Acta Physiologiae Plantarum最新文献

Cadmium (Cd), an unnecessary trace element in plants, destructively affects ecosystems. This pollutant exists everywhere in the environment, enters the plant through the soil, and causes extensive changes from the macro to the cellular level. This study investigated the effect of cadmium chloride (CdCl₂) at three concentrations of 0, 1, and 1.5 mM on morphological, biochemical, and molecular indicators in the Nicotiana tabacum plant as a significant agricultural plant and a common model organism. The results showed that an increase in CdCl₂ concentration significantly decreased plant growth and the concentration of photosynthetic pigments compared to the control plant. In contrast, the amounts of soluble sugar, free amino acids, and total phenol increased in plants under stress. In addition, the amount of nicotine and the expression of genes related to the pathway of nicotine biosynthesis increased in plants under Cd stress. The expression of NtA622, NtQPT, NtODC, and NtPMT genes at 1 mM CdCl₂ increased by 2, 1.7, 2.4, and 2.9 times, respectively, and at 1.5 mM, CdCl₂ increased by 2.9, 2.2, 2.7, and 3.8 times, respectively, compared to the control plant. Therefore, among the four studied genes, the relative expression of the NtPMT gene (the significant gene of the nicotine biosynthesis pathway) was higher. The nicotine content increased by 17.9% and 25.4% with 1- and 1.5-mM CdCl₂ compared to the control plant. Tobacco cultivation in Cd-contaminated environments should be managed and it seems that using Cd can increase the biosynthesis of nicotine for agricultural and medicinal purposes.

Agrostemma githago, a poisonous, noxious, and competitive weed species, can threaten crop yields in various agricultural regions worldwide. Experiments were performed twice to ascertain the effect of temperature, salt stress, osmotic potential, and burial depth on the germination and seedling emergence of A. githago. Seeds germinated across various temperatures ranging between 5 and 35 °C, while germination was completely inhibited at 40 °C. The optimum temperature for maximum germination percentage (GP), maximum germination rate (GR), and minimum mean germination time (MGT) ranged from 17.47 °C to 19.37 °C. The 50% reduction in GP occurred at 27 °C. The seeds of A. githago germinated over a wide range of osmotic potentials, from 0 to –1.2 MPa. However, the GP decreased with increasing osmotic potential, where at –1.2 MPa, germinability was 19%. Similarly, seeds germinated across a broad range of salinities, with a GP of 21% at 300 mM. However, no germination was observed at 350 mM. Osmotic potential and salinity concentration required to inhibit 50% of maximum GP were estimated to be −0.99 MPa and 272 mM, respectively. Thus, it is expected that A. githago can germinate in saline and arid environments. The maximum seedling emergence (99%) was observed when seeds were placed on the soil surface. In contrast, no seedling emergence was recorded when seeds were buried at depths greater than 4 cm. Accordingly, deep conventional tillage might be helpful for managing A. githago. This knowledge can be implemented for both the future research and the development of effective management for A. githago.

Herbicides are often used in modern agriculture to control weed growth. Uneducated farmers often use herbicides in excessive quantities as recommended by local shopkeepers. These excessive not only harm crops but also negatively impact the growth of non-target plants. The present research was performed to evaluate the adverse effects of low (0.5%), recommended (1%), and high (2 and 4%) atrazine herbicide concentrations on morphological, biochemical, and anatomical growth parameters of maize plants without and with moringa leaf extract. High doses of atrazine herbicide significantly reduced seed germination, shoot/root length, and fresh weight of maize plants. The biochemical results revealed that the levels of chlorophyll a, b, and carotenoids were significantly reduced, while the levels of total phenolic and 1.1-diphenyl-2-picryl-hydrazyl (DPPH) were increased in the maize seedlings. Moringa leaf extract effectively mitigated the severe effects of atrazine concentrations on maize growth traits, including morphological (e.g., shoot and root length, shoot and root fresh weight), physicochemical (e.g., photosynthetic pigment content, phenolic content, total antioxidant activity), and anatomical (e.g., area of leaf vascular bundles, phloem and collenchyma tissue, xylem diameter) parameters. These results suggested that higher doses of atrazine herbicide negatively affect maize growth, while moringa leaf extract can mitigate the toxic effects of the atrazine herbicide at high concentrations.

Plant U-box (PUB) E3 ubiquitin ligases are implicated in diverse plant growth, development, and stress responses. However, research on PUB genes in poplar remains limited. In the present work, we conducted comprehensive analysis of the U-box gene family in poplar, investigating molecular physiochemical properties, chromosomal localization, phylogenetic relationships, gene structure, gene tissue specific expression patterns, and gene expression profiles under abiotic stress. A total of 87 PUBs were identified and categorized into seven groups based on phylogenetic analysis. Analysis of gene structure and protein domain revealed that all members possess a typical U-box domain, but variations exist in gene structure and conserved motifs among different groups. Analysis of promoter and tissue specific gene expression demonstrated that PUBs are extensively associated with plant growth, development, and abiotic stress response. Expression profile analysis of seven representative PUBs revealed that they exhibited specific responses to hormone and polyethylene glycol (PEG) treatments. Together, we conducted thorough analysis of the molecular features of poplar PUB family members and their transcriptional responses to abiotic stress, laying groundwork for in-depth exploration of their regulatory role in poplar growth and stress response.

