RESUMO
Salinity limits the growth and productivity of crops, to reverse these effects, natural pigments with antioxidant bioactivity can be studied, such as turmeric (Curcuma longa L.) and paprika (Capsicum annum L.). Therefore, it aimed to evaluate turmeric and paprika as possible saline stress attenuators and biostimulants during germination and initial development of smooth lettuce seedlings. In the laboratory, the seeds were treated for 1 hour with a solution of paprika and turmeric at doses 0 (negative control), 1, 2, 3 and 4 g L-1, and placed on a substrate with saline solution of sodium chloride 4 g L-1 (-0,4 Mpa), and a positive control, composed of dry seeds arranged in a substrate moistened with distilled water. Physiological quality analysis were carried out, and for the dose that showed the best result (4 g L-1), the treated seeds were grown in a greenhouse, and received weekly applications via foliar with a 4 g L-1 solution for turmeric and paprika. After the crop cycle, morphometric analyzes were performed. The turmeric and paprika solutions were analyzed by High-Performance Liquid Chromatography (HPLC) to identify the presence of bioactive substances. The turmeric doses were not efficient in overcoming the effects of salinity on seeds and seedlings, which was attributed to the low solubility of turmeric in water. Paprika, although it did not provide the biostimulant effect, was efficient in attenuating the effects of excess salt, at a concentration of 4 g L-1, promoting increases in physiological quality. In HPLC, a very low signal response was noted in relation to samples composed of turmeric and paprika solutions, indicating a low percentage of soluble compounds, which compromises bioactivity, and leads to the need for further analyses using surfactants and/or other solvents with which there is greater affinity.
Assuntos
Antioxidantes , Curcuma , Germinação , Antioxidantes/farmacologia , Curcuma/química , Germinação/efeitos dos fármacos , Germinação/fisiologia , Lactuca/efeitos dos fármacos , Lactuca/química , Lactuca/crescimento & desenvolvimento , Cromatografia Líquida de Alta Pressão , Salinidade , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/química , Sementes/química , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Cloreto de Sódio/farmacologiaRESUMO
Salinity stress represents a major threat to crop production by inhibiting seed germination, growth of seedlings, and final yield and, therefore, to the social and economic prosperity of developing countries. Recently, plant growth-promoting substances have been widely used as a chemical strategy for improving plant resilience towards abiotic stresses. This study aimed to determine whether melatonin (MT) and glycine betaine (GB) alone or in combination could alleviate the salinity-induced impacts on seed germination and growth of maize seedlings. Increasing NaCl concentration from 100 to 200 mM declined seed germination rate (4.6-37.7%), germination potential (24.5-46.7%), radical length (7.7-40.0%), plumule length (2.2-35.6%), seedling fresh (1.7-41.3%) and dry weight (23.0-56.1%) compared to control (CN) plants. However, MT and GB treatments lessened the adverse effects of 100 and 150 mM NaCl and enhanced germination comparable to control plants. In addition, results from the pot experiments show that 200 mM NaCl stress disrupted the osmotic balance and persuaded oxidative stress, presented by higher electrolyte leakage, hydrogen peroxide, superoxide radicals, and malondialdehyde compared to control plants. However, compared to the NaCl treatment, NaCl+MT+GB treatment decreased the accumulation of malondialdehyde (24.2-42.1%), hydrogen peroxide (36.2-44.0%), and superoxide radicals (20.1-50.9%) by up-regulating the activity of superoxide dismutase (28.4-51.2%), catalase (82.2-111.5%), ascorbate peroxidase (40.3-59.2%), and peroxidase (62.2-117.9%), and by enhancing osmolytes accumulation, thereby reducing NaCl-induced oxidative damages. Based on these findings, the application of MT+GB is an efficient chemical strategy for improving seed germination and growth of seedlings by improving the physiological and biochemical attributes of maize under 200 mM NaCl stress.
Assuntos
Betaína , Germinação , Melatonina , Estresse Salino , Plântula , Sementes , Zea mays , Melatonina/farmacologia , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Zea mays/fisiologia , Zea mays/metabolismo , Betaína/farmacologia , Betaína/metabolismo , Germinação/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Estresse Salino/efeitos dos fármacos , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Cloreto de Sódio/farmacologia , Malondialdeído/metabolismo , Salinidade , Antioxidantes/metabolismo , Peróxido de Hidrogênio/metabolismo , Sinergismo Farmacológico , Estresse Oxidativo/efeitos dos fármacosRESUMO
Pathogenesis-related proteins (PR), including osmotins, play a vital role in plant defense, being activated in response to diverse biotic and abiotic stresses. Despite their significance, the mechanistic insights into the role of osmotins in plant defense have not been extensively explored. The present study explores the cloning and characterization of the osmotin gene (WsOsm) from Withania somnifera, aiming to illuminate its role in plant defense mechanisms. Quantitative real-time PCR analysis revealed significant induction of WsOsm in response to various phytohormones e.g. abscisic acid, salicylic acid, methyl jasmonate, brassinosteroids, and ethrel, as well as biotic and abiotic stresses like heat, cold, salt, and drought. To further elucidate WsOsm's functional role, we overexpressed the gene in Nicotiana tabacum, resulting in heightened resistance against the Alternaria solani pathogen. Additionally, we observed enhancements in shoot length, root length, and root biomass in the transgenic tobacco plants compared to wild plants. Notably, the WsOsm- overexpressing seedlings demonstrated improved salt and drought stress tolerance, particularly at the seedling stage. Confocal histological analysis of H2O2 and biochemical studies of antioxidant enzyme activities revealed higher levels in the WsOsm overexpressing lines, indicating enhanced antioxidant defense. Furthermore, a pull-down assay and mass spectrometry analysis revealed a potential interaction between WsOsm and defensin, a known antifungal PR protein (WsDF). This suggests a novel role of WsOsm in mediating plant defense responses by interacting with other PR proteins. Overall, these findings pave the way for potential future applications of WsOsm in developing stress-tolerant crops and improving plant defense strategies against pathogens.
