Microplastics and nanoplastics: Source, behavior, remediation, and multi-level environmental impact.

Plastics introduced into the natural environment persist, degrade, and fragment into smaller particles due to various environmental factors. Microplastics (MPs) (ranging from 1 µm to 5 mm) and nanoplastics (NPs) (less than 1 µm) have emerged as pollutants posing a significant threat to all life forms on Earth. Easily ingested by living organisms, they lead to ongoing bioaccumulation and biomagnification. This review summarizes existing studies on the sources of MPs and NPs in various environments, highlighting their widespread presence in air, water, and soil. It primarily focuses on the sources, fate, degradation, fragmentation, transport, and ecotoxicity of MPs and NPs. The aim is to elucidate their harmful effects on marine organisms, soil biota, plants, mammals, and humans, thereby enhancing the understanding of the complex impacts of plastic particles on the environment. Additionally, this review highlights remediation technologies and global legislative and institutional measures for managing waste associated with MPs and NPs. It also shows that effectively combating plastic pollution requires the synergization of diverse management, monitoring strategies, and regulatory measures into a comprehensive policy framework.

Occurrence of plant hormones in composts made from organic fraction of agri-food industry waste.

Utilizing the organic fraction of agri-food industry waste for fertilization represents one approach to waste management, with composting emerging as a popular method. Composts derived from this waste may contain plant hormones alongside primary macronutrients. This study aimed to evaluate the content of plant hormones in composts crafted from the organic fraction of agri-food industry waste. The presence of these substances was ascertained using liquid chromatography-mass spectrometry (LC-MS) analysis, applied to extracted samples from three composts produced in a bioreactor and three obtained from companies. The results indicate the presence of 35 compounds, which belong to six types of plant hormones: auxins, cytokinins, gibberellins, brassinosteroids, abscisic acid, and salicylic acid, in composts for the first time. The highest amount of plant hormones was noted in buckwheat husk and biohumus extract (35 compounds), and the lowest in hemp chaff and apple pomace (14 compounds). Brassinosteroids (e.g., brassinolide, 28-homobrassinolide, 24-epicastasterone, 24-epibrassinolide, and 28-norbrassinolide) and auxins (e.g., indolilo-3-acetic acid) are dominant. The highest concentration of total phytohormones was reported in biohumus extract (2026.42 ng g-1 dry weight), and the lowest in organic compost (0.18 ng g-1 dry weight).

Biosynthetic Pathways of Hormones in Plants.

Phytohormones exhibit a wide range of chemical structures, though they primarily originate from three key metabolic precursors: amino acids, isoprenoids, and lipids. Specific amino acids, such as tryptophan, methionine, phenylalanine, and arginine, contribute to the production of various phytohormones, including auxins, melatonin, ethylene, salicylic acid, and polyamines. Isoprenoids are the foundation of five phytohormone categories: cytokinins, brassinosteroids, gibberellins, abscisic acid, and strigolactones. Furthermore, lipids, i.e., α-linolenic acid, function as a precursor for jasmonic acid. The biosynthesis routes of these different plant hormones are intricately complex. Understanding of these processes can greatly enhance our knowledge of how these hormones regulate plant growth, development, and physiology. This review focuses on detailing the biosynthetic pathways of phytohormones.

In Which Way Do the Flower Properties of the Specialist Orchid Goodyera repens Meet the Requirements of Its Generalist Pollinators?

This article is the next part of a series of studies documenting the influence of flower traits on the reproductive success (RS) of orchids. Knowledge of factors influencing RS helps to understand the mechanisms and processes crucial for shaping plant-pollinator interactions. The aim of the present study was to determine the role of flower structure and nectar composition in shaping the RS of the specialist orchid Goodyea repens, which is pollinated by generalist bumblebees. We found a high level of pollinaria removal (PR) and female reproductive success (fruiting, FRS) as well as a high level of variation between populations, although in certain populations pollination efficiency was low. Floral display traits, mainly inflorescence length, influenced FRS in certain populations. Among the flower traits, only the height of flowers was correlated with FRS in one population, suggesting that the flower structure of this orchid is well adapted to pollination by bumblebees. The nectar of G. repens is diluted and dominated by hexoses. Sugars were less important in shaping RS than amino acids. At the species level, twenty proteogenic and six non-proteogenic AAs were noted, along with their differentiated amounts and participation in particular populations. We found that distinct AAs or their groups mainly shaped PR, especially when correlations were considered at the species level. Our results suggest that both the individual nectar components and the ratios between them have an impact on G. repens RS. Because different nectar components influence the RS parameters in different ways (i.e., negatively or positively), we suggest that different Bombus species play the role of main pollinators in distinct populations.

