Waterlogged Conditions Research Articles

The role of ethylene in the regulation of plant response mechanisms to waterlogging stress.

Waterlogging stands as a common environmental challenge, significantly affecting plant growth, yield, and, in severe cases, survival. In response to waterlogging stress, plants exhibit a series of intricate physiologic, metabolic, and morphologic adaptations. Notably, the gaseous phytohormone ethylene is rapidly accumulated in the plant submerged tissues, assuming an important regulatory factor in plant-waterlogging tolerance. In this review, we summarize recent advances in research on the mechanisms of ethylene in the regulation of plant responses to waterlogging stress. Recent advances found that both ethylene biosynthesis and signal transduction make indispensable contributions to modulating plant adaptation mechanisms to waterlogged condition. Ethylene was also discovered to play an important role in plant physiologic metabolic responses to waterlogging stress, including the energy mechanism, morphologic adaptation, ROS regulation and interactions with other phytohormones. The comprehensive exploration of ethylene and its associated genes provides valuable insights into the precise strategies to leverage ethylene metabolism for enhancing plant resistance to waterlogging stress.

The impact of irrigation duration on crop N uptake, lint yield and internal NUE in cotton using standard urea

Context This is the first research to investigate the impact of irrigation duration on crop productivity and nitrogen (N) performance indicators in southern New South Wales (SNSW), Australia, as the industry strives for improved N productivity. Aim To benchmark the impact of different irrigation durations on waterlogging and related impacts on available soil and fertiliser N, cotton productivity and nitrogen use efficiency (NUE). Methods Two field experiments were conducted in SNSW where cotton was grown with varying rates of fertiliser N application interacting with different durations of furrow irrigation applications during the period from first flower to crop maturity. Key results Waterlogged conditions occurred within the top 20 cm of the soil profile during irrigations. These conditions coincided with fertiliser placement and high concentrations of available mineral N, which created conditions conducive for N loss. However, the internal NUE (kg lint kg crop N uptake−1) and N balance were not impacted by irrigation duration in either experiment, despite differences in duration of waterlogged conditions that averaged 15 h irrigation−1. Partial N budgets suggested that 48% of the available N to the crop could not be found in the plant or soil mineral N pools after harvest. Conclusion Modification of the duration of irrigation applications was not an effective management option to improve NUE in irrigated cotton; however, it improved water productivity (bales per megalitre). Implications Further research is required to consider the implications of other irrigation systems such as overhead sprinkler and drip systems for improvement of NUE.

Unlocking the Potential of Teff for Sustainable, Gluten-Free Diets and Unravelling Its Production Challenges to Address Global Food and Nutrition Security: A Review.

Sustainable diets, as defined by the Food and Agriculture Organisation, aim to be nutritionally adequate, safe, and healthy, while optimising natural and human resources. Teff (Eragrostis tef), a gluten-free grain primarily grown in Ethiopia, has emerged as a key contender in this context. Widely regarded as a "supergrain", teff offers an outstanding nutrition profile, making it an excellent choice for people with gluten-related disorders. Rich with protein, essential amino acids, polyunsaturated fats, and fibre, and abundant in minerals like calcium and iron, teff rivals other popular grains like quinoa and durum wheat in promoting human health. Beyond its nutritional benefits, teff is a hardy crop that thrives in diverse climates, tolerating both drought and waterlogged conditions. Due to its resilience and rich nutrient content, teff holds the potential to address nine of the 17 United Nations' Sustainable Development Goals (SDGs), including SDG 1 (no poverty), SDG 2 (zero hunger), and SDG 3 (good health and wellbeing), which are tied to improving food and nutrition security. However, teff production in Ethiopia faces significant issues. Traditional farming practices, insufficient storage infrastructure, and food safety challenges, including adulteration, hinder teff's full potential. This review explores teff's dual role as a nutritious, sustainable food source and outlines the key challenges in its production to conclude on what needs to be done for its adoption as a golden crop to address global food and nutrition security.