Assuntos
Defensinas , Regulação da Expressão Gênica de Plantas , Nicotiana , Proteínas de Plantas , Plantas Geneticamente Modificadas , Estresse Fisiológico , Withania , Withania/genética , Withania/fisiologia , Withania/metabolismo , Withania/efeitos dos fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Nicotiana/genética , Nicotiana/fisiologia , Nicotiana/efeitos dos fármacos , Nicotiana/microbiologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Estresse Fisiológico/genética , Defensinas/genética , Defensinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Alternaria/fisiologia , Secas , Plântula/genética , Plântula/fisiologia , Plântula/efeitos dos fármacos , Ácido Salicílico/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Peróxido de Hidrogênio/metabolismo , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Raízes de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/fisiologiaRESUMO
Australian saltbush (Atriplex spp.) survive in exceptionally saline environments and are often used for pasture in semi-arid areas. To investigate the impact of salinity on saltbush root morphology and root exudates, three Australian native saltbush species (Atriplex nummularia , Atriplex amnicola , and Atriplex vesicaria ) were grown in vitro in optimised sterile, semi-hydroponic systems in media supplemented with different concentrations of salt (NaCl). Histological stains and chromatographic techniques were used to characterise the root apical meristem (RAM) type and root exudate composition of the saltbush seedlings. We report that saltbush species have closed-type RAMs, which release border-like cells (BLCs). Monosaccharide content, including glucose and fructose, in the root mucilage of saltbush was found to be uniquely low, suggesting that saltbush may minimise carbon release in polysaccharides of root exudates. Root mucilage also contained notable levels of salt, plus increasing levels of unidentified compounds at peak salinity. Un-esterified homogalacturonan, xyloglucan, and arabinogalactan proteins between and on the surface of BLCs may aid intercellular adhesion. At the highest salinity levels, root cap morphology was altered but root:shoot ratio remained consistent. While questions remain about the identity of some components in saltbush root mucilage other than the key monosaccharides, this new information about root cap morphology and cell surface polysaccharides provides avenues for future research.
Assuntos
Atriplex , Meristema , Raízes de Plantas , Plântula , Plântula/efeitos dos fármacos , Plântula/metabolismo , Plântula/crescimento & desenvolvimento , Meristema/efeitos dos fármacos , Meristema/citologia , Meristema/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Atriplex/efeitos dos fármacos , Atriplex/metabolismo , Cloreto de Sódio/farmacologia , Mucilagem Vegetal/metabolismo , Xilanos/metabolismo , Glucanos/metabolismo , SalinidadeRESUMO
BACKGROUND: The growth and yield of pepper, a typical temperature-loving vegetable, are limited by low-temperature environments. Using low-temperature sensitive 'Hangjiao No. 4' (Capsicum annuum L.) as experimental material, this study analyzed the changes in plant growth and photosynthesis under different treatments: normal control (NT), low-temperature stress alone (LT), low-temperature stress in strigolactone pretreated plants (SL_LT), and low-temperature stress in strigolactone biosynthesis inhibitor pretreated plants (Tis_LT). RESULTS: SL pretreatment increased the net photosynthetic rate (Pn) and PSII actual photochemical efficiency (φPSII), reducing the inhibition of LT on the growth of pepper by 17.44% (dry weight of shoot). Due to promoting the accumulation of carotenoids, such as lutein, and the de-epoxidation of the xanthophyll cycle [(Z + A)/(Z + A + V)] by strigolactone after long-term low-temperature stress (120 h), non-photochemical quenching (NPQ) of pepper was increased to reduce the excess excitation energy [(1-qP)/NPQ] and the photoinhibition degree (Fv/Fm) of pepper seedlings under long-term low-temperature stress was alleviated. Twelve cDNA libraries were constructed from pepper leaves by transcriptome sequencing. There were 8776 differentially expressed genes (DEGs), including 4473 (51.0%) upregulated and 4303 (49.0%) downregulated genes. Gene ontology pathway annotation showed that based on LT, the DEGs of SL_LT and Tis_LT were significantly enriched in the cellular component, which is mainly related to the photosystem and thylakoids. Further analysis of the porphyrin and chlorophyll biosynthesis, carotenoid biosynthesis, photosynthesis-antenna protein, and photosynthetic metabolic pathways and the Calvin cycle under low-temperature stress highlighted 18, 15, 21, 29, and 31 DEGs for further study, which were almost all highly expressed under SL_LT treatment and moderately expressed under LT treatment, whereas Tis_LT showed low expression. CONCLUSION: The positive regulatory effect of SLs on the low-temperature tolerance of pepper seedlings was confirmed. This study provided new insights for the development of temperature-tolerant pepper lines through breeding programs.
