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Water stress in agricultural systems may occur slowly or abruptly. Plant reactions to stress differ with regard to its level and duration. The level of plant susceptibility to water deprivation primarily depends on the management of the water content and metabolism adjustments. The aim of this study was to determine the correlation between water-based plant parameters and the yield components of 90 genotypes of winter wheat (Triticum aestivum L.). Since the loss of water is frequently used as a selection criterion to assess drought tolerance, the relationships between the yield and leaf water content, osmotic potential, and gas exchange characteristics were examined. Genotypes 1, 25, 34, 36, 42, 43, 46, 57, 66, 73, and 90 showed 33–45% larger numbers of grains/plant, 19–25% higher weights of grains/plant, and 4% higher thousand grain weights compared to other genotypes. The higher values of the yield components were accompanied by 20–30% lower leaf water content, 39–52% lower osmotic potential, and 4–39% lower water use efficiency. The principal component analysis revealed that the wheat genotypes had noticeable differences in a few physiological parameters that depended on the sowing date. Electrolyte leakage showed a substantial correlation with the sowing date, suggesting that it may not be a suitable factor for the prediction of drought tolerance. The factors that distinguished the examined genotypes the most were the leaf water content, osmotic potential, and water use efficiency. In addition, a significant correlation was observed between the mentioned parameters and yield components. As a result, these parameters may be helpful in genotype characterization in relation to water stress susceptibility, offering a trustworthy plant selection test. [ABSTRACT FROM AUTHOR]

Historically, traditional crossbreeding schemes have predominated in oat breeding. In vitro culture techniques seek to expedite the breeding process and enhance selection efficiency. Maximum yields are achieved from hybrid plants produced by crossing pure (homozygous) lines with the desired traits. Homozygous lines can be produced through conventional breeding methods, which are time-consuming and costly. Alternatively, the production of homozygous lines can be accelerated by producing doubled haploid (DH) plants derived from (haploid) male gametophytes or their microspores (androgenesis). This method condenses the various stages required for producing homozygous lines in a single generation, resulting in significant time and cost savings. These and other advantages render androgenic DHs the preferred choice in numerous important crops where any of the various in vitro experimental techniques (anthers culture or isolated microspores culture) are well-established. However, in the case of oat (Avena sativa L.), an efficient plant regeneration method remains not very effective compared to the most common cereals, possibly due to the known recalcitrance of this cereal to in vitro culture. This review presents the methods through anther and microspore cultures utilized in the production of oat DHs revealing the crucial factors influencing the efficiency of this method in oat (Avena sativa L.). [ABSTRACT FROM AUTHOR]

Pollution of arable land with heavy metals is a worldwide problem. Cadmium (Cd) is a toxic metal that poses a severe threat to humans' and animals' health and lives. Plants can easily absorb Cd from the soil, and plant-based food is the main means of exposure to this hazardous element for humans and animals. Phytoremediation is a promising plant-based approach to removing heavy metals from the soil, and plant growth-promoting micro-organisms such as the fungi Trichoderma can enhance the ability of plants to accumulate metals. Inoculation of Avena sativa L. (oat) with Trichoderma viride enhances germination and seedling growth in the presence of Cd and, in this study, the growth of 6-month-old oat plants in Cd-contaminated soil was not increased by inoculation with T. viride, but a 1.7-fold increase in yield was observed. The content of Cd in oat shoots depended on the Cd content in the soil. Still, it was unaffected by the inoculation with T. viride. A. sativa metallothioneins (AsMTs) participate in plant–fungi interaction, however, their role in this study depended on MT type and Cd concentration. The inoculation of A. sativa with T. viride could be a promising approach to obtaining a high yield in Cd-contaminated soil without increasing the Cd content in the plant. [ABSTRACT FROM AUTHOR]

Water deficit affects the growth as well as physiological and biochemical processes in plants. The aim of this study was to determine differences in physiological and biochemical responses to drought stress in two wheat cultivars—Chinese Spring (CS) and SQ1 (which are parents of a mapping population of doubled haploid lines)—and to relate these responses to final yield and agronomic traits. Drought stress was induced by withholding water for 14 days, after which plants were re-watered and maintained until harvest. Instantaneous gas exchange parameters were evaluated on the 3rd, 5th, 10th, and 14th days of seedling growth under drought. After 14 days, water content and levels of chlorophyll a+b, carotenoids, malondialdehyde, soluble carbohydrates, phenolics, salicylic acid, abscisic acid (ABA), and polyamines were measured. At final maturity, yield components (grain number and weight), biomass, straw weight, and harvest index were evaluated. Physiological and biochemical parameters of CS responded more than those of SQ1 to the 14-day drought, reflected in a greater reduction in final biomass and yield in CS. Marked biochemical differences between responses of CS and SQ1 to the drought were found for soluble carbohydrates and polyamines. These would be good candidates for testing in the mapping population for the coincidence of the genetic control of these traits and final biomass and yield. [ABSTRACT FROM AUTHOR]

As a result of oat (Avena sativa L.) × maize (Zea mays L.) crossing, maize chromosomes may not be completely eliminated at the early stages of embryogenesis, leading to the oat × maize addition (OMA) lines development. Introgression of maize chromosomes into oat genome can cause morphological and physiological modifications. The aim of the research was to evaluate the leaves' anatomy, chlorophyll a fluorescence, and yield parameter of oat doubled haploid (DH) and OMA lines obtained by oat × maize crossing. The present study examined two DH and two disomic OMA lines and revealed that they differ significantly in the majority of studied traits, apart from: the number of cells of the outer bundle sheath; light energy absorption; excitation energy trapped in PSII reaction centers; and energy dissipated from PSII. The OMA II line was characterized by larger size of single cells in the outer bundle sheath and greater number of seeds per plant among tested lines. [ABSTRACT FROM AUTHOR]

Aims: Due to the lack of experimental databases, together with the chemical complexity and the dynamic nature of plants' metabolome, most of the metabolites in complex biological materials (like plant in vitro tissue cultures) are not‐annotated, unidentified metabolites. In this study, a method for further metabolite characterization and classification based on the UPLC‐HESI‐HRMS/MS approach for small‐leaved basil (Ocimum basilicum L. var. minimum Alef.) callus and cell suspension culture is presented. Key results: A total of 2168 metabolic features were detected, out of which the database for exact mass metabolic profiling for 1949 metabolites is presented here since there is no available database dedicated to O. basilicum. We further focused on secondary metabolites (particularly phenolic compounds). The presence of 60 different phenolic compounds belonging mainly to the groups of flavonoids, glycosides, terpenoids, and phenolic acids is confirmed. By comparing relative abundances of phenolic compounds from callus culture and cell suspension culture, both grown on two types of media, via svd‐PCА, univariate analysis, post‐hoc tests, and heatmapping of metabolites, we provided a practical example of how resources presented here can be further applied in tissue culture‐based basil metabolomics studies. Utility: This study represents the first approach toward routine targeted investigation of secondary metabolites in basil in vitro cultures and provides various opportunities for new‐generation analyses. [ABSTRACT FROM AUTHOR]

Plant in vitro cultures have been a crucial component of efforts to enhance crops and advance plant biotechnology. Traditional plant breeding is a time-consuming process that, depending on the crop, might take up to 25 years before an improved cultivar is available to farmers. This is a problematic technique since both beneficial qualities (such as pest resistance) and negative ones (such as decreased yield) can be passed down from generation to generation. In vitro cultures provide various advantages over traditional methods, including the capacity to add desirable characteristics and speed up the development of new cultivars. When it comes to oat (Avena sativa L.), the efficient method of plant regeneration is still missing compared to the most common cereals, possibly because this cereal is known to be recalcitrant to in vitro culture. In this review, an effort has been made to provide a succinct overview of the various in vitro techniques utilized or potentially involved in the breeding of oat. The present work aims to summarize the crucial methods of A. sativa L. cultivation under tissue culture conditions with a focus on the progress that has been made in biotechnological techniques that are used in the breeding of this species. [ABSTRACT FROM AUTHOR]