Response of growth and chlorophyll fluorescence parameters of mulberry seedlings to waterlogging stress

This study aimed to investigate the adaptive mechanisms of mulberry (Morus alba) to waterlogged conditions, with a specific focus on the development of adventitious roots (ARs), alteration of growth strategies, and adjustment of chlorophyll fluorescence parameters. To achieve this goal, 4-year-old potted mulberry plants were selected for research, and a waterlogging simulation method was implemented. Four treatments were established to investigate the effects of varying water conditions on leaf waterlogging damage, the number of ARs, plant height, chlorophyll fluorescence parameters, and proton motive force (pmf) parameters in mulberry plants. These treatments included the control group (CK), shallow submerged group (SS), half-submerged group (HS) and deep submerged group (DS). Our results showed that (1) The number of ARs in each group increased with increasing waterlogging time. (2) Waterlogging stress inhibited the height growth of mulberry, and the changes in plant height in the HS and DS groups were significantly lower than those in the CK and SS groups. (3) The maximum photochemical quantum yield (Fv/Fm) in the HS and DS groups decreased significantly under waterlogging stress. The nonphotochemical quenching (NPQt) of mulberry leaves in the submergence group increased significantly in the early stage of waterlogging stress, and the NPQt in the submergence group increased continuously with increasing waterlogging time. (4) Thylakoid conductivity to protons (gH+) in the leaves of mulberry decreased significantly under waterlogging stress, whereas the steady-state rate of proton flux (vH+) and total electrochromic shift (ECSt) increased significantly. The morphological, physiological, and ecological responses of mulberry plants to waterlogging stress include the timely generation of ARs at the stem base, the adjustment of plant growth strategies, and the repair of photosynthetic response centers in leaves through heat dissipation and thylakoid acidification mechanisms.

Effectiveness of Biochar application on the growth of red chili plants during the vegetative stage under waterlogging

The riparian wetland offers potential for horticultural crop cultivation, such as chili peppers. It is important to consider cultivation techniques and the use of organic matter to improve soil properties, particularly to combat waterlogging during the rainy season. This study aimed to assess the impact of biochar application on the growth of chili peppers (Capsicum annuum L.) during the vegetative stage under waterlogging conditions. This research was conducted at the experimental land of the Agrotechnology Department, Faculty of Plant and Animal Sciences, Universitas Bina Insan from December 2022 to February 2023. This research employed a complete randomized design (RAL) factorial with two factors. The first factor involved waterlogging stress, including control (C) and waterlogging stress (W). The second factor (N) encompassed the application of biochar, namely without biochar (N0), rice husk biochar (N1) and coconut shell biochar (N2) at a dose of 200 g plant-1. The results showed that waterlogging conditions (W) and biochar application (N) showed significantly different results in shoot length, root length, number of leaves, and total dry weight of chili plants, while the interaction (WxN) showed significantly different in shoot length and root length of plants. Treatment without biochar (N0) in waterlogging conditions actually showed shoot length, root length, number of leaves and total dry weight of plants that were significantly higher than treatment coconut shell biochar (N1) and rice husk applications (N2).

Feasibility Study of Marigold as Intercrop in Drumstick Cultivation for Interim Income Generation