Assuntos
Capsicum , Temperatura Baixa , Lactonas , Fotossíntese , Plântula , Capsicum/fisiologia , Capsicum/genética , Capsicum/efeitos dos fármacos , Lactonas/metabolismo , Plântula/efeitos dos fármacos , Plântula/fisiologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Fotossíntese/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Resposta ao Choque Frio/fisiologia , Resposta ao Choque Frio/efeitos dos fármacos , Clorofila/metabolismo , Estresse Fisiológico , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologiaRESUMO
The growth and yield of rapeseed are significantly hampered by salt stress. Indole-3-butyric Acid Potassium Salt (IBA-K) has been found to alleviate the impact of salt stress on plant growth. However, the regulatory effect of IBA-K dipping on salt-stressed rapeseed remains unclear. To explore the implications of IBA-K on the growth and development of rapeseed during the seedling stage, we conducted potting experiments using the Huayouza 62 variety. Five different concentrations of IBA-K for seed soaking (0, 10, 20, 40, 80 mg·L- 1) were tested. The promotional impact of IBA-K on rapeseed demonstrated an initial increase followed by a decline, reaching a peak at 20 mg·L- 1. Therefore, 20 mg·L- 1 was determined as the optimal concentration for subsequent experiments. To further understand the mechanism of IBA-K's action on salt-stressed rapeseed seedlings, we utilized the moderately salt-resistant cabbage rapeseed variety Huayouza 158R and the highly salt-resistant Huayouza 62 as specimens. The investigation focused on their response and repair mechanisms under 150 mmol·L- 1 NaCl stress. The findings demonstrated that compared with the sole NaCl stress, the 20 mg·L- 1 IBA-K seed soaking treatment under salt stress significantly enhanced the plant height, stem diameter, and leaf area of both rapeseed varieties. It also led to greater biomass accumulation, increased chlorophyll content, and improved photosynthetic efficiency in rapeseed. Furthermore, this treatment bolstered the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while significantly reducing the levels of electrolyte leakage (EL) and malondialdehyde (MDA). Consequently, it alleviated the membrane lipid peroxidation damage induced by NaCl stress, enhanced the accumulation of soluble proteins, maintained cellular osmotic pressure, and effectively mitigated the adverse effects of NaCl stress on rapeseed.
Assuntos
Brassica napus , Indóis , Estresse Salino , Plântula , Sementes , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Brassica napus/efeitos dos fármacos , Brassica napus/crescimento & desenvolvimento , Brassica napus/fisiologia , Indóis/farmacologia , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Estresse Salino/efeitos dos fármacos , Clorofila/metabolismo , Antioxidantes/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Tolerância ao Sal/efeitos dos fármacosRESUMO
The synthetic auxin 2,4-D and the 4-hydroxyphenylpyruvate dioxygenase inhibitor pyrasulfotole are phloem-mobile post-emergence herbicides, the latter applied in co-formulation with either bromoxynil (a contact herbicide causing leaf desiccation) or MCPA (another synthetic auxin). Previous studies have shown a wide range of 2,4-D translocation phenotypes in resistant populations of the agricultural weed Raphanus raphanistrum, but it was hypothesised that enhanced movement out of the apical meristem could contribute to resistance. Little is known about pyrasulfotole translocation or the effect of bromoxynil on pyrasulfotole movement. Therefore, the behaviour of pyrasulfotole and 2,4-D applied to the growing point of susceptible and resistant R. raphanistrum seedlings was assessed, along with the effect of bromoxynil on pyrasulfotole translocation. The small amount of herbicide directly contacting the growing point after spraying was sufficient to induce herbicide symptoms, and there was no enhancement of translocation away from the growing point in either pyrasulfotole- or 2,4-D-resistant populations. Bromoxynil had a slightly inhibitory effect on pyrasulfotole translocation in some populations, somewhat negating the minor differences observed among populations when pyrasulfotole was applied alone. Resistance to pyrasulfotole could not explained by enhanced metabolism or vacuolar sequestration of the herbicide. Overall, differential translocation in either the treated leaves or apical meristems does not appear to be a major determinant of resistance to pyrasulfotole or 2,4-D.
