Search

Flooding, an abiotic stressor that has increased in frequency, could undermine progress made in building climate-resilient crops and soil-microbe-assisted plant resilience. Flooding impacts all aspects of the above and belowground plant-driven economy and drives changes in root-produced metabolites and soil microbes that underpin plant health, with consequences for all plant-associating communities. Understanding the understudied impacts of flooding could significantly expand the solutions generated to mitigate flooding. Flooding threatens crop productivity, agricultural sustainability, and global food security. In this article I review the effects of flooding on plants and highlight three important gaps in our understanding: (i) effects of flooding on ecological interactions mediated by plants both below (changing root metabolites and exudates) and aboveground (changing plant quality and metabolites, and weakening the plant immune system), (ii) flooding impacts on soil health and microorganisms that underpin plant and ecosystems health, and (iii) the legacy impacts of flooding. Failure to address these overlooked aspects could derail and undermine the monumental progress made in building climate-resilient crops and soil-microbe-assisted plant resilience. Addressing the outlined knowledge gaps will enhance solutions developed to mitigate flooding and preserve gains made to date. [ABSTRACT FROM AUTHOR]

The number and intensity of flood events will likely increase in the future, raising the risk of flooding stress in terrestrial plants. Understanding flood effects on plant physiology and plant‐associated microbes is key to alleviate flooding stress in sensitive species and ecosystems. Reduced oxygen supply is the main constrain to the plant and its associated microbiome. Hypoxic conditions hamper root aerobic respiration and, consequently, hydraulic conductance, nutrient uptake, and plant growth and development. Hypoxia favours the presence of anaerobic microbes in the rhizosphere and roots with potential negative effects to the plant due to their pathogenic behaviour or their soil denitrification ability. Moreover, plant physiological and metabolic changes induced by flooding stress may also cause dysbiotic changes in endosphere and rhizosphere microbial composition. The negative effects of flooding stress on the holobiont (i.e., the host plant and its associated microbiome) can be mitigated once the plant displays adaptive responses to increase oxygen uptake. Stress relief could also arise from the positive effect of certain beneficial microbes, such as mycorrhiza or dark septate endophytes. More research is needed to explore the spiralling, feedback flood responses of plant and microbes if we want to promote plant flood tolerance from a holobiont perspective. [ABSTRACT FROM AUTHOR]

The Brazilian Cerrado is the second largest Brazilian biome. In recent decades, a reduction in rainfall has indicated an extension of the dry season. Among the many native species of the Cerrado of the Annonaceae family and used in folk medicine, Annona crassiflora Mart. has fruits of high nutritional value and its by-products are sources of bioactive compounds, such as alkaloids. The aim of the study was to investigate how water stress impacts the production of alkaloids. The study was carried out in a nursery, and the knowledge was flood, field capacity and drought. Gas exchange, chlorophyll a fluorescence, antioxidant enzymes, total soluble sugars, starch, reducing sugars, sucrose, total alkaloids and liriodenine were analyzed. We observed that plants subjected to drought had an increase in the production of total alkaloids and liriodenine, without a reduction in photosynthetic metabolism. Plants kept under drought and flood conditions dissipated higher peroxidase activity, while catalase was higher in flooded plants. Starch showed the highest concentration in flooding plants without differing from drought plants; the lowest trehalose concentrations were found in both drought and flooding plants. The drought stimulated the synthesis of total alkaloids and liriodenine without reducing the primary metabolism, which suggests adaptation to Cerrado conditions. [ABSTRACT FROM AUTHOR]