Drumstick (Moringa oliefera Lam.) PKM-1(Annual) is an important perennial vegetable crop present cultivating in India not only as vegetable and for moringa leaf powder. India is the main producer of drumstick in the world because higher contribution is due to favourable temperature during flowering and fruit development stages. Even though encountered several production hurdles resulting greater yield loss due to existing climatic conditions during fruit developmental stages. But this crop gave them perfect assurance in giving good income in an average about 2-3 Lakhs rupees over a period of 2 years. Based on weather conditions farmers were being come forwarded by training programmes conducted by our KVK from 2017-till date, we have documented the farmers results by growing intercrops mainly marigold crop. Which gives good yield and good income to the farmers before pod formation of drumstick. Marigold is 110 days crop where drumstick gives first yield after 7 months. In between marigold crop not only giving accountable benefits to the farmers and it reduces the nematode problems in the field as well explained by Steiner, 1941 Marigold (Tagetes erecta) is one of the most widely studied plant genera due to its allelopathic potential against PPNs. Marigolds’ repressive impact on nematodes has been documented for over 50 years and some studies said that spiral (Helicotylenchus multicinctus) nematodes are responsible for yield losses of 30–60% in many banana-producing countries in the tropics (Davide, 1995, Speijer and Kajumba, 1996, Kashaija et al., 2004) . The partner crops of the intercropping system share space, water, and nutrients making the most efficient utilization of available resources (Xu et al., 2020). Earlier farmers were paddy growers where they didn’t see profits by selling paddy in IKP centers or as individual sales. So We conducted trails in Huzurabad Division and Errabelli villages of Karimnagar District (Old Karimnagar District), got successful results by doubling the farmer’s income. Raised marigold seedlings in KVK during June month and supplied to the farmers. Transplanted marigold and Drumstick in July month with 60cm x60cm and Drumstick spacing was 3mx3m where 444 plants were accommodated in one acre area, Intercropping is an agricultural system that improves land use efficiency through simultaneous cultivation of more different crops in the same field using functional complementarity to increase resources utilization, increase the productivity of crops and nutrient-use efficiency (Chifflot et al., 2006; Zhan and Li, 2003) Even went through many hurdles in marigold and drumstick crops in rainy season due to paddy growing soils and water logging conditions. In this, observed positive effects on soil carbon and nitrogen of intercropping found in previous intercropping studies (Makumba et al., 2007), [1]. Results are as follows we harvested 36.80Q per acre in 8 pickings and after drumstick pods harvested from February up to June 134 pods per tree. It shows C: B ratio as drumstick (PKM1) contribution 1:11.7 and marigold (Tanindo (Yellow and Orange) contribution 1:4.3 to the farmers. The demonstration plots reported that yield of marigold and drumsticks are 38.6Q and 49.58Q per acre. Farmers got good income Rs. 2, 74,160.00 through two crops in one acre area with Marigold as inter crop in Drumstick plantation. Based on this success story of the farmers, NABARD bank started giving loans to the farmers and they published this success story in their credit linkage plan 2018-19.

Material Analysis and Conservation Treatment of Wooden Artifacts Excavated at the Ssangbuk-ri 280-10 Site in Buyeo, Korea

Numerous Baekje historical sites are located in Ssangbuk-ri, Buyeo, where a diverse array of wooden artifacts, including lacquerware, was excavated in a waterlogged condition. Consequently, comprehensive analysis and conservation treatments were undertaken. The study encompassed four wooden artifacts and one lacquerware. Species identification was conducted for all five artifacts, and the coating residue on the surface of one lacquerware was discerned using FT-IR. The results revealed that the Y-shaped and Drill-shaped wooden artifacts were crafted from Hard pine, the Square container with a handle from <i>Juglans</i> spp., the Arrow-shaped wooden object from <i>Pyrus</i> spp., and the Lacquerware from <i>Castanea</i> spp.. Additionally, the surface coating of the lacquerware was confirmed to be lacquer. Conservation treatments involved PEG(Polyethylene glycol) impregnation and freeze-drying methods, ensuring the stable storage and display of these artifacts.

Experimental verification of solubilization effect of soil bromine by waterlogging reduction

ABSTRACT Although the concentration of bromine in the Earth’s crust is only approximately 2 µg g−1, it is one of the most crucial elements in daily human life. On the Earth’s surface, bromine is thought to be widely transported and circulated in the hydrosphere, atmosphere, lithosphere, and biosphere. However, little is known regarding the dynamics of bromine in the terrestrial environments. In this study, waterlogging incubation tests were conducted on two soil types, Lowland soil and Andosol, to verify the solubilization effect of waterlogging on soil bromine. The amount of bromine in the soil extracts increased considerably with incubation time in Lowland soil and Andosol, proving that the soil reduction caused by waterlogging enhanced the solubilization of soil bromine. The amount of bromine solubilized by soil reduction tended to be higher in Andosols, which had a higher total bromine concentration than Lowland soil. The amount by soil reduction during the 28 days period ranged from 0.18 to 1.14 µg g−1 for the Lowland soil group and from 0.20 to 30.2 µg g−1 for the Andosol group. Solubilized bromine could not remain in the soil, and most of it leached out with the percolation water, as shown by the soil-filled column tests. To estimate the amount of bromine leached from a rice paddy field under waterlogged conditions, a percolation test was conducted using Wagner pot-cropped paddy rice plants. The results showed that 531 to 544 mg of bromine per square meter of soil surface leached during one growing season. The amount of bromine leached from the soil was much higher than the previously reported annual amount of bromine addition to land from atmospheric deposition.