Does Reproductive Success in Natural and Anthropogenic Populations of Generalist Epipactis helleborine Depend on Flower Morphology and Nectar Composition?

The purpose of our study was to determine the role of flower structure and nectar composition in shaping the reproductive success (RS) of the generalist orchid Epipactis helleborine in natural and anthropogenic populations. We supposed that the distinct character of two groups of habitats creates different conditions for plant-pollinator relationships, thus influencing reproductive success in E. helleborine populations. Both pollinaria removal (PR) and fruiting (FRS) were differentiated between the populations. On average, FRS was almost two times higher in the anthropogenic than in the natural populations. The difference between the two population groups in PR was smaller but still statistically significant. RS parameters were correlated with some floral display and flower traits. Floral display influenced RS only in three anthropogenic populations. Flower traits had a weak influence on RS (10 of the 192 cases analyzed). The more important trait in shaping RS was nectar chemistry. The nectar of E. helleborine is relatively diluted with a lower sugar concentration in the anthropogenic than in the natural populations. In the natural populations, domination of sucrose over hexoses was found, while in the anthropogenic populations, hexoses were more abundant and the participation of sugars was balanced. In some populations, sugars influenced RS. In E. helleborine nectar, 20 proteogenic and 7 non-proteogenic amino acids (AAs) were found with a clear domination of glutamic acid. We noted relationships between some AAs and RS, but distinct AAs shaped RS in different populations, and their impact was independent of their participation. Our results indicate that the flower structure and nectar composition of E. helleborine reflect its generalistic character and meet the requirements of a wide range of pollinators. Simultaneously, the differentiation of flower traits suggests a variation in pollinator assemblages in particular populations. Knowledge about the factors influencing RS in distinct habitats helps to understand the evolutionary potential of species and to understand mechanisms and processes crucial for shaping interactions between plants and pollinators.

Exogenous α-Tocopherol Regulates the Growth and Metabolism of Eggplant (Solanum melongena L.) under Drought Stress.

The present investigation was designed to improve drought stress tolerance in eggplant (Solanum melongena L.) through the exogenous application of α-tocopherol (TOC). For exogenous application, two modes, i.e., foliar spray (FS) and pre-sowing seed treatment (PS), were used. Water deficiency treatment (50% field capacity (FC)) was applied on 32-day-old seedlings of two eggplant cultivars, i.e., Janak and Black Beauty. Five levels of TOC (0 mg/L, 50 mg/L PS, 100 mg/L PS, 50 mg/L FS, and 100 mg/L FS) were applied as PS and FS. Pre-sowing seed treatment was conducted before seed sowing, while FS treatment after 30 days of drought stress treatment. After 15 days of TOC as an FS application, it was observed that drought stress significantly reduced plant growth (5-15%) and chlorophyll contents (4-10%), while it increased proline (4-6%), glycine betaine (GB) (5-10%), malondialdehyde (MDA) (10.8%), hydrogen peroxide (15-16%), relative membrane permeability (RMP) (5-8%), and the activities of peroxidase (7-8%) and superoxide dismutase (12-15%) in both eggplant cultivars. The TOC application (FS and PS) exhibited a positive role in overcoming the adverse effect of water stress on eggplants. Plant growth increased (15-18%) as a result of the application of TOC, which could be linked with improved chlorophyll, ascorbic acid (AsA), GB, proline, total soluble proteins (TSP), and the activities of peroxidase (POD) and superoxide dismutase (SOD) activities. The reactive oxygen species H2O2 was also decreased by TOC application. Overall, TOC as a foliar spray was more effective in improving the accumulation of proline, GB, AsA, and activities of SOD and POD enzymes, while PS treatment was more effective in reducing RMP and improving the TSP of eggplant. Cv. Black Beauty was comparatively better in root dry weight, chlorophyll a and b, and MDA contents, while cv. Janak in RMP, AsA, TSP, and activity of the POD enzyme. It can be inferred that the application of TOC was useful in counteracting the harmful effects of drought stress on both cultivars of eggplants.

