Background and AimsGlobal climate change is intensifying the co-occurrence of abiotic stresses, particularly combined waterlogging/submergence and salinity, posing severe and escalating threats to woody plant ecosystems critical for biodiversity, carbon storage, and soil stabilization. Despite extensive research on herbaceous species, understanding of woody plant responses remains fragmented and disproportionately focused on specific groups like mangroves and halophytes. This review aims to synthesize and critically evaluate the current state of knowledge on the integrated physiological, morphological, and molecular responses of diverse woody plants to this challenging combined stress scenario.MethodsA comprehensive synthesis and analysis of existing scientific literature was conducted. This involved systematically examining empirical studies, comparative analyses, and theoretical frameworks related to the responses of various woody plant species to the concurrent application of waterlogging/submergence and salinity stress, drawing comparisons to single-stress effects and herbaceous model systems.ResultsThe majority of woody plants exhibit synergistic, more detrimental effects under combined stress compared to either stress alone. Key manifestations include significantly heightened inhibition of photosynthesis, severe disruption of ion (particularly Na+ and Cl-) homeostasis leading to toxicity, and exacerbated oxidative damage. Woody plants utilize core stress tolerance mechanisms analogous to herbaceous species, such as ion exclusion/compartmentalization, activation of enzymatic and non-enzymatic antioxidant systems, and osmotic adjustment via compatible solute accumulation. Crucially, they also deploy distinctive structural and long-term adaptive strategies, including the development of specialized organs (pneumatophores, hypertrophic lenticels), deep root systems for accessing less saline groundwater, and physiological acclimation processes leveraging their perennial nature. Nevertheless, critical knowledge gaps persist, particularly concerning the underlying molecular signaling networks, the mechanisms of long-term adaptation over years/decades, and the specific responses of mature trees in natural ecosystems.ConclusionSignificant gaps hinder a comprehensive understanding of how woody plants cope with combined waterlogging/submergence and salinity stress. To advance fundamental knowledge and inform effective ecological restoration strategies for climate-resilient landscapes, future research must prioritize the application of integrated multi-omics approaches (genomics, transcriptomics, proteomics, metabolomics), the development of high-efficiency genetic transformation techniques for recalcitrant woody species, the deployment of advanced high-throughput phenotyping platforms, and crucially, long-term field-based studies simulating realistic future stress scenarios.

Waterlogging, or excessive accumulation of water in the soil, poses significant stress to riparian ecosystems and agroforestry, especially with increasing global rainfall. Cenchrus fungigraminus is a vital agricultural resource, biomaterial, and super-energy plant with high resistance and adaptability. This study examined its morphological and physiological responses under root and above-ground waterlogging for up to 30 days. Results showed that waterlogging significantly inhibited growth, reducing membrane permeability, and root activity, and accelerating leaf senescence (P < 0.05). Despite this, C. fungigraminus achieved 100 % survival after 30 days of waterlogging. The plant adapted to the hypoxic environment by enhancing oxygen channels through cortex cell loosening, lysigenous tissue formation, and adventitious root development. It also activated defense mechanisms, increasing the activities of antioxidant enzymes (SOD, POD, and CAT), levels of non-enzymatic antioxidants (AsA and GSH), osmotic regulators (SS, SP, and Pro), and anaerobic respiratory enzymes (PDC, ADH, and LDH), and hormones (ABA, IAA, GA, and ETH). Under two levels of waterlogging depth, the plant initially adopted the LowO2 escape strategy (LOES), but over time, it transitioned to the Low-O2 quiescence strategy (LOQS), while still retaining some features of the LOES. Our results revealed that C. fungigraminus demonstrates strong adaptability to waterlogging, especially in response to root waterlogging. By employing anatomical adjustments and exceptional cellular defense mechanisms, the species effectively mitigates damage, establishing itself as an excellent forage grass for slope protection under waterlogged conditions. These results offer valuable guidance for selecting waterlogging-tolerant species to restore and rehabilitate degraded riparian ecosystems in the Yellow River Basin, optimize land use in waterlogging-prone areas, and advance the genetic improvement of waterlogging tolerance in other forage varieties.

