Acta Physiologiae Plantarum最新文献

Nonstructural carbohydrates and antioxidants affect the yield of any plant. In this study, changes in nonstructural carbohydrates and antioxidant metabolism in leaf and spike, as well as their effects on grain yield, were examined in relation to elevated CO₂ and nitrogen supply. For this, a wheat (Triticum aestivum) was grown at two levels of CO₂, i.e., ambient 400 ppm (T1) and elevated 800 ppm (T2), with two levels of nitrogen supply, i.e., 0 gN (N1) and 1 gN (N2). In the sink, elevated CO₂ and nitrogen caused a several-fold increase in glucose content. Fructose showed an increase of 53% and 60% in N₂ treatment under both carbon levels. At the same time, sucrose content decreased by 112% and 100% with an increase in nitrogen doses under 400 ppm and 800 ppm. Higher N decreased the superoxide dismutase activity at ambient CO₂, while higher N at elevated carbon levels increased the superoxide dismutase activity. Elevated CO₂ decreased the catalase activity, while the peroxidases activity increased. In the spike, catalase activity increased at a higher N level. Grain yield was significantly enhanced at elevated CO₂. The correlation analysis showed that catalase has a strong positive correlation with grain yield. The changes in nonstructural carbohydrates and antioxidant enzyme activities are associated with the altered leaf-spike relationship under N availability at high CO₂ levels, which could be a key factor contributing to variable yield. Differential response of nonstructural carbohydrates and antioxidant enzymes in leaf and spike is responsible for changes in grain yield.

Industrialization has accelerated the rate of heavy metal discharge into the environment and among trace metals, cadmium (Cd) gains attention due to its relative mobility from soil to plant and potential toxicity to humans. Phytoremediation is a plant-based, cost-effective approach to remediate the contaminated soil and water, and an attempt has been made in the present study to explore the potential of an invasive plant Alternanthera tenella for Cd removal. The physiological and morpho-anatomical modifications of plant tissues including the elemental allocation pattern and bioaccumulation potential were studied in response to 170 µM of Cd(NO₃)₂. Cd negatively affects the growth parameters, biomass, and photosynthetic efficacy of the plant. Cd treatment influenced the distribution of macro and microelements in the plant and the structural moieties in the biomolecules on the interaction of metal ions. Anatomical modifications included the alterations in the diameter and thickness of cell walls, especially xylem walls, the presence of cell structural distortions and blockage, and fully opened stomata with thick guard cells and depositions. Metabolites like proline, flavonoids, phenol, and malondialdehyde marked a significant increase in stress tolerance. Despite having a relatively low transfer factor (TF), A. tenella exhibits high values of biological concentration factor (BCF) and biological accumulation factor (BAF), suggesting its suitability for phytostabilization of Cd-contaminated environments.

The present study was designed to functionally characterize the promoters associated with AtMYB42, AtMYB85, and BjuMYB85. These genes are well known to be involved in lignin synthesis via phenylpropanoids, which are crucial for secondary cell wall development. We previously reported the complete absence of homologs of MYB42 from Brassica species. Inspite of their known role in secondary cell wall development, detailed knowledge about cis-element and transcriptional regulation of AtMYB42, AtMYB85 and BjMYB85 (BjuA013029) is lacking. It is therefore crucial investigating the transcriptional regulation of AtMYB42, AtMYB85, and BjMYB85 (BjuA013029), analyze functional and regulatory conservation and divergence and address whether BjMYB85 potentially compensates for the absence of MYB42 homologs in Brassica. In silico analysis revealed differences in the promoter sequences but shared transcription factor-binding sites and motifs, suggesting a common cis-regulatory pathway. Functional characterization using transcriptional fusion constructs revealed tissue-specific expression patterns not only in the stem, as has been reported earlier, but also in anther walls and siliques where lignin deposition plays an important role in dehiscence. Hormone and stress responsiveness of these promoters were assessed in seedlings. The AtMYB42 promoter displayed greater responsiveness to ethylene, cytokinin, and salicylic acid compared to AtMYB85 and BjuA013029MYB85. Expression was observed in various tissues, including seedlings, anthers, and silique and leaf midribs. This study provides novel insights into the expression patterns of these promoters, shedding light on their roles in non-stem tissues and contributing to our understanding of secondary cell wall formation.

