adverse stresses that affect plant growth and yield. Disturbances in metabolic activity resulting from drought cause overproduction of reactive oxygen species. It is postulated that brassinosteroids (BRs) regulate plant tolerance to the stress conditions, but the underlying mechanisms remain largely unknown. An involvement of endogenous BRs in regulation of the antioxidant homeostasis is not fully clarified either. Therefore, the aim of this study was to elucidate the role of endogenous BRs in regulation of non-enzymatic antioxidants in barley (Hordeum vulgare) under control and drought conditions. The plant material included the 'Bowman' cultivar and a group of semi-dwarf near-isogenic lines (NILs), representing mutants deficient in BR biosynthesis or signaling. In general, accumulations of 11 compounds representing various types of non-enzymatic antioxidants were analyzed under both conditions. The analyses of accumulations of reduced and oxidized forms of ascorbate indicated that the BR mutants contain significantly higher contents of dehydroascorbic acid under drought conditions when compared with the 'Bowman' cultivar. The analysis of glutathione accumulation indicated that under the control conditions the BR-insensitive NILs contained significantly lower concentrations of this antioxidant when compared with the rest of genotypes. Therefore, we postulate that BR sensitivity is required for normal accumulation of glutathione. A complete accumulation profile of various tocopherols indicated that functional BR biosynthesis and signaling are required for their normal accumulation under both conditions. Results of this study provided an insight into the role of endogenous BRs in regulation of the non-enzymatic antioxidant homeostasis.

Steroids constitute one of the most important groups of compounds of regulatory properties both in the animal and plant kingdom. In plants, steroids such as brassinosteroids or progesterone, by binding to protein receptors in cell membranes, regulate growth and initiate processes leading to increased tolerance to stress conditions. Due to their structural similarities to sterols, these steroids may also directly interact with cellular membranes. Our aim was to determine the changes of the structural parameters of lipid membranes under the influence of hydrophobic steroid compounds, i.e., 24-epibrassinolide (EBR) and its precursor—24-epicastasterone (ECS) and progesterone (PRO). Lipids were isolated from wheat seedlings with different tolerances to frost, grown at low temperatures (5 °C) for 1.5 and 3 weeks (acclimation process). Control plants were cultured continuously at 20 °C. From galactolipids and phospholipids, the main polar lipid fractions, the monolayers were formed, using a technique of Langmuir trough. EBR and ECS were introduced into monolayers, together with lipids, whereas the PRO was dissolved in the aqueous sub-phase upon which the monolayers were spread. Measurements performed at 25 °C and 10 °C showed a significant action of the tested compounds on the physicochemical properties of the monolayers. EBR and PRO increased the area per lipid molecule in monolayers, resulting in formation of more flexible surface structures while the presence of the ECS induced the opposite effect. The influence of the polarity of lipids and steroids on the interactions in the monolayer was discussed. Lipids extracted from the membranes of wheat with the most tolerance to frost were characterized by the highest fatty acid unsaturation and steroids had a relatively weak effect on the parameters of the structure of their monolayers.

Understanding of the physiological role of mammalian hormone—androstenedione (AN)—in plants is scant and the mechanisms of its action at a cellular level are practically unknown. The aim of this study was to investigate the physicochemical and biochemical background of AN activity in winter wheat exposed to low temperature. Cold periods are important in the lifecycle of this species as they induce frost resistance and further generative development. Wheat seedlings (control and AN-supplemented) were acclimated 2 weeks in cold and then exposed to frost (−12 °C). AN supplementation reduced frost damages by 30%. Moreover, AN also accelerated generative development of wheat. The AN-induced changes in redox homeostasis seemed to be important for processes of acclimation to low temperature and generative induction. AN influenced hormonal balance in wheat and stimulated accumulation among other gibberellins and cytokinins. For example, in aerial part of plants, the content of GA3was increased by AN in 12 days of cold by about 30%, whereas the content ofcis-zeatin was increased by 65%. AN was absorbed into plant membranes (Langmuir bath studies). The membrane absorption of AN increased the distance between lipid molecules and this may be an important step in the AN-induced enhancement of frost resistance. AN interaction with lipid membranes showed similarity to the interactions of some known regulators stimulating flowering in plants, and thus it may also underlie the acceleration of wheat development. Androstenedione was naturally present in wheat leaves (5–21 pg g−1 FW).