As a result of the continuous global warming in recent years, the average annual number of rain days in China has been on the decline, while the number of rainstorm days has gradually increased. These conditions make it extremely easy to form a waterlogging environment, which has an adverse impact on plant growth and development. In many apple-producing areas in China, apples are subject to severe flooding during planting. In this study, two-year-old apple rootstock M9T337 was used to explore the effects of interval water stress on the morphological and physiological parameters of apple leaves. The purpose was to determine the plant’s adaptability to waterlogged environments and provide theoretical reference for management and maintenance after waterlogging. The results showed that the effect on flooded (T2) on apple stock was greater than that of waterlogged (T1), Short-term (7 d) waterlogging (T1) did not affect the growth of seedlings but was conducive to the accumulation of dry matter. Furthermore, the initial stress was be imprinted on the plants, which could directly affect their response to later stress. The results of principal component analysis (PCA) revealed that PC1, PC2, and PC3 explained 26.92%, 17.46%, and 13.03% of the physiological changes under water stress, respectively. By calculating the weight of each indicator, we concluded that high-frequency resistance r, relative chlorophyll content (SPAD) and maximum photochemical efficiency Fv/Fm are important parameters for apple rootstocks affected by water stress. [ABSTRACT FROM AUTHOR]

Extensive studies have shown that the relationship between flooding duration and wetland plant biomass is context specific. The underlying mechanisms, however, are uncertain. A likely explanation is that flooding has both direct effects by exerting stress on plants and indirect effects by affecting soil nutrient availability. The net effect would be context‐specific and might depend on season. Here, we tested two potential factors mediating the flooding effects on wetland plant biomass: soil nutrient availability and season.We carried out a field investigation in the lakeshore meadows of the Poyang Lake floodplain, China, along a flooding duration gradient during the non‐flooding period. To test the interaction between flooding duration and soil nutrients, we carried out a nutrient (N and P) addition experiment in two types of communities with different flooding durations.The above‐ground biomass (AGB) decreased with flooding duration in winter but had a quadratic response in spring, suggesting that the direct negative effect of flooding was stronger in winter than in spring. Soil total N content, total P content, and N:P ratio showed quadratic responses to flooding duration.Our results supported the hypotheses that the influence of nutrient limitation decreased with flooding duration and was greater in spring than in winter. The evidence showed that, with longer flooding duration and in winter than in spring, the correlations between AGB and soil nutrient content were weaker, leaf N and P content of Carex cinerascens were stronger, and AGB response ratio to nutrient addition was lower. Meanwhile, the relative importance of N versus P to wetland plant biomass varied with flooding duration.Consequently, indirect effects of flooding duration on AGB via soil nutrient availability were much less important than direct effects in winter or with long flooding duration, but were more important in spring or with short flooding duration. Therefore, the effects of flooding on wetland plant biomass depended on flooding duration, soil nutrient availability, and season. [ABSTRACT FROM AUTHOR]

In mangrove forests, the hydroperiod is strongly related to tidal dynamics, where the periodic oceanic water movement regulates the level, duration, and frequency of the flooding events. In fringe mangrove forests, Rhizophora mangle propagules deal with variable hydroperiod conditions that sometimes compromise their survival. To disentangle the combined effects of duration and intensity of flooding on physiological and growth variables, we imposed a continuous experiment with three levels of flooding and four flooding durations on seedlings of R. mangle. We collected data at 3 and 6.5 months after exposure to the treatments. Propagule reserves allowed plants to evade the effects of the flood level after a 3-month treatment period. After a 6.5-month exposure, physiology and growth were modulated by the flooding time. Individual plants had higher stem length and lower root and total biomass at prolonged and high flooding levels compared to any other flooding combinations. In both ages, the highest total plant biomass was exhibited in the medium flooding levels and 6 h flooding duration. The plasticity index was higher for morphological and biomass variables than for physiological variables. The high morphological plasticity of R. mangle plants constitutes a competitive advantage to colonize flooded sites in fringed mangrove areas. Our results identify schemes to improve the success of mangrove restoration plans, a critical tool for carbon sequestration and ecosystem service provision. • Mangrove seedlings enhance their flood tolerance with age. • High flooding increased stem mass fraction and length. • High flooding reduced foliar area, root, and total plant mass. • Increased flooding duration decreases stem biomass and length. • Stem and root variables showed the largest phenotypic plasticity. [ABSTRACT FROM AUTHOR]