Assuntos
Ácido 2,4-Diclorofenoxiacético , Resistência a Herbicidas , Herbicidas , Raphanus , Herbicidas/farmacologia , Ácido 2,4-Diclorofenoxiacético/farmacologia , Raphanus/efeitos dos fármacos , Raphanus/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Pironas/farmacologia , Transporte Biológico , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacologia , Isoxazóis , Nitrilas , SulfonasRESUMO
Glyphosate (GLY), the most widely used herbicide, has been regarded as an emergent environmental contaminant due to its constant and cumulative use, with potential harm to non-target organisms, such as crops, disrupting cells' redox balance. Therefore, plants need to fine-tune their antioxidant (AOX) mechanisms to thrive under GLY-contaminated environments. Proline overaccumulation is a common response in plants exposed to GLY, yet its role in GLY-induced toxicity remains unclear. Thus, this study explores whether Pro overaccumulation in response to GLY is perceived as a downstream tolerance mechanism or an early-warning stress signal. To investigate this, Arabidopsis thaliana T-DNA mutant lines for Pro biosynthetic (P5CS1) and catabolic genes (ProDH) were used and screened for their GLY susceptibility. Upon seedlings' exposure to GLY (0.75 mg L-1) for 14 days, the herbicide led to reduced biomass in all genotypes, accompanied by Pro overaccumulation. Mutants with heightened Pro levels (prodh) exhibited the greatest biomass reduction, increased lipid peroxidation (LP), and hydrogen peroxide (H2O2) levels, accompanied by a compromised performance of the AOX system. Conversely, p5cs1-4, mutants with lower Pro levels, demonstrated an enhanced AOX system activation, not only with increased levels of glutathione (GSH) and ascorbate (AsA), but also with increased activity of both ascorbate peroxidase (APX) and catalase (CAT). These findings suggest that Pro overaccumulation under GLY exposure is associated with stress sensitivity rather than tolerance, highlighting its potential as an early-warning signal for GLY toxicity in non-target plants and for detecting weed resistance.
Assuntos
Arabidopsis , Glicina , Glifosato , Herbicidas , Prolina , Glicina/análogos & derivados , Glicina/farmacologia , Glicina/toxicidade , Prolina/metabolismo , Arabidopsis/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Herbicidas/toxicidade , Herbicidas/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Antioxidantes/metabolismo , Peróxido de Hidrogênio/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/fisiologia , Plântula/metabolismoRESUMO
Rice grown in cadmium (Cd)-contaminated soil, is a potential threat to human health, but exogenous selenium (Se) application on rice can mitigate Cd toxicity. However, the mechanisms underlying Se mitigation of Cd stress in ratoon rice (RR) are still poorly understood. We conducted a pot experiment with moderate Cd-contaminated yellow-brown paddy soil on two rice varieties 'Taoyouxiangzhan' (TX) and 'Liangyou 6326'(LY). For all treatments, 1.0 mg kg-1 sodium selenite solution was added to soil. Treatment T1 was sodium selenite only, and in the other treatments 100 mg L-1 Se solution was sprayed on the leaves at seedling stage (T2), at tillering stage (T3), and in early anthesis stage (T4). Se treatments decreased Cd accumulation in rice grains and herbage. Under foliar spraying 100 mg L-1 Se at the seedling + 1.0 mg kg-1 Se in soil (T2), leaf Cd content decreased 16.95% in the current season and grains content decreased 46.67% in the subsequent season. Furthermore, grain Se content increased 0.94 mg kg-1 for the TX variety combined with the analysis of Cd bio-accumulation factor in grains, and Se treatments effectively decreased Cd grain concentrations due to reduced Cd translocation from roots to grains. TX variety rice showed a more pronounced response to Se treatments than LY.
Assuntos
Cádmio , Oryza , Selênio , Poluentes do Solo , Oryza/metabolismo , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Cádmio/metabolismo , Cádmio/toxicidade , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade , Selênio/metabolismo , Selênio/farmacologia , Folhas de Planta/metabolismo , Folhas de Planta/efeitos dos fármacos , Solo/química , Plântula/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimentoRESUMO
Although graphene oxide (GO) has extensive recognized application prospects in slow-release fertilizer, plant pest control, and plant growth regulation, the incorporation of GO into nano herbicides is still in its early stages of development. This study selected a pair of sweet corn sister lines, nicosulfuron (NIF)-resistant HK301 and NIF-sensitive HK320, and sprayed them both with 80 mg kg-1 of GO-NIF, with clean water as a control, to study the effect of GO-NIF on sweet corn seedling growth, photosynthesis, chlorophyll fluorescence, and antioxidant system enzyme activity. Compared to spraying water and GO alone, spraying GO-NIF was able to effectively reduce the toxic effect of NIF on sweet corn seedlings. Compared with NIF treatment, 10 days after of spraying GO-NIF, the net photosynthetic rate (A), stomatal conductance (Gs), transpiration rate (E), photosystem II photochemical maximum quantum yield (Fv/Fm), photochemical quenching coefficient (qP), and photosynthetic electron transfer rate (ETR) of GO-NIF treatment were significantly increased by 328.31%, 132.44%, 574.39%, 73.53%, 152.41%, and 140.72%, respectively, compared to HK320. Compared to the imbalance of redox reactions continuously induced by NIF in HK320, GO-NIF effectively alleviated the observed oxidative pressure. Furthermore, compared to NIF treatment alone, GO-NIF treatment effectively increased the activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in both lines, indicating GO induced resistance to the damage caused by NIF to sweet corn seedlings. This study will provides an empirical basis for understanding the detoxification promoting effect of GO in NIF and analyzing the mechanism of GO induced allogeneic detoxification in cells.