Melatonin Involved in Protective Effects against Cadmium Stress in Wolffia arrhiza.

Melatonin (MT) is a new plant hormone that protects against adverse environmental conditions. In the present study, the responses of Wolffia arrhiza exposed to cadmium (Cd) and MT were analyzed. Quantitative analysis of MT and precursors of its biosynthesis was performed using LC-MS-MS. The photosynthetic pigments and phytochelatins (PCs) contents were determined using HPLC, while protein and monosaccharides, stress markers, and antioxidant levels were determined using spectrophotometric methods. Interestingly, the endogenous level of MT and its substrates in W. arrhiza exposed to 1-100 µM Cd was significantly higher compared to the control. Additionally, the application of 25 µM MT and Cd intensified the biosynthesis of these compounds. The most stimulatory effect on the growth and content of pigments, protein, and sugars was observed in plants treated with 25 µM MT. In contrast, Cd treatment caused a decrease in plant weight and level of these compounds, while the application of 25 µM MT mitigated the inhibitory effect of Cd. Additionally, Cd enhanced the level of stress markers; simultaneously, MT reduced their content in duckweed exposed to Cd. In plants treated with Cd, PC levels were increased by Cd treatment and by 25 µM MT. These results confirmed that MT mitigated the adverse effect of Cd. Furthermore, MT presence was reported for the first time in W. arrhiza. In summary, MT is an essential phytohormone for plant growth and development, especially during heavy metal stress.

Zinc oxide nanoparticles mediated biostimulant impact on cadmium detoxification and in silico analysis of zinc oxide-cadmium networks in Zea mays L. regulome.

Cadmium (Cd) toxicity can significantly limit plant growth and development. To eliminate the toxic effects of Cd stress, we intended to evaluate the biochemical mediated physiological responses in maize treated with biostimulant and zinc oxide nanoparticles (ZnPs). In silico analysis exhibited that the maize treated with Cd stress (200 µM) had an adverse impact on CAT1, CAT2, CAT3 and gor1 proteins, which are influential in managing the machinery of redox homeostasis. While maize inoculated with bacteria-based biostimulant and ZnPs (10 ppm) showed prominently improved biomass, chlorophyll a, b and carotenoid content. We found a significant increase in the total sugar, protein, proline content and antioxidants under the effect of Cd stress. However, these parameters are further enhanced by applying biostimulants and ZnPs. Declined lipid peroxidation and membrane solubilization index under the effect of biostimulant and ZnPs was observed. Furthermore, these treatments improved maize's zinc, copper, sodium, magnesium, iron, potassium and calcium content. Based on these results, an antagonistic relationship between Zn and Cd uptake that triggered efficient Cd detoxification in maize shoot was found. Scanning electron micrography showed distorted leaf structure of the Cd stressed plants while the biostimulant and ZnPs reduced the structural cell damage of maize leaves. In silico study showed that ZnO positively regulates all protein interactors, including GRMZM2G317386_P01 (Metallo endo proteinase 1-MMP), GRMZM2G110220_P01 (Metallo endo proteinase 5-MMP), GRMZM2G103055_P01 (Alpha-amylase) and GRMZM2G006069_P01 (Zn-dependent exo peptidase superfamily) proteins which are involved in energy generating processes, channels formation, matrix re-localization and stress response. This suggests that ZnO offers an ideal role with protein interactors in maize. Our findings depict that these treatments, i.e., biostimulant and ZnPs alone, are efficient enough to exhibit Cd remediation potential in maize; however, their combination showed synergistic effects.

The involvement of hydrogen sulphide in melatonin-induced tolerance to arsenic toxicity in pepper (Capsicum annuum L.) plants by regulating sequestration and subcellular distribution of arsenic, and antioxidant defense system.