Flooding duration is a major factor determining wetland plant growth and community composition. While there have been extensive studies on how direct effects of flooding duration on plant functional traits, very few have tested the indirect effects on these traits, including those arising from competition. We hypothesized that there would be a shift in importance of competition ability and flooding tolerance to functional traits along the flooding duration gradient. We investigated plant functional traits along a flooding duration gradient for two-dominant wetland plant species (Carex cinerascens and Phalaris arundinacea) in a lakeshore meadow of Poyang Lake, China. We found that these two species tended to have different strategies to adapt to flooding stress. P. arundinacea tended to adopt escape strategy with high growth rate (e.g. greater height, specific leaf area, and leaf N and P content) at longer flooding duration, while C. cinerascens tended to adopt more quiescence strategy, with only 5 of 13 of its traits showing a significant response. With shorter flooding duration, both species tended to have lower leaf N and P content, indicating greater nutrient limitation. Meanwhile, relative abundance of C. cinerascens with relatively higher belowground nutrient competition ability (i.e. greater root/shoot biomass ratio) decreased with flooding duration. These results suggest that belowground competition intensifies at shorter flooding duration, because of increased nutrient limitation with increased productivity. Therefore, our study indicates that both flooding stress and nutrient competition could affect plant functional traits along a flooding duration gradient. [ABSTRACT FROM AUTHOR]

Highlights • Rural innovation is the best practice of farmers' adaptation. • Rural innovations include innovative farming and water management practices. • Informal learning networks enable farmers to learn and share knowledge. • Interactions with extension officials enable the translation of farmers' innovations into adaptation policy. Abstract Agriculture is exposed to climatic impacts, especially in developing countries. Adaptation is the predominant practice that farming communities undertake to deal with these climate-induced challenges. While significant attention has been devoted to farmers' adaptation strategies, little is known about how innovative practices are associated with the improvement of rural livelihoods. To address this gap, the paper attempts to investigate how farmers lead the process of rural innovations that constitute successful forms of adaptation to address the mixed impacts of dyke policies and climate change in two distinct agro-ecological zones (i.e. flooding and salinity) in the Vietnamese Mekong Delta (VMD). Drawing on qualitative information collected from focus group discussions and interviews across the case studies, the paper argues that farmers are the key innovation actors who contribute to improving rural farming and water management practices. The study suggests that the evolution of farmer-led innovations is mainly attributed to the operation of various informal learning networks that provide important platforms for the generation and diffusion of effective innovative practices across farming communities. It also highlights how farmers contribute their innovative knowledge to local adaptation policies. From the policy perspective, this study sees the development of rural innovation systems as the best practices of farmers' adaptation, which needs to be scaled out to better support agricultural water management in the delta. [ABSTRACT FROM AUTHOR]

Climate change will have large consequences for flooding frequencies in freshwater systems. In interaction with anthropogenic activities (flow regulation, channel restoration and catchment land‐use) this will both increase flooding and drought across the world. Like in many other ecosystems facing changed environmental conditions, it remains difficult to predict the rate and trajectory of vegetation responses to changed conditions. Given that critical ecosystem services (e.g. bank stabilization, carbon subsidies to aquatic communities or water purification) depend on riparian vegetation composition, it is important to understand how and how fast riparian vegetation responds to changing flooding regimes. We studied vegetation changes over 19 growing seasons in turfs that were transplanted in a full‐factorial design between three riparian elevations with different flooding frequencies. We found that (a) some transplanted communities may have developed into an alternative stable state and were still different from the target community, and (b) pathways of vegetation change were highly directional but alternative trajectories did occur, (c) changes were rather linear but faster when flooding frequencies increased than when they decreased, and (d) we observed fastest changes in turfs when proxies for mortality and colonization were highest. These results provide rare examples of alternative transient trajectories and stable states under field conditions, which is an important step towards understanding their drivers and their frequency in a changing world. To explore pathways of vegetation change after various flooding regime changes, we transplanted vegetation turfs full‐factorial between three riparian elevations (upland, middle and low elevation). Vegetation changes were directional and faster when flooding frequencies increased than when they decreased. After 19 growing seasons, we found indications for alternative stable states and alternative trajectories under field conditions, which is an important step towards understanding their drivers and their frequency in a changing world. [ABSTRACT FROM AUTHOR]