Plant growth and physiological responses of the invasive plant Acmella radicans to contrasting light and soil water conditions

Acmella radicans (Jacquin) R.K. Jansen is a new invasive species record for Yunnan Province, China, as of 2017 and little is known about its invasion mechanisms. To better understand its invasive strategies, we investigated the growth, physiological and soil nutrient use parameters of the invader under combined conditions of light (25%, 50%, 75%, and 100% of light availability) and soil water content (full, high, medium, and low soil water content) in the glasshouse. The results showed that light level, soil water content and their interaction had a significant effect on all plant morphological, physiological and soil nutrient parameters for A. radicans (P < 0.05). For the most part, plant height, total branch length, leafstalk length, leaf area, inflorescence number, seed number, leaf biomass, stem biomass, aboveground biomass, and total biomass of A. radicans were significantly increased with increased shading rate and soil water content and were generally greater at intermediate light levels and intermediate to high soil water levels. Under high-irradiance conditions, the chlorophyll content was greatly reduced compared to other treatments. We also observed that leafstalk length, leaf area, Pn, chlorophyll a, and chlorophyll b of A. radicans were markedly increased with increased shading rate and soil water content, and were generally highest under intermediate irradiance and soil water conditions, but many plant physiological parameters also exhibited relatively high values under waterlogging conditions. The concentrations of organic matter, available N and available K of A. radicans soils at high-irradiance and full-high soil water content treatments and medium-irradiance and high-medium soil water content treatments were often less than those of other treatments indicated that hypothetically soil absorption was increased by moderate shading and high soil water. This was the first study demonstrating that A. radicans thrives best under moderate light conditions in combination with high soil water. Furthermore, we surmised that its higher phenotypic and physiological plasticity contributes to its invasion success.

Drought Stress Effects and Ways for Improving Drought Tolerance in Impatiens walleriana Hook.f.—A Review

Drought is one of the main abiotic stresses affecting plant growth and development. Reduced plant yield and quality are primarily caused by the reductions in photosynthesis, mineral uptake, metabolic disorders, damages from the increased production of reactive oxygen species, and many other disruptions. Plants utilize drought resistance mechanisms as a defense strategy, and the systems’ activation is dependent upon several factors, including plant genotype, onthogenesis phase, drought intensity and duration, and the season in which the drought occurs. Impatiens walleriana is a worldwide popular flowering plant recognized for its vibrant flower colors, and is an indispensable plant in pots, gardens and other public areas. It prefers well-draining, moisturized soil, and does not perform well in overly dry or waterlogged conditions. Consequently, inadequate water supply is a common problem for this plant during production, transportation, and market placement, which has a substantial impact on plant performance overall. This review article outlines certain features of morphological, physiological, and molecular alterations induced by drought in ornamental, drought-sensitive plant species I. walleriana, as well as research carried out to date with the aim to improve the drought tolerance. Stress proteins aquaporins and dehydrins, whose molecular structure was described for the first time in this plant species, are highlighted specifically for their role in drought stress. Furthermore, the effective improvement of drought tolerance in I. walleriana by exogenous application of Plant Growth Regulators and Plant Growth-Promoting Bacteria is discussed in detail. Finally, this review can provide valuable insights for improving plant resilience and productivity in the face of water scarcity, which is critical for sustainable agriculture and horticulture.

Uncovering waterlogging-responsive genes in cucumber through machine learning and differential gene correlation analysis

