Search Results (85)

The premature senescence of red raspberry leaves severely affects plant growth. In this study, the double-season red raspberry cultivar ‘Polka’ was used, with N₁₅₀ (0.10 g N·kg⁻¹) selected as the treatment group (T150) and N₀ (0 g N·kg⁻¹) set as the control (CK). This study systematically investigated the mechanism of premature senescence in red raspberry leaves under different nitrogen application levels by measuring physiological parameters and conducting a combined multi-omics analysis of transcriptomics and metabolomics. Results showed that T150 plants had 8.34 cm greater height and 1.45 cm greater ground diameter than CK. The chlorophyll, carotenoid, soluble protein, and sugar contents in all leaf parts of T150 were significantly higher than those in CK, whereas soluble starch contents were lower. Malondialdehyde (MDA) content and superoxide anion (O₂⁻) generation rate in the lower leaves of T150 were significantly lower than those in CK. Superoxide sismutase (SOD) and peroxidase (POD) activities in the middle and lower functional leaves of T150 were higher than in CK, while catalase (CAT) activity was lower. Transcriptomic analysis identified 4350 significantly differentially expressed genes, including 2062 upregulated and 2288 downregulated genes. Metabolomic analysis identified 135 differential metabolites, out of which 60 were upregulated and 75 were downregulated. Integrated transcriptomic and metabolomic analysis showed enrichment in the phenylpropanoid biosynthesis (ko00940) and flavonoid biosynthesis (ko00941) pathways, with the former acting as an upstream pathway of the latter. A premature senescence pathway was established, and two key metabolites were identified: chlorogenic acid content decreased, and naringenin chalcone content increased in early senescent leaves, suggesting their pivotal roles in the early senescence of red raspberry leaves. Modulating chlorogenic acid and naringenin chalcone levels could delay premature senescence. Optimizing fertilization strategies may thus reduce senescence risk and enhance the productivity, profitability, and sustainability of the red raspberry industry. Full article

Leaf phenology of trees responds to temperature and photoperiod cues, mediated by underlying genes and plasticity. However, uncertainties remain regarding how smaller-scale phenological variation in cold-limited regions has been affected by modified selection pressures from herbivores, pathogens, and climate conditions, and whether this leaves genetic signatures allowing for projections of future responses. We investigated environmental correlates and genetic variation putatively associated with spring and autumn leaf phenology in northern range margin oak (Quercus robur L.) populations in Sweden (55.6° N–60.8° N). Results suggested that budburst occurred later at higher latitudes and in locations with colder spring (April) temperatures, whereas leaf senescence occurred earlier at higher latitudes. Several candidate loci associated with phenology were identified (n = 40 for budburst and 47 for leaf senescence), and significant associations between these loci and latitude were detected. Functions associated with some of the candidate loci, as identified in previous studies, included host defence and heat stress tolerance. The proportion of polymorphic candidate loci associated with budburst decreased with increasing latitude, towards the range margin. Overall, the Swedish oak population seems to comprise genetic diversity in phenology-related traits that may provide resilience to a rapidly changing climate. Full article

Inselbergs are rocky outcrops with specialized vegetation, including woody species growing in poorly developed soils. We investigated whether populations of the lithophytic tree Pseudobombax petropolitanum A. Robyns (Malvaceae), a key species endemic to Atlantic Forest inselbergs, have convergent or divergent patterns of functional traits related to leaf chemistry. This study was carried out on three inselbergs located in southeastern Brazil. Green and senescent leaves from nine healthy trees and soil samples were collected in each inselberg. The carbon, nitrogen, phosphorus, potassium, calcium, and magnesium concentrations, and the natural abundances of δ¹³C and δ¹⁵N, were measured in leaves and soil, and the C/N, C/P, and N/P ratios were calculated. The specific leaf area (SLA) was measured, and the nutrient retranslocation rate between green and senescent leaves was estimated. Divergences between populations were observed in the concentrations of potassium and magnesium in the green and senescent leaves, as well as in the C/P and N/P ratios in senescent leaves. Our results suggest that nutrient and water dynamics may differ in some inselbergs due to specific nutrients or their relationships, even though there were convergences in most functional traits related to leaf chemistry among the Pseudobombax populations. The divergences among the populations could have important implications for species selection in the ecological restoration context. Full article