Assuntos
Antioxidantes , Clorofila , Grafite , Herbicidas , Fotossíntese , Compostos de Sulfonilureia , Zea mays , Fotossíntese/efeitos dos fármacos , Clorofila/metabolismo , Zea mays/efeitos dos fármacos , Zea mays/metabolismo , Zea mays/crescimento & desenvolvimento , Compostos de Sulfonilureia/farmacologia , Compostos de Sulfonilureia/toxicidade , Antioxidantes/metabolismo , Grafite/toxicidade , Herbicidas/toxicidade , Herbicidas/farmacologia , Piridinas/farmacologia , Fluorescência , Superóxido Dismutase/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismoRESUMO
Plant growth regulators are cost-effective and efficient methods for enhancing plant defenses under stress conditions. This study investigates the ability of two plant growth-regulating substances, thiourea (TU) and arginine (Arg), to mitigate salinity stress in wheat. The results show that both TU and Arg, particularly when used together, modify plant growth under salinity stress. Their application significantly increases the activities of antioxidant enzymes while decreasing the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and relative electrolyte leakage (REL) in wheat seedlings. Additionally, these treatments significantly reduce the concentrations of Na+ and Ca2+ and the Na+/K+ ratio, while significantly increasing K+ levels, thereby preserving ionic osmotic balance. Importantly, TU and Arg markedly enhance the chlorophyll content, net photosynthetic rate, and gas exchange rate in wheat seedlings under salinity stress. The use of TU and Arg, either individually or in combination, results in a 9.03-47.45% increase in dry matter accumulation, with the maximum increase observed when both are used together. Overall, this study highlights that maintaining redox homeostasis and ionic balance are crucial for enhancing plant tolerance to salinity stress. Furthermore, TU and Arg are recommended as potential plant growth regulators to boost wheat productivity under such conditions, especially when applied together.
Assuntos
Arginina , Homeostase , Oxirredução , Estresse Salino , Plântula , Tioureia , Triticum , Triticum/metabolismo , Triticum/efeitos dos fármacos , Triticum/crescimento & desenvolvimento , Tioureia/farmacologia , Tioureia/análogos & derivados , Arginina/metabolismo , Plântula/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Antioxidantes/metabolismo , Malondialdeído/metabolismo , Fotossíntese/efeitos dos fármacos , Clorofila/metabolismo , Reguladores de Crescimento de Plantas/metabolismoRESUMO
Chromium, being among the most toxic heavy metals, continues to demand immediate attention in the remediation of Cr-contaminated environments. In this study, a strain of LBA36 (Bacillus toyonensis) was isolated from heavy metal contaminated soil in Luanchuan County, Luoyang City, China. The reduction and adsorption rates of LBA36 in 30 mg·L-1 Cr-containing medium were 97.95% and 8.8%, respectively. The reduction mechanism was confirmed by Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). Cr(VI) reduction by this strain predominantly occurred outside the cell, with hydroxyl, amide, carboxyl, C-N group, carbonyl, and sulfur carbonyl as the main reaction sites. XPS analysis revealed the presence of Cr2p1/2 and Cr2p3/2. Furthermore, the hydroponic experiment showed that the fresh weight and plant height of radish seedlings increased by 87.87% and 37.07%, respectively, after inoculation with LBA36 strain under 7 mg·L-1 Cr(VI) stress. The levels of chlorophyll, total protein, malondialdehyde, superoxide dismutase and catalase were also affected to different degrees. In conclusion, this study demonstrated the potential of microbial and phytoremediation in the treatment of heavy metal toxicity, and laid the foundation for the development of effective bioremediation methods for Cr(VI) pollution.
Assuntos
Bacillus , Biodegradação Ambiental , Cromo , Raphanus , Plântula , Poluentes do Solo , Cromo/metabolismo , Cromo/toxicidade , Raphanus/microbiologia , Raphanus/metabolismo , Plântula/metabolismo , Plântula/microbiologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Bacillus/metabolismo , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade , Microbiologia do Solo , ChinaRESUMO
Background: Climate change is leading to severe and long-term droughts in European forest ecosystems. can have profound effects on various physiological processes, including photosynthesis, gene expression patterns, and nutrient uptake at the developmental stage of young trees. Objectives: Our study aimed to test the hypothesis that the application of silica (SiO2) influences photosynthetic efficiency and gene expression in 1- to 2-year-old Fagus sylvatica (L.) seedlings. Additionally, we aimed to assess whether silicon application positively influences the structural properties of leaves and roots. To determine whether the plant physiological responses are genotype-specific, seedlings of four geographically different provenances were subjected to a one-year evaluation under greenhouse conditions. Methods: We used the Kruskal-Wallis test followed by Wilcoxon's test to evaluate the differences in silicon content and ANOVA followed by Tukey's test to evaluate the physiological responses of seedlings depending on treatment and provenance. Results: Our results showed a significantly higher Si content in the roots compared with the leaves, regardless of provenance and treatment. The most significant differences in photosynthetic performance were found in trees exposed to Si treatment, but the physiological responses were generally nuanced and provenance-dependent. Expression of hsp70 and hsp90 was also increased in leaf tissues of all provenances. These results provide practical insights that Si can improve the overall health and resilience of beech seedlings in nursery and forest ecosystems, with possible differences in the beneficial role of silicon application arising from the large differences in wild populations of forest tree species.