Peanut stem rot disease, caused by the necrotrophic soil-borne fungus Sclerotium rolfsii, has a significant negative impact on crop yields. Chemical fungicides can mitigate the loss incurred by fungus, however, their usage raises environmental and human health concern. Seaweeds extracts are getting importance as bio-stimulant for improving growth and disease resistance in different plants. In the present study, we investigated the potential of Sargassum tenerrimum extract (S-extract) in controlling stem rot disease in peanuts. The foliar application of S-extract was applied at vegetative and reproductive stages on peanut plants to study plant growth and reduction of S. rolfsii-induced disease. Plant height, number of branches and branch length increased in S-extract treated plants (S) as compared to S-extract + S. rolfsii treated plants (S + F). Similarly, the activity of anti-oxidative enzymes such as catalase (CAT), guaiacol peroxidase (GPOX), polyphenol oxidase (PPO), and superoxide dismutase (SOD) increased by application of S-extract. Pigments such as chlorophyll a, chlorophyll b, and carotenoids showed higher accumulation in S-extract treated plants. The increased membrane stability index and reduced electrolyte leakage in S and S + F plants, positively affected the health and biotic stress tolerance of the plants. S-extract reduced the reactive oxygen species (ROS) such as O₂^•− and H₂O₂. Total phenol, soluble sugars and total amino acid accumulation were higher in S and S + F plants compared to C and F at vegetative stage. The mitigation of disease can be attributed to the application of S-extract leading to the elevated activity of antioxidant enzymes and the accumulation of non-enzymatic antioxidants, osmolytes, and pigments. Therefore, S-extract represents an environmentally friendly resource that can be employed in sustainable agriculture practices to boost plant growth and enhance disease tolerance.

Water deficit significantly affects the growth and survival of young plants following transplantation. We performed morphophysiological and biochemical analyses on young yellow passion fruit (Passiflora edulis Sims) plants under well-watered and water-deficit irrigation regimes and pre-treated with three plant growth regulators (PGRs) application—an agrochemical composed of auxins, gibberellins, and cytokinins; salicylic acid (SA); and sodium nitroprusside (SNP), a nitric oxide donor—and a control group with no PGRs. Results showed significant damage by water restriction on biometric attributes; however, the application of PGRs mitigated these effects, reducing growth inhibition processes. In terms of water stress mitigation, differences were observed between PGRs, depending on the morphophysiological or biochemical characteristic. The effectiveness of SNP was higher than the other PGRs in preventing stomatal conductance reduction and maintaining CO₂ assimilation, while the agrochemical was the most effective in preventing photosynthetic pigments content decrease. All PGRs promoted osmoregulation in plants subjected to water deficit, thus helping to preserve cell turgor. Furthermore, PGRs application attenuated oxidative stress, either by increasing antioxidant enzymes activity, or by preventing or decreasing the content of thiobarbituric acid-reactive substances, thus preventing lipid peroxidation. These findings suggest that the application of PGRs can be a useful strategy to improve young passion fruit plants tolerance to water restriction following transplantation. The multiple beneficial effects do not allow us to indicate the only one most effective PGR; however, a chemical constituents-related principal component analysis suggests that the agrochemical and SA are the most effective PGRs on mitigating water deficit stress.

Biochar and nanoparticles (NPs) are potential strategies for increasing plant yield and minimizing the negative effects of toxic metals on sweet basil (Ocimum basilicum L). The current study aims to reduce the access of toxic elements to the oil extracted from basil plants growing in polluted soils by biochar and NPS of silicon (Si) and boron (B). Sweet basil plants were grown in contaminated soil that contained cadmium (Cd) and lead (Pb) at concentrations of 58 and 800 mg kg⁻¹, respectively. The experiment included two doses of biochar (0 and 1%, w/w) and four foliar combinations of Si and B nanoparticles at the dose of 100 mg L⁻¹ of Si and/or B. Cd and Pb availability were reduced by 44 and 48%, respectively, compared to the control. The soil pH raised significantly (p < 0.05) as a result of biochar addition. Furthermore, biochar addition at the dose of 1%, (w/w) caused a 14% increase in the soil organic matter. The highest growth parameters of basil plants were obtained from the biochar treatment with Si + B NPs foliar application. The treatment that was amended with biochar and sprayed with Si + B showed the greatest significant values of nitrogen (N), phosphorus (P), potassium (K), and calcium (Ca) content in basil plants. The chlorophyll content of basil leaves rose along with the synthesis of proline and soluble carbohydrates after the addition of biochar to the polluted soil and Si + B spraying. Biochar minimized Cd in the leaf and oil by 48 and 49%, respectively, compared to the control, while Pb concentrations were reduced by 29 and 49%, respectively. The oil extracted from the basil plants grown in the soil amended with biochar contained 50–52 and 23–26 μg kg⁻¹ of Cd and Pb, respectively. Adding biochar to the contaminated soil increases the oil yield of sweet basil and reduces its content of toxic elements, while spraying the basil plant with silicon and boron nanoparticles increases the plant’s resistance to metal toxicity.

Boron (B) nutrition can contribute to the conservation of seed quality during storage. Thus, it is crucial to investigate which source and amount of B applied to the soil is most suitable to increase the yield and maintain the quality of germination and carbohydrate content in soybean seeds during 180 days of storage. The cultivar Bonus 8579 Ipro® was evaluated in a field experiment in a 5 × 2 factorial scheme, with five B doses: 0, 1, 2, 4 and 8 kg ha⁻¹, and two sources: boric acid and ulexite, arranged in randomized block design with three replicates. After harvest, the B content and accumulation of B in yield and seed quality were analyzed. Subsequently, the seeds were stored in a cold chamber at 17 °C and controlled relative humidity of 20% for 180 days. Soybean plants responded positively to the boric acid and ulexite with an increase in yield and seed quality up to the doses of 3.17 and 3.36 kg ha⁻¹ of B, respectively. Furthermore, both sources potentiated the carbohydrate content in the seeds over the storage time. Our findings reveal that the application from 3.2 to 4.0 kg ha⁻¹ of B using boric acid maintains high seed germination after 180 days of storage.

