Search Results (133)

Information on the effects of differences in root and soil properties on Saturated hydraulic conductivity (K_s) is crucial for estimating rainfall infiltration and evaluating sustainable ecological development. This study selected typical grass shrub composite plots widely distributed in hilly and gully areas of the Loess Plateau: Caragana korshinskii, Caragana korshinskii and Agropyron cristatum (fibrous root), and Caragana korshinskii and Artemisia gmelinii (taproot). Samples were collected at different distances from the base of the shrub (0 cm, 50 cm), with a sampling depth of 0–30 cm. The constant head method is used to measure the K_s. The K_s decreased with increasing soil depth. Due to the influence of shrub growth, there was significant spatial heterogeneity in the distribution of K_s at different positions from the base of the shrub. Compared to the sample location situated 50 cm from the base of the shrub, it was observed that in a single shrub plot, the K_s at the base were higher, while in a grass shrub composite plot, the K_s at the base were lower. Root length density, >0.25 mm aggregates, and organic matter were the main driving factors affecting K_s. The empirical equation established by using principal component analysis to reduce the dimensions of these three factors and calculate the comprehensive score was more accurate than the empirical equation established by previous researchers, who considered only root or soil properties. Root length density and organic matter had significant indirect effects on K_s, reaching 52.87% and 78.19% of the direct effects, respectively. Overall, the composite plot of taproot herbaceous and shrub (Caragana korshinskii and Artemisia gmelinii) had the highest K_s, which was 82.98 cm·d⁻¹. The ability of taproot herbaceous plants to improve K_s was higher than that of fibrous root herbaceous plants. The research results have certain significance in revealing the influence mechanism of the grass shrub composite on K_s. Full article

High nitrogen use efficiency is crucial for enhancing spinach’s tolerance to low nitrogen stress and minimizing nitrate accumulation. Here, we report that SoNRT3, a NAR2 family protein, modulates nitrate uptake and plant growth under low-nitrate conditions. SoNRT3 expression was induced by low nitrate availability in roots and prolonged nitrogen deficiency in shoots. Compared to wild-type Arabidopsis thaliana, lines overexpressing SoNRT3 exhibited higher root fresh weight, activities of nitrogen reduction/assimilation-related enzymes, tap root length, and total root diameter under low-nitrate (0.25 mM) conditions. SoNRT3 silencing reduced taproot length, lateral root number, shoot/root biomass, and ¹⁵${\mathrm{N}\mathrm{O}}_3^{-}$ uptake in spinach grown under low-nitrate conditions. SoNRT3 partially compensated for ¹⁵${\mathrm{N}\mathrm{O}}_3^{-}$ uptake in atnrt2.1 and atnrt3.1 mutants. Transcriptome analysis showed that SoNRT3 may enhance nitrate uptake and root development by promoting the expression of high-affinity nitrate transporters, nitrogen assimilation, auxin signaling, and cell differentiation. Additionally, SoNRT3 can interact with a spinach NRT2 family protein (SoNRT2a), whose transcription level was also induced by low N and N deficiency. Together, this study clarifies the key roles and regulatory network of SoNRT3 in low-nitrate tolerance, which contributes to a novel understanding of nitrate utilization in spinach. Full article

Background: F. hirta vahl is a famous Chinese medicinal plant. The root is the main organ accumulating bioactive compounds, and its development is directly related to the yield and quality of the harvested F. hirta. However, the molecular mechanisms underlying the bioactive compound biosynthesis occurring during the root development of F. hirta are unknown. Method: Transcriptome and widely targeted metabolome analyses were performed to investigate gene expression and metabolite variation during the development of F. hirta taproots. Results: A total of 3792 differentially expressed genes (DEGs) were identified between the one- and three-year-old F. hirta taproots; they are related to circadian rhythm–plant, phenylpropanoid biosynthesis, starch and sucrose metabolism, and plant–pathogen interaction pathways. In total, 119 differentially accumulated metabolites (DAMs) were identified between the one- and three-year-old F. hirta taproots, including flavonols, phenolic acids, and coumarins compounds. Integrative transcriptome and metabolome analyses revealed a significant correlation between 172 DEGs and 21 DAMs; they were predominantly enriched for processes associated with phenylpropanoid biosynthesis, flavonoid biosynthesis, plant hormone signal transduction, and stilbenoid, diarylheptanoid, and ginerol biosynthesis. In addition, 26 DEGs were identified to be significantly correlated with the DAMs that accumulated in the phenylpropanoid biosynthesis pathway, and these DEGs may be the key genes for the biosynthesis of F. hirta active compounds. Conclusions: The phenylpropanoid biosynthesis pathway plays a dual role in both development and bioactive compound synthesis in F. hirta taproots. These findings provide a molecular regulatory network in the relationships between F. hirta taproot development and the accumulation of secondary metabolites. The identification of candidate genes and pathways provides a genetic resource for quality control and future molecular breeding in F. hirta. Full article