Phytohormone levels and the expression of genes encoding key enzymes participating in hormone biosynthetic pathways were investigated in pepper leaves inoculated with two different tobamoviruses. Obuda pepper virus (ObPV) inoculation led to the development of hypersensitive reaction (incompatible interaction), while Pepper mild mottle virus (PMMoV) inoculation resulted in a systemic, compatible interaction. ObPV-inoculation markedly increased not only the levels of salicylic acid (SA) (73-fold) and jasmonic acid (8-fold) but also those of abscisic acid, indole-3-acetic acid, indole-3-butyric acid, cis-zeatin, cis-zeatin-9-riboside and trans-zeatin-9-riboside in the inoculated pepper leaves 3 days post inoculation. PMMoV infection increased only the contents of gibberellic acid and SA. Hormone contents did not change significantly after ObPV or PMMoV infection in non-infected upper leaves 20 days post inoculation. Concentrations of some brassinosteroids (BRs) and progesterone increased both in ObPV- and PMMoV inoculated leaves. ObPV inoculation markedly induced the expression of three phenylalanine ammonia-lyase (PAL) and a 1-aminocyclopropane-1-carboxylate oxidase (ACO) genes, while that of an isochorismate synthase (ICS) gene was not modified. PMMoV inoculation did not alter the expression of PAL and ICS genes but induced the transcript abundance of ACO although later than ObPV. Pre-treatment of pepper leaves with exogenous 24-epi-brassinolide (24-epi-BR) prior to ObPV-inoculation strongly mitigated the visible symptoms caused by ObPV. In addition, 24-epi-BR pre-treatment markedly altered the level of several hormones in pepper leaves following ObPV-inoculation. These data indicate that ObPV- and PMMoV-inoculations lead to intricate but well harmonized hormonal responses that are largely determined by the incompatible or compatible nature of plant-virus interactions.

Janeczko Dominika, Orzeł Anna, Klatka Barbara, Hołowczuk Magdalena, Szlichta Grzegorz. Current pharmacotherapy and diagnostic methods of Pompe Disease in Poland. Journal of Education, Health and Sport. 2019;9(9):703-707. eISNN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.3457463 http://ojs.ukw.edu.pl/index.php/johs/article/view/7491 The journal has had 5 points in Ministry of Science and Higher Education parametric evaluation. § 8. 2) and § 12. 1. 2) 22.02.2019. © The Authors 2019; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike. (http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 10.09.2019. Revised: 19.09.2019. Accepted: 22.09.2019. Current pharmacotherapy and diagnostic methods of Pompe Disease in Poland Dominika Janeczko, Anna Orzeł, Barbara Klatka, Magdalena Hołowczuk, Grzegorz Szlichta Students’ Research Group at the Department of Epidemiology and Methodology of Clinical Research, Medical University of Lublin Abstract: Pompe disease is estimated to happen in 1 out of 40000 borns. It is rare metabolic disease connected to autosomal recessive genetic mutation. Disease is characterised by deficit of α-glucosidase (GAA) which is lysosomal glycogen hydrolizing enzyme acid. Decreased activity of enzyme leads to glycogen storage in lysosomes which appears as disfunction of tissues, especially cardiac muscle and skeletal muscles. In Poland, we have two common and very simple methods to diagnose Pompe disease. First test is dried blood spot (DBS), second is full peripheral blood test. Currently, in Poland, drug containing alglucosidase alpha is refunded. Drug is available as powder for infusion. Periodic assessment of therapy effectiveness is performed at least every 6 months based on rating the patient's clinical condition and assessment of the effectiveness of the therapy used. Keywords: Pompe disease, alglucosidade alpha, chromosome 17, glycogen storage disease type ii &nbsp