Melatonin (MT) and hydrogen sulphide (H2S) are recognised as vital biomolecules actively taking part in plant defence systems as free radical scavengers and antioxidants against a myriad of biotic and abiotic stressors. However, it has been yet unknown in plants subjected to arsenic (As) toxicity whether or not H2S interacts with MT to regulate endogenous antioxidant defence system. Prior to beginning As stress (As-S) treatments, MT (0.10 mM) was applied externally to plants daily for three days. AsS was then started for two weeks with As(V) (0.1 mM as Na2HAsO4·7H2O). The treatment of As reduced plant biomass (24.4%) and chlorophyll a (51.7%), chlorophyll b (25.9%), while it increased subcellular As in roots and leaves, levels of glutathione (GSH), hydrogen peroxide (H2O2), malondialdehyde (MDA), methylglyoxal (MG), H2S and phytochelatins (PCs) in pepper plants. In As-stressed pepper plants, the application of MT increased plant biomass (16.3%), chlorophyll a (52.7%), chlorophyll b (28.2%), antioxidant enzymes' activities, and H2S accumulation, while it lowered the concentrations of MDA and H2O2. In As-treated plants, GSH and phytochelatins (PCs) were increased by MT by regulating As sequestration to make it harmless. The addition of MT increased As accumulation in the vacuoles of roots and caused the soluble fraction of As in vacuoles to become less toxic to vital organelles. MT-induced tolerance to As stress was further enhanced using NaHS, a source of H2S. Hypotaurine (0.1 mM HT), a H2S scavenger, was applied to the control and As-stressed plants together with MT and MT + NaHS to determine whether H2S was implicated in MT-induced increased As-S tolerance. By reducing H2S generation in pepper plants, HT counteracted the beneficial effects of MT, whereas the addition of NaHS to MT + HT restored the negative effects of HT, proving that H2S is necessary for the pepper plants As-stress tolerance caused by MT.

The participation of nitric oxide in hydrogen sulphide-mediated chromium tolerance in pepper (Capsicum annuum L) plants by modulating subcellular distribution of chromium and the ascorbate-glutathione cycle.

The promising response of chromium-stressed (Cr(VI)-S) plants to hydrogen sulphide (H2S) has been observed, but the participation of nitric oxide (NO) synthesis in H2S-induced Cr(VI)-S tolerance in plants remains to be elucidated. It was aimed to assess the participation of NO in H2S-mediated Cr(VI)-S tolerance by modulating subcellular distribution of Cr and the ascorbate-glutathione (AsA-GSH) cycle in the pepper seedlings. Two weeks following germination, plants were exposed to control (no Cr) or Cr(VI)-S (50 µM K2Cr2O7) for further two weeks. The Cr(VI)-S-plants grown in nutrient solution were supplied with 200 µM sodium hydrosulphide (NaHS, donor of H2S), or NaHS plus 100 µM sodium nitroprusside (SNP, a donor of NO). Chromium stress suppressed plant growth and leaf water status, while elevated proline content, oxidative stress, and the activities of AsA-GSH related enzymes, as well as endogenous H2S and NO contents. The supplementation of NaHS increased Cr accumulation at root cell walls and vacuoles of leaves as soluble fraction to reduce its toxicity. Furthermore it limited oxidative stress, improved plant growth, modulated leaf water status, and the AsA-GSH cycle-associated enzymes' activities, as well as it further improved H2S and NO contents. The positive effect of NaHS was found to be augmented on those parameters in the CrS-plants by the SNP supplementation. However, 0.1 mM cPTIO, the scavenger of NO, inverted the prominent effect of NaHS by decreasing NO content. The supplementation of SNP along with NaHS + cPTIO reinstalled the positive effect of NaHS by restoring NO content, which suggested that NO might have a potential role in H2S-induced tolerance to Cr(VI)-S in pepper plants by stepping up the AsA-GSH cycle.

Phytoecdysteroids: Distribution, Structural Diversity, Biosynthesis, Activity, and Crosstalk with Phytohormones.