Plant growth and the process of yield formation in crops are moderated by surrounding conditions, as well as the interaction of the genetic background of plants and the environment. In the last two decades, significant climatic changes have been observed, generating unfavorable and harmful impacts on plant development. Drought stress can be considered one of the most dangerous environmental factors affecting the life cycle of plants, reducing biomass production and, finally, the yield. Plants can respond to water deficit in a wide range, which depends on the species, genetic variability within the species, the plant's ontogenesis stage, the intensity of the stress, and other potential stress factors. In plants, it is possible to observe hybrids between different taxa that certain traits adopted to tolerate stress conditions better than the parent plants. Oat × maize addition (OMA) plants are good examples of hybrids generated via wide crossing. They can exhibit morphological, physiological, and biochemical variations implemented by the occurrence of extra chromosomes of maize, as well as the interaction of maize and oat chromatin. The initial goal of the study was to identify OMA lines among plants produced by wide crossing with maize. The main goal was to investigate differences in OMA lines according to the Excised Leaf Water Loss (ELWL) test and to identify specific biochemical changes and agronomic traits under optimal water conditions and soil drought. Additionally, detection of any potential alterations that are stable in F2 and F3 generations. The aforementioned outcomes were the basis for the selection of OMA lines that tolerate growth in an environment with limited water availability. The molecular analysis indicated 12.5% OMA lines among all tested descendants of wide oat-maize crossing. The OMA lines significantly differ according to ELWL test results, which implies some anatomical and physiological adaptation to water loss from tissues. On the first day of drought, plants possessed 34% more soluble sugars compared to control plants. On the fourteen day of drought, the amount of soluble sugars was reduced by 41.2%. A significant increase of phenolic compounds was observed in the fourteen day of drought, an average of 6%, even up to 57% in line 9. Soil drought substantially reduced stem biomass, grains number, and mass per plant. Lower water loss revealed by results of the ELWL test correlated with the high yield of OMA lines. Phenolic compound content might be used as a biochemical indicator of plant drought tolerance since there was a significant correlation with the high yield of plants subjected to soil drought. [ABSTRACT FROM AUTHOR]

Osmotic stress frequently caused by drought is the most threatening environmental stress that remarkably reduces crop yield. Oat (Avena sativa L.) is sensitive to water deficiency during growth. Plant metallothioneins (pMTs) show tremendous promise in enhancing general stress tolerance in plants. This study aimed to verify whether pMTs and elements of the antioxidant defence system protect oat against osmotic stress. Coding and genomic regions of A. sativa L. MTs belonging to three different types were cloned. To evaluate the role of MTs in osmotic stress, the expression of genes encoding AsMT1‐3 was checked by qRT‐PCR in the roots and shoots of oat plants growing in a hydroponic culture in the presence of polyethylene glycol (PEG 6000) and mannitol. The expression of AsMT1‐3 changed in response to osmotic stress; however, the changes depended on the type of MT and the treatment. The amount of AsMT3 transcript was about five‐fold and nine‐fold higher in shoots and roots, respectively, in the presence of mannitol. To further analyse the response of oat to osmotic stress, the level of phenolic compounds, soluble sugars, abscisic acid, and the activity of antioxidant enzymes were tested using spectrophotometric and chromatographic methods. During osmotic stress, the content of phenols, soluble sugars, abscisic acid, and the activity of catalase and peroxidase in shoots increased. In roots treated with PEG 6000, the amount of phenolic compounds was higher than that in roots treated with mannitol. The activity of superoxide dismutase was about 5‐fold higher in roots than in shoots. MTs are involved in plant response to osmotic stress. In the future, insight provided in this study will lead to application in agriculture either by using MTs as molecular markers for stress‐resistant crop cultivars or by a generation of genetically modified crops overexpressing MTs. [ABSTRACT FROM AUTHOR]

Light-emitting diodes (LEDs) have emerged as efficient light sources for promoting in vitro plant growth and primary and secondary metabolite biosynthesis. This study investigated the effects of blue, red, and white-red LED lights on plant biomass growth, photosynthetic pigments, soluble sugars, phenolic compounds, the production of Amaryllidaceae alkaloids, and the activities of antioxidant enzymes in Leucojum aestivum L. cultures. A white fluorescent light was used as a control. The plants that were grown under white-red and red light showed the highest fresh biomass increments. The blue light stimulated chlorophyll a, carotenoid, and flavonoid production. The white-red and blue lights were favourable for phenolic acid biosynthesis. Chlorogenic, p-hydroxybenzoic, caffeic, syringic, p-coumaric, ferulic, sinapic, and benzoic acids were identified in plant materials, with ferulic acid dominating. The blue light had a significant beneficial effect both on galanthamine (4.67 µg/g of dry weight (DW)) and lycorine (115 µg/g DW) biosynthesis. Red light treatment increased catalase and superoxide dismutase activities, and high catalase activity was also observed in plants treated with white-red and blue light. This is the first report to provide evidence of the effects of LED light on the biosynthesis of phenolic acid and Amaryllidaceae alkaloids in L. aestivum cultures, which is of pharmacological importance and can propose new strategies for their production. [ABSTRACT FROM AUTHOR]

Drought is one of the major threats to food security. Among several mechanisms involved in plant stress tolerance, one protein family—the plant metallothioneins (MTs)—shows great promise for enhancing drought resistance. Plant metallothioneins in oat (Avena sativa L.) have not yet been deeply analysed, and the literature lacks a comprehensive study of the whole family of plant MTs in response to drought. In this study, we showed that the number and nature of cis-elements linked with stress response in promoters of AsMTs1–3 differed depending on the MT type. Drought stress in oat plants caused an increase in the expression of AsMT2 and AsMT3 and a decrease in the expression of AsMT1 compared to well-watered plants. Moreover, the low values of relative water content, water use efficiency, net photosynthesis (PN), transpiration (E), stomatal conductance (gs), chlorophyll a, and carotenoid were accompanied by high levels of electrolyte leakage, internal CO2 concentration (Ci) and abscisic acid content, and high activity of antioxidants enzymes in plants under drought stress. The present study puts forward the idea that AsMTs are crucial for oat response to drought stress not only by regulating antioxidant activity but also by changing the plant water regime and photosynthesis. Our results support the hypothesis that structural differences among types of plant MTs reflect their diversified physiological roles. [ABSTRACT FROM AUTHOR]

The ontogenesis and yield formation in crop plants are modified by environmental conditions. Due to climatic change detected over two decades, the harmful influence of abiotic factors is increasing. One of the most threatening issues reducing plant productivity is drought stress. The strength of plant response to water shortages could differ depending on the strength of the drought stress, type of crop, genetic background, presence of additional stresses, and stage of plant development. There are examples of sexual hybridization between crop plants like oat (Avena sativa L.) and maize (Zea mays L.) with which stable fertile hybrids were generated. Additional maize chromosomes in oat plants (oat × maize addition, OMA) often infer morphological and physiological (e.g., PS II photosystem activity and chlorophyll production) changes modulated by the interaction of certain maize chromosomes added to the oat genome. The aim of the research was to evaluate the chosen physiological, biochemical, and agronomic parameters of OMA plants subjected to soil drought. Analysis of variance indicated that the main effects of genotype as well as treatment × genotype interaction were significant for all the traits studied (photosynthetic pigment content, selected PSII indices, mass of stem, number of grains/plant, mass of grains/plant). Most of the examined lines severely reduced PSII photosystem parameters, pigment content, and yield-related traits under drought stress. The results indicated that two lines (9 and 78b) retained high yielding potential under drought stress compared to commercial cv. Bingo. [ABSTRACT FROM AUTHOR]