As climate change intensifies, the frequency and severity of waterlogging are expected to increase, necessitating a deeper understanding of the cucumber response to this stress. In this study, three public RNA-seq datasets (PRJNA799460, PRJNA844418, and PRJNA678740) comprising 36 samples were analyzed. Various feature selection algorithms including Uncertainty, Relief, SVM (Support Vector Machine), Correlation, and logistic least absolute shrinkage, and selection operator (LASSO) were performed to identify the most significant genes related to the waterlogging stress response. These feature selection techniques, which have different characteristics, were used to reduce the complexity of the data and thereby identify the most significant genes related to the waterlogging stress response. Uncertainty, Relief, SVM, Correlation, and LASSO identified 4, 4, 10, 21, and 13 genes, respectively. Differential gene correlation analysis (DGCA) focusing on the 36 selected genes identified changes in correlation patterns between the selected genes under waterlogged versus control conditions, providing deeper insights into the regulatory networks and interactions among the selected genes. DGCA revealed significant changes in the correlation of 13 genes between control and waterlogging conditions. Finally, we validated 13 genes using the Random Forest (RF) classifier, which achieved 100% accuracy and a 1.0 Area Under the Curve (AUC) score. The SHapley Additive exPlanations (SHAP) values clearly showed the significant impact of LOC101209599, LOC101217277, and LOC101216320 on the model’s predictive power. In addition, we employed the Boruta as a wrapper feature selection method to further validate our gene selection strategy. Eight of the 13 genes were common across the four feature weighting algorithms, LASSO, DGCA, and Boruta, underscoring the robustness and reliability of our gene selection strategy. Notably, the genes LOC101209599, LOC101217277, and LOC101216320 were among genes identified by multiple feature selection methods from different categories (filtering, wrapper, and embedded). Pathways associated with these specific genes play a pivotal role in regulating stress tolerance, root development, nutrient absorption, sugar metabolism, gene expression, protein degradation, and calcium signaling. These intricate regulatory mechanisms are crucial for cucumbers to adapt effectively to waterlogging conditions. These findings provide valuable insights for uncovering targets in breeding new cucumber varieties with enhanced stress tolerance.

Ultrasonic treatment can improve maize seed germination and abiotic stress resistance

Constant-frequency ultrasonic treatment helped to improve seed germination. However, variable-frequency ultrasonic treatment on maize seed germination were rarely reported. In this study, maize seeds were exposed to 20–40 kHz ultrasonic for 40 s. The germination percentage and radicle length of maize seeds increased by 10.4% and 230.5%. Ultrasonic treatment also significantly increased the acid protease, α-amylase, and β-amylase contents by 96.4%, 73.8%, and 49.1%, respectively. Transcriptome analysis showed that 11,475 differentially expressed genes (DEGs) were found in the ultrasonic treatment and control groups, including 5,695 upregulated and 5,780 downregulated. Metabolic pathways and transcription factors (TFs) were significantly enriched among DEGs after ultrasonic treatment. This included metabolism and genetic information processing, that is, ribosome, proteasome, and pyruvate metabolism, sesquiterpenoid, triterpenoid, and phenylpropanoid biosynthesis, and oxidative phosphorylation, as well as transcription factors in the NAC, MYB, bHLH, WRKY, AP2, bZIP, and ARF families. Variable-frequency ultrasonic treatment increased auxin, gibberellin, and salicylic acid by 5.5%, 37.3%, and 28.9%, respectively. Abscisic acid significantly decreased by 33.2%. The related DEGs were upregulated and downregulated to varying degrees. Seed germination under the abiotic stress conditions of salt stress (NaCl solution), drought (PEG solution), and waterlogging (water-saturated sand bed) under ultrasonic treatment were promoted, radicle length was significantly increased by 30.2%, 30.5%, and 27.3%, respectively; and germination percentage by 14.8%, 20.1%, and 21.6%, respectively. These findings provide new insight into the mechanisms through ultrasonic to promote maize seed germination.

Molecular Responses to Drought and Waterlogging Stresses of Kiwifruit (Actinidia chinensis var. deliciosa) Potted Vines

Environmental extremes, such as drought and flooding, are becoming increasingly common, resulting in significant crop losses. The aim of the present study was to understand the molecular response induced by drought and waterlogging conditions, and to link these responses to the physiological adaptation of plants. For this purpose, leaf RNA expression was analyzed in potted kiwifruit plants by Illumina Next Generation Sequences. Stressed plants showed an impairment of all physiological parameters (leaf-gas exchange and stem-water potential) with a more evident effect in waterlogging condition than in drought condition. However, the impact on the transcriptome in waterlogged plants was less intense than in drought stress. Drought affected several metabolic pathways, among which “plant hormone signal transduction”, “protein processing in endoplasmic reticulum”, and “mitogen-activated protein kinase signaling pathway” were the most representative in terms of number of genes involved. The genes involved in the biosynthesis of phenylpropanoids were positively influenced by both drought and waterlogging. Finally, waterlogging stimulated secondary metabolisms by upregulating the genes responsible for the biosynthesis of terpenoids and flavonoids, such as stilbenoids. The obtained results show that the two contrasting stress conditions share several common physiological responses and molecular mechanisms.