Integrated application of chemical fertilizers with organic manure might improve crop yields and N-use efficiency (NUE, grain yield per unit N uptake), but the underlying physiological mechanisms are unclear. In this study, we aimed to examine the effects of combined inorganic and organic fertilizers on wheat biomass allocation, root growth, water-soluble carbohydrates (WSCs) translocation, leaf senescence, N uptake, and their relationship with yield and NUE. We established a 2-year factorial field experiment with five nutrient treatments with ratios of inorganic: organic fertilizers from 0 to 1, and three varieties—two new: Weilong169 and Zhongmai578; and one reference: Xiaoyan22. The yield ranged from 3469 to 8095 kg ha⁻¹, and it generally declined in response to a higher proportion of organic fertilizer. The NUE increased when there was a higher proportion of organic fertilizer. Weilong169 exhibited higher NUE than Zhongmai578, and both new cultivars outperformed the reference variety in the N harvest index. The yield correlated with leaf senescence traits and harvest index, and NUE was associated with WSC translocation and N uptake. The combination of fertilizers with a low portion of organic maintained yield and improved NUE; Weilong169 had the highest yield, NUE, and N harvest index. A low portion of organic manure substitution for chemical fertilizer suited all varieties. A new variety with a higher yield, N harvest index, and NUE highlights the importance of N traits in breeding programs. Full article

To identify optimal strategies for high-yield and high-efficiency cultivation under a “short-season direct-seeded cotton with once-only irrigation” regime, we conducted two-year field experiments (2022 and 2023) using a split-plot factorial design with three planting densities (30,000 (D1), 45,000 (D2), and 60,000 (D3) plants·ha⁻¹) and three nitrogen application rates (150 (N1), 180 (N2), and 210 (N3) kg·ha⁻¹). Our study systematically examined how these treatment combinations influenced canopy architecture, physiological traits, yield components, and fiber quality. The results showed that increased planting density significantly enhanced plant height, the leaf area index (LAI), and the number of fruiting branches, with the highest density (D3) contributing to a more compact and efficient canopy. Moderate nitrogen input (N2) significantly increased peroxidase (POD) activity, reduced malondialdehyde (MDA) accumulation, delayed functional leaf senescence, and prolonged the canopy’s photosynthetic performance. A significant interaction between planting density and nitrogen application was observed. The D3N2 treatment (high density with moderate nitrogen) consistently achieved the highest fruiting branch count, boll number per plant, and yields of both seed cotton and lint in both years, while maintaining stable fiber quality. This indicates its strong capacity to balance high yield with quality and maintain physiological resilience. By contrast, the D1N1 treatment (low density and low nitrogen) exhibited a loose canopy, premature photosynthetic decline, and the lowest yield. The D3N3 treatment (high density and high nitrogen) promoted vigorous early growth but reduced stress tolerance during later growth stages, leading to yield instability. These findings demonstrate that moderately increasing planting density while maintaining appropriate nitrogen levels can effectively optimize canopy structure, improve stress resilience, and enhance yield under short-season direct-seeded cotton systems with once-only irrigation. This provides both theoretical underpinning and practical guidance for achieving stable and efficient cotton production under such systems. Full article

Background: This study aimed to explore the therapeutic potential of a dietary regimen of banaba leaf extract (BNB), policosanol (PCO, Raydel^®), and their combination (BNB+PCO), to mitigate high cholesterol (HC) and high galactose (HG) diet-induced dyslipidemia, hyperglycemia, oxidative stress, senescence, and organ damage in zebrafish (Danio rerio). Methodology: Zebrafish (n = 28/group) were fed with HC (4% w/w)+HG (30% w/w) or HC+HG supplemented either with BNB (0.1% w/w) or PCO (0.1% w/w) or BNB+PCO (0.1% w/w each). Following 6 weeks of dietary intervention, biochemical and histopathological examinations across the groups were performed. Results: Post 6 weeks of consumption, the BNB+PCO group exhibited a significant 40% decrease in body weight (BW) relative to the BW of the HC+HG group, while the BNB or PCO groups displayed nonsignificant changes in BW. Both BNB and PCO reduced HC+HG-induced dyslipidemia and hyperglycemia; however, co-administration (BNB+PCO) demonstrated a significantly greater therapeutic effect in countering these conditions compared to either BNB or PCO alone. A similar effect of the BNB+PCO combination was observed on the elevation of plasma sulfhydryl content, paraoxonase (PON), and ferric ion reduction activity (FRA), with notably ~1.2-times (p < 0.01) higher levels compared to their corresponding values observed in the BNB or PCO groups. Significantly diminished plasma AST, ALT, hepatic interleukin 6 (IL-6) levels, and fatty liver changes were observed in response to BNB+PCO, compared to either BNB or PCO alone. Also, BNB+PCO displayed a higher curative effect against HC+HG-induced impairment of tissue regeneration than BNB or PCO alone. A notable effect of BNB+PCO was perceived in protecting kidneys, testis, and ovary damage. Consistently, BNB+PCO showed a profound impact on mitigating HC+HG elevated reactive oxygen species (ROS) generation, apoptosis, cellular senescence, and accumulation of brain-binding lipid proteins (BLBPs) and 4-hydroxynoneal (4-HNE) in the brain. Conclusions: The findings highlight the synergistic effects of the BNB and PCO combination to mitigate the adversity posed by the consumption of the HC+HG diet. Full article