Previous research has shown the benefits of splitting nutrient application to plant roots either temporally or spatially. A split-root nutrient film technique (SR-NFT) was developed for lettuce where an NFT channel is divided longitudinally into two separate channels, each with its own input and drain line. In this system, plant roots can be intentionally divided to supply different nutrient solutions without mixing them. Plant growth was observed using combinations of three different hydroponic fertilizer concentrations: EC 0.5 dS∙m⁻¹ (L, tap water), EC 1.8 dS∙m⁻¹ (M, nutrient solution), and EC 3.1 dS∙m⁻¹ (H, nutrient solution). For the same average concentration of solution (EC 1.8 dS∙m-1), SR-NFT that supplied different concentrations of solution on the left and right side (SHL, Left; EC 0.5 dS∙m⁻¹, Right; EC 3.1 dS∙m⁻¹) increased the shoot fresh and dry weight by 15%, shoot dry weight by 14%, and root dry weight by 25% without increasing number of tipburn leaves compared to conventional NFT (MM, EC 1.8 dS∙m⁻¹). In addition, the lowest concentration with SR-NFT (SML, Left; EC 1.8 dS∙m⁻¹, Right; EC 0.5 dS∙m⁻¹) reduced the number of tipburn leaves without reducing the shoot fresh weight in all conditions except SMM (Left; EC 1.8 dS∙m⁻¹, Right; EC 1.8 dS∙m⁻¹). In other words, the use of tap water on one side is expected to suppress tipburn or increase yield. Full article

The cell wall, acting as the first line of defense against aluminum (Al) toxicity, is the primary cellular structure that encounters and perceives Al³⁺. Xyloglucan endotransglucosylase/hydrolase (XTH) plays a pivotal role in mediating cell wall remodeling, a critical mechanism for Al toxicity tolerance. In our previous studies, the candidate gene BnaXTH22 was identified through GWAS and RNA-seq analyses. Under Al toxicity stress, overexpression lines (OEs) exhibited a significant increase in the relative elongation of taproots (9.44–13.32%) and total root length (8.15–12.89%) compared to the wild type (WT). Following Al treatment, OEs displayed reduced MDA content and lower relative electrical conductivity, alongside a significantly higher root activity than WT. Transcriptomic analysis revealed that differentially expressed genes in OE under Al toxicity were predominantly enriched in stress-related biological processes, including phenylpropanoid metabolism, fatty acid biosynthesis, and lignin biosynthesis. These results suggest that BnaXTH22 overexpression could enhance Al toxicity tolerance in rapeseed, potentially by modulating cell wall synthesis to bolster plant resistance. Full article

Global agricultural systems are predominantly concentrated in regions characterized by fertile soils, abundant precipitation, and gentle slopes. However, a significant proportion of farmland is situated in areas with poor soil quality, arid conditions, and steep slopes. In such challenging environments, particularly sandy-arid sloping farmlands, selecting native crops that are well-adapted to local conditions is critical for sustainable agricultural practices. This study categorizes local crops in arid regions into four distinct types: tall-stem monocotyledonous plants (represented by maize, Zea mays L.), short-stem monocotyledonous plants (represented by millet, Setaria italica), tap-rooted dicotyledonous plants (represented by soybean, Glycine max (L.) Merr.), and tuberous dicotyledonous plants (represented by potato, Solanum tuberosum L.). A quantitative evaluation framework was developed using five key indices: nitrogen fixation, anti-wind erosion, roots reinforcement, anti-water erosion, and water conservation. These indices were used to calculate the suitability index values for each crop type. The findings revealed that in sandy-arid sloping farmland regions, maize and millet emerged as the most suitable crops for cultivation, followed by soybean, while potato was identified as the least suitable. Maize exhibited high values across all five indices, particularly demonstrating exceptional performance in nitrogen fixation. Additionally, the study demonstrated that traditional farming practices are highly effective in sloping farmlands, since they not only promote crop growth but also mitigate soil erosion. This research offers insights into agricultural management in regions affected by drought, soil erosion, and steep terrain. The results highlight the feasibility of employing traditional farming methods to cultivate maize in such challenging environments, providing practical guidance for sustainable agricultural development. Full article