Leucojum aestivum is known for its ability to biosynthesize alkaloids with therapeutic properties, among which galanthamine used for the treatment of Alzheimer's disease. New sources of this alkaloid are still being explored. In this study, a novel strain PLV of endophytic bacterium Paenibacillus lautus was isolated from in vitro L. aestivum plants. We report the whole genome sequence of that strain and its capacity to produce alkaloids and growth regulators. The effect of elicitation with autoclaved bacteria on the production of alkaloids was examined. Ten alkaloids were identified in bacteria extracts: galanthamine, lycorine, ismine, lycoramine, haemanthamine, tazettine, galanthine, homolycorine, 1,2-dihydrochlidanthine, and hippeastrine. The mean contents of galanthamine and lycorine were 37.51 µg/g of dry weight (DW) and 129.93 µg/g of DW, respectively. Moreover, isolated P. lautus strain synthesized: indole-3-acetic acid, t-zeatin, c-zeatin, kinetin, gibberellin A1, abscisic acid, salicylic acid, benzoic acid. In vitro elicitation of cultures with P. lautus increased dry biomass, stimulated galanthamine and lycorine production, contributed to 8,9-desmethylenebis (oxy)-7,9 dimethoxy-crinan biosynthesis, change pigments content, and antioxidant enzymes activities. Our findings for the first time point out that galanthamine can be synthesized by an microorganism. Moreover isolated strain can be used as a new elictor of Amaryllidaceae alkaloids biosynthesis. [ABSTRACT FROM AUTHOR]

Leucojum aestivum is known for its ability to biosynthesize alkaloids with therapeutic properties, among which galanthamine used for the treatment of Alzheimer's disease. New sources of this alkaloid are still being explored. In this study, a novel strain PLV of endophytic bacterium Paenibacillus lautus was isolated from in vitro L. aestivum plants. We report the whole genome sequence of that strain and its capacity to produce alkaloids and growth regulators. The effect of elicitation with autoclaved bacteria on the production of alkaloids was examined. Ten alkaloids were identified in bacteria extracts: galanthamine, lycorine, ismine, lycoramine, haemanthamine, tazettine, galanthine, homolycorine, 1,2-dihydrochlidanthine, and hippeastrine. The mean contents of galanthamine and lycorine were 37.51 µg/g of dry weight (DW) and 129.93 µg/g of DW, respectively. Moreover, isolated P. lautus strain synthesized: indole-3-acetic acid, t-zeatin, c-zeatin, kinetin, gibberellin A1, abscisic acid, salicylic acid, benzoic acid. In vitro elicitation of cultures with P. lautus increased dry biomass, stimulated galanthamine and lycorine production, contributed to 8,9-desmethylenebis (oxy)-7,9 dimethoxy-crinan biosynthesis, change pigments content, and antioxidant enzymes activities. Our findings for the first time point out that galanthamine can be synthesized by an microorganism. Moreover isolated strain can be used as a new elictor of Amaryllidaceae alkaloids biosynthesis. [ABSTRACT FROM AUTHOR]

Species from the genus Ocimum L. (basil) are among the most cultivated plants due to their large content of secondary metabolites, in particular essential oils and phenolic compounds. Still, different conditions of basil cultivation cause significant variations of quantitative and qualitative characteristics of material originating from basil plants. The application of plant tissue culture to produce biologically active compounds is a well-established alternative to the cultivation of whole plants. It provides the opportunity to obtain biotechnologically valuable plant characteristics, including a high content of secondary metabolites such as phenolic acids and flavonoids for the shortest period. The present paper summarizes the most cultivated basil genotypes worldwide and data about the mass propagation, somatic embryogenesis, basil cell and organ cultures, together with the main properties regarding the enhanced synthesis of secondary metabolites under tissue culture conditions. For most of the studies, increased synthesis of biologically active compounds (in particular phenolic acids, isoprenoids, and flavonoids) can be seen. However, for many of them, information regarding the used genotype or origin of plant material is missing. Considering the large number of species and cultivars belonging to the genus Ocimum L., appropriate utilization can provide maximal exploitation. Understanding how particular genotypes respond to specific conditions, treatments, and types of culture for enhancing the production of secondary metabolites could be the basis in designing protocols and further progress. Key message: In this review, we described recent progress in secondary metabolites production of Ocimum L. species. The content of secondary metabolites, mainly phenolics and flavonoids, can be enhanced by various types of in vitro cultures. [ABSTRACT FROM AUTHOR]

A critical step in the production of doubled haploids is a conversion of the haploid embryos into plants. Our study aimed to recognize the reasons for the low germination rate of Avena sativa haploid embryos obtained by distant crossing with maize. Oat cultivars of 'Krezus' and 'Akt' were investigated regarding embryo anatomy, the endogenous phytohormone profiles, and antioxidant capacity. The zygotic embryos of oat were used as a reference. It was found that twenty-one days old haploid embryos were smaller and had a less advanced structure than zygotic ones. Morphology and anatomy modifications of haploid embryos were accompanied by extremely low levels of endogenous auxins. Higher levels of cytokinins, as well as tenfold higher cytokinin to auxin ratio in haploid than in zygotic embryos, may suggest an earlier stage of development of these former. Individual gibberellins reached higher values in 'Akt' haploid embryos than in the respective zygotic ones, while the differences in both types of 'Krezus' embryos were not noticed. Additionally to the hormonal regulation of haploid embryogenesis, the poor germination of oat haploid embryos can be a result of the overproduction of reactive oxygen species, and therefore higher levels of low molecular weight antioxidants and stress hormones. [ABSTRACT FROM AUTHOR]

Background. Development of new cultivars is one of the vital options for adapting agriculture to climate change, and the production of doubled haploid (DH) plants can make a significant contribution to accelerating the breeding process. Oat is one of the cereals with particular health benefits, but it unfortunately still remains recalcitrant to haploidization. Our previous studies have clearly demonstrated that post-pollination with hormone treatment is a key step in haploid production through wide hybridization and indicated it as the most effective method for this species. Therefore, we subsequently addressed the problem of the influence of 2,4-dichlorophenoxyacetic acid (2,4-D) concentration on consecutive stages of DH production. Methods. Twenty-nine genotypes were tested, 9,465 florets were pollinated with maize pollen 2 days after emasculation and then treated with 2,4-D at 50 mg/L and 100 mg/L. Results. The applied treatments did not reveal any differences in the number of obtained haploid embryos. However, almost twice as many haploid plants formed on MS medium after applying a higher auxin concentration and 20% more successfully acclimatized. Moreover, 100 mg/L 2,4-D treatment resulted in twice as many DH lines that produced almost three times more seeds compared to 50 mg/L treatment. Nevertheless, the results have confirmed the existence of strong genotypic variation, which may significantly limit the development of an effective and economically feasible method that could be incorporated into breeding programs. [ABSTRACT FROM AUTHOR]

Diverse processes leading to doubled haploid (DH) plant production, such as microspore embryogenesis, gynogenesis, and distant hybridization followed by genome elimination, are based on the unique ability of plant cells to form haploid embryos without fertilization. All of these are possible because of various in vitro culture systems that enable the growth and development of tissues or single cells outside of the parental organism. The possibility of re-directing cell development from its original pathway to embryogenesis brings several benefits to many research areas, but the most important is the possibility of its implementation in breeding programs. This review summarizes the achievements of Polish research groups in studies of the mechanisms of haploid/DH embryo development and demonstrates the practical applications of these systems in basic studies and plant breeding. It shows the results of studies on economically important crops including barley (Hordeum vulgare L.), oilseed rape (Brassica napus L.), triticale (Ã--Triticosecale Wittm.), oat (Avena sativa L.), rye (Secale cereale L.), sugar beet (Beta vulgaris ssp. vulgaris L.), and some vegetable species, including carrot (Daucus carota L.), onion (Allium cepa L.), red beet (Beta vulgaris L.), and members of the Brassicaceae. [ABSTRACT FROM AUTHOR]