Transcription factors play a key role in plant growth and development. As the largest family of plant-specific transcription factors, the NAC family plays a central role in coordinating plant growth and development and environmental adaptation through its unique molecular design paradigm of “fixed N-terminal structural domain + variable C-terminal regulatory domain”. This review systematically analyses the multidimensional regulatory mechanisms of NAC transcription factors in developmental processes such as cell wall remodelling, root system architecture, leaf senescence and fruit ripening, and reveals their molecular basis for responding to biotic/abiotic stresses through strategies such as hormone signalling integration (ABA, SA, JA, etc.), antioxidant defence activation and metabolic reprogramming. The study found that NAC proteins precisely control plant growth through multiple regulatory mechanisms and have evolved to form both conservative and diverse functional modules, which are of great value for crop improvement. However, research still faces three major challenges: the NAC regulatory network in different crops is still unclear, the coordinated response to multiple stresses has not been solved, and the ecological risks of gene editing have not been assessed. To this end, this paper proposes to build an ‘NAC regulatory map database’ and use synthetic biology and artificial intelligence technology to design smarter, stress-tolerant and high-yielding crops, overcoming the limitations of traditional research. Full article

Populus euphratica Oliv, a representative species in arid ecosystems, serves vital ecological functions, including windbreak, sand stabilization and carbon sequestration. Investigating its nutrient resorption mechanisms is important for elucidating plant adaptation and growth strategies in nutrient-deficient environments. This study selected thirty sampling sites in Xinjiang across different locations and collected Populus euphratica leaves. Correlation analysis, regression analysis and redundancy analysis (RDA) were employed to assess the characteristics of nutrient resorption in Populus euphratica and their driving factors. We determined the leaf nitrogen (N) and phosphorus (P) concentrations in plants and then calculated the N:P ratio, nitrogen resorption efficiency (NRE) and phosphorus resorption efficiency (PRE). The results of the correlation analysis indicated that the NRE was not significantly correlated with the N and P contents or the N:P ratio in green leaves but was significantly related to those in senescent leaves. In contrast, the PRE was negatively correlated with the P content in the senescent leaves. The NRE:PRE ratio was positively correlated with the N in the green leaves and the P in the senescent leaves but negatively related to the N:P ratio in the senescent leaves. Nutrient resorption efficiency appeared to change with varying environments. Regression analysis revealed that both the NRE:PRE ratio and the NRE were positively correlated with latitude and mean annual precipitation (MAP) but negatively correlated with altitude and mean annual temperature (MAT). However, the PRE showed a negative correlation with latitude and MAP and positive correlations with altitude and MAT. Among these factors, the contribution of the MAP was the greatest, accounting for 85.1% and thus dominating the nutrient resorption processes in Populus euphratica. This study has enhanced the understanding of nutrient resorption conservation strategy and contributes to revealing the adaptation mechanisms of Populus euphratica under stress conditions such as drought and high temperatures. Full article

Coordinating the spatial distribution of crop roots with soil nutrients, along with selecting appropriate types of fertilizers, is an effective strategy to enhance root nutrient absorption and increase crop yield. In Xinjiang’s current surface drip irrigation practices for rice (Oryza sativa L.), premature leaf senescence and N deficiency are common issues, resulting in decreased yields. This study investigated whether different N forms under subsurface drip irrigation can modulate rice root morphological strategies to delay senescence in later growth stages, enhancing rice N uptake and yield formation. A field experiment compared the effects of different drip irrigation positions (surface drip irrigation at the surface, DI0; subsurface drip irrigation at 10 cm depth, DI10) and N forms (urea N, UN; ammonium N, AN) in four combination treatments (DI0-UN, DI0-AN, DI10-UN, DI10-AN) on rice root morphology, aboveground growth, and yield formation. During the grain-filling stage, the total root length (RL) and root number (RN) in the DI10-AN treatment were higher than in other treatments. Root vitality increased by 23.24–133.72% during the later filling stages, while the root decline rate decreased by 1.16–32.80%. The root configuration parameters β in the DI10-AN treatment were superior to those in other treatments, indicating that roots tend to distribute deeper in the soil. The DI10-AN treatment reduced Malondialdehyde (MDA) levels and increased Superoxide Dismutase (SOD) activity, thereby alleviating water and N stress on the leaves in later growth stages and maintaining higher photosynthetic parameter values. The DI10-AN treatment significantly increased N absorption (14.37–52.88%) and yield (13.32–46.31%). Correlation analysis showed that RL, RN, and root activity (Ra) were significantly positively correlated with transpiration rate (Tr), intercellular CO₂ concentration (Ci), N uptake (NUP), one thousand-kernel weight (TKW), seed setting rate (SR), Efficient panicle (EP), and yield (r > 0.90). This study presents a new rice drip fertigation technique that combines subsurface irrigation with ammonium to enhance root growth and increase crop productivity. Full article