As an endogenous hormone, auxin plays a crucial role in regulating plants’ growth and development, and also in the responses to abiotic stresses. However, the effects and mechanism of auxin and its inhibitors on plant growth and mineral nutrient absorption in citrus have not been thoroughly studied. Therefore, we used trifoliate orange (citrus’s rootstock, Poncirus trifoliata) as the experimental material to supplement the research content in this area. The trifoliate orange seedlings were treated with exogenous auxin (indolebutyric acid, IBA) and auxin inhibitor (2-naphthoxyacetic acid, 2-NOA) in a sand culture system. The results showed that compared to the control, exogenous auxin (1.0 µmol L⁻¹ IBA) significantly enhanced the taproot length, lateral root length, and lateral root number by 17.56%, 123.07%, and 88.89%, respectively, while also markedly elevating the levels of nitrogen (N), phosphorus (P), potassium (K), copper (Cu), and zinc (Zn) by 14.29%, 45.61%, 23.28%, 42.86%, and 59.80%, respectively. Again compared to the control, the auxin inhibitor (50.0 µmol L⁻¹ 2-NOA) dramatically reduced the taproot length, lateral root length, and lateral root number by 21.37%, 10.25%, and 43.33%, respectively, while also markedly decreasing the levels of N, magnesium (Mg), iron (Fe), Cu, and Zn by 7.94%, 10.42%, 24.65%, 39.25%, and 18.76%, respectively. Furthermore, IBA increased auxin accumulation in the root hair, stele, and epidermal tissues of citrus taproots, and promoted the up-regulation of auxin synthesis genes (TAR2, YUC3, YUC4, YUC6, YUC8) and transport genes (ABCB1, ABCB19, AUX1, LAX1, LAX2, PIN1, PIN3, PIN4). In contrast, 2-NOA decreased auxin levels in the root hair, stele, and epidermal tissues of citrus taproots, and was involved in the down-regulation of auxin synthesis genes (TAR2, YUC3, YUC4, YUC6) and transport genes (ABCB1, AUX1, LAX1, LAX2, LAX3, PIN3). Interestingly, 2-NOA dramatically elevated auxin level specifically in the root tip of citrus taproot. Therefore, 2-NOA disrupts auxin reflux from the root tip to root hair and epidermal tissues in citrus taproot through down-regulation of auxin transport genes, thereby creating localized (i.e., root hair zone and epidermal tissues) auxin deficiencies that compromise root system architecture and nutrient acquisition capacity. According to the results of this study, exogenous auxin analogs could regulate citrus growth and mineral nutrient absorption through the auxin synthesis and transport pathways. Full article

It is well known that modern agriculture would not be able to meet the current demand for food without the help of pesticides. However, conventional pesticides have been proven to be extremely harmful to the environment, to the species they are applied to, and, ultimately, to humans. As a result, bio-pesticides have been introduced in recent years and include natural substances that control pests, such as biochemical pesticides, microorganisms used as pest control agents (microbial pesticides), and pesticide substances produced by plants containing added genetic material, known as plant-incorporated protectants (PIPs). Although these are natural products, their widespread use has led to an increased presence in the environment, raising concerns regarding their potential impact on both the environment and human health. The aim of our study was to determine the phyto- and cytogenotoxicity caused by two insecticides, both certified for use in ecological agriculture: one biochemical (BCP) and the other microbial (MP), which were applied in three concentrations (the maximum recommended concentration by the manufacturers (MRFC), 1.5X MRFC, and 2X MRFC) to the meristematic root tissues of Allium cepa. The results were compared to a negative control (tap water) and a positive control (a chemical pesticide (CP) containing mainly Deltamethrin). Phytotoxic and cytogenotoxic effects were analyzed at two time intervals (24 and 48 h) by measuring root length, growth percentage, root growth inhibition percentage (phytotoxicity tests), and micronuclei frequency and chromosome aberrations (anaphase bridges, chromosomal fragments, anaphase delays, sticky chromosomes, laggard/vagrant chromosomes) (cytogenotoxicity analyses), respectively. The tests conducted in this study showed that the microbial insecticide provides greater safety when applied, even at higher doses than those recommended by the manufacturers, compared with the biochemical insecticide, whose effects are similar to those induced by the chemical pesticide containing Deltamethrin. However, the results suggest that both insecticides have clastogenic and aneugenic effects, highlighting the need for prior testing of any type of pesticide before large-scale use, especially since the results of the A. cepa tests showed high sensitivity and good correlation when compared to other test systems, e.g., mammals. Full article