A literature-based, manually-curated database of PCR primers for the detection of antibiotic resistance genes in various environments was constructed (LCPDb-ARG; lcpdb.ddg.biol.uw.edu.pl and lcpdb.ddlemb.com). Currently, this database is comprised of 607 PCR primer pairs designed for the amplification of various genes conferring resistance to antibiotics representing 10 classes of antimicrobial agents. Three parameters were assigned for each primer pair: specificity, efficacy and taxonomic efficacy. These parameters were evaluated using a novel bioinformatic tool, UniPriVal, developed for this study. UniPriVal was used to validate each primer pair against various databases, including the Bacterial Antimicrobial Resistance Reference Gene Database (BARRGDB) and those of the National Center of Biotechnology Information (NCBI). Primer pairs specific for each antibiotic resistance gene were ranked based on their model success metric value. To validate the utility and correctness of the information collected in the LCPDb-ARG, selected primer pairs were tested in bioinformatic and experimental PCR surveys. To our knowledge, this is the first database designed to facilitate PCR monitoring of the occurrence and diversity of antibiotic resistance genes in environmental and clinical samples. The internal validation system of this user-friendly application enables the quantified ranking of PCR primer pairs, which assists selection of the best primers for each application.

This study focused on the idea that the toxic effect of zearalenone (ZEA) and the protective actions of the brassinosteroid - 24-epibrassinolide (EBR) as well as selenium are dependent on its accumulation in chloroplasts to a high degree. These organelles were isolated from the leaves of oxidative stress-sensitive and stress-tolerant wheat cultivars that had been grown from grains that had been incubated in a solution of ZEA (30 μM), Na2SeO4 (Se, 10 μM), EBR (0.1 μM) or in a mixture of ZEA with Se or EBR. Ultra-high performance liquid chromatography techniques indicated that ZEA was adsorbed in higher amounts in the chloroplasts in the sensitive rather than tolerant cultivar. Although the brassinosteroids and Se were also accumulated in the chloroplasts, higher levels were only found in the tolerant cultivar. The application of EBR increased the homocastasterone content, especially in the chloroplasts of the tolerant plant and after the addition of ZEA. The presence of both protectants caused a decrease in the ZEA content in studied organelles and resulted in diminishing of the oxidative stress (i.e. changes in the activity of the antioxidative enzymes). Moreover, a recovery of photosystem II and decrease in the negative impact of ZEN on Hsp90 transcript accumulation was observed in plants.

The purpose of experiments was to describe the alterations of content of steroid regulators (brassinosteroids, progesterone) during cold hardening of winter wheat. Further we studied physiological and biochemical changes induced by these steroids in cold hardened winter wheat together with estimation of plant frost tolerance. The endogenous brassinosteroid content was elevated in winter wheat during cold hardening while level of progesterone was lowered. A higher content of brassinosteroids (but not progesterone) was connected to better frost tolerance of winter wheat cultivars. Plant supplementation with brassinosteroid (24-epibrassinolide) and progesterone before cold hardening reduced frost damage. Tests with the inhibitors of the biosynthesis of brassinosteroids and progesterone suggested that these steroids are one of players in regulating the antioxidant system in winter wheat during cold hardening. Their role in regulating the expression of Rubisco or the Rubisco activase gene was less clear. Steroid regulators did not affect the content of the stress hormone ABA. Model studies of the membranes, made on a Langmuir bath, showed an increase in the value of the parameter describing differences in membrane compressibility (resulting from stronger interactions among the molecules in the monolayers). This suggests that 24-epibrassinolide and progesterone enter into the lipid layer and - in a similar way to sterols - stabilise the interaction among lipids. It may be significant step for better frost tolerance. The use of steroid regulators (especially brassinosteroids) as agrochemicals improving frost tolerance of winter cereals will be discussed.

Brassinosteroids (BRs) are plant steroid hormones that are characterised by a sterane skeleton of four rings with a number of functional groups attached (mainly hydroxyl). The first species from the Poaceae family in which BRs were found was rice (Oryza sativa L., cv. Arborio J1) – castasterone (13.6 pg g−1 F.W.) and dolichosterone (8.4 pg g−1 F.W.). BRs were also found in corn, wheat, rye, barley as well as Phalaris canariensis L. or ryegrass. There are significant differences between the different cereals in the types of BRs that are present and in their concentration. In agricultural and biological experiments whose aim was to clarify the role of these compounds in cereals, exogenous 28-homobrassinolide and 24-epibrassinolide and less often, brassinolide or other BRs were most commonly used. Recently, however, the number of articles in which BR-biosynthetic deficient mutants or BR-signalling mutants are being used in studies has increased. BR mutants of cereals include mutants of rice (i.e. d61), barley (i.e. uzu) and corn (Brd1). It is worth emphasising that in the case of cereal plants, studies on mutants have confirmed lot of the physiological functions of BRs that have previously been reported in works in which exogenous BR was applied. One can also mention the participation of BRs in regulating plant growth, CO2 assimilation, proline and sugar production, their protective effects on the PSII (under stress conditions) or their participation in a complicated network of connections with other plant hormones. In addition to being a good model for studies of the role of BRs in cereals, mutants of cereal crops can be used in agricultural practice, i.e. to create new dwarf cultivars. This chapter will review the knowledge about brassinosteroids in cereals – their presence, physiological activity and practical applications.