Androgenic responsiveness in anther (AC) and isolated microspore cultures (MC) was analysed using 15 lines of Polish winter rye (Secale cereale L.). The effect of low temperature (LT) alone or in combination with osmotic stress induced by mannitol treatment (MAN) and/or with reduced glutathione (GSH) on the effectiveness of the process was studied. Interestingly, each treatment had a different effect on microspore (mcs) vitality and capability to divide symmetrically. The first criterion for successful embryogenesis was to exceed the threshold number of at least 25% dividing microspores, which determined 'embryogenic suspension culture'. In some configurations a spectacular effect was achieved, especially in lines highly recalcitrant to androgenesis induction. Relatively high effectiveness of androgenesis induction (up to 4.58 AS per 105 mcs per spike in MC and 21.29 AS per spike in AC) showed that the developed protocol with GSH and/or MAN tiller pre-treatments overcomes the genotypic barrier for androgenesis initiation in rye. Moreover, relatively high, spontaneous genome diploidization (55%) of regenerated plants demonstrated that the described protocols could be effectively integrated into conventional rye breeding programmes. Key message: Glutathione and mannitol break the barrier of androgenesis initiation by increasing the dividing and vital microspores ratio. This marker is useful for screening material in breeding programs utilizing DH technology. [ABSTRACT FROM AUTHOR]

Leucojum aestivum L. is an important medicinal plant which produces Amaryllidaceae alkaloids, especially galanthamine and lycorine. Research is currently exploring the possibility of producing these alkaloids using biotechnological methods, including in vitro cultures. The biosynthesis of alkaloids may be affected by the types and concentrations of carbohydrate sources used in the medium. In the present investigation we performed such studies on in vitro cultures of L. aestivum with a view to obtaining plant material of good quality, characterized, in particular, by a high content of valuable Amaryllidaceae alkaloids. Methods We examined the effects of various types of carbohydrate sources-sucrose, glucose, fructose and maltose-at different concentrations (30, 60 and 90 g/L)-on the quality of L. aestivum plants grown in the RITA® bioreactor. The plants' quality was assessed by their biomass increments, as well by as analysing photosynthetic pigments, endogenous sugar, phenolics and Amaryllidaceae alkaloid content. We also investigated the effect of sugars on the activity of the antioxidant enzymes catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Results The highest biomass increments were observed in plants cultivated in the medium containing 90 g/L sucrose. The highest CAT activity was noted in cultures growing in the medium supplemented with 90 g/L maltose, while the highest POD activity was observed in the presence of 90 g/L fructose and 60 g/L maltose. No differences in SOD activity were observed. Moreover, the sugars did not affect the contents of chlorophyll a and carotenoids, whereas the highest amount of chlorophyll b was recorded in plants growing in the medium with 60 g/L maltose. No statistically significant differences were observed in the contents of endogenous sugars and phenolics in any in vitro conditions. However, the addition of sugar had a decisive effect on the biosynthesis of the Amaryllidaceae alkaloids. The highest distribution of alkaloids occurred in plants cultured in the medium containing 60 g/L sucrose. Six Amaryllidaceae alkaloids were detected in the plant tissue. The addition of 30 g/L fructose in the medium resulted in the accumulation of five alkaloids, including ismine, which was not identified in other analysed tissues. The highest concentration of galanthamine was observed in plants cultured in the presence of 30 g/L fructose and 60 g/L sucrose (39.2 and 37.5 μg/g of dry weight (DW), respectively). The plants grown in the medium containing 60 g/L sucrose exhibited the highest lycorine content (1048 μg/g of DW). Conclusions The type and concentration of sugar used in the medium have an essential influence on the biosynthesis of Amaryllidaceae alkaloids in L. aestivum plants cultured in a RITA® bioreactor. The results point to an interesting approach for commercial production of galanthamine and lycorine. [ABSTRACT FROM AUTHOR]

The efficiency of embryogenesis of anther culture was compared using four cultivars of oat (Avena sativa L.): 'Akt', 'Bingo', 'Bajka', and 'Chwat'. Despite the high resistance of oat to the process of androgenesis, all tested cultivars produced embryo-like structures and only two of them, 'Akt' and 'Chwat', produced fertile doubled haploid plants. A strong cultivar dependency was observed during induction of androgenesis. Further, cold pretreatment together with high temperature shock enhanced the efficiency of this technique. The highest number of embryo-like structures and haploid plants was obtained from cv. 'Chwat' (3.6% and 0.8%, respectively). Embryo-like structure formation also depended on the distance from the base of the flag leaf to the penultimate leaf of the panicle. Most of them were observed on anthers harvested from panicles of which the distance from the base of the flag leaf to the penultimate leaf was less than 4 cm. The presence of the induction medium supplemented with different plant growth regulators was essential for the induction of embryo-like structures but did not increase the production of haploid plants and doubled haploid lines. The highest number of embryo-like structures and plants was obtained on W14 medium with the addition of 2.0 mg/dm3 2,4-dichlorophenoxyacetic acid and 0.5 mg/dm3 kinetin (2.7%). The low haploid plant regeneration rate (from 0.03 to 0.05%) still limits the practical application of anther culture for the production of doubled haploid lines in oat. [ABSTRACT FROM AUTHOR]

The development of embryos requires interaction of many endogenous hormones. The aim of the study was to determine which endogenous phytohormones are involved in the process of oat (Avena sativa L.) haploidization. Oat haploids were obtained by wide crossing with Zea mays L. The hormonal profiles of the ovaries with (OE) and without developed embryo (OWE) were compared. Phytohormone contents were measured by UHPLC coupled with mass spectrometer. The total content of indole-3-acetic acid (IAA), trans-zeatin (tZ), and kinetin (KN) in OE was significantly higher than in OWE. 4-Chloroindole-3-acetic acid was detected only in OWE. There were no differences between OE and OWE in the content of gibberellins (GA1, GA3, GA4, GA6, GA7) and stress hormones (abscisic, salicylic, jasmonic acids). Content of endogenous KN was highly negatively correlated with the percentage of haploid embryos, germinated haploid embryos, haploid plants on MS (in vitro), haploid plants in soil (ex vitro), and doubled haploid lines. The tZ content negatively correlated with the frequency of haploid embryo formation, germination, and haploid plants obtained in vitro, as opposed to GA1, which correlated positively. A positive correlation was found between IAA and tZ in OE, whereas in OWE it was a negative correlation. The profiles of phytohormones in OE and OWE were determined; however, their mode of action needs to be clarified. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effect of indole-3-butyric acid (IBA) and exogenous sucrose concentrations on in vitro rooting, soluble sugar, starch and phenolic production, and ex vitro survival of four magnolia cultivars. There was a significant linear increase in rooting of most magnolia genotypes with an increase in IBA concentration in the medium from 1 to 6 mg L−1. A further increase of IBA concentration to 10 mg L−1 decreased ('Elizabeth', 'Burgundy') or had no effect on rooting frequency ('Spectrum'). The effect of IBA on rooting of magnolia shoots was modified by sucrose supply. The three out of four magnolia cultivars showed the highest rooting efficiency in the presence of 6 mg L−1 IBA and 30 g L−1 of sucrose. Generally, decreasing and increasing the sucrose supply from 30 g L−1 significantly lowered the rooting frequency. In 'Yellow Bird', sucrose at 40 g L−1 totally blocked root formation. It has been found that the poor rooting ability of 'Yellow Bird' coincided with a low soluble sugar content, and high production of starch and phenolics in the shoot bases during the whole rooting period as compared to easy-to-root cultivars. After 5 weeks of the growth on IBA medium, rooted and unrooted shoots were transferred to ex vitro conditions. Both types of shoots showed a high survival and rooting rate (85.4-100%), but they differed in their growth activity and quality. Sucrose concentration in the rooting medium had a post-effect on ex vitro root formation and survival of magnolia plantlets. Ex vitro establishment (13.3%) of recalcitrant 'Yellow Bird' was obtained only when the shoots were taken from rooting medium containing the lowest level of sucrose (20 g L−1). [ABSTRACT FROM AUTHOR]

