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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]

Oat (Avena sativa L.) has recently gained importance due to the discovery of a variety of health benefits and new opportunities of use. There is no efficient protocol for the production of oat doubled haploid (DH) lines. The aim of this study was to increase the efficiency of obtaining DHs of oat by the wide crossing method. The study was performed on five oat genotypes. We have compared the induction of embryos after pollination with maize, sorghum and millet pollen as well as the development of haploid embryos isolated 2, 3 and 4 weeks after pollination and cultivated on media with different sugar content. Haploid plants were treated with colchicine after or before acclimation to natural conditions. Of the three types of pollen used, the largest number of haploid embryos was obtained using maize pollen. Three weeks after pollination was the most suitable time for the isolation and cultivation of the embryos. The most efficient medium enabling the development of embryos and conversion to plants was 190-2 containing 9% of maltose. Colchicine treatment of acclimated plants provided high survival rate.

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]

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]

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]

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]

Microbial soil additives and plant biostimulants contain substances and microorganisms that can enhance stress tolerance in plants and increase the yield and quality of the crop. The interest in such inputs for sustainable and agroecological farming systems has led to the development of a range of products. The aim of the study was to determine the effects of some microbial soil additives (MSADs), plant growth promoters (PGPs) and biological control agents (BCAs) on photosynthetic efficiency, canopy vegetation indices and yield of common buckwheat (Fagopyrum esculentum Moench), an under-utilised nutraceutical crop. The study showed that soaking the seeds in the BCAs Pythium oligandrum and Bacillus subtilis, on their own, had significant effects on the yield of the buckwheat. Increases in chlorophyll a fluorescence indices were observed in plants grown from seeds soaked in a solution containing P. oligandrum (ET0/RC) and also in soil treated with the MSAD UG Max (ABS/RC, TR0/RC). Treatment with either of the two MSADs also increased the normalised differential vegetation index (NDVI). Soaking the seeds in PGPs combined with BCAs affected only the chlorophyll a fluorescence parameters, whereas the combined treatment of spraying the plants with PGPs and treating the soil with MSADs affected not only the chlorophyll a fluorescence parameters (FV/FM, ET0/RC, DI0/RC), but also indicated a tendency for a decrease in the leaf area index (LAI) (p = 0.058) and the NDVI (p = 0.186). The correlations between grain yield, chlorophyll a fluorescence parameters and vegetation indices of the canopy were discussed. [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]

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]

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]

The current study presents a method for the plant regeneration from stem segments of Cordyline australis (G. Forst.) Endl. ‘Red Star’ through somatic embryogenesis. We tested the effect of 3 kinds of auxin 4-amino-3,5,6-trichloropicolinic acid (picloram), 2,4-dichlorophenoxyacetic acid (2,4-D), and 2-methoxy-3,6-dichlorobenzoic acid (dicamba), with a combination of 2 kinds of cytokinin, 6-benzyladenine (BA) and thidiazuron (TDZ), on the induction of embryogenic callus and its capacity to induce somatic embryogenesis under dark culture condition. The highest percentage of explants forming callus (nodular and friable) was observed on medium containing 25 μM picloram and 0.5 μM BA. The embryogenic callus, with white-yellowish nodular structures, was proliferated in the initial media and finally produced somatic embryos on all media with picloram and 2,4-D. Somatic globular embryos were obtained with a higher frequency from explants cultured on MS medium supplemented with 25 μM picloram and 0.5 μM BA. On this medium, a mean number of 23.0 embryos developed per gram of callus. Globular embryos developed most efficiently into cotyledonary stage on MS medium supplemented with 5 μM picloram and 1 μM BA. The addition of zeatin (5 and 2.5 μM) and NAA (0.5 and 0.25 μM) to the medium was found to be essential for the highest conversion of somatic embryos into plants. Plantlets were successfully acclimatized in the greenhouse with 90% survival rate. Callus was tested for phenolic compounds, sugars, peroxidase activity and protein contents in order to find if these compounds might be the indicators of further embryos development. The embryogenic callus of C. australis with various stages of embryo development had higher level of protein than the non-regenerable one, whereas level of sugars increased only in callus with embryos in cotyledonary stage. Callus with globular embryos contained high concentration of phenolics and low activity of peroxidase, comparing to other types of callus. [ABSTRACT FROM AUTHOR]

In plants cultivation, some species influencing each other in a favorable manner, and others adversely affect the result of the release of physiologically active substances. These substances, called allelopathic compounds are excreted primarily by underground and aboveground plants' organs or formed during the decomposition of their remains. Allelopathins show the inhibitory or stimulating effects on the processes of seed germination, growth and physiological activity of plants. The aim of the study was to determine the allelopathic effects of aqueous extracts from the peppermint (Mentha ? piperita L.) leaves at various concentrations (1, 3, 5, 10, 15%) on seeds germination and the selected physiological processes of common sunflower (Helianthus annuus L.) seedlings. Seeds were germinated and plants were grown under greenhouse conditions for 30 days. Germination of sunflower seeds was reduced and electrolyte leakage from seedlings increased with increasing concentrations of aqueous extracts of the peppermint leaves. Increasing concentrations of aqueous extracts of peppermint also caused decrease of chlorophyll a and an increase of chlorophyll b content. The highest increase of the maximum photochemical efficiency of photosystem II was observed in H. annuus L. treated with 15% peppermint extract in comparison to the lower concentration of extracts and to the control. Non-photochemical and photochemical quenching and vitality index of photosystem II decreased with increasing concentrations of allelopathic substances in peppermint extracts. [ABSTRACT FROM AUTHOR]

The objective of this study was to facilitate the resistance of barley to Fusarium culmorum according to direct (disease rating (DR), fresh weight) and indirect (physiological and biochemical) parameters. Significant correlations were detected between most measured parameters. Hulled lines revealed less root susceptibility to infection of F. culmorum expressed in DR and fresh weight. Infection in roots significantly increased phenolics content, especially in most hull-less genotypes, but decreased soluble sugars, pigment content and overall performance index of the PSII photosystem. Significant correlations suggest the possibility of applying the measured indirect parameters in selection of barley DH lines resistant to F. culmorum infection. [ABSTRACT FROM AUTHOR]