The aim of the study was to examine combinations of base oils and herbal additives with a view to obtaining macerates with improved health benefits. Base oils were cold-pressed from the seeds of black cumin, borage, evening primrose, safflower, walnut, common hazel, and oilseed rape, as well as the flesh of sea-buckthorn fruits. They were then supplemented with herbs, including basil, thyme, and sage, in order to create macerates. Total antioxidant activity and tocopherol level were analyzed in oils, macerates, and oil cakes. Additionally, chemical properties of oil cakes—such as the level of fibre, vitamin C, β-carotene, and lutein—were also examined. Supplementation with herbs caused diversified effects on antioxidant activity and tocopherol level in macerates depending on the base oil, herb, and supplementation method. The obtained results indicate that tocopherol level does not play a decisive role in determining the antioxidant properties of oils, macerates, and oil cakes, suggesting significant involvement of other antioxidants. Among the tested macerates, the most promising one seems to be oilseed rape oil enriched with sage or basil to maximize its health benefits. The study can serve as a starting point for the development and implementation of functional macerates and oil cakes in healthy nutrition.

Plants have developed various acclimation strategies in order to counteract the negative effects of abiotic stresses (including temperature stress), and biological membranes are important elements in these strategies. Brassinosteroids (BR) are plant steroid hormones that regulate plant growth and development and modulate their reaction against many environmental stresses including temperature stress, but their role in modifying the properties of the biological membrane is poorly known. In this paper, we characterise the molecular dynamics of chloroplast membranes that had been isolated from wild-type and a BR-deficient barley mutant that had been acclimated to low and high temperatures in order to enrich the knowledge about the role of BR as regulators of the dynamics of the photosynthetic membranes. The molecular dynamics of the membranes was investigated using electron paramagnetic resonance (EPR) spectroscopy in both a hydrophilic and hydrophobic area of the membranes. The content of BR was determined, and other important membrane components that affect their molecular dynamics such as chlorophylls, carotenoids and fatty acids in these membranes were also determined. The chloroplast membranes of the BR-mutant had a higher degree of rigidification than the membranes of the wild type. In the hydrophilic area, the most visible differences were observed in plants that had been grown at 20 &deg, C, whereas in the hydrophobic core, they were visible at both 20 and 5 &deg, C. There were no differences in the molecular dynamics of the studied membranes in the chloroplast membranes that had been isolated from plants that had been grown at 27 &deg, C. The role of BR in regulating the molecular dynamics of the photosynthetic membranes will be discussed against the background of an analysis of the photosynthetic pigments and fatty acid composition in the chloroplasts.

In temperature stress, the main role of heat-shock proteins (HSP) is to act as molecular chaperones for other cellular proteins. However, knowledge about the hormonal regulation of the production of the HSP is quite limited. Specifically, little is known about the role of the plant steroid hormones&mdash, brassinosteroids (BR)&mdash, in regulating the HSP expression. The aim of our study was to answer the question of how a BR deficit or disturbances in its signaling affect the accumulation of the HSP90, HSP70, HSP18, and HSP17 transcripts and protein in barley growing at 20 &deg, C (control) and during the acclimation of plants at 5 &deg, C and 27 &deg, C. In barley, the temperature of plant growth modified the expression of HSPs. Furthermore, the BR-deficient mutants (mutations in the HvDWARF or HvCPD genes) and BR-signaling mutants (mutation in the HvBRI1 gene) were characterized by altered levels of the transcripts and proteins of the HSP group compared to the wild type. The BR-signaling mutant was characterized by a decreased level of the HSP transcripts and heat-shock proteins. In the BR-deficient mutants, there were temperature-dependent cases when the decreased accumulation of the HSP70 and HSP90 transcripts was connected to an increased accumulation of these HSP. The significance of changes in the accumulation of HSPs during acclimation at 27 &deg, C and 5 &deg, C is discussed in the context of the altered tolerance to more extreme temperatures of the studied mutants (i.e., heat stress and frost, respectively).