Survival in desert ecosystems poses significant challenges for plants due to harsh conditions. Plant microbiomes are thought to promote resilience; however, whether plant hormones, specifically strigolactones (SLs) and karrikins (KARs), shape plant microbiomes remains unknown. The recruitment of root-associated microbiomes in Nicotiana attenuata, a model desert plant, silenced in specific genes associated with SL biosynthesis (CCD7) and perception (D14), karrikin perception (KAI2), and in the shared receptor (MAX2), required for both pathways, was studied. SL and KAR signaling, with MAX2 as a co-regulator, fine-tuned the assembly of root-associated microbiomes, with unique and shared regulatory functions on bacterial microbiome recruitment, particularly in taproot. Significant variation among the different plant genotypes in bacterial diversity and composition in taproot and lateral roots provides a foundation for future research to explore how microbiomes function in plant resilience in these harsh environments. Full article

This study aims to explore the effect of pulsed electric field (PEF) treatment as a method very likely to result in reversible electroporation of Scutellaria baicalensis Georgi underground organs, resulting in increased mass transfer and secondary metabolites leakage. PEF treatment with previously established empirically tailored parameters [E = 0.3 kV/cm (U = 3 kV, d = 10 cm), t = 50 µs, N = 33 f = 1 Hz] was applied 1–3 times to S. baicalensis roots submerged in four different Natural Deep Eutectic Solvents (NADES) media (1—choline chloride/xylose (1:2) + 30% water, 2—choline chloride/glucose (1:2) + 30% water, 3—choline chloride/ethylene glycol (1:2), and 4—tap water (EC = 0.7 mS/cm). Confocal microscopy was utilized to visualize the impact of PEF treatment on the root cells in situ. As a result of plant cell membrane permeabilization, an extract containing major active metabolites was successfully acquired in most media, achieving the best results using medium 1 and repeating the PEF treatment twice (baicalein <LOQ, baicalin 12.85 µg/mL, wogonin 2.15 µg/mL, and wogonoside 3.01 µg/mL). Wogonin concentration in NADES media was on par with the control (plants harvested on the day of the experiment, ultrasound-mediated methanolic extraction, C_wogonin = 2.15 µg/mL). After successful extraction, PEF treatment allowed the plants to continue growing, with the lowest survival rate across treated groups being 60%. Additionally, an enhancement in plant growth parameters (length and fresh mass of the roots) and significant changes in the S. baicalensis root phytochemical profile were also observed. Full article

Adenophora triphylla, a perennial plant widely used in traditional medicine, produces secondary metabolites like lupenone and β-sitosterol. Understanding how environmental factors influence the concentrations of these metabolites is crucial for optimizing their medicinal use and cultivation. This study examined the relationships between soil physicochemical properties, climatic variables, and the growth and metabolite content of A. triphylla roots across 17 cultivation sites in South Korea. Methods included UHPLC-MS/MS analysis for quantifying lupenone and β-sitosterol, alongside correlation analysis of growth traits and environmental factors. The results showed that higher soil pH and calcium/magnesium content were positively correlated with the fresh weight of the root, whereas lower temperatures increased biomass accumulation. Additionally, lupenone was significantly associated with the elongation of various root growth, whereas β-sitosterol showed a correlation only with the diameter of the taproot. These findings suggest that environmental factors, particularly soil pH, Ca²⁺, Mg²⁺, and temperature, play key roles in influencing both the growth and metabolite production of A. triphylla, providing valuable insights into improving its medicinal and agronomic potential. Full article

Live stump-supported slopes are an environmentally friendly form of support that utilizes the powerful anchoring and reinforcing effects of deep-rooted plants to enhance slope stability. In order to ensure the safety and stability of embankment slopes during their service life, it is necessary to carry out research on the dynamic characteristics and stability of live stump slopes under train vibration loading. In this study, a large-scale indoor dynamic loading model test with a geometry of 1:7 was carried out on the live stump slope of a ballasted passenger railroad track to explore the attenuation characteristics of additional dynamic stresses, the dynamic displacement response law of the slope surface and the stress response characteristics of the live stumps, and to further investigate the influence of the live stumps on the stability of the slope under the dynamic loading. The results are as follows. (i) Additional dynamic stresses decayed at the bed surface and bed floor at a greater rate than the embankment body, and were significantly affected by dynamic loading when the vertical depth was less than 0.89 m. (ii) The dynamic displacement of the foundation bed is larger than that of the embankment body. The displacement response of the slope near the top and about 1/4 of the elevation of slope is the largest. (iii) The taproot of the living poles has many reverse bending points, and the bending moment of the taproot between the lateral roots shows the law of being larger on the top and smaller on the bottom. (iv) The slope facing has an amplifying effect on the vibration load of the train, and the farther away from the track, the smaller the amplifying effect. The research results have reference significance for the theoretical research and engineering application of living poles. Full article

