Haploid oat embryos obtained by distant crossing of oat (Avena sativa L.) with maize (Zea mays L.) are morphologically diverse. Since large haploid oat embryos convert into plants more easily, the aim of our research was to investigate anatomical and metabolic differences between large (≥ 1.5 mm) and small (< 1.5 mm) haploid embryos of hulled ‘Krezus’ and hulless ‘Akt’ oat cultivars. Anatomical sections of the embryos were compared with the profile of phytohormones, amino acids, phenolic acids, polyamines, and sugars determined by HPLC. We noticed that the development rate of haploid oat embryos depends on the genotype, as 21-day-old ‘Krezus’ embryos were characterized by a more advanced anatomical structure compared to ‘Akt’ embryos. We have shown that small ‘Krezus’ embryos accumulate significant amounts of active phytohormones: auxins, cytokinins, gibberellins, as well as amino acids: tryptophan, phenylalanine, methionine; phenolic acids: cinnamic, ferulic, sinapinic, chlorogenic, and polyamines: spermidine and spermine. These metabolites, remaining closely interdependent, guarantee the embryo’s further growth and development.

Recurrent soil droughts reduce the number of leaflets and reduce biochemical integrity within the compound leaves. They also promote leaflet specialization in the synthesis of carbohydrates and phenolic compounds, and limit allocation of these substances within the compound leaves.

Phytohormones play a key role in regulating every life process of the plant, at every stage of ontogeny [...]

Phytohormones play a key role in regulating every life process of the plant, at every stage of ontogeny [...].

Auxins play a critical role in establishing the embryo axis and embryonic pattern. Our study aimed to determine the developmental stage of 21-day old oat (Avena sativa L.) haploid embryos, obtained by distant crossing with maize, and examined oat zygotic embryos at different developmental stages for their levels of endogenous indole-3-acetic acid (IAA), its metabolites, and IAA localization. The content of auxin metabolites was determined by HPLC-MS/MS, while IAA visualization in embryos was performed by immunohistochemistry and observed under confocal microscopy. We found that 21-day-old haploid embryos contained half the IAA concentration of age-matched zygotic embryos. Simultaneously, the total conjugated auxins (IAA-Asp, IAA-Glu, meIAA) were higher than in zygotic embryos, regardless of their age. Immunolocalization revealed IAA accumulation in embryos aligned with regions of tissue differentiation (e.g., shoot apical meristem, radicle primordium, and coleptile). We conclude that limited morphogenetic progression, evidenced by microscopic sections accompanied by changes in IAA content and distribution in haploid embryos, indicates a developmental stage earlier than the coleoptilar stage of zygotic embryos which occurs 9 days after pollination. Our findings may be useful in embryo rescue techniques, suggesting modulation of auxin concentration in in vitro culture.

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.

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.

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.

The observations of fruiting and formation of offspring through generative propagation presented in this study were aimed at determination of propagation potential in Iris aphylla L. The low percentage of germinating seeds largely limits its generative reproduction. The germination tests confirmed deep dormancy of the Iris aphylla seeds. The dormancy was disrupted by isolation of embryos from seeds, which were further cultivated in vitro. The germination of isolated embryos proved the localization of endogenous inhibitors of germinating seeds of I. aphylla in the endosperm. The comparison of phytohormonal profiles of seeds, endosperm and embryos of I. aphylla and Iris sibirica, i.e. a species with a high percentage of germinating seed, revealed that the deep dormancy of I. aphylla seeds was associated with the balance between abscisic acid and gibberellins (ABA/GA), a significant predominance of ABA and a massive accumulation of salicylic acid. Isolation of embryos from seeds and their germination in growing medium in vitro is recommended as the most efficient method for I. aphylla propagation. Results of this study can be applied in conservation efforts of this attractive and important native species.

In this study, we examined responses of maize hybrids differing in susceptibility to soil compaction and drought in the case of their separate or combined action. We ran field and greenhouse experiments and determined effects on grain yield, biomass, weight of 1000 grains, shoot and roots dry matter (DM), shoot-to-roots ratio, harvest index, plant height, emergence index, leaf area and greening and root number and length. Individual and combined effects of both stresses were observed in the field and greenhouse. Compared with plants growing in loose soil and optimal irrigation (LI), the resistant hybrids in treatments HI, LD and HD showed a smaller reduction in GY, BY, S, R, R-N and R-L than the sensitive. In both groups, stress influence on HA, W-1000, LA and SPAD was smaller and the differences were insignificant. Compared with LI treatment, the roots of LD, HI and HD increased their DM, number and length in the upper level of the soil profile and the number of roots developed at 0-30 degrees and 30-60 degrees in relation to the root main axis. Analysis of those traits in the hybrids resistant and sensitive to both stress factors enabled to explain a defence response. Our study demonstrated that soil compaction and soil drought, which usually occurs simultaneously, caused significant changes in components of plant yield and showed plant plasticity in response to environmental factors under natural conditions.