This study investigated the impact of mutation in the HvDWARF gene, encoding C6-oxidase involved in brassinosteroid (BR) biosynthesis, on disease resistance of barley against the fungal pathogen powdery mildew (Blumeria graminis f. sp. hordei). The mutation results in significant BR deficiency in leaf tissue. Since increase in the BR content by their exogenous application was reported to improve plant resistance to viral, bacterial and fungal infection, we wanted to find out, if lowered content of BR may affect plant resistance to this pathogen. The 527DK mutant carrying the aforementioned mutation and its respective wild type Delisa were inoculated by powdery mildew fungus (Bgh, race A6). However, no symptoms of disease were visually noted neither on 527DK nor on Delisa. Microscopic observations showed that after germination of the conidia the germ tubes started to penetrate, developed appressorium but could not develop further in the two genotypes. The cell wall thickening (papillae) around the penetration was only visible. However, inoculated plants showed changes in some of parameters describing photosynthetic efficiency or water relations. Similarly, alterations in hormonal homeostasis not only between wild type and mutant, but between control and infected plants were observed. Inoculation with the pathogen induced especially accumulation of compounds from auxin group (indole-3-carboxylic acid, oxindole-3-acetic acid, 4-chloroindole-3-acetic acid and 5-chloroindole-3-acetic acid). Interestingly, the stronger effect was observed in plants with mutation in the HvDWARF gene. Taking into account that the HvDWARF gene mutation finally did not affect resistance to powdery mildew (no symptoms appearance), we suggest that the conclusion of our study may be of importance for breeding of barley.

Reduced plant height and culm robustness are quantitative characteristics important for assuring cereal crop yield and quality under adverse weather conditions. A very limited number of short-culm mutant alleles were introduced into commercial crop cultivars during the Green Revolution. We identified phenotypic traits, including sturdy culm, specific for deficiencies in brassinosteroid biosynthesis and signaling in semidwarf mutants of barley (Hordeum vulgare). This set of characteristic traits was explored to perform a phenotypic screen of near-isogenic short-culm mutant lines from the brachytic, breviaristatum, dense spike, erectoides, semibrachytic, semidwarf, and slender dwarf mutant groups. In silico mapping of brassinosteroid-related genes in the barley genome in combination with sequencing of barley mutant lines assigned more than 20 historic mutants to three brassinosteroid-biosynthesis genes (BRASSINOSTEROID-6-OXIDASE, CONSTITUTIVE PHOTOMORPHOGENIC DWARF, and DIMINUTO) and one brassinosteroid-signaling gene (BRASSINOSTEROID-INSENSITIVE1 [HvBRI1]). Analyses of F2 and M2 populations, allelic crosses, and modeling of nonsynonymous amino acid exchanges in protein crystal structures gave a further understanding of the control of barley plant architecture and sturdiness by brassinosteroid-related genes. Alternatives to the widely used but highly temperature-sensitive uzu1.a allele of HvBRI1 represent potential genetic building blocks for breeding strategies with sturdy and climate-tolerant barley cultivars.

Quantitative PCR studies need proper reference genes with expression stability exclusively validated under certain experimental conditions. The expression stability of several genes commonly used as references was tested under 24-epibrassinolide (EBR) and temperature treatment. Different statistical approaches (qBase PLUS , BestKeeper, NormFinder) were used to prepare rankings of expression stability in two species of an economic importance: common wheat ( Triticum aestivum ) and perennial ryegrass ( Lolium perenne ). Candidate reference genes were shown to be regulated differentially in these two plant species. The maximum stability values indicated that the expression stability was higher in T. aestivum . Taking into account of all ranks it seems that TBP-1 and UBI in ryegrass and ACT , ADP and EF1A in wheat should be used as reference genes in the brassinosteroids and temperature involving studies.