Reclamation of coastal marshes to croplands shifts molecular composition of soil organic matter in the Bohai Rim

AbstractReclamation of coastal marshes to croplands lost massive reserves of soil organic matter (SOM). However, it is uncertain how reclamation shifts chemical composition of SOM and its size fractions. Here, we investigated this issue at two coastal marshes (Qilihai, degradation with seasonal waterlog; Beidagang, annual long‐term waterlog) along with adjacent long‐term reclaimed croplands on the coast of the Bohai Bay, China. Three SOM fractions: coarse particulate (cPOM, &gt;250 μm), fine particulate (fPOM, 53–250 μm), and mineral‐associated organic matter (&lt;53 μm) were analyzed by pyrolysis‐gas chromatography–mass spectrometry. Compared with the Qilihai marsh, the Beidagang marsh had higher SOM contents and lower proportions of microbial‐derived N‐containing compounds, which was attributed to the waterlogging‐induced weaker decomposition. Reclamation decreased the SOM contents (−53.6% to −63.3%) and proportions of lignin in cPOM (−44% to −52%) at both sites. However, reclamation‐induced shifts of molecular composition of SOM between the two sites diverged. At the Qilihai site, reclamation decreased the relative abundances of N‐containing compounds (−28%) but increased the proportions of lipids (+17%) and phenolics (+40.7%) in mineral‐associated organic matter. At the Beidagang site, reclamation decreased the proportions of monocyclic aromatics (−60.3% to −70.2%), but increased the relative abundances of N‐containing compounds (+175% to +407%) in all fractions. By contrast, the molecular composition of SOM at the two croplands had covergent pattern. In conclusion, despite of marsh locations with different waterlogging conditions, long‐term reclamation of wetlands to croplands generated convergent patterns in storage and molecular composition of SOM, which was attributed to the similar cropland cultivation.

Response of high yielding varieties of sugarcane (Saccharum spp. hybrid complex) to planting materials under waterlogged condition

A 3 -years field experiment consisting of 2 planting materials viz., 3- bud setts and bud chips and 5 sugarcane (Saccharum spp. hybrid complex) varieties (‘BO 91’, ‘CoP 16437’, ‘CoP 16438’ and ‘BO 156’) was conducted during spring seasons of 2016-17, 2017-18 and 2018-19, to study the effect of planting materials and varieties on productivity of sugarcane under waterlogged conditions. Significantly higher plant population (157, 000/ha), plant height (292 cm), LAI (4.12), mortality percent (38.4%), length of internode (11.8 cm), millable canes (96, 300/ha) and B: C ratio (0.70) was observed with bud chip as planting material than three bud setts. However, significantly higher number of nodes having aerial roots (8.3), cane diameter (2.09 cm) and single cane weight (828 g) were observed with 3 bud setts. Among the varieties, ‘BO 156’ exhibited better growth performance under waterlogged conditions with higher tillers (175, 000/ha), plant height (295 cm), drymatter accumulation (29.5 t/ha) and number of internode/cane (12). The LAI (4.26) and number of nodes having aerial roots (8.9) were found higher in ‘BO 91’. Higher cane diameter (2.11 cm) and single cane weight (936 g) were obtained from ‘CoP 16437’. But the variety ‘BO 91’ recorded higher millable canes (107, 500/ha) which was statistically comparable to ‘BO 156’. The data indicated that variety ‘BO 156’ recorded significantly higher cane yield (78.0 t/ha), gross returns (₹226, 200/ha), net returns (₹107, 000/ha) and B: C ratio (0.90) but it was at par ‘CoP 16437’ in respect to cane yield and gross returns. The quality in terms of brix (19.5%) and pol (17.11%) of ‘CoP 16438’ and ‘CoP 16437’ was better than ‘CoP 092’ and ‘BO 156’ but the sugar yield of varieties ‘BO 156’ (9.1 t/ha) and ‘CoP 16437’ (8.4 t/ha) were at par to each other. The productivity and economic parameters indicated that bud chip raised settlings and sugarcane variety ‘BO 156’ is economically viable options under waterlogged conditions.