Astragalus penduliflorus Lam. is an alpine-subalpine species. Several isolated populations occur in Europe: in the Alps, Pyrenees, Carpathians and in central Sweden. Astragalus penduliflorus is considered as critically endangered species in Poland, growing only at the locality in the Smytnia Valley, in the Western Tatra Mountains. The population is at risk, due to the limited reproduction caused by law rate of seed germination, periodically shortened vegetation period that prevent seed development and gnawing the aerial plant parts by deer. The aim of the study was to explain the reason for the poor germination of A. penduliflorus seeds. As a result of mechanical scarification, 100% of A. penduliflorus seeds germinated, which proved that these seeds are characterized by a water-impermeable seed coat, which classified them as hard seeds that go through physical dormancy. Results obtained in this work can be used for effective reproduction and active conservation of threatened A. penduliflorus. [ABSTRACT FROM AUTHOR]

Background. Wheat is widely affected by drought. Low excised-leaf water loss (ELWL) has frequently been associated with improved grain yield under drought. This study dissected the genetic control of ELWL in wheat, associated physiological, morphological and anatomical leaf traits, and compared these with yield QTLs. Methods. Ninety-four hexaploid wheat (Triticum aestivum L.) doubled haploids, mapped with over 700 markers, were tested for three years for ELWL from detached leaf 4 of glasshouse-grown plants. In one experiment, stomata per unit area and leaf thickness parameters from leaf cross-sections were measured. QTLs were identified using QTLCartographer. Results. ELWL was significantly negatively correlated with leaf length, width, area and thickness. Major QTLs for ELWL during 0-3 h and 3-6 h were coincident across trials on 3A, 3B, 4B, 5B, 5D, 6B, 7A, 7B, 7D and frequently coincident (inversely) with leaf size QTLs. Yield in other trials was sometimes associated with ELWL and leaf size phenotypically and genotypically, but more frequently under non-droughted than droughted conditions. QTL coincidence showed only ELWL to be associated with drought/control yield ratio. Discussion. Our results demonstrated that measures of ELWL and leaf size were equally effective predictors of yield, and both were more useful for selecting under favourable than stressed conditions. [ABSTRACT FROM AUTHOR]

Background. The oat x maize addition (OMA) lines are used for mapping of the maize genome, the studies of centromere-specific histone (CENH3), gene expression, meiotic chromosome behavior and also for introducing maize C4 photosynthetic system to oat. The aim of our study was the identification and molecular-cytogenetic characterization of oat x maize hybrids. Methods. Oat DH lines and oat x maize hybrids were obtained using the wide crossing of Avena sativa L. with Zea mays L. The plants identified as having a Grande- 1 retrotransposon fragment, which produced seeds, were used for genomic in situ hybridization (GISH). Results. A total of 138 oat lines obtained by crossing of 2,314 oat plants from 80 genotypes with maize cv. Waza were tested for the presence of maize chromosomes. The presence of maize chromatin was indicated in 66 lines by amplification of the PCR product (500 bp) generated using primers specific for the maize retrotransposon Grande-1. Genomic in situ hybridization (GISH) detected whole maize chromosomes in eight lines (40%). All of the analyzed plants possessed full complement of oat chromosomes. The number of maize chromosomes differed between the OMA lines. Four OMA lines possessed two maize chromosomes similar in size, three OMA--one maize chromosome, and one OMA--four maize chromosomes. In most of the lines, the detected chromosomes were labeled uniformly. The presence of six 45S rDNA loci was detected in oat chromosomes, but none of the added maize chromosomes in any of the lines carried 45S rDNA locus. Twenty of the analyzed lines did not possess whole maize chromosomes, but the introgression of maize chromatin in the oat chromosomes. Five of 66 hybrids were shorter in height, grassy type without panicles. Twenty-seven OMA lines were fertile and produced seeds ranging in number from 1-102 (in total 613). Sixty-three fertile DH lines, out of 72 which did not have an addition of maize chromosomes or chromatin, produced seeds in the range of 1-343 (in total 3,758). Obtained DH and OMA lines were fertile and produced seeds. Discussion. In wide hybridization of oat with maize, the complete or incomplete chromosomes elimination of maize occur. Hybrids of oat and maize had a complete set of oat chromosomes without maize chromosomes, and a complete set of oat chromosomes with one to four retained maize chromosomes. [ABSTRACT FROM AUTHOR]

Background. Melatonin (MEL) is a signaling molecule in plants that affects developmental processes during vegetative and reproductive growth. Investigations have proved that exogenously applied MEL also has the potential to improve seed germination and plant development. Methods. In the present study, seeds of stevia, a species with a very low germination rate, were germinated on an agar gel (AG) containing MEL at various concentrations (5, 20, 100, and 500 µM) in light. Seeds germinated on AG without MEL were used as controls. For the first 24 or 48 h of germination, the seeds were maintained in darkness as a pre-incubation step. Some seeds were not exposed to this pre-incubation step. Results. At concentrations of 20 and 5 µM, MEL significantly improved germination, but only in seeds pre-incubated in darkness for 24 h (p < 0.001). At concentrations of 100 and 500 µM, MEL had an inhibitory effect on germination, regardless of the pre-incubation time. Melatonin also affected plantlet properties. At a concentration of 20 µM, MEL increased plantlet fresh weight and leaf numbers. At a concentration of 5 µM, it promoted plantlet height. Regarding root development, the most favorable MEL concentration was 500 µM. Biochemical analysis revealed that MEL promoted higher pigment concentrations but hampered superoxide dismutase activity. On the other hand, the concentrations of sugars and phenolics, as well as the activities of catalase and peroxidase, increased at a MEL concentration of 500 µM. Discussion. The results suggest that MEL can improve germination of positively photoblastic stevia seeds and that it can play a role in plantlet development. However, the effects observed in the present study depended on the quantity of MEL that was applied. [ABSTRACT FROM AUTHOR]

Polyamines (PAs) are related to many physiological processes, including soil drought stress. Two yellow lupin 'Morocco 4' (drought tolerant) and 'Taper' (drought sensitive) were exposed to soil drought for 2 weeks. The half of the examined plants were additionally sprayed with a solution of polyamine biosynthesis inhibitor- dl-α-difluoromethylarginine (DFMA). Yellow lupin leaves showed a 19% increase and seeds a 54% decrease in the total PA contents. The seeds contained fourfold less PAs than the leaves under drought conditions. The highest amount of spermidine and lack of agmatine were found in the leaves, while in the seeds the highest content of spermine and the presence of agmatine was confirmed. The use of DFMA under drought conditions decreased the content of spermine in 'Morocco 4' and 'Taper' (41 and 19%, respectively) and spermidine in 'Taper' (by 13%), as well as reduced two out of three of the yield components. More tolerant 'Morocco 4', after DFMA treatment was characterized by a higher spermidine and spermine content and a smaller decrease in yield components compared to the less tolerant 'Taper'. Simultaneously subjecting plants to soil drought and DFMA treatment caused in 'Morocco 4' a decline in the number of pods and seeds per plant and seeds dry weight per plant (64, 50 and 54%, respectively), while in 'Taper' a reduction of the number of pods per plant and seeds per pod (32 and 27%, respectively) was observed. These results confirm that PAs are involved in yellow lupin tolerance and may play a protective function under soil drought conditions. [ABSTRACT FROM AUTHOR]