Cadmium (Cd) is a widespread and strongly toxic environmental pollutant. In this study, the interaction between Cd and essential nutritional metals, such as iron (Fe) and zinc (Zn), was investigated in banana plants (Musa spp. cultivar Grand Nain), cultured in vitro, using Fourier-transform infrared (FT-IR) and physiological analysis. Plantlets were treated in vitro with Fe and Zn (200 and 500 mg/L) under 500 mg/L Cd exposure. The results showed that Cd toxicity increased Cd uptake and raised % of damage. However, Fe and Zn addition ameliorated the negative impact of Cd stress by reducing Cd and enhancing Fe, Zn, P, and K contents. The FT-IR analysis showed alterations within the bands correlated to the foremost macromolecules in plants under Cd stress and its interactions with Fe or Zn. The peaks of some functional groups at 3381.7 cm⁻¹ for carbohydrates, proteins, alcohols, and phenolic compounds, 2922.02 cm⁻¹ for lipids, 1643.97 cm⁻¹ for amide I, 1517.46 cm⁻¹ for amide II, 1057.63 cm⁻¹ for cellulose and hemicellulose, and 616.94 cm⁻¹ for aromatic compounds were negatively shifted by Cd stress. However, Fe and Zn regulated transmittance and intensity of these bands, showing improved tolerance to Cd. Moreover, Fe and Zn modulated the total antioxidants and enzymatic antioxidant activities for catalase and ascorbate peroxidase. The study concluded that the nutrition with Fe and Zn enhanced banana tolerance against Cd toxicity. It also highlighted the powerful role of FT-IR in understanding the mechanisms involved in minimizing Cd toxicity in banana shoots under Fe and Zn.

Sinojackia xylocarpa is a rare endemic genus in China, and is endangered in their wild habitats. For endangered rare species, sexual propagation is significant for the protection of genetic diversity and restoration of wild population. Especially for S. xylocarpa, the artificially cultivated population is expanded by vegetative propagation, which could lead to a lack of diversity. The seeds of S. xylocarpa require stratification to germinate, during which the hard pericarp becomes soft, and endophytes and soil microorganisms are considered to be involved in the process. Amplicon sequencing was used to analyze the changes in microbial community structure and the role of microorganisms in pericarp degradation. Analyses of pericarp from fresh and stratified seeds of different stages revealed that the abundance of endophytic bacteria in pericarp presented an overall increasing trend during the stratification process; endophytic bacteria in stratified pericarp produce β-glucosidase to participate in the degradation of the pericarp. Soil fungal diversity analyses of different stages showed that the highest levels of the two samples of fungi function clustering is saprophytic in nutritional type; guild model also indicated that wooden saprophytic fungi abundance increased obviously; further the effect of degrading pericarp of four strains isolated from stratified pericarp are confirmed. The above results indicate that soil fungi are involved in degradation. The potential of microorganisms to break seed dormancy has been applied to endangered plants that face difficulties in germination, especially in their natural habitats.

Cassava is an important staple food for millions, but its growth is often hindered by poor soil quality and limited access to fertilizers. Efficient utilization of nutrients is essential to maximize the yield and nutritional value of cassava while minimizing resource use and environmental adverse impacts. Thus, identification of nutrient-responsive genotypes as well as genes that govern/regulate nutrient use efficiency is highly imperative to breed nutrient-efficient genotypes to enhance the productivity and resilience of cassava. In this study, we studied the performance of thirty genetically diverse cassava genotypes in the field with low availability of nitrogen (N) and insufficient exchangeable potassium (K) and identified two high N responsive genotypes, 17S36 and 15S409; two low N responsive genotypes, Kumkumrose and Export kappa; two high K responsive genotypes, Ambakkadan and Karutha malabar and two low K responsive genotypes, 17S143 and 16-5. Also, genome-wide analysis resulted in the identification of 39 N-responsive and 22 K-responsive candidate genes with diverse functional groups, including transporter, transcription factors, transferase, kinase, and permease in cassava. Meta-analysis of RNA-seq datasets of 11 cassava tissues revealed constitutive and tissue-specific expression of N-responsive and K-responsive genes. Five N responsive genes MeNRT1, MeNRT3, MeNLP1, MeGPT2 and MeTAR2, displayed enhanced expression in the high N efficient genotypes, 17S36 and 15S409 in comparison with the low N responsive genotypes, Kumkumrose and Export kappa, whereas three K responsive genes, viz., MeKUP3, MeKUP4, and MeKUP8, displayed enhanced expression in the high K efficient genotypes, Ambakkadan and Karutha malabar in comparison with the low K responsive genotypes, 17S143 and 16-5 under nutrient-deprived conditions. Allele mining analysis showed the presence of allelic variations in NRT3, whereas no sequence differences at the allelic level were observed for the AMT1 gene among the genotypes 15S409 and Export Kappa. Thus, our comprehensive analysis unravels the genetic complexity of N responsive and K responsive genes in cassava and provides the basis for the selection of genotypes and candidate genes for further functional analysis and breeding for the development of N responsive and K responsive genotypes.