Foliar-applied sulfur is supplemental to soil application in alleviating waterlogging stress through the mitigation of oxidative stress and ion homeostasis in rapeseed (Brassica napus L.)

Waterlogging has appeared as a major issue for agricultural production and has an adverse effect on rapeseed growth. A pot experiment was conducted to investigate the effect of soil and/or foliar applied S in alleviating the waterlogging stress in rapeseed (Brassica napus L. cv. Campino). The experiment treatments included, no soil S application (-SS), soil S fertilization (SS, 70 mg S kg−1 soil as MgSO4), foliar S application (FS, 300 ppm MgSO4) and both soil and foliar application of S (SS+FS). All the treatments were subjected to normal soil water (control) and waterlogged condition. Foliar S was applied two days prior to the onset of waterlogging treatment, which was imposed at vegetative stage (BBCH-31) for 7 days. The results demonstrated that without foliar S application, both unfertilized (-S) and S-fertilized (+S) waterlogged plants showed elevated level of hydrogen peroxide (35 % and 15 %) and malondialdehyde (84 % and 101 %) and reduced nutrients uptake, net photosynthesis and plant growth compared to their non-waterlogged counterparts. Although all S treatments alleviated the suppressing effects of waterlogging stress, the alleviative effect of soil plus foliar applied S was higher than these individual treatments. It increased dry matter by 17 %, superoxide dismutase activity by 15 %, catalase activity by 15 %, glutathione reductase activity by 14 %, ascorbate peroxidase activity by 18 %, ascorbate content by 19 %, glutathione content by 28 %. The increase in the growth and antioxidant activities of the soil plus foliar S supplemented plants was attributed to the increase in the contents of some nutrients (S 8 %, P 18 %, Mg 9 %, Zn 13 %) and net photosynthesis rate (19 %), whereas decrease in hydrogen peroxide (15 %), malondialdehyde (20 %), oxidized glutathione content (9 %), dehydroascorbic acid content (5 %) compared with untreated (without foliar-S) waterlogged plants. Collectively, the study concludes that foliar-S application supplements soil S fertilization in alleviating waterlogging stress in rapeseed plants, through inducing physiological and biochemical resistance, and improving homeostasis as well.

Physiological, Cellular, and Transcriptomic Analyses Provide Insights into the Tolerance Response of Arundo donax to Waterlogging Stress

Arundo donax is widely used as an ornamental plant in landscape gardening because of its adaptability to varying degrees of waterlogged conditions. However, to date, little information is available about the adaptive mechanism of A. donax under waterlogging stress. The results showed that long-term mild waterlogging efficiently induced the formation of adventitious roots (ARs) and further promoted root aerenchyma development, and that the activity of antioxidant enzymes (SOD, POD, and CAT) in Ars also was greatly enhanced after waterlogging. At the transcriptomic level, the expression of genes related to apoptosis, the regulation of cell division, ethylene biosynthesis, alginate synthesis, auxin signaling pathways, and anaerobic respiration was mostly up-regulated after the occurrence of waterlogging stress but genes involved in the abscisic acid signaling pathways were partly down-regulated, which indicated a preferential and favorable transcriptional response in regulating adventitious root development. Taken together, this study definitely advances our knowledge of the morphological, physiological, and transcriptomic responses of A. donax under waterlogging stress and sheds new lights on its adaptive mechanisms.

Comprehensive Expression Analysis of the WRKY Gene Family in Phoebe bournei under Drought and Waterlogging Stresses.