Assuntos
Secas , Fagus , Regulação da Expressão Gênica de Plantas , Fotossíntese , Plântula , Silício , Fagus/genética , Fagus/efeitos dos fármacos , Fagus/metabolismo , Fotossíntese/efeitos dos fármacos , Fotossíntese/genética , Plântula/genética , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Silício/farmacologia , Silício/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismoRESUMO
Pyraclostrobin-based fungicides play an effective role in controlling fungal diseases and are extensively used in agriculture. However, there is concern regarding the potential adverse effects attributed to exposure to these fungicides on non-target organisms and consequent influence exerted on ecosystem functioning. Thus, it is essential to conduct studies with model organisms to determine the impacts of these fungicides on different groups of living organisms. The aim of this study was to examine the ecotoxicity associated with exposure to commercial fungicides containing pyraclostrobin. The focus of the analysis involved germination and initial development of seedlings of 4 plant models (Lactuca sativa, Raphanus sativus, Pennisetum glaucum and Triticum aestivum), in addition to determining the population growth rate and total carbohydrate content in microalga Raphidocelis subcapitata. The fungicide pyraclostrobin adversely influenced growth and development of the tested plants, indicating a toxic effect. The fungicide exerted a significant impact on the initial development of seedlings of all model species examined with T. aestivum plants displaying the greatest susceptibility to pyraclostrobin. Plants of this species exhibited inhibitory effects on both aerial parts and roots when treated with a concentration of 4.75 mg/L pyraclostrobin. In addition, the green microalga R. subcapitata was also significantly affected by the fungicide, especially at relatively high concentrations as evidenced by a reduction in total carbohydrate content. This commercial fungicide demonstrated potential phytotoxicity for the tested plant models and was also considered toxic to the selected microalgae, indicating an ecotoxic effect that might affect other organisms in aquatic environments.
Assuntos
Fungicidas Industriais , Microalgas , Estrobilurinas , Fungicidas Industriais/toxicidade , Estrobilurinas/toxicidade , Microalgas/efeitos dos fármacos , Carbamatos/toxicidade , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Pirazóis/toxicidade , Plantas/efeitos dos fármacos , Clorófitas/efeitos dos fármacos , Clorófitas/crescimento & desenvolvimentoRESUMO
Maize (Zea mays L.) is sensitive to salt stress, especially during seed germination and seedling morphogenesis, which limits maize growth and productivity formation. As a novel recognized plant hormone, melatonin (MT) participates in multiple growth and developmental processes and mediates biotic/abiotic stress responses, yet the effects of salt stress on maize seedlings remain unclear. Herein, we investigated the effects of 150 µM exogenous MT on multiple phenotypes and physiologic metabolisms in three-leaf seedlings across eight maize inbred lines under 180 mM NaCl salt stress, including growth parameters, stomatal morphology, photosynthetic metabolisms, antioxidant enzyme activities, and reactive oxygen species (ROS). Meanwhile, the six gene expression levels controlling antioxidant enzyme activities and photosynthetic pigment biosynthesis in two materials with contrasting salt resistance were examined for all treatments to explore the possible molecular mechanism of exogenous MT alleviating salt injury in maize. The results showed that 150 µM exogenous MT application protected membrane integrity and reduced ROS accumulation by activating the antioxidant system in leaves of maize seedlings under salt stress, their relative conductivity and H2O2 level average reduced by 20.91% and 17.22%, while the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) averaged increased by 13.90%, 17.02%, 22.00%, and 14.24% relative to salt stress alone. The improvement of stomatal size and the deposition of photosynthetic pigments were more favorable to enhancing photosynthesis in leaves when these seedlings treated with MT application under salt stress, their stomatal size, chlorophyll content, and net photosynthetic rate averaged increased by 11.60%, 19.64%, and 27.62%. Additionally, Gene expression analysis showed that MT stimulation significantly increased the expression of antioxidant enzyme genes (Zm00001d009990, Zm00001d047479, Zm00001d014848, and Zm00001d007234) and photosynthetic pigment biosynthesis genes (Zm00001d011819 and Zm00001d017766) under salt stress. At the same time, 150 µM MT significantly promoted seedling growth and biomass accumulation. In conclusion, our study may unravel crucial evidence of the role of MT in maize seedlings against salt stress, which can provide a novel strategy for improving maize salt stress resistance.