Phytoecdysteroids (PEs) are naturally occurring polyhydroxylated compounds with a structure similar to that of insect molting hormone and the plant hormone brassinosteroids. PEs have a four-ringed skeleton composed of 27, 28, 29, or 30 carbon atoms (derived from plant sterols). The carbon skeleton of ecdysteroid is known as cyclopentanoperhydrophenanthrene and has a ß-sidechain on C-17. Plants produce PEs via the mevalonate pathway with the help of the precursor acetyl-CoA. PEs are found in algae, fungi, ferns, gymnosperms, and angiosperms; more than 500 different PEs are found in over 100 terrestrial plants. 20-hydroxyecdysone is the most common PE. PEs exhibit versatile biological roles in plants, invertebrates, and mammals. These compounds contribute to mitigating biotic and abiotic stresses. In plants, PEs play a potent role in enhancing tolerance against insects and nematodes via their allelochemical activity, which increases plant biological and metabolic responses. PEs promote enzymatic and non-enzymatic antioxidant defense systems, which decrease reactive oxygen species in the form of superoxide radicals and hydroxyl radicals and reduce malondialdehyde content. PEs also induce protein biosynthesis and modulate carbohydrate and lipid synthesis. In humans, PEs display biological, pharmacological, and medicinal properties, such as anti-diabetic, antioxidant, anti-microbial, hepatoprotective, hypoglycemic, anti-cancer, anti-inflammatory, antidepressant, and tissue differentiation activity.

Specific Roles of Lipoxygenases in Development and Responses to Stress in Plants.

Lipoxygenases (LOXs), naturally occurring enzymes, are widely distributed in plants and animals. LOXs can be non-sulfur iron, non-heme iron, or manganese-containing dioxygenase redox enzymes. LOXs catalyze the oxidation of polyunsaturated fatty acids into fatty acid hydroperoxides. Linolenic acid, a precursor in the jasmonic acid (JA) biosynthesis, is converted to 12-oxo-phytodienoic acid through oxygenation with LOX, allene oxide synthase, and allene oxide cyclase. Moreover, JA participates in seed germination, fruit ripening, senescence, and many other physio-biochemical processes. LOXs also play crucial roles in defense responses against biotic stress, i.e., insects, pests, pathogenic attacks, and abiotic stress, such as wounding, UV-rays, extreme temperature, oxidative stress, and drought.

Newly-synthesized iron-oxide nanoparticles showed synergetic effect with citric acid for alleviating arsenic phytotoxicity in soybean.

In the current investigation, we presented the success of the modified hydrothermal method for synthesizing the iron-oxide nanoparticles (Fe2O3-NPs) efficiently. These NPs were further characterized by using different techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) micrographs, energy-dispersive X-ray spectroscopy (EDAX)/Mapping pattern, Raman Spectroscopy Pattern, ultra violet (UV) and Photoluminescence (PL). All these analyses revealed highly pure nature of Fe2O3-NPs with no internal defects, and suggested its application for plant growth improvement. Therefore, we further investigated the separate as well as combined effects of the Fe2O3-NPs and citric acid (CA) in the alleviation of arsenic (As) toxicity in the soybean (Glycine max L.), by evaluating the different plant growth and metabolic attributes. Results of our study revealed that As-induced growth inhibition, reduction of photosynthesis, water use efficiency (WUE), and reactive oxygen species (ROS) accumulation whereas application of the Fe2O3-NPs and CA significantly reversed all these adverse effects in soybean plants. Moreover, the As-stress induced malondialdehyde (MDA) and hydrogen peroxide (H2O2) production were partially reversed by the Fe2O3-NPs and CA in the As-stressed plants by 16% and 10% (MDA) and 29% and 12% (H2O2). This might have resulted due to the Fe2O3-NPs and CA induced activities of the antioxidant defense in plants. Overall, the Fe2O3-NPs and CA supplementation separately and in combination positively regulated the As tolerance in soybean; however, the effect of the combined application on the As tolerance was more profound relative to the individual application. These results suggested the synergetic effect of the Fe2O3-NPs and CA on the As-tolerance in soybean. However, in-depth mechanism underlying the defense crosstalk between the Fe2O3-NPs and CA needs to be further explored.

Defense interplay of the zinc-oxide nanoparticles and melatonin in alleviating the arsenic stress in soybean (Glycine max L.).