Global warming-induced abiotic stresses, such as waterlogging, significantly threaten crop yields. Increased rainfall intensity in recent years has exacerbated waterlogging severity, especially in lowlands and heavy soils. Its intensity is projected to increase by 14-35% in the future, posing a serious risk to crop production and the achievement of sustainable development goals. Soybean, a major global commercial crop cultivated across diverse climates, is highly sensitive to waterlogging, with yield losses of up to 83% due to impaired root morphology and growth. Therefore, understanding the stage-specific response of soybean to varying intensities of waterlogging under different climate regimes is crucial to mitigate the impact of climate change. This study evaluated two climate regimes (Summer: C-S and Rainy: C-R), four growth stages (S-15: 15 days after emergence, S-30, S-45, and S-60), and five waterlogging durations (D-2: 2 days, D-4, D-6, D-8, and D-10) using a randomized complete block design (RCBD) with seven replications in 2023. Results revealed that waterlogging adversely affected soybean root morphology (reducing root volume by 8.6% and dry weight by 5.3%) and growth (decreasing leaf area by similar to 6% and dry matter by 48.2%), with more severe effects observed during the summer compared to the rainy season. Among growth stages, soybean was most sensitive at S-45, showing greater reductions in growth attributes and seed yield (similar to 64.9%) across climate regimes. Prolonged waterlogging (2-10 days) had a pronounced negative impact on root and shoot parameters, resulting in yield reductions of 25.4-47.8% during summer and 47.0-68.2% during the rainy season, compared to the control. Yield stability was highest at D-2 (yield stability index: 0.53) with minimal yield reductions, while D-10 caused the greatest yield loss (similar to 58%). Interestingly, the summer climate regime, characterized by bright sunshine hours and higher temperatures, supported better post-stress recovery, leading to higher grain yields. In conclusion, waterlogging during C-R x S-45 x D-10 caused the most substantial yield reduction (similar to 91%).

Urban grasslands span climates and topography in soils with variable water infiltration and drainage rates that result in occasional waterlogging stress, while data on grass species tolerance to waterlogging stress is scant. Whole plant responses to waterlogging stress among cool-season grass species were quantified in a controlled environment. The following grasses were grown in well-drained vs. waterlogged soil for 55 d: strong creeping red fescue (Festuca rubra ssp. rubra), slender creeping red fescue (F. rubra ssp. littoralis), Chewings fescue (F. rubra ssp. commutata), hard fescue (F. brevipila), tall fescue (F. arundinacea syn. Schedonorus arundinaceus), Kentucky bluegrasses (Poa pratensis), annual bluegrass (P. annua), rough bluegrass (P. trivialis), creeping bentgrass (Agrostis stolonifera), perennial ryegrass (Lolium perenne), and alkaligrass (Puccinellia distans). Five cultivars of each fine fescue (Festuca spp.) taxon were included for comparison. When grown in waterlogged soil compared to well-drained conditions, relative differences generally ranged from -3% to -26% (shoots) and -13% to -33% (roots) for creeping bentgrass, tall fescue, and Kentucky bluegrass indicating higher waterlogging stress tolerance. The relative differences ranged from -18% to -43% in shoots and -3% to -34% in roots for annual bluegrass and perennial ryegrass indicating fair performance under waterlogging stress. Fine fescues, rough bluegrass, and alkaligrass exhibited the poorest performance during waterlogging stress with plant responses ranging from -12% to -64% (shoots) and -17% to -73% (roots). Negative whole plant responses among cultivars of four fine fescue taxa were similar. The selection of grasses tolerant to waterlogging stress will be important in developing resilient landscapes.

The initial outbreak of Xylella fastidiosa subsp. pauca (Xfp) on olive groves in Salento (Apulia, Italy) dates back to the years 2008 and 2009 when extensive twig and branch diebacks were observed in the area of Gallipoli area (province of Lecce). Subsequently, the bacterium also spread northwards to other areas of Apulia. In many cases, entire olive groves, also including the centennial ones, died. After the crown collapse, in many cases, it has been observed that the suckers are resprouting at the base of the trunk. After two to three years, such suckers usually died as well. However, during the last four to five years, in the first Xfp outbreak area, a complete restoration of the crown of the Xfp-susceptible cultivars Ogliarola salentina and Cellina di Nard & ograve; has been noticed. Such trees or olive groves also started to yield again. To monitor this tree resilience phenomenon, together with local non-profit organizations, a survey in the province of Lecce has been carried out to find olive groves for which any curative or agronomical practices have been applied since the bacterium outbreak. Resilient olive groves are scattered in many municipalities all over the province of Lecce. The phenomenon regards both young and adult olive groves and also includes some centennial trees. In many cases, the trees are yielding fruits, and farmers started to cultivate them again. Olive resilience in Salento is already being studied and can represent a significant opportunity to restore the local and valuable olive germplasm.