Leaves of a pepper cultivar harboring the L 3 resistance gene were inoculated with Obuda pepper virus (ObPV), which led to the appearance of hypersensitive necrotic lesions approx. 72 h post-inoculation (hpi) (incompatible interaction), or with Pepper mild mottle virus (PMMoV) that caused no visible symptoms on the inoculated leaves (compatible interaction). ObPV inoculation of leaves resulted in ion leakage already 18 hpi, up-regulation of a pepper carotenoid cleavage dioxygenase ( CCD ) gene from 24 hpi, heat emission and declining chlorophyll a content from 48 hpi, and partial desiccation from 72 hpi. After the appearance of necrotic lesions a strong inhibition of photochemical energy conversion was observed, which led to photochemically inactive leaf areas 96 hpi. However, leaf tissues adjacent to these inactive areas showed elevated ΦPSII and Fv/Fm values proving the advantage of chlorophyll a imaging technique. PMMoV inoculation also led to a significant rise of ion leakage and heat emission, to the up-regulation of the pepper CCD gene as well as to decreased PSII efficiency, but these responses were much weaker than in the case of ObPV inoculation. Chlorophyll b and total carotenoid contents as measured by spectrophotometric methods were not significantly influenced by any virus inoculations when these pigment contents were calculated on leaf surface basis. On the other hand, near-infrared FT-Raman spectroscopy showed an increase of carotenoid content in ObPV-inoculated leaves suggesting that the two techniques detect different sets of compounds.

Brassinosteroids are known to protect plants against various abiotic and biotic stresses, however, very limited information is available about the role of progesterone. Therefore the effects of Pseudomonas syringae pv. syringae (P.s.) wild type strain 61, its hrcC mutant, and the saprophytic P. fluorescens (P.f.) strain 55 were investigated in wild type Arabidopsis thaliana cv. Columbia and its rbohF knock-out mutant, with and without progesterone pre-treatment. The reactions of wild type and rbohF mutant Arabidopsis to bacterial inoculations were similar, although 2 h after injection of P.s. a larger increase of electrolyte leakage was measured in wild type than in rbohF knockout mutant leaves. The hrcC mutant caused weak necrotic symptoms and increased leakage in both types of Arabidopsis, although to a much lesser extent than P.s. The P.f. did not induce any visible symptom, but slightly increased the electrolyte leakage in both types of Arabidopsis. Inoculation by all Pseudomonas bacteria led to significant alterations in photosystem 2 efficiency as compared to control plants. Pre-treatment of leaves with progesterone diminished the necrotic symptoms, the electrolyte leakage and improve the efficiency of photosystem 2 caused by Pseudomonas bacteria.

Brassinosteroids (BRs) are plant steroid hormones, regulating a broad range of physiological processes. The largest amount of data related with BR biosynthesis has been gathered in Arabidopsis thaliana, however understanding of this process is far less elucidated in monocot crops. Up to now, only four barley genes implicated in BR biosynthesis have been identified. Two of them, HvDWARF and HvBRD, encode BR-6-oxidases catalyzing biosynthesis of castasterone, but their relation is not yet understood. In the present study, the identification of the HvDWARF genomic sequence, its mutational and functional analysis and characterization of new mutants are reported. Various types of mutations located in different positions within functional domains were identified and characterized. Analysis of their impact on phenotype of the mutants was performed. The identified homozygous mutants show reduced height of various degree and disrupted skotomorphogenesis. Mutational analysis of the HvDWARF gene with the “reverse genetics” approach allowed for its detailed functional analysis at the level of protein functional domains. The HvDWARF gene function and mutants’ phenotypes were also validated by measurement of endogenous BR concentration. These results allowed a new insight into the BR biosynthesis in barley.