Present study showed the successful application of the modified hydrothermal method for synthesizing the zinc oxide nanoparticles (ZnO-NPs) efficiently. Well as-synthesized ZnO-NPs are analyzed for various techniques viz., X-ray diffraction (XRD), SEM micrographs, EDAX/Mapping pattern, Raman Spectroscopy Pattern, UV, Photoluminescence (PL) and X-ray photoemission spectroscopy (XPS) analysis. All these measurements showed that ZnO-NPs are highly pure with no internal defects, and can be potentially used in the plant applications. Hence, we further determined the effect of these nanoparticles and melatonin for the modulation of the As tolerance in soybean plants by examining the various growth attributes and metabolic parameters. Our results demonstrated that As-stress inhibited growth (∼34%), photosynthesis-related parameters (∼18-28%) and induced ROS accumulation; however, all these attributes are substantially reversed by the ZnO-NPs and melatonin treatments. Moreover, the As stress induced malondialdehyde (MDA; 71%) and hydrogen peroxide (H2O2; 82%) are partially reversed by the ZnO-NPs and melatonin in the As-stressed plants. This might have resulted due to the ZnO-NPs and melatonin induced activities of the antioxidants plant defense. Overall, the ZnO-NPs and melatonin supplementation separately and in combination positively regulated the As tolerance in soybean; however, the effect of their combined application on the As tolerance was more profound relative to the individual application. These results suggested the synergetic effect of the ZnO-NPs and melatonin on the As tolerance in soybean. However, the in-depth mechanism underlying the defense crosstalk between the ZnO-NPs and melatonin needs to be further explored.

Evaluation of total phenols content, anti-DPPH activity and the content of selected antioxidants in the honeybee drone brood homogenate.

The subject of the present research is the evaluation of health-promoting properties caused by the presence of some vitamins as well as the antioxidative potential of the honeybee drone brood homogenate (DBH). The study used 139 homogenate samples obtained from various apiaries and collected over 3 years, three times during each beekeeping season. Samples differed in terms of varroa infestation, stage of brood development, location of the apiary, and the degree of environmental contamination. The content of ascorbic acid, α-tocopherol, all-trans-retinol, and coenzyme Q10 in the tested samples was determined through the application of HPLC/DAD/UV and LC/QQQ/MS methods. The antioxidant potential of samples was assessed using the Folin-Ciocalteu and DPPH methods.

Ascorbate-Glutathione Oxidant Scavengers, Metabolome Analysis and Adaptation Mechanisms of Ion Exclusion in Sorghum under Salt Stress.

Salt stress is one of the major significant restrictions that hamper plant development and agriculture ecosystems worldwide. Novel climate-adapted cultivars and stress tolerance-enhancing molecules are increasingly appreciated to mitigate the detrimental impacts of adverse stressful conditions. Sorghum is a valuable source of food and a potential model for exploring and understanding salt stress dynamics in cereals and for gaining a better understanding of their physiological pathways. Herein, we evaluate the antioxidant scavengers, photosynthetic regulation, and molecular mechanism of ion exclusion transporters in sorghum genotypes under saline conditions. A pot experiment was conducted in two sorghum genotypes viz. SSG 59-3 and PC-5 in a climate-controlled greenhouse under different salt concentrations (60, 80, 100, and 120 mM NaCl). Salinity drastically affected the photosynthetic machinery by reducing the accumulation of chlorophyll pigments and carotenoids. SSG 59-3 alleviated the adverse effects of salinity by suppressing oxidative stress (H2O2) and stimulating enzymatic and non-enzymatic antioxidant activities (SOD, APX, CAT, POD, GR, GST, DHAR, MDHAR, GSH, ASC, proline, GB), as well as protecting cell membrane integrity (MDA, electrolyte leakage). Salinity also influenced Na+ ion efflux and maintained a lower cytosolic Na+/K+ ratio via the concomitant upregulation of SbSOS1, SbSOS2, and SbNHX-2 and SbV-Ppase-II ion transporter genes in sorghum genotypes. Overall, these results suggest that Na+ ions were retained and detoxified, and less stress impact was observed in mature and younger leaves. Based on the above, we deciphered that SSG 59-3 performed better by retaining higher plant water status, photosynthetic assimilates and antioxidant potential, and the upregulation of ion transporter genes and may be utilized in the development of resistant sorghum lines in saline regions.

Genotype-Dependent Effect of Silencing of TaCKX1 and TaCKX2 on Phytohormone Crosstalk and Yield-Related Traits in Wheat.