Functionality of the photosynthetic system under water stress is of major importance in drought tolerance. Oat ( Avena sativa L.) doubled haploid (DH) lines obtained by pollination of F oat crosses with maize were used to assess the differences in plant genotypic response to soil drought. The investigations were based on the measurements of gas exchange and chlorophyll a fluorescence kinetics. Drought was applied to 17-day-old seedlings by withholding water for 14 days and subsequent plant recovery. Non-stressed optimally watered plants served as controls. Yield components were determined when plants reached full maturity. It was shown differences among the oat lines with respect to drought stress susceptibility (SI) and stress tolerance index mean productivity and drought susceptibility index. Sensitivity to drought of individual DH lines was significantly different, as demonstrated by the correlation between drought susceptibility index and yield components, such as dry weight (GW) or grain number (GN) of the harvested plants. GW and GN were lower in drought-sensitive genotypes exposed to drought stress compared to those resistant to drought. The principal component analysis allow to separate three groups of lines differing in their sensitivity to drought stress and indicated that tolerance to drought in oat has a common genetic background. [ABSTRACT FROM AUTHOR]

Obtaining oat DH lines is only effective via wide crossing with maize. Seven hundred haploid embryos from 21 single F progeny obtained from wide crosses with maize were isolated, divided into four groups according to their size (<0.5 mm, 0.5-0.9 mm, 1.0-1.4 mm, and ≥1.5 mm), and transferred into 190-2 regeneration medium with different growth regulators: 0.5 mg L kinetin (KIN) and 0.5 mg L 1-naphthaleneacetic acid (NAA); 1 mg L zeatin (ZEA) and 0.5 mg L NAA; or 1 mg L dicamba (DIC), 1 mg L picloram (PIC), and 0.5 mg L kinetin (KIN). Among all isolated embryos, approximately 46.1% were between 1.0-1.4 mm, while the smallest group of embryos (7.1%) were those <0.5 mm. The ability of haploid embryos to germinate varied depending on oat genotypes and the size of embryos. Haploid embryos <0.5 mm were globular and did not germinate, whereas embryos ≥1.5 mm had clearly visible coleoptiles, radicles, and scutella, and were able to germinate. Germination of oat haploid embryos varied depending on growth regulators in the regeneration medium. Most haploid embryos germinated on medium with 0.5 mg L NAA and 0.5 mg L KIN, while the fewest germinated on medium with 1 mg L DIC, 1 mg L PIC, and 0.5 mg L KIN. One hundred thirty germinated haploid embryos converted into haploid plants. Fifty oat DH lines were obtained after colchicine treatment. [ABSTRACT FROM AUTHOR]

Taraxacum pieninicum is an extremely threatened species. It seems that traditional protection methods of this species are insufficient and it is necessary to use biotechnology tools that allow the in vitro storage of plant material. The present study describes in vitro conservation of T. pieninicum by slow-growth storage. Various light conditions and abscisic acid (ABA) treatments and combinations thereof were tested. Viability, proliferation rate and ability of shoots to root were evaluated during regrowth. Moreover, the effect of shoot storage conditions on the ABA level was analysed. The results showed that light during 3-months' storage increased the level of endogenous ABA. Similar results were observed when storage at a low temperature was prolonged to 9 months. Changes in ABA level had a negative effect on shoot condition. However, these changes were related to leaves and did not affect the ability of shoot tips to proliferate after long-term storage. Addition of ABA to storage medium increased several folds the level of ABA in plant tissues, which resulted in a reduction in the visual rating and proliferation rate. Shoots obtained after post-storage regrowth were able to root. All rooted shoots survived adaptation to field conditions and were able to flower in the second year after acclimatization. The analysis of DNA content indicated that all the regenerants had the same ploidy level independent of treatments during storage. Cold storage of T. pieninicum as used in this study enabled the interval between subcultures to be extended to 9 months. [ABSTRACT FROM AUTHOR]

The total soluble sugar content and antioxidant enzyme activities were studied for the first time during axillary shoot formation in Magnolia × 'Spectrum' in vitro in response to BAP (0.3 mg l−1), different levels of gibberellic acid (GA3; 0.0, 0.1, 0.5, 1.0 mg l−1), sucrose (20 and 30 g l−1) and nitrogen salts (KNO3/NH4NO3; 100/100% and 75/50% relative to MS medium). Among various GA3 and sucrose/nitrogen salts ratios, the most effective axillary multiplication (5.9 shoots/explant) and leaf formation (25.7 leaves per multiplied clumps) were obtained after addition of GA3 at 0.1 mg l−1 to a BAP medium containing 20 g l−1 sucrose and reduced levels of nitrogen salts (75% KNO3 and 50% NH4NO3). The addition of GA3 to the BAP medium enhanced shoot formation by 36% and leaf formation by 27%. The highest shoot formation capacity of M. × 'Spectrum' in vitro coincided with enhanced levels of soluble sugar and peroxidase (POD) activity. Increasing GA3 concentration from 0.1 to 1.0 mg l−1 in the above medium resulted in inhibition of shoot and leaf formation and a decrease in the soluble sugar content. The influence of GA3 on the activities of catalase (CAT) and POD depended on its concentration and the levels of sucrose and nitrogen salts in the medium. The highest increase in CAT and POD activities, that coincided with the enhanced shoot formation capacity of M. × 'Spectrum' in vitro, was observed after addition of GA3 to the medium containing high levels of sucrose and nitrogen salts. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the influence of aqueous extracts from the leaves of peppermint (Mentha ×piperita L.) on the seedlings and plants of common sunflower (Helianthus annuus L.). Different concentration of peppermint leaves extract: 1, 3, 5, 10, 15% was used to examine the growth (length), fresh and dry mass of common sunflower seedlings and plants watered peppermint extracts in phase of growth. We measured the length of seedlings and separated organs of plant: root, hypocotyl, epicotyl, petioles of the first row and remainder of the shoot. Additionally, we determined fresh and dry mass of these organs and cotyledons, leaves of the first order and remainder of the leaves. Depending on the concentration the aqueous extracts showed a stimulatory (low extract concentration) or inhibitory (high extract concentration) effect on growth, fresh and dry mass of common sunflower seedlings and plants. [ABSTRACT FROM AUTHOR]

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The QTLs controlling germination and early seedling growth were mapped using seeds acquired from mapping population and parental lines of Chinese Spring and SQ1 grown under water-limited conditions, severe drought (SDr) and well-watered plants (C). Germination ability was determined by performing a standard germination test based on the quantification of the germination percentage (GP24) of seeds incubated for 24 h at 25°C in the dark. Early seedling growth was evaluated on the basis of the length of the root and leaf at the 6th day of the experiment. QTLs were identified by composite interval mapping method using Windows QTLCartographer 2.5 software. For the traits studied, a total of thirty eight additive QTLs were identified. Seventeen QTLs were mapped in C on chromosomes: 1A, 2A, 7A, 1B, 2B, 3B, 4B, 5B, 6B, 7B, 2D, 3D, 4D and 6D, while twenty one QTLs were identified in SDr on chromosomes: 1A, 2A, 5A, 2B, 3B, 4B, 5B, 6B, 7B, 3D, 5D and 6D. Most of the QTLs for GP and early leaf growth parameters were clustered on chromosome 4B (associated with the Rht-B1 marker) both in C and SDr plants. The results indicate the complex and polygenic nature of germination. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the role of salicylic acid (SA) and abscisic acid (ABA) in osmotic stress tolerance of wheat seedlings. This was accomplished by determining the impact of the acids applied exogenously on seedlings grown under osmotic stress in hydroponics. The investigation was unique in its comprehensiveness, examining changes under osmotic stress and other conditions, and testing a number of parameters simultaneously. In both drought susceptible (SQ1) and drought resistant (CS) wheat cultivars, significant physiological and biochemical changes were observed upon the addition of SA (0.05 mM) or ABA (0.1 µM) to solutions containing half-strength Hoagland medium and PEG 6000 (-0.75 MPa). The most noticeable result of supplementing SA or ABA to the medium (PEG + SA and PEG + ABA) was a decrease in the length of leaves and roots in both cultivars. While PEG treatment reduced gas exchange parameters, chlorophyll content in CS, and osmotic potential, and conversely, increased lipid peroxidation, soluble carbohydrates in SQ1, proline content in both cultivars and total antioxidants activity in SQ1, PEG + SA or PEG + ABA did not change the values of these parameters. Furthermore, PEG caused a two-fold increase of endogenous ABA content in SQ1 and a four-fold increase in CS. PEG + ABA increased endogenous ABA only in SQ1, whereas PEG + SA caused a greater increase of ABA content in both cultivars compared to PEG. In PEG-treated plants growing until the harvest, a greater decrease of yield components was observed in SQ1 than in CS. PEG + SA, and particularly PEG + ABA, caused a greater increase of these yield parameters in CS compared to SQ1. In conclusion, SA and ABA ameliorate, particularly in the tolerant wheat cultivar, the harmful effects and after effects of osmotic stress induced by PEG in hydroponics through better osmotic adjustment achieved by an increase in proline and carbohydrate content as well as by an increase in antioxidant activity. [ABSTRACT FROM AUTHOR]