Leaf senescence in plants is the last stage of leaf development and is characterized by a decline in photosynthetic activity, an active degeneration of cellular structures, and the recycling of accumulated nutrients to areas of active growth, such as buds, young leaves, flowers, fruits, and seeds. This process holds economic significance as it can impact yield, influencing the plant’s ability to maintain an active photosynthetic system during prolonged periods, especially during the grain filling stage, which affects plant weight and oil content. It can be associated with different stresses or environmental conditions, manifesting itself widely in the context of climate change and limiting yield, especially in crops of agronomic relevance. In this work, we study the stability of two widely described sunflower (Helianthus annuus L.) genotypes belonging to the INTA Breeding Program against differential N conditions, to verify their yield stability in control conditions and under N supply. Two inbred lines were utilized, namely R453 (early senescence) and B481-6 (late senescence), with contrasting nitrogen availability in the soil but sharing the same ontogeny cycle length. It was observed that, starting from R5.5, the B481-6 genotype not only delayed senescence but also exhibited a positive response to increased nitrogen availability in the soil. This response included an increase in intercepted radiation, resulting in a statistically significant enhancement in grain yield. Conversely, the R453 genotype did not show significant differences under varying nitrogen availability and exhibited a tendency to decrease grain yield when nitrogen availability was increased. The response to nitrogen can vary depending on the specific genotype. Full article

Nitrogen use efficiency (NUE) is important for the growth and development of rice and is significant in reducing the costs of rice production. OsNRT1.1b is involved in nitrate assimilation, and the alleles at position 21,759,092 on chromosome 10 clearly separate indica (Pathum Thani 1 (PTT1) and Homcholasit (HCS)) and japonica (Azucena and Leum Pua (LP)) rice varieties. Rice morphological and physiological traits were collected at three nitrogen levels (N0 = 0 kg ha⁻¹, N7 = 43.75 kg ha⁻¹, and N14 = 87.5 kg ha⁻¹). Leaf and tiller numbers in PTT1 and HCS at N7 and N14 were two to three times higher than those at N0. At harvest, the biomass yield in PTT1 was the highest, while the total grain number in HCS was the maximum. The leaf widths and total chlorophyll contents (SPAD units) of Azucena and LP increased with nitrogen application as well as photosynthetic pigment parameters; for example, plant senescence reflectance indices (PSRIs), structure-insensitive pigment indices (SIPIs), and modified chlorophyll absorption ratio indices (MCARIs) were highly related in the japonica varieties. PTT1 and HCS, both carrying the A allele at OsNRT1.1b, had better NUE than Azucena and LP with the G allele. HCS, overall, had better NUE than PTT1. The translation to grain yield of assimilates was remarkable in PTT1 and HCS compared with Azucena and LP. In addition, HCS converted biomass for a 75% higher yield than PTT1. The ability of HCS to produce high yields was achieved even at N7 nitrogen fertilization, manifesting efficient use of nitrogen. Full article

The continuous release of glucosinolates into the soil by Brassicaceae root exudation is a prerequisite to maintaining toxic levels of breakdown products such as isothiocyanates (ITCs). ITCs influence plant and microbial diversity in ecosystems, while fungi and Rhizobiaceae are particularly injured. Studies explaining the molecular mechanisms of the negative effects are presently limited. Therefore, we investigated the early effects of cyclic ITC goitrin on proteomes of the host and symbiotic Mesorhizobium loti in the nodules of Lotus japonicus and of free-living bacteria. In the nodules, many host proteins had a higher abundance, among them, peroxidases and pathogenesis-related PR-10 proteins functioning in the abscisic-acid-activated signaling pathway. In the microsymbiont, transporter proteins as a prominent group are enhanced; some proteins involved in N-fixation decreased. The proteomes give a report about the loss of immunity suppression resulting in the termination of symbiosis, which initiates nodule senescence. Free-living M. loti are severely damaged, indicated, i.a., by a decrease in transporter proteins, the assumed candidates for goitrin protein complex formation, and high proteolysis. The production of chicoric acid by the accompanying bacteria is inhibitory for M. loti but connected to goitrin elimination, as confirmed by mass spectrometric (MS) analysis. In summary, the nodulation process is severely affected by goitrin, causing nodule dysfunction and failed nodule development. N deficiency conditions leads to yellowish leaves and leaf abscission. Full article