The plant peptide-containing sulfated tyrosine (PSY) family plays critical roles in plant cell proliferation and stress responses. However, the functional characterization of the PSY peptide family in wheat remains unclear. This study systematically identified a total of 29 TaPSY genes at the genome-wide level, classifying them into six subgroups based on PSY-like motifs. These peptides contain a highly conserved active peptide domain, closely resembling the Arabidopsis AtPSY1 motif. All TaPSY homologs are predicted to have a sulfated tyrosine catalyzed by plant tyrosylprotein sulfotransferase (TPST). The TaPSY genes displayed distinct expression patterns across various tissues, with most genes showing higher expression levels in roots and stems. Synthetic sulfated TaPSY peptides enhanced root growth in both wild-type Arabidopsis and the tpst-1 mutant plants. In wheat, exogenous application of TaPSY peptides also promoted root growth, with the synthetic TaPSY5 peptide affecting reactive oxygen species levels in wheat taproots to stimulate primary root growth. Furthermore, transgenic Arabidopsis plants overexpressing TaPSY10 exhibited longer primary roots and increased lateral root numbers. These findings provide insights into the physiological roles of TaPSY peptides in regulating wheat root growth. Full article

Wheat can tolerate a mild water deficit, but prolonged drought causes a number of detrimental physiological changes resulting in a substantial decrease in productivity. The present study evaluates the potential of the natural plant growth regulator melatonin to alleviate the negative effects of moderate drought in two Bulgarian winter wheat cultivars at the early vegetative stage. Melatonin doses of 75 µM were root-supplemented 24 h before or after the stress period. The levels of several biometric parameters, osmolyte content and stress indicators as well as the expression of genes coding for key enzymes of the proline biosynthesis pathway were analyzed in leaves at the end of the drought stress and after two and four days of recovery. Applied alone, melatonin did not exert significant effects on most of the monitored parameters. Water deprivation negatively affected seedlings’ fresh weight and water content and increased the stress markers and osmolyte levels. These were accompanied by a high accumulation of TaP5CS and TaP5CR transcripts coding for the enzymes Δ-pyrroline-5-carboxylate synthase and Δ-pyrroline-5-carboxylate reductase, respectively. The effect of melatonin in reducing drought stress was similar whether applied before or after exposure, though slightly more effective when used as a pre-treatment. Full article

Microbes such as bacteria and fungi play important roles in nutrient cycling in soils, often leading to the bioavailability of metabolically important mineral elements such as nitrogen (N), phosphorus (P), iron (Fe), and zinc (Zn). Examples of microbes with beneficial traits for plant growth promotion include mycorrhizal fungi, associative diazotrophs, and the N₂-fixing rhizobia belonging to the α, β and γ class of Proteobacteria. Mycorrhizal fungi generally contribute to increasing the surface area of soil-root interface for optimum nutrient uptake by plants. However, when transformed into bacteroids inside root nodules, rhizobia also convert N₂ gas in air into ammonia for use by the bacteria and their host plant. Thus, nodulated legumes can meet a high proportion of their N requirements from N₂ fixation. The percentage of legume N derived from atmospheric N₂ fixation varies with crop species and genotype, with reported values ranging from 50–97%, 24–67%, 66–86% 27–92%, 50–92%, and 40–75% for soybean (Gycine max), groundnut (Arachis hypogea), mung bean (Vigna radiata), pigeon pea (Cajanus cajan), cowpea (Vigna unguiculata), and Kersting’s groundnut (Macrotyloma geocarpum), respectively. This suggests that N₂-fixing legumes require little or no N fertilizer for growth and grain yield when grown under field conditions. Even cereals and other species obtain a substantial proportion of their N nutrition from associative and endophytic N₂-fixing bacteria. For example, about 12–33% of maize N requirement can be obtained from their association with Pseudomonas, Hebaspirillum, Azospirillum, and Brevundioronas, while cucumber can obtain 12.9–20.9% from its interaction with Paenebacillus beijingensis BJ-18. Exploiting the plant growth-promoting traits of soil microbes for increased crop productivity without any negative impact on the environment is the basis of green agriculture which is done through the use of biofertilizers. Either alone or in combination with other synergistic rhizobacteria, rhizobia and arbuscular mycorrhizal (AM) fungi have been widely used in agriculture, often increasing crop yields but with occasional failures due to the use of poor-quality inoculants, and wrong application techniques. This review explores the literature regarding the plant growth-promoting traits of soil microbes, and also highlights the bottle-necks in tapping this potential for sustainable agriculture. Full article