In the natural environment, plants are subjected to simultaneous or sequential presence of various abiotic and/or biotic stresses, including soil compaction and soil drought. The effects of these stresses tested separately are relatively well understood, but still little is known about their simultaneous effects on plants. Our research involved four single hybrids of maize differing in their degree of susceptibility to soil compaction and drought. We investigated the effects of low and high soil compaction under optimal irrigation (LI, HI) and under three-week long soil drought (LD, HD), on the gas exchange (Pn, E, g(S), Ci) and chlorophyll fluorescence parameters (F-0, F-m, F-v, F-v/F-m), total leaf area (LA), leaf greening (SPAD), leaf water deficit (WD), leaf water potential (psi) and membrane injury (MI). The plants experiencing high soil compaction (HI) showed a decrease in all parameters of gas exchange (Pn, E, g(S), Ci), leaf area (LA), leaf greening (SPAD) and the maximal quantum efficiency of PSII (F-v/F-m) in comparison with plants growing in non-compacted soil (LI). An increase was observed in the other fluorescence parameters, i.e., F-0, F-m and F-v and leaf WD, psi and MI in HI vs. LI variants. In the plants exposed to drought (LD, HD), the changes in the measured traits were greater, especially for the sensitive hybrids P-8400 and NS-3023, than for the plants from LI treatment. A significant interaction between the degree of stress susceptibility and relative trait change was observed for practically all of the measured features. Moreover, in the short recovery period after the end of drought, the measured traits in LD and HD plants did not fully return to the control level, especially in the case of the sensitive hybrids (P-8400 NS-3023). The physiological reaction of maize hybrids to soil compaction and/or soil drought indicated the genetically determined variability of tolerance to those stresses. Significant correlation between RTC and stress susceptibility indexes (S-SI) provided suitable criteria for the hybrid selection. Also, our results showed the plasticity and capability of maize hybrids to respond to environmental conditions.

In tomato, the beneficial fungus Beauveria bassianaperturbs key molecular pathways related to primary and secondary metabolism, and growth- and defense-related hormones, and is effective against necrotrophic infection.

The aim was to identify subgenome-related specific responses in two types of triticale, that is, of the wheat-dominated genome (WDG) and rye-dominated genome (RDG), to water stress induced in the early phase (tillering) of plant growth. Higher activity of the primary metabolism of carbohydrates is a feature of the WDG type, while the dominance of the rye genome is associated with a higher activity of the secondary metabolism of phenolic compounds in the RDG type. The study analyzed carbohydrates and key enzymes of their synthesis, free phenolic compounds and carbohydrate-related components of the cell wall, monolignols, and shikimic acid (ShA), which is a key link between the primary and secondary metabolism of phenolic compounds. Under water stress, dominance of the wheat genome in the WDG type was manifested by an increased accumulation of the large subunit of Rubisco and sucrose phosphate synthase and a higher content of raffinose and stachyose compared with the RDG type. In dehydrated RDG plants, higher activity of L-phenylalanine ammonia lyase (PAL) and L-tyrosine ammonia lyase (TAL), as well as a higher level of ShA, free and cell wall-bound p-hydroxybenzoic acid, free homovanillic acid, free sinapic acid, and cell wall-bound syringic acid can be considered biochemical indicators of the dominance of the rye genome.

Plants experience a wide array of external factors, some of which negatively affect their metabolism, growth, and development [...].