Nitrogen (N) deposition levels and the frequency of lead (Pb) contamination events are increasing globally. In an effort to improve our understanding of plant responses to these stressors, we investigated moss responses to single and combined Pb and N stress. Three mosses from different habitats (Syntrichia caninervis, Bryum argenteum and Plagiomnium acutum) were studied and simulated Pb/N single and complex stresses were applied to them indoors. The chlorophyll (Chl) content, osmotic adjustment substances content, and antioxidant enzyme activities were measured at 7, 14, 21, and 28 days. The results revealed that the tolerance of the three bryophyte species to Pb or N stress was in the order of P. acutum > B. argenteum > S. caninervis, which was closely related to the conditions of their respective natural habitats. S. caninervis and B. argenteum were stress tolerant for 7 days and P. acutum for 14 days. The bryophytes were tolerant to Pb or N stress after the contents of osmoregulatory substances and antioxidant enzyme activities increased; however, as toxicity accumulated over time, all three species suffered irreversible damage, as indicated by an abrupt decrease in the Chl content and osmoregulatory substances, as well as a sudden drop in antioxidant enzyme activities. Under the combined effects of Pb-N stress, the Chl content, osmoregulatory substance contents, and antioxidant enzyme activities were significantly higher in the N-loving P. acutum (N produced significant benefits) than in P. acutum exposed to Pb stress alone. This phenomenon is likely because Pb and N have antagonistic effects on the growth of P. acutum; thus, their recombination generates a counter-balancing effect. In the N-sensitive species, S. caninervis and B. argenteum (N caused obvious toxicity), the indicators were slightly better than under N tress alone (indicated by the reduction of membrane lipid peroxidation and increased osmoregulatory substance contents and enzyme activities), suggesting that there is a certain antagonistic effect exerted by the simultaneous addition of Pb and N. Therefore, the detrimental effects of a single abiotic stress (Pb or N) on bryophytes may be diminished under the combined conditions of N deposition and presence of the heavy metal, Pb.

The study investigates the dual function of chitosan/zinc oxide nanocomposites (CS/ZnO NCPs) in enhancing plant growth and mitigating zinc oxide nanoparticles (ZnO NPs) toxicity. While ZnO NPs hold promise for agriculture, concerns exist regarding their potential harm to plants and the environment. Incorporating ZnO NPs into a CS matrix to form CS/ZnO NCPs offers a solution. The metal-chelating properties of CS can regulate the release of Zn²⁺ ions from the NPs, reducing their availability to plants and mitigating potential toxicity. In the present work, the effect of ZnO NPs and CS/ZnO NCPs at two different concentrations, i.e., 100 and 200 ppm, has been tested on Sorghum bicolor plants. The ZnO NPs and CS/ZnO NCPs were chemically synthesized and characterized with various microscopic and spectroscopic techniques. Plants grown in ZnO NPs-treated soil for 30 days exhibited reduced growth, decreased chlorophyll, starch, and cellulose levels as well as nutrient (K, Mg and P) uptake. In addition, these nanoparticles increased malondialdehyde (MDA) content and the activities of antioxidant enzymes in the shoots, indicating their phytotoxicity to S. bicolor plants. Conversely, CS/ZnO NCPs application stimulated plant growth, nutrient uptake, chlorophyll and starch contents, while reducing MDA content and superoxide dismutase activity. The CS/ZnO NCPs-treated plants also accumulated 2.5–3.5 times less Zn²⁺ than ZnO NP-treated plants. Results of the study established that utilizing ZnO NPs in the form of CS/ZnO NCPs can maximize the beneficial characteristics of both nanomaterials while simultaneously limiting the toxic effects of ZnO on S. bicolor plants.

Methyl jasmonate (MeJA) is a phytohormone involved in plant defense against stress. However, its application as pretreatment in soybean seeds is limited. Here, we investigated whether seed pretreatment with MeJA mitigated the negative effects of water restriction (WR) and mechanical wounding (MW) in soybean seedlings at the V1 vegetative stage. Seeds of Glycine max (Monsoy 6410 variety) were pretreated with water or 12.5 µM MeJA for 14 h. The obtained seedlings were transferred to pots containing substrate (soil and sand) kept in a greenhouse and subjected to different growth conditions: control (no stress), WR (40% water retention), and MW. The experiment was conducted in a 2 × 3 factorial scheme (2 seed pretreatments × 3 growth conditions). The variables analyzed were ethylene levels, hydrogen peroxide, lipid peroxidation, antioxidant system enzymes, sugars, amino acids, proteins, proline, and growth (root and shoot length). WR negatively affected seedling growth, regardless of seed pretreatment, but proline levels increased with MeJA application. In seedlings subjected to MW, MeJA increased ethylene release, which was related to reduced damage. It suggests that pretreatment of soybean seeds with MeJA is a promising tool to mitigate the deleterious effects of biotic and abiotic stresses during seedling establishment, inducing distinct tolerance strategies.