Tropical trees that remain evergreen and exhibit leaf litterfall that is gradual over time coexist with trees that are seasonally deciduous and exhibit pulsed litterfall. The manner in which these trees acquire, store, and contribute nutrients to the biogeochemical cycle may differ. Green and senesced leaves from deciduous Ficus prolixa trees were compared with those from Ficus tinctoria on the island of Guam. The results enabled stoichiometry and resorption calculations. F. prolixa’s young green leaf nitrogen (N) and potassium (K) concentrations were double, and the phosphorus (P) concentration was triple, those of F. tinctoria. Concentrations converged as the leaves aged such that no differences in concentration occurred for senesced leaves, indicating that nutrient resorption proficiency did not differ between the two species. In contrast, the resorption efficiency was greater for F. prolixa than F. tinctoria for all three nutrients. The N:P values of 6–11 and K:P values of 5–7 were greater for young F. tinctoria leaves than young F. prolixa leaves. The N:K values were 1.1–1.6 and did not differ between the two species. No differences in pairwise stoichiometry occurred for senesced leaves for any of the nutrients. These Guam results conformed to global trends indicating that seasonally deciduous plants are more acquisitive and exhibit greater nutrient resorption efficiency. The differences in how these two native trees influence the community food web and nutrient cycling lies mostly in the volume and synchronicity of pulsed F. prolixa litter inputs, and not in differences in litter quality. These novel findings inform strategic foresight about sustaining ecosystem health in Guam’s heavily threatened forests. Full article

N6–methyladenosine (m⁶A) is a widespread post–transcriptional modification in eukaryotic mRNAs. Proteins with the YTH structural domain act as m⁶A–binding proteins by recognizing the m⁶A modification and regulating mRNA through this recognition. In this study, SlYTHDF2, a prototypical m⁶A –binding protein gene in the YTH family was expressed in various tissues, and subcellular localization analyses indicated that the SlYTHDF2 protein was localized in the nucleus and cytoplasm. SlYTHDF2 knockout lines were obtained using CRISPR/Cas9 technology and showed the senesced leaves prematurely increased endogenous ABA accumulation compared with the wild type. Moreover, we found that dark promoted leaf senescence in SlYTHDF2 knockout lines and exogenous ABA further accelerated leaf senescence under dark conditions. The qRT–PCR analysis revealed significant alterations in the expression of genes associated with the ABA pathway. Relative to the wild type, the CR–slythdf2 plants exhibited reduced levels of photosynthetic pigments, higher accumulation of reactive oxygen species, and increased damage to cell membranes. Additionally, we discovered that SlYTHDF2 interacts with the chloroplast–binding protein SlRBCS3 through yeast two–hybrid and BiFC experiments. Overall, our data suggest the important role of SlYTHDF2 in regulating tomato leaf senescence. Full article

Serotonin N-acetyltransferase (SNAT) is a pivotal enzyme for melatonin biosynthesis in all living organisms. It catalyzes the conversion of serotonin to N-acetylserotonin (NAS) or 5-methoxytrypytamine (5-MT) to melatonin. In contrast to animal- and plant-specific SNAT genes, a novel clade of archaeal SNAT genes has recently been reported. In this study, we identified homologues of archaeal SNAT genes in ciliates and dinoflagellates, but no animal- or plant-specific SNAT homologues. Archaeal SNAT homologue from the ciliate Stylonychia lemnae was annotated as a putative N-acetyltransferase. To determine whether the putative S. lemnae SNAT (SlSNAT) exhibits SNAT enzyme activity, we chemically synthesized and expressed the full-length SlSNAT coding sequence (CDS) in Escherichia coli, from which the recombinant SlSNAT protein was purified by Ni²⁺ affinity column chromatography. The recombinant SlSNAT exhibited SNAT enzyme activity toward serotonin (K_m = 776 µM) and 5-MT (K_m = 246 µM) as substrates. Furthermore, SlSNAT-overexpressing (SlSNAT-OE) transgenic rice plants showed higher levels of melatonin synthesis than wild-type controls. The SlSNAT-OE rice plants exhibited delayed leaf senescence and tolerance against treatment with the reactive oxygen species (ROS)-inducing herbicide butafenacil by decreasing hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels, suggesting that melatonin alleviates ROS production in vivo. Full article