Glaucous (811, L35, and RXL10) and non-glaucous (811bw, L35bw, and RXL10bw) near-isogenic lines (NILs) of rye (Secale cereale L.) forming three pairs of inbred lines were the subject of the research. The research aimed to study the relationship between wax cover attributes and the physio-biochemical drought reactions and yield of rye NILs and to uncover the differences in drought resistance levels of these lines. The greatest differences between glaucous and non-glaucous NILs were observed in the RXL10/RXL10bw pair. Of particular note were the stable grain number and the thousand grain weight of the non-glaucous line RXL10bw under drought and the accompanying reactions, such as an approximately 60% increase in MDA and a two-fold increase in wax amount, both of which were significantly higher than in the glaucous line RXL10 and in other NILs. The surprisingly high level of MDA in the RXL10bw line requires further analysis. Moreover, additional wax crystal aggregates were found under drought conditions on the abaxial leaf surface of the glaucous lines 811 and RXL10. The use of rye NILs indicated that line-specific drought resistance could be associated with wax biosynthetic pathways involved in physiological and biochemical responses important for increased drought resistance.

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.

Biochar applicability as culture medium amendment is rarely investigated due to its uncovered impact on in vitro cultured plants. This study assessed the feasibility of several biochars as alternatives to activated charcoal, for micropropagation of two ornamental Daphne species (Thymelaeaceae). We distinguished metabolic responses that were specific for: a) medium supplementation with any type of charcoal; b) biochar addition; c) biochar activation; d) the process of charcoal activation itself. We compared impacts of industrially produced biochar and three different biochars made in small-scale stoves (from residues of Gliricidia sepium) on organogenic capacity and physiological status in Daphne sp. shoots. Metabolite profiling revealed that biochars differently modulated accumulation of endogenous phytohormones and osmolytes in the shoots. Biochars reduced accumulation of proline, betaines and stress-related phytohormones (ABA, jasmonates), and impacted carbohydrate profile. For D. jasminea the most impactful was biochar activation, which increased micropropagation efficiency by elevating cytokinin and soluble sugars content. For D. tangutica charcoal/biochar activation, and application of biochar reduced accumulation of ABA and jasmonic acid, increased level of gibberellins, salicylic and benzoic acid, and altered carbohydrate composition. The study revealed that tested biochars can be used as a sustainable medium supplements without negative impact on production of new microshoots. Based on studied species we showed that biochar supplements could stimulate plantlet formation (D. jasminea,) ameliorate stress response (D. tangutica), and constitute a way of undesired biomass utilization (invasive species G. sepium).

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.

Cultures of Nasturtium officinale were cultivated in vitro under illumination with different wavelengths of light-emitting diode (LED) light (white LED light—WLED, blue light—B, red light—R, 70% red and 30% blue light—RB, 50% green, 35% red and 15% blue light—RBG, 50% yellow, 35% red and 15% blue light—RBY, 50% far red, 35% red and 15% blue light—RBfR, 50% UV, 35% red and 15% blue light—RBUV, darkness—D), and under white fluorescent light (WF)—control conditions. The study investigated the influence of the applied lighting conditions on biomass growth and the production of glucosinolates, phenolic compounds, as well as photosynthetic pigments, and soluble sugars. The study showed a significant beneficial effect of the RBG light on biomass growth (Gi = 11.81 after 20 days) and the production of glucosinolates. The total glucosinolate content under these conditions increased 5.8 and 1.4 times in comparison with the WF light and D condition, respectively, reaching 237.92 mg 100 g −1 DW. The production of phenolic compounds, sugars, and photosynthetic pigments was comparable to the production under the control conditions. The antioxidant potential of extracts from the cultivated biomass was assessed by the CUPRAC, DPPH, and FRAP assays. Extracts obtained from the biomass of cultures grown under the RBG light had an antioxidant potential similar to that of the control cultures. This is the first report providing evidence of the stimulating effect of light quality on the biomass yield and production of glucosinolates by N. officinale microshoot cultures in vitro.

Environmental changes are inevitable with time, but their intensification and diversification, occurring in the last several decades due to the combination of both natural and human-made causes, are really a matter of great apprehension. As a consequence, plants are exposed to a variety of abiotic stressors that contribute to their morpho-physiological, biochemical, and molecular alterations, which affects plant growth and development as well as the quality and productivity of crops. Thus, novel strategies are still being developed to meet the challenges of the modern world related to climate changes and natural ecosystem degradation. Innovative methods that have recently received special attention include eco-friendly, easily available, inexpensive, and, very often, plant-based methods. However, such approaches require better cognition and understanding of plant adaptations and acclimation mechanisms in response to adverse conditions. In this succinct review, we have highlighted defense mechanisms against external stimuli (mainly exposure to elevated levels of metal elements) which can be activated through permanent microevolutionary changes in metal-tolerant species or through exogenously applied priming agents that may ensure plant acclimation and thereby elevated stress resistance.