Soil flooding, manifesting as submergence or waterlogging stress, significantly impacts plant species composition and agricultural productivity, particularly in regions with low rainfall. This study investigates the biochemical responses of two peanut (Arachis hypogaea L.) genotypes, DH-86 and GJG-32, under waterlogging stress. The experiment involved in-vivo pot trials where peanut plants were subjected to continuous waterlogging for 12 days at the flowering stage. Biochemical analyses of leaves conducted and revealed significant alterations in enzyme activities and metabolite concentrations. Key findings include variations in superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPOD), alpha-amylase, invertase, acid phosphomonoesterase activities, and changes in starch, proline, reducing sugars, and chlorophyll content. SOD, CAT, and GPOD activities exhibited differential responses between genotypes, highlighting DH-86's quicker recovery post-waterlogging. Notably, DH-86 demonstrated higher resilience, reflected in its rapid normalization of biochemical parameters, while GJG-32 showed prolonged stress effects. These findings underscore the importance of antioxidative enzyme systems in mitigating oxidative damage induced by waterlogging. This study enhances our understanding of the biochemical adaptations of peanut genotypes to waterlogging stress, offering valuable insights for breeding programs focused on improving flood tolerance in crops.

Flooding, as a natural disaster, plays a pivotal role in constraining the growth and development of plants. Flooding stress, including submergence and waterlogging, not only induces oxygen, light, and nutrient deprivation, but also alters soil properties through prolonged inundation, further impeding plant growth and development. However, hypoxia (or anoxia) is the most serious and direct damage to plants caused by flooding. Moreover, flooding disrupts the structural integrity of plant cell walls and compromises endoplasmic reticulum functionality, while hindering nutrient absorption and shifting metabolic processes from normal aerobic respiration to anaerobic respiration. It can be asserted that flooding exerts comprehensive effects on plants encompassing phenotypic changes, transcriptional alterations, protein dynamics, and metabolic shifts. To adapt to flooding environments, plants employ corresponding adaptive mechanisms at the phenotypic level while modulating transcriptomic profiles, proteomic characteristics, and metabolite levels. Hence, this study provides a comprehensive analysis of transcriptomic, proteomic, and metabolomics investigations conducted on flooding stress on model plants and major crops, elucidating their response mechanisms from diverse omics perspectives.

Waterlogging increasingly challenges crop production, affecting 10% of global arable land, necessitating the development of pragmatic strategies for mitigating the downside risk of yield penalty. Here, we conducted experiments under controlled (tank) and field conditions to evaluate the efficacy of nitrogenous fertiliser in alleviating waterlogging stress. Without intervention, we found that waterlogging reduced grain yields, spike numbers and shoot biomass, but had a de minimus impact on grain number per spike and increased grain weight. Soil fertiliser mitigated waterlogging damage, enhancing yields via increased spike numbers, with crop recovery post-waterlogging catalysed via improved tiller numbers, plant height and canopy greenness. Foliar nitrogen spray has little impact on crop recovery, possibly due to stomatal closure, while modest urea application during and after waterlogging yielded similar results to greater N application at the end of waterlogging. Waterlogging-tolerant genotypes (P-17 and P-52) showed superior growth and recovery during and after waterlogging compared to the waterlogging-sensitive genotypes (Planet and P-79). A comparison of fertiliser timing revealed that field fertilizer treatment two (F2: 90 kgha(-1) at 28 DWL, 45 kgha(-1) at sowing and 45 kgha(-1) at 30 DR) yielded the highest and fertilizer treatment three (F3: 45 kgha(-1) at sowing and 45 kgha(-1) at 30 DR) recovered the lowest yield and spike number, while fertilizer treatment one (F1: 45 kgha(-1) at 28 DWL, 45 kgha(-1) at 0 DR, 45 kgha(-1) at sowing and 45 kgha(-1) at 30 DR) and four (F4: 90 kgha(-1) at 0 DR, 45 kgha(-1 )at sowing and 45 kgha(-1 )at 30 DR) had the highest shoot biomass in the field. Treatment five (T5: 180 kgha-1 at 0 DR, 30 kgha(-1) at sowing and 90 kgha(-1) at 30 DR) presented the most favourable results in the tank. Our results provide rigorous evidence that long periods of waterlogging caused significant yield penalty, mainly due to decreased spike numbers. We contend that increasing fertiliser rates during waterlogging up to 90 kgha(-1) can provoke crop growth and mitigate waterlogging-induced grain yield losses, and is more beneficial than applying nitrogen post-waterlogging.