Climate change, e.g., elevated CO₂, warmer temperature, and nitrogen (N) deposition, can have substantial effects on tree physiology and growth. This study explored the effects of future CO₂ and temperature (fCT, representative of future climate conditions) on the growth and photosynthetic traits of amur linden and white birch seedlings under different N availability. The results showed that fCT significantly increased the total seedling biomass and total seedling leaf area of amur linden and white birch synergistically with increasing nitrogen supply. However, the specific leaf area (leaf area to leaf mass ratio) of amur linden was significantly reduced by the two treatments. Increases in N availability alleviated the photosynthetic downregulation associated with fCT as indicated by the photosynthetic capacity parameters of V_cmax and J_max. Our results indicate that the primary limitation of photosynthesis under fCT in the two species will likely shift from Rubisco carboxylation to RuBP regeneration. However, the rate of photosynthesis was significantly higher under the fCT than control conditions in amur linden but was not significantly different between the two treatment conditions in white birch, indicating that the photosynthetic downregulation completely offset the positive effect of increased CO₂ on photosynthesis in white birch. Our results suggest that the relative performance and competitiveness of the two species may be very different in future, and more detailed studies are warranted on the responses of the two species to climate change.

Pyruvate kinase (PK) catalyzes the last glycolytic reaction to produce ATP and pyruvate, providing energy and intermediates for numerous biological processes. While the functions of Arabidopsis and rice PKs have been reported, little is known about this gene family in soybean (Glycine max). Herein, an in-silico genome wide scan revealed the presence of 21 PK genes in soybean, which were distributed in 11 chromosomes, and were classified into cytosolic and plastidial subfamilies (PKc and PKp) based on phylogenetic analysis. Collinearity analysis indicated that gene duplication contributed largely to the expansion of GmPK gene family and further Ka/Ks calculation suggested that this family experienced strong purifying selection during evolution. All GmPKs contain the conserved PK domain but the two subfamilies show distinct conserved motif composition and exon–intron organization. Gene ontology analysis and subcellular localization implied that seven GmPKs might function in plastid, while the rest function in cytoplasm. According to expression profile analysis, different GmPKcs were found highly expressed in seed, roots, or leaves, but GmPKps were mainly expressed in soybean seed. Abiotic stress responsive cis-acting elements were discovered on the promoters of GmPKs. Correspondingly, different GmPKs were found responsive to abiotic stresses, especially submergence stress. All these findings facilitated our understanding of soybean PK gene family, and established a foundation for further studies on the biological functions of GmPKs.

Peanut, being moderately salt sensitive, requires efficient management strategies to endure salt stress. A pot experiment was envisaged to evaluate the effect of exogenous calcium chloride (CaCl₂) on the underlying physiological and biochemical mechanisms in peanut during salinity stress. Salinity-induced membrane destabilization significantly increased thiobarbituric acid reactive substances (TBARS) and H₂O₂ (hydrogen peroxide) accumulation with susceptible cultivars (TG 37A and GJG 31) experiencing greater oxidative stress. There was a significant reduction in leaf stomatal conductance and net photosynthetic rate (P_N), concomitant with the decrease in shoot and root potassium (K⁺) and shoot calcium (Ca²⁺) concentrations due to greater accumulation of sodium (Na⁺). The salt stress alleviating potential of calcium was exhibited by a significant increase in shoot K⁺/ Na⁺ ratio along with elevated Ca²⁺ concentrations, which aided in restricting Na⁺ accumulation in roots and shoots of calcium-treated, salt-stressed cultivars. This ionic homeostasis was accompanied with a significant increase in membrane stability index with reduced TBARS and H₂O₂ accumulation, ROS detoxification through elevated total antioxidant activity and increased osmoregulatory compounds such as proline, total phenols and soluble sugars in calcium-treated salt-stressed plants compared to control. The improved pigment retention, stomatal conductance and ionic balance contributed to a significant increase in P_N, which was also reflected in the improved yield attributes of the peanut cultivars. Thus, the foliar application of CaCl₂ offers a promising approach to alleviate the adverse impact of salt stress in peanut, particularly at 4 dSm⁻¹, which otherwise imposes severe yield losses in the crop.