Assuntos
Antioxidantes , Melatonina , Fotossíntese , Estômatos de Plantas , Espécies Reativas de Oxigênio , Estresse Salino , Plântula , Zea mays , Zea mays/efeitos dos fármacos , Zea mays/metabolismo , Zea mays/crescimento & desenvolvimento , Melatonina/farmacologia , Melatonina/metabolismo , Fotossíntese/efeitos dos fármacos , Antioxidantes/metabolismo , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/metabolismo , Plântula/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Folhas de Planta/metabolismo , Folhas de Planta/efeitos dos fármacosRESUMO
Ascorbic acid (AsA), an essential non-enzymatic antioxidant in plants, regulates development growth and responses to abiotic and biotic stresses. However, research on AsA's role in cold tolerance remains largely unknown. Here, our study uncovered the positive role of AsA in improving cold stress tolerance in tomato seedlings. Physiological analysis showed that AsA significantly enhanced the enzyme activity of the antioxidant defense system in tomato seedling leaves and increased the contents of proline, sugar, abscisic acid (ABA), and endogenous AsA. In addition, we found that AsA is able to protect the photosynthetic system of tomato seedlings, thereby relieving the declining rate of chlorophyll fluorescence parameters. qRT-PCR analysis indicated that AsA significantly increased the expression of genes encoding antioxidant enzymes and involved in AsA synthesis, ABA biosynthesis/signal transduction, and low-temperature responses in tomato. In conclusion, the application of exogenous AsA enhances cold stress tolerance in tomato seedlings through various molecular and physiological responses. This provides a theoretical foundation for exploring the regulatory mechanisms underlying cold tolerance in tomato and offers practical guidance for enhancing cold tolerance in tomato cultivation.
Assuntos
Ácido Ascórbico , Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Plântula , Solanum lycopersicum , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/fisiologia , Ácido Ascórbico/metabolismo , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Temperatura Baixa , Antioxidantes/metabolismo , Clorofila/metabolismo , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genéticaRESUMO
Enhancement of plant growth at early growth stages is usually associated with the stimulation of various metabolic activities, which is reflected on morphological features and yield quantity and quality. Vitamins is considered as anatural plant metabolites which makes it a safe and ecofriendly treatment when used in appropriate doses, for that this research aimed to study the effect of two different vitamin B forms (thiamine and pyridoxine) on Vicia faba plants as agrowth stimutator in addition to study it's effect on plant as astrong antioxidant under salinity stress.Our findings demonstrated that both vitamin forms significantly increased seedling growth at germination and early growth stages, especially at 50 ppm for pyridoxine and 100 ppm for thiamine. Pyridoxine at 50 ppm increased seedling length by approximately 35% compared to control, while thiamine at 100 ppm significantly promoted seedling fresh and dry wt by 4.36 and 1.36 g, respectively, compared to control seedling fresh wt 2.17 g and dry weight 1.07 g. Irrigation with 100 mM NaCl had a negative impact on plant growth and processes as well as the uptake of several critical ions, such as K+ and Mg+2, increasing Na uptake in comparison to that in control plants. Compared to control plants irrigated with NaCl solution, the photosynthetic pigments, soluble sugars, soluble proteins, and total antioxidant capacity increased in the presence of pyridoxine and thiamine, both at 50 and 100 ppm salinity. The proline content increased in both treated and untreated plants subjected to salt stress compared to that in control plants. Thiamine, especially at 50 ppm, was more effective than pyridoxine at improving plant health under saline conditions. An increase in Vicia faba plant tolerance to salinity was established by enhancing antioxidant capacity via foliar application of vitamin B through direct and indirect scavenging methods, which protect cell macromolecules from damage by oxidative stress, the highest antioxidant capacity value 28.14% was recorded at 50 ppm thiamine under salinity stress.The provided results is aguide for more researches in plant physiology and molecular biology to explain plant response to vitamins application and the suggest the sequence by which vitamins work inside plant cell.
Assuntos
Antioxidantes , Piridoxina , Estresse Salino , Tolerância ao Sal , Plântula , Tiamina , Vicia faba , Vicia faba/efeitos dos fármacos , Vicia faba/crescimento & desenvolvimento , Vicia faba/metabolismo , Piridoxina/farmacologia , Piridoxina/metabolismo , Tiamina/metabolismo , Estresse Salino/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Tolerância ao Sal/efeitos dos fármacos , Antioxidantes/metabolismo , Fotossíntese/efeitos dos fármacos , Salinidade , Germinação/efeitos dos fármacos , Vitaminas/farmacologiaRESUMO
Insecticides and fungicides present potential threats to non-target crops, yet our comprehension of their combined phytotoxicity to plants is limited. Silicon (Si) has been acknowledged for its ability to induce crop tolerance to xenobiotic stresses. However, the specific role of Si in alleviating the cypermethrin (CYP) and hymexazol (HML) combined stress has not been thoroughly explored. This study aims to assess the effectiveness of Si in alleviating phytotoxic effects and elucidating the associated mechanisms of CYP and/or HML in tomato seedlings. The findings demonstrated that, compared to exposure to CYP or HML alone, the simultaneous exposure of CYP and HML significantly impeded seedling growth, resulting in more pronounced phytotoxic effects in tomato seedlings. Additionally, CYP and/or HML exposures diminished the content of photosynthetic pigments and induced oxidative stress in tomato seedlings. Pesticide exposure heightened the activity of both antioxidant and detoxification enzymes, increased proline and phenolic accumulation, and reduced thiols and ascorbate content in tomato seedlings. Applying Si (1 mM) to CYP- and/or HML-stressed seedlings alleviated pigment inhibition and oxidative damage by enhancing the activity of the pesticide metabolism system and secondary metabolism enzymes. Furthermore, Si stimulated the phenylpropanoid pathway by boosting phenylalanine ammonia-lyase activity, as confirmed by the increased total phenolic content. Interestingly, the application of Si enhanced the thiols profile, emphasizing its crucial role in pesticide detoxification in plants. In conclusion, these results suggest that externally applying Si significantly alleviates the physio-biochemical level in tomato seedlings exposed to a combination of pesticides, introducing innovative strategies for fostering a sustainable agroecosystem.