Brassinosteroids (BRs) are a class of steroid phytohormones, which regulate various processes of morphogenesis and physiology – from seed development to regulation of flowering and senescence. An accumulating body of evidence indicates that BRs take part in regulation of physiological reactions to various stress conditions, including drought. Many of the physiological functions of BRs are regulated by a complicated, and not fully elucidated network of interactions with metabolic pathways of other phytohormones. Therefore, the aim of this study was to characterize phytohormonal homeostasis in barley (Hordeum vulgare) in reaction to drought and validate role of BRs in regulation of this process. Material of this study included the barley cultivar ‘Bowman’ and five Near-Isogenic Lines (NILs) representing characterized semi-dwarf mutants of several genes encoding enzymes participating in BR biosynthesis and signaling. Analysis of endogenous BRs concentrations in these NILs confirmed that their phenotypes result from abnormalities in BR metabolism. In general, concentrations of eighteen compounds, representing various classes of phytohormones, including brassinosteroids, auxins, cytokinins, gibberellins, abscisic acid, salicylic acid and jasmonic acid were analyzed under control and drought conditions in the ‘Bowman’ cultivar and the BR-deficient NILs. Drought induced a significant increase in accumulation of the biologically active form of BRs – castasterone in all analyzed genotypes. Another biologically active form of BRs – 24-epi-brassinolide - was identified in one, BR-insensitive NIL under normal condition, but its accumulation was drought-induced in all analyzed genotypes. Analysis of concentration profiles of several compounds representing gibberellins allowed an insight into the BR-dependent regulation of gibberellin biosynthesis. The concentration of the gibberellic acid GA7 was significantly lower in all NILs when compared with the ‘Bowman’ cultivar, indicating that GA7 biosynthesis represents an enzymatic step at which the stimulating effect of BRs on gibberellin biosynthesis occurs. Moreover, the accumulation of GA7 is significantly induced by drought in all the genotypes. Biosynthesis of jasmonic acid is also a BR-dependent process, as all the NILs accumulated much lower concentrations of this hormone when compared with the ‘Bowman’ cultivar under normal condition, however the accumulation of jasmonic acid, abscisic acid and salicylic acid were significantly stimulated by drought.

The aim of the present studies was to assess the possibility of compensating the negative effects of drought stress on gaseous exchange and efficiency of photosystem II in soybean seedlings by application of the androgen — androstenedione. Androstenedione (0.25 mg dm−3) was applied via presowing seed soaking (12 h). Control seeds were untreated with steroid. Plants were cultured in pots. On the 12th day of growth, the plants were watered for the last time. Drought symptoms occurred during the next 10 days. On the 22nd day of growth, leaf gaseous exchange and PSII measurements were taken. Afterwards the plants were watered. Two days later measurements were taken again. Androstenedione improved the intensity of leaf net photosynthesis. The effect of androstenedione was manifested during the rehydration of plants that have undergone a period of drought. An increase in net photosynthesis intensity was accompanied by higher transpiration. Possible mechanisms of androstenedione action — effect on aquaporin functionality and membrane stability — are discussed. The significance of ethanol and DMSO (solvents of steroid) in experiments on the physiological activity of androstenedione is also considered.

Steroids are present in living organisms as one of the most essential groups of compounds. Continuous research has led to new discoveries and the revision of existing information concerning the occurrence and the role of steroids, both in animals and plants. This article will focus on reviewing the literature studying progesterone in the plant kingdom, including its discovery, its occurrence in different plant species as well as its biological activity and molecular basis of action. This review will present and discuss the current data in addition to introducing potential directions for further research on the subject of progesterone in plants.

This paper presents a study of the metabolic response (dark respiration intensity, photosystem II efficiency, metabolic activity) and the yield of barley treated with 24-epibrassinolide and subjected to high-temperature stress. Transport of exogenously applied 24-epibrassinolide in barley and changes in the profile of brassinosteroids that may occur in tissues after 24-epibrassinolide application were also studied. The water solution of 24-epibrassinolide (0.005 and 0.25 mg dm−3) was applied via infiltration of the first and second leaves of 12-day-old seedlings. Control plants were treated with water solution of hormone solvent (ethanol). Fifteen-day-old plants were subjected to high-temperature stress (42°C for 3 h). The influence of hormone treatment and stress conditions was investigated in the first and second leaves based on measurements of PSII efficiency. The aftereffect of plant treatment was investigated in the seventh leaf (measurements of PS II efficiency, dark respiration intensity, metabolic activity). The transport efficiency of 24-epibrassinolide exogenously applied to the first and second leaves, as well as the profile of other brassinosteroids, was also measured on the seventh leaf. Finally, yield formation was estimated. 24-epibrassinolide showed protective action, which manifested itself in the improved functioning of PSII, but this was observed in case of higher hormone concentration and only for the first, older leaf. The PSII efficiency of the seventh leaf was similar in plants treated with brassinosteroid and in the control plants, whereas the respiration intensity and metabolic activity decreased in plants previously treated with higher concentration of 24-epibrassinolide. The use of a higher hormone concentration at the seedling phase ultimately resulted also in lower crop yield. Brassinosteroids—brassinolide and castasterone—were detected in barley leaves. 24-epibrassinolide was found only in trace amounts in control plants. Its exogenous application directly to the apoplast of the first and second leaves resulted in an increase in the 24-epibrassinolide content in the seventh leaf, but did not depend on whether a high or low concentration had been applied to the plants.