In vitro cultures of Leucojum aestivum are considered as an alternative for the production of galanthamine, which is used for the symptomatic treatment of Alzheimer's disease. We studied the effects of auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro- o-anisic acid (dicamba) at concentrations of 25 and 50 µM on the induction of embryogenic callus and its capacity to induce somatic embryogenesis and alkaloid accumulation. The embryogenic response of the explants was from 30% for 25 µM of dicamba to 100% for picloram (for both 25 and 50 µM). 2,4-D (50 µM) stimulated greater callus proliferation and somatic embryo induction as compared to the other auxins. Polyethylene glycol (PEG) stimulated somatic embryo maturation. Callus grown on media containing 50 µM of auxins produced fewer phenolic compounds as compared with callus grown on media containing 25 µM of auxins. GC-MS analyses showed seven alkaloids in the in vivo bulbs and two to four in callus culture. Galanthamine was detected in callus cultivated with 2,4-D (25, 50 µM), picloram (25 µM), and dicamba (50 µM). Other alkaloids, trisphaeridine, tazettine, and 11-hydroxyvittatine were accumulated only in callus growing on medium with picloram (50 µM). [ABSTRACT FROM AUTHOR]

The aim of the study was to optimize the method of oat haploid production by pollination with maize. Seventeen oat genotypes were used in the experiment. Various factors influencing the growth and development of ovaries and embryo production were investigated: genotype, time of pollination, growth regulators and time of their application. Emasculated before anthesis, oat florets were pollinated with maize pollen after 0, 1 or 2 days. Next, one of two auxins analogues (2,4-D or dicamba) were applied to oat pistils. These auxins had no significant influence on the number of enlarged ovaries and embryos. The time of application of these growth regulators had a significant influence on embryo production. Haploid embryos were obtained from all used genotypes, although the frequency of enlarged ovaries and obtained embryos did not differ markedly between the genotypes. On average, 85% of ovaries were enlarged and 11.7% of them produced haploid embryos. Depending on the regeneration medium, 24-41% of embryos were germinated, of which 12% had developed into green plants. A strong significant difference in the number of germinating embryos and haploid plants was observed between the kind of regenerating medium used. There were no albino plants and all the obtained plants were haploid. [ABSTRACT FROM AUTHOR]

In this study, the seedlings of two wheat cultivars were used: drought-resistant Chinese Spring (CS) and drought-susceptible (SQ1). Seedlings were subjected to osmotic stress in order to assess the differences in response to drought stress between resistant and susceptible genotype. The aim of the experiment was to evaluate the changes in physiological and biochemical characteristics and to establish the optimum osmotic stress level in which differences in drought resistance between the genotypes could be revealed. Plants were subjected to osmotic stress by supplementing the root medium with three concentrations of PEG 6000. Seedlings were grown for 21 days in control conditions and then the plants were subjected to osmotic stress for 7 days by supplementing the root medium with three concentrations of PEG 6000 (D1, D2, D3) applied in two steps: during the first 3 days of treatment −0.50, −0.75 and −1.00 and next −0.75, −1.25 and −1.5 MPa, respectively. Measurements of gas exchange parameters, chlorophyll content, height of seedlings, length of root, leaf and root water content, leaf osmotic potential, lipid peroxidation, and contents of soluble carbohydrates and proline were taken. The results highlighted statistically significant differences in most traits for treatment D2 and emphasized that these conditions were optimum for expressing differences in the responses to osmotic stress between SQ1 and CS wheat genotypes. The level of osmotic stress defined in this study as most suitable for differentiating drought resistance of wheat genotypes will be used in further research for genetic characterization of this trait in wheat through QTL analysis of mapping population of doubled haploid lines derived from CS and SQ1. [ABSTRACT FROM AUTHOR]

We propose that oxidative stress resulting from an imbalance between generation and scavenging hydrogen peroxide contributes to tissue regeneration efficiency during somatic embryogenesis of hexaploid winter wheat ( Triticum aestivum cv. Kamila) and organogenesis of faba bean ( Vicia faba ssp. minor cv. Nadwislanski). Endogenous hydrogen peroxide content and antioxidant capacity of cells were determined in initial explants and callus cultures derived from these explants. Regeneration-competent explants (immature embryos) contained more endogenous HO than explants initiated from regeneration-recalcitrant tissue (mature wheat embryos and faba bean epicotyls). Higher HO levels were observed despite the higher activity of antioxidative enzymes (superoxide dismutase and catalase) and the induction of their gene expression. Calli originating from immature embryos retained the capacity of the initial explants: high HO production was observed during the whole culture period. Low temperature treatment (4°C) was found to be an effective factor, which improved both regeneration ability and HO production. Exogenous application to the medium of HO and catalase blocker (3-aminotriazole), but not FeEDTA and superoxide dismutase blocker (diethyldithiocarbamate), also resulted in the enhancement of regeneration efficiency. These results clearly indicate that plant regeneration is specifically regulated by endogenous HO and by factors, which improve its accumulation. Moreover, a study of the activity of various SOD isoforms suggests that not only the absolute concentration of HO, but also its localisation might be responsible for controlling regeneration processes. [ABSTRACT FROM AUTHOR]

Vigor and selected physiological parameters (content of phenolic compounds, soluble sugars, chlorophyll a and b, and carotenoids) of eight naked and two husked oat cultivars harvested at 15% moisture content were determined. Oat seeds were threshed using two rotational speeds of the threshing drum: 1.6 m s (LS) and 2.4 m s (HS). They were then inoculated with a medium pathogenicity strain of Fusarium culmorum, strain IPO 348-01. In naked cultivars, the use of HS resulted in more severe mechanical damage; in consequence, seedling vigor decreased by 16%. In naked cultivars chlorophyll a and b and carotenoids content were significantly reduced-by more than 64%-when the HS was used. The inoculation caused over a 100% increase of carbohydrates in roots at LS but only a slight increase at HS. Phenolic compound content was twice as high in roots than in leaves after inoculation for both LS and HS. Area of microdamage and reduction of root fresh weight (f.wt.) are significantly correlated with biochemical parameters. Smaller microdamage area and root f.wt. reduction are connected with higher physiological parameters, which confirms lower seedling susceptibility to pathogen infection. [ABSTRACT FROM AUTHOR]