Assuntos
Piretrinas , Plântula , Silício , Solanum lycopersicum , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Piretrinas/toxicidade , Silício/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Antioxidantes/metabolismo , Inseticidas/toxicidadeRESUMO
Plants are an important source for the discovery of novel natural growth regulators. We used activity screening to demonstrate that treatment of Nipponbare seeds with 25 µg/mL isopimaric acid significantly increased the resulting shoot length, root length, and shoot weight of rice seedlings by 11.37 ± 5.05%, 12.96 ± 7.63%, and 27.98 ± 10.88% and that it has a higher activity than Gibberellin A3 (GA3) at the same concentration. A total of 213 inbred lines of different rice lineages were screened, and we found that isopimaric acid had different growth promotional activities on rice seedlings of different varieties. After induction with 25 µg/mL isopimaric acid, 15.02% of the rice varieties tested showed increased growth, while 15.96% of the varieties showed decreased growth; the growth of the remaining 69.02% did not show any significant change from the control. In the rice varieties showing an increase in growth, the shoot length and shoot weight significantly increased, accounting for 21.88% and 31.25%. The root length and weight significantly increased, accounting for 6.25% and 3.13%. Using genome-wide association studies (GWASs), linkage disequilibrium block, and gene haplotype significance analysis, we identified single nucleotide polymorphism (SNP) signals that were significantly associated with the length and weight of shoots on chromosomes 2 and 8, respectively. After that, we obtained 17 candidate genes related to the length of shoots and 4 candidate genes related to the weight of shoots. Finally, from the gene annotation data and gene tissue-specific expression; two genes related to this isopimaric acid regulation phenotype were identified as OsASC1 (LOC_Os02g37080) on chromosome 2 and OsBUD13 (LOC_Os08g08080) on chromosome 8. Subcellular localization analysis indicated that OsASC1 was expressed in the plasma membrane and the nuclear membrane, while OsBUD13 was expressed in the nucleus. Further RT-qPCR analysis showed that the relative expression levels of the resistance gene OsASC1 and the antibody protein gene OsBUD13 decreased significantly following treatment with 25 µg/mL isopimaric acid. These results suggest that isopimaric acid may inhibit defense pathways in order to promote the growth of rice seedlings.
Assuntos
Abietanos , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Oryza , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/efeitos dos fármacos , Oryza/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Polimorfismo de Nucleotídeo Único , Plântula/crescimento & desenvolvimento , Plântula/genética , Plântula/efeitos dos fármacos , Locos de Características Quantitativas , Reguladores de Crescimento de Plantas/farmacologia , Reguladores de Crescimento de Plantas/metabolismoRESUMO
Low-temperature (LT) is one of the major abiotic stresses that restrict the growth and development of maize seedlings. Brassinolides (BRs) have been shown to enhance LT tolerance in several plant species; the physiological and molecular mechanisms by which BRs enhance maize tolerance are still unclear. Here, we characterized changes in the physiology and transcriptome of N192 and Ji853 seedlings at the three-leaf stage with or without 2 µM 2,4-epibrassinolide (EBR) application at 25 and 15 °C environments via high-performance liquid chromatography and RNA-Sequencing. Physiological analyses revealed that EBR increased the antioxidant enzyme activities, enhanced the cell membrane stability, decreased the malondialdehyde formation, and inhibited the reactive oxygen species (ROS) accumulation in maize seedlings under 15 °C stress; meanwhile, EBR also maintained hormone balance by increasing indole-3-acetic acid and gibberellin 3 contents and decreasing the abscisic acid level under stress. Transcriptome analysis revealed 332 differentially expressed genes (DEGs) enriched in ROS homeostasis, plant hormone signal transduction, and the mitogen-activated protein kinase (MAPK) cascade. These DEGs exhibited synergistic and antagonistic interactions, forming a complex LT tolerance network in maize. Additionally, weighted gene co-expression network analysis (WGCNA) revealed that 109 hub genes involved in LT stress regulation pathways were discovered from the four modules with the highest correlation with target traits. In conclusion, our findings provide new insights into the molecular mechanisms of exogenous BRs in enhancing LT tolerance of maize at the seedling stage, thus opening up possibilities for a breeding program of maize tolerance to LT stress.