In recent years, global climate anomalies and frequent flooding disasters have led to large-scale reduction and even crop failures of ginger production, severely restricting the normal production of ginger. However, the mitigation mechanism under waterlogging stress has not been reported in ginger. In order to investigate the physiological mechanism of the mitigation of waterlogging stress in ginger, the experiment was set up by soil application of urea peroxide(UHP) of different concentration (T1: 0 g & sdot; L - 1 ; T2: 40 g & sdot; L - 1 ; T3: 80 g & sdot; L - 1 ; T4:120 g & sdot; L - 1 ) after 2 d of waterlogging. The results showed that waterlogging stress significantly increased the accumulation of ROS and membrane lipid peroxidation in ginger roots and leaves. The chlorophyll content and photosynthetic performance were significantly decreased, and the net photosynthetic rate (Pn), Fv/Fm and Phi PSII of T1 were reduced by 123.5%, 18.8%, and 43.4% compared with that of CK, respectively. Exogenous application of UHP significantly improved the growth of ginger seedlings after waterlogging stress. UHP promoted the rapid recovery of ginger seedlings under waterlogging stress by restoring the normal physiological activity of the root system, and the root activity of T3 was significantly increased by 118.9% compared with that of T1. UHP protected the cellular structure of ginger leaves and improved the H 2 O-CO 2 exchange capacity, and the Pn and stomatal conductance (Gs) of T3 were significantly increased by 961% and 21.8% compared with that of T1, respectively. In addition, the Fv/Fm and Phi PSII of T3 were increased by 20.6% and 48.2% compared with that of T1, respectively. UHP also significantly increased the activity of antioxidant enzymes, and the levels of ROS and membrane damage were significantly reduced.

Rainfall variability, waterlogging and frequent natural hazards are the major obstacles for cropping system intensification in heavy textured soils of the coastal areas of Bangladesh. While earlier monsoon rice harvesting by introducing short duration varieties created opportunities for cultivating low water demanding non-rice crops in the dry season, such crops failed in many instances because of heavy rainfall and waterlogging. To address such issue, we have analysed dry season (Nov-Apr) rainfall patterns of six meteorological stations of coastal Bangladesh for studying the feasibility of growing irrigated rice and non-rice crops that can be harvested by April. Very heavy rainfall (>20 mm) occurred in 18-23% of the studied years and heavy rainfall (>10 mm) in 42-43% of cases creating the risk of water stagnation and damage to non-rice crops. The return intervals between occurrences of heavy rainfall and very heavy rainfall in November to December were 1.3-1.4 years and 1.5-2.5 years, respectively. These rainfall events generally delay establishment of non-rice crops. Similarly, in March and April, the return periods for heavy and very heavy rainfall were 1.3-1.5 years and 1.6-2.1 years, respectively. These rainfall events had a detrimental impact on non-rice crops, especially during their ripening stages. Such rainfall events during field experiments at the study locations were found in three years out of four cropping seasons that reduced sunflower and maize yields by 50-64% and sweet gourd and watermelon yields by 55-84% compared to their absence. The probability of high yield of non-rice crops was <25% and the yield variability was very high (40-75%) compared to general rice yield variability (5-6%). Risk factor analysis also revealed that dry season rice is less risky compared to other non-rice crops. To enhance risk management, intensification of cropping systems can be achieved by promoting cultivation of dry season irrigated rice where there is sufficient stored water for irrigation and encouraging farmers to grow pre-monsoon rice.