The aim of the study was to examine the effect of exogenous 24-epibrassinolide on its uptake and content of endogenous brassinosteroids in wheat seedlings. 24-Epibrassinolide was applied at two concentrations (0.1 and 2.0 μM) and in three different methods: by soaking seeds, by drenching and by spraying plants. Brassinosteroids were determined by high-performance liquid chromatography combined with electrospray mass spectrometry. Three important brassinosteroids, 24-epibrassinolide, brassinolide and castasterone, were detected in the wheat leaves, but their contents varied with leaf insertion and plant age. Increased 24-epibrassinolide content in the leaf tissue was found when this hormone was applied by soaking or drenching. Additionally the seed treatment influenced brassinosteroid balance in seedlings. The growth response of wheat seedlings treated with 24-epibrassinolide has been also investigated.

The aim of the study was to test the synergistic activity of zearalenone and thidiazuron with commonly used regulators (6-benzylaminopurine, 2,4-dichlorophenoxyacetic acid) in callus tissue growth and the regeneration processes of winter oilseed rape and winter wheat. Oilseed rape callus was obtained from the upper fragments of seedling hypocotyls. Wheat callus tissue was obtained from immature embryos. Zearalenone, in combination with 6-benzylaminopurine, stimulated the regeneration of oilseed rape and, in combination with 2,4-dichlorophenoxyacetic acid, the regeneration of wheat. An additional application of thidiazuron to these media increased the percentage of shoot regeneration from callus in both species tested. Zearalenone is proposed as a new regulator in in vitro plant cultures for use in protocols of plant regeneration.

The seeds of soybean cv. Aldana and spring wheat cv. Torka were soaked for 24 h in solution of zearalenone [ZEN, 2,4-dihydroxy-6-(10-hydroxy-6-oxo-trans-1-undecenyl)-benzonic acid lactone, 4 mg dm−3] and then they were sown in the pot experiment in an open vegetation hall. The after-effects of ZEN on growth of plants, net photosynthetic (P N) and transpiration (E) rates, stomatal conductance (g s), photochemical efficiency of photosystem II (PSII) and on final seeds yield, were determined. A significant increase of seeds yield was revealed in plants of both cultivars i.e. by 22% and 19% of seed (grain) number and by 28 and 24% of seed (grain) mass, in soybean and in wheat, respectively. The photosynthetic rate (P N) was stimulated during the juvenile and final phase by about 13.6% (average) in soybean plants. During other developmental stages, assimilation of CO2 was retarded. The response of CO2 assimilation in wheat plants was less pronounced as compared to that in soybean, but an increase of P N by over 24% near the final stage of development was observed. The quantum yield of PSII electron transport (ΦPSII) in soybean plants was changed after the treatment of seeds by ZEN similarly as for the rate of CO2, whereas in wheat it continued to gradually increase i.e. during the whole growth period. Changes of ΦPSII both in soybean and in wheat plants, as the response to ZEN treatment, were accompanied with an increase in the efficiency of changes occurring within the antenna (Fv′/Fm′) as well as within centres of photochemical reactions (qp). The conclusion is that ZEN can affect plant growth and development in many ways, as well as in the status and functioning of the photosynthetical apparatus. Some of the effects can be very longlasting, as e.g. stimulation of production of seed yield in response to treatment of seeds with this substance.

The presence and location of specific binding sites for progesterone and 17beta-estradiol in cells of wheat were estimated using radioligand binding assay. Membrane and cytosolic fractions of non-vernalized and vernalized plants were tested using tritium-labelled ligands. Specific binding of [(3)H]progesterone and [(3)H]17beta-estradiol occurs in wheat cells. The binding sites are located in membranes and in the cytosol. Specific binding of [(3)H]17beta-estradiol is higher in the membranes than in the cytosol. Specific binding of both ligands in the cytosolic fraction is higher in vernalized plants than in non-vernalized ones. The possibility of the occurrence of steroid binding proteins specific for progesterone and 17beta-estradiol, putative steroid receptors for these steroids in Triticum aestivum L., is discussed.