In response to biotic and abiotic stresses, the WRKY gene family plays a crucial role in plant growth and development. This study focused on Phoebe bournei and involved genome-wide identification of WRKY gene family members, clarification of their molecular evolutionary characteristics, and comprehensive mapping of their expression profiles under diverse abiotic stress conditions. A total of 60 WRKY gene family members were identified, and their phylogenetic classification revealed three distinct groups. A conserved motif analysis underscored the significant conservation of motif 1 and motif 2 among the majority of PbWRKY proteins, with proteins within the same class sharing analogous gene structures. Furthermore, an examination of cis-acting elements and protein interaction networks revealed several genes implicated in abiotic stress responses in P. bournei. Transcriptomic data were utilized to analyze the expression patterns of WRKY family members under drought and waterlogged conditions, with subsequent validation by quantitative real-time PCR (RT-qPCR) experiments. Notably, PbWRKY55 exhibited significant expression modulation under drought stress; PbWRKY36 responded prominently to waterlogging stress; and PbWRKY18, PbWRKY38, and PbWRKY57 demonstrated altered expression under both drought and waterlogging stresses. This study revealed the PbWRKY candidate genes that potentially play a pivotal role in enhancing abiotic stress resilience in P. bournei. The findings have provided valuable insights and knowledge that can guide further research aimed at understanding and addressing the impacts of abiotic stress within this species.

Cucumber JASMONATE ZIM-DOMAIN 6 interaction with transcription factor MYB6 impairs waterlogging-triggered adventitious rooting.

Waterlogging is a serious abiotic stress that drastically decreases crop productivity by damaging the root system. Jasmonic acid (JA) inhibits waterlogging-induced adventitious root (AR) formation in cucumber (Cucumis sativus L.). However, we still lack a profound mechanistic understanding of how JA governs AR formation under waterlogging stress. JAZ (JASMONATE ZIM-DOMAIN) proteins are responsible for repressing JA signaling in a transcriptional manner. In this study, we showed that overexpressing CsJAZ8 inhibited the formation of ARs triggered by waterlogging. Molecular analyses revealed that CsJAZ8 inhibited the activation of the R2R3-MYB transcription factor CsMYB6 via direct interaction. Additionally, silencing of CsMYB6 negatively impacted AR formation under waterlogging stress, as CsMYB6 could directly bind to the promoters of 1-aminocyclopropane-1-carboxylate oxidase2 gene CsACO2 and gibberellin 20-oxidases gene CsGA20ox2, facilitating the transcription of these genes. The overexpression of CsACO2 and CsGA20ox2 led to increased levels of ethylene and gibberellin, which facilitated AR formation under waterlogging conditions. On the contrary, silencing these genes resulted in contrasting phenotypes of AR formation. These results highlight that the transcriptional cascade of CsJAZ8 and CsMYB6 plays a critical role in regulating hormonal-mediated cucumber waterlogging-triggered AR formation by inhibiting ethylene and gibberellin accumulation. We anticipate that our findings will provide insights into the molecular mechanisms that drive the emergence of AR in cucumber plants under waterlogging stress.

Human health and ecological risk assessment of heavy metals in topsoil of different peatland use types

Peatlands, known for their ability to retain and immobilize heavy metals due to unique waterlogged conditions and organic matter, face challenges when subjected to disturbances such as land use changes. These disruptions alter the organic matter, redox potential, and pH of the peatsoil, potentially influencing the migration, mobilization, and increased availability of stored heavy metals. Peatsoil samples from various peatland use types (improved and semi-natural grassland, forest, industrial cutaway bog) were collected to assess the human health and ecological risk associated with heavy metals (Cd, Cu, Hg, Pb, and Zn) in Co-Offaly, Ireland. Results reveal variations in heavy metal concentrations across peatland use types, with Cd, Hg, and Pb in improved and semi-natural grassland peatsoils exceeding the World Health Organization (WHO) permissible safety limits. Contamination factors (CF) were higher in improved grassland, especially for Cd and Pb, exceeding one. Hakanson potential ecological risk assessment indicates acceptable overall risk levels, though variations exist between improved grassland, unimproved grassland, forest, and industrial cutaway bog. Combined exposure routes (dermal, ingestion and inhalation routes) to all heavy metals do not exceed safe exposure levels (indicating low non-carcinogenic risks. However, the cancer risk (CR) exceeds acceptable thresholds across all use types, with higher CR in improved grassland, especially for children. Overall, the findings emphasize the need for careful consideration of heavy metal risks associated with land use changes in peatlands, particularly in the improved grassland areas.