The influence of silenced TaCKX1 and TaCKX2 on coexpression of other TaCKX gene family members (GFMs), phytohormone regulation and yield-related traits was tested in awned-spike cultivar. We documented a strong feedback mechanism of regulation of TaCKX GFM expression in which silencing of TaCKX1 upregulated expression of TaCKX2 genes and vice versa. Additionally, downregulation of TaCKX2 highly upregulated the expression of TaCKX5 and TaNAC2-5A. In contrast, expression of these genes in silenced TaCKX1 was downregulated. Silenced TaCKX1 T2 lines with expression decreased by 47% had significantly higher thousand grain weight (TGW) and seedling root mass. Silenced TaCKX2 T2 lines with expression of TaCKX2.2.1 and TaCKX2.2.2 decreased by 33% and 30%, respectively, had significantly higher chlorophyll content in flag leaves. TaCKX GFM expression, phytohormone metabolism and phenotype were additionally modified by Agrobacterium-mediated transformation. Two novel phytohormones, phenylacetic acid (PAA) and topolins, lack of gibberellic acid (GA) and changed phytohormone contents in the 7 days after pollination (DAP) spikes of the awned-spike cultivar compared to a previously tested, awnless one, were detected. We documented that major mechanisms of coregulation of the expression of TaCKX GFMs were similar in different spring wheat cultivars, but, depending on content and composition of phytohormones, regulation of yield-related traits was variously impacted.

Nectar Chemistry or Flower Morphology-What Is More Important for the Reproductive Success of Generalist Orchid Epipactis palustris in Natural and Anthropogenic Populations?

The aim of this study was to determine the level of reproductive success (RS) in natural and anthropogenic populations of generalist orchid Epipactis palustris and its dependence on flower structure and nectar composition, i.e., amino acids and sugars. We found that both pollinaria removal and female reproductive success were high and similar in all populations, despite differences in flower traits and nectar chemistry. Flower structures were weakly correlated with parameters of RS. Nectar traits were more important in shaping RS; although, we noted differentiated selection on nectar components in distinct populations. Individuals in natural populations produced nectar with a larger amount of sugars and amino acids. The sucrose to (fructose and glucose) ratio in natural populations was close to 1, while in anthropogenic ones, a clear domination of fructose and glucose was noted. Our results indicate that the flower traits and nectar composition of E. palustris reflect its generalist character and meet the requirements of a wide range of pollinators, differing according to body sizes, mouth apparatus, and dietary needs. Simultaneously, differentiation of nectar chemistry suggests a variation of pollinator assemblages in particular populations or domination of their some groups. To our knowledge, a comparison of nectar chemistry between natural and anthropogenic populations of orchids is reported for the first time in this paper.

Jasmonic acid (JA) and gibberellic acid (GA3) mitigated Cd-toxicity in chickpea plants through restricted cd uptake and oxidative stress management.

Cadmium stress is one of the chief environmental cues that can substantially reduce plant growth. In the present research, we studied the effect of jasmonic acid (JA) and gibberellic acid (GA3) applied individually and/or in combination to chickpea (Cicer arietinum) plants exposed to 150 µM cadmium sulphate. Cadmium stress resulted in reduced plant growth and pigment contents. Moreover, chickpea plants under cadmium contamination displayed higher levels of electrolytic leakage, H2O2, and malonaldehyde, as well as lower relative water content. Plants primed with JA (1 nM) and those foliar-fed with GA3 (10-6 M) showed improved metal tolerance by reducing the accumulation of reactive oxygen species, malonaldehyde and electrolytic leakage, and increasing relative water content. . Osmoprotectants like proline and glycinebetaine increased under cadmium contamination. Additionally, the enzymatic activities and non-enzymatic antioxidant levels increased markedly under Cd stress, but application of JA as well as of GA3 further improved these attributes. Enzymes pertaining to the ascorbate glutathione and glyoxylase systems increased significantly when the chickpea plants were exposed to Cd. However, JA and GA3 applied singly or in combination showed improved enzymatic activities as well as nutrient uptake, whereas they reduced the metal accumulation in chickpea plants. Taken together, our findings demonstrated that JA and GA3 are suitable agents for regulating Cd stress resistance in chickpea plants.