Drought is one of the major factors limiting wheat yield in many developing countries worldwide. Parameters of chlorophyll a fluorescence kinetics under drought stress conditions have been used to characterize dehydration tolerance in wheat. In the present study, a set of 94 doubled haploid lines obtained from Chinese Spring × SQ1 (CSDH), mapped with 450 markers, was evaluated for yield (grain dry weight/main stem ear), number of grains/main stem ear (NG) and chlorophyll a fluorescence parameters (FC) under moderate and severe drought stress, and compared with results for well-watered plants. quantitative trait loci (QTLs) were identified using Windows QTLCartographer version 2.5 software and the results were analysed using single-marker analysis (SMA) and composite interval mapping (CIM). Analysis using SMA and CIM showed mostly similar QTLs for all traits, though more QTLs were identified by SMA than by CIM. The genetic control of yield, NG and FC varied considerably between drought-stressed and non-stressed plants. Although no major QTL co-locations were found for yield and FC using CIM, the co-location of QTLs for NG, yield and Fv/Fm in drought-stressed plants was observed on chromosome 5A using SMA. [ABSTRACT FROM AUTHOR]

The purpose of this study was to identify endogenous factors that induce gummosis and to show their role in gummosis in tulip (Tulipa gesnerianaL. cv. Apeldoorn) stems. Using procedures to detect endogenous factors that induce gum in the stem of tulips, jasmonic acid (JA) and methyl jasmonate (JA-Me) were successfully identified using gas-liquid chromatography-mass spectrometry. Total amounts of JA and JA-Me designated as jasmonates in tulip stems were also estimated at about 70-80 ng/g fresh weight, using deuterium-labeled jasmonates as internal standards. The application of JA and JA-Me as lanolin pastes substantially induced gums in tulip stems with ethylene production. The application of ethephon, an ethylene-generating compound, however, induced no gummosis although it slightly affected jasmonate content in tulip stems. These results strongly suggest that JA and JA-Me are endogenous factors that induce gummosis in tulip stems. [ABSTRACT FROM AUTHOR]

In our study, we focused on the link among various parameters of chlorophyll a fluorescence and yield elements in the barley doubled haploid (DH) lines. There were significant differences in all studied DH lines, both in yield components and parameters of chlorophyll a fluorescence. The most variable parameter was overall performance index of PSII (PI) while the least was the amount of energy trapped in PSII reaction centers (TRo/CS). Considering yield components, high variation was also observed in the subsequent order from highest to lowest variation: biomass, thousand-grain weight (TGW) and grain number per plant (GNP). Significant negative correlation was found among the following fluorescence parameters: PI and light energy absorption (ABS/CS), as well as between maximum photochemical efficiency (Fv/Fm) and TGW, and between biomass and electron acceptors pool size from PSII (Area). Conversely, significant positive correlation was found between: Area and PI, Area and energy used for electron transport (ETo/CS), Area and GNP, PI and ETo/CS, PI and GNP, ABS/CS and TRo/CS, as well as between ETo/CS and GNP. Yield components combined with fluorescence parameters of chlorophyll a expressed with canonical variate analysis did not clearly distinguish the barley DH lines into hulled and hull-less groups. The mean value for these groups significantly differs only for ETo/CS and TGW values. The other parameters are distributed almost uniformly in hulled and hull-less lines. However, certain hull-less DH lines possess higher yield parameters compared to parental forms, which suggests a possibility of occurrence of transgression effects. The results suggest the chance to find valuable hull-less forms that are desired by breeders and plant producers, since these forms possess favorable functional features. [ABSTRACT FROM AUTHOR]

Oat (Avena sativa L.) cultivars 'Bingo' and 'Chwat' were used to compare the embryogenesis competence of another culture. Despite the embryo-like structures obtained from both tested cultivars, only 'Chwat' produced green plantlets, which confirmed the cultivar dependency. 'Chwat' produced the highest number of embryo-like structures and green plantlets (0.7/100 anthers and 0.1/100 anthers, respectively). The embryo-like structure formation also depended on cold pretreatment combined with Cu2+, Zn2+, or Ag+ ion supplementation, which was applied during the tiller pretreatment or added to the induction media. The highest number of embryo-like structures (2.1/100 anthers) were observed on anthers derived from the tillers kept in a 50% Hoagland medium with the addition of 10 µM of CuSO4. In turn, the induction media supplemented with the ions Cu2+, Zn2+, or Ag+ increased neither the number of embryo-like structures nor the green plantlet production compared to the control conditions. However, such ion applications turned out to be most effective when the induction medium was enriched with 25 µM of AgNO3 and left to obtain the highest number of embryo-like structures and green plantlets (0.8/100 anthers and 0.2/100 anthers, respectively). Therefore, more attention should be paid to the possibilities of adjusting the media nutrient composition, as this may be the only way to significantly increase the efficiency of this method. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the profile of endogenous phenolic acids in yellow-flowered magnolias and to evaluate the effects of endogenous and exogenous phenolic acids on the in vitro rooting of three magnolia cultivars ('Butterflies', 'Yellow Bird', and 'Elizabeth'). It has been shown that magnolia cultivars are phenolic acid-rich plants. Of the 16 phenolic acids tested, all were detected in each magnolia cultivar. The most abundant was gallic acid (max. 34,946 ng·mg−1 dry mass), followed by chlorogenic acid, ferulic acid, and caffeic acid. The amount of individual phenolic acids differed between the cultivars and media. The total phenolic production was enhanced by auxin, the main factor promoting rooting in magnolia in vitro. It has been found that the difficult-to-root 'Butterflies' and 'Yellow Bird' rooted better when they were grown on medium containing a mixture of auxins—3-indolebutyric acid (IBA) and 1-naphthaleneacetic acid (NAA)—as compared to IBA alone. The highest rooting frequency was observed for 'Elizabeth' (95.8%), followed by 'Butterflies' (46.1%) and 'Yellow Bird' (21.4%). In the case of 'Yellow Bird', the auxin treatment enhanced the leaf yellowing. The present work indicates a clear relationship between the overaccumulation of chlorogenic acid and coumaric acid in the late phase of rooting in vitro and the low rooting responses of magnolia 'Butterflies' and 'Yellow Bird'. On the other hand, 'Elizabeth' produced more soluble sugars by 29.2% than easy-to-root ones. The biochemical status of the plantlets can influence their further ex vitro establishment, which was the highest for 'Elizabeth' (97.5%), followed by 'Butterflies' (49.9%) and 'Yellow Bird' (24.6%). [ABSTRACT FROM AUTHOR]

The oat × maize chromosome addition (OMA) lines, as hybrids between C3 and C4 plants, can potentially help us understand the process of C4 photosynthesis. However, photosynthesis is often affected by adverse environmental conditions, including drought stress. Therefore, to assess the functioning of the photosynthetic apparatus in OMA lines under drought stress, the chlorophyll content and chlorophyll a fluorescence (CF) parameters were investigated. With optimal hydration, most of the tested OMA lines, compared to oat cv. Bingo, showed higher pigment content, and some of them were characterized by increased values of selected CF parameters. Although 14 days of drought caused a decrease of chlorophylls and carotenoids, only slight changes in CF parameters were observed, which can indicate proper photosynthetic efficiency in most of examined OMA lines compared to oat cv. Bingo. The obtained data revealed that expected changes in hybrid functioning depend more on the specific maize chromosome and its interaction with the oat genome rather than the number of retained chromosomes. OMA lines not only constitute a powerful tool for maize genomics but also are a source of valuable variation in plant breeding, and can help us to understand plant susceptibility to drought. Our research confirms more efficient functioning of hybrid photosynthetic apparatus than oat cv. Bingo, therefore contributes to raising new questions in the fields of plant physiology and biochemistry. Due to the fact that the oat genome is not fully sequenced yet, the mechanism of enhanced photosynthetic efficiency in OMA lines requires further research. [ABSTRACT FROM AUTHOR]