Highlights • Baldcypress tree growth and stand density are differentially affected by flooding. • Tree and stand level growth metrics were compared using new data and meta-analyses. • Sparse, flood-disturbed, freshwater sites often contained vigorously growing trees. • Sparse, flood-disturbed, saline sites mostly contained poorly growing trees. Abstract Stand production, a common indicator of site productivity, is often low in flooded wetland forests. However, it remains unclear whether the low production reflects flood stress limiting tree growth, flood disturbance limiting tree density, or both. Here, we investigate how tree growth and stand density vary in baldcypress forests, across gradients of flooding by both fresh and saline waters. We used three investigations to conduct this analysis: (a) a meta-analysis of previously reported tree- and stand-production measurements; (b) an analysis of tree cores from 204 baldcypress trees in 16 sites; and (c) intensive stand surveys and growth measurements across two freshwater flooding gradients in southern Louisiana. The meta-analysis (a) showed that stand production generally varies linearly with stand density, and that detrimental effects of flooding on tree-level growth are only consistently evident in saline systems. The tree-core investigation (b) showed that tree basal area growth was largely a function of tree sapwood area, but basal area growth per sapwood area (i.e. sapwood efficiency, a measure of how efficiently trees grow per growing space occupied) was higher in the more flooded sites of freshwater gradients and lower in the more saline sites of salinity gradients. The intensively studied sites (c) showed that deeper flooding was associated with sparse stands with lower production; however, trees in those sparser sites had higher sapwood efficiency, implying that the benefits of reduced competition were greater than any potential physiological limitations caused by that deeper flooding. Our findings generally show that sparser stands with saline flooding contained poorly growing trees, but sparser stands with freshwater flooding generally did not. These dichotomous effects of freshwater flooding on tree growth versus stand density demonstrate the need to conceptualize production as a dual function of disturbance effects on stand structure and environmental limitations on individual trees, each with potentially different limiting factors. [ABSTRACT FROM AUTHOR]

Flooding has globally become common, and thus cultivation techniques to adapt to the stress are required. We have developed a technique called "close mixed-planting" using flood-adapted rice (Oryza sativa L.) and upland crops with tangled root systems, showing that this technique can mitigate the damage caused to upland crops by flooding. However, the plant response during the reproductive stage has not yet been examined. In this study, we estimated the alleviative effects of close mixed-planting on the growth inhibition and physiological damage to pearl millet (Pennisetum glaucum) caused by flooding at the reproductive stage in northern Namibia. Pearl millet and NERICA4 (Oryza spp., interspecies of O. sativa and O. glaberrima) were used. Four-week-old single- and mixed-crop pearl millets were transplanted and grown for 22 days, and then flooding treatment was administered for 28 days. The growth and physiological parameters of single pearl millet were significantly decreased by flooding stress, and the parameters did not recover during a 14-day recovery period compared with those of unflooded single and mix-cropped pearl millet. On the other hand, the damage to mix-cropped pearl millet by flooding was suppressed. Thus, the mixed-cropping mitigated the anoxic stress of pearl millet caused by flooding at the reproductive stage and contributed to the improved growth after the recovery period. This result suggested that the close mixed-planting with rice can contribute to the mitigation of flooding damage not only at the vegetative stage but also at the reproductive stage of pearl millet in the semi-arid African country, Namibia. [ABSTRACT FROM AUTHOR]

Managed flooding is increasingly being used to maintain and restore the ecological values of floodplain wetlands. However, evidence for its effectiveness is sometimes inconsistent and water available for environmental purposes often limited. We experimentally inundated a floodplain wetland (or "billabong") in late spring by pumping water from its adjacent creek, aiming to promote the native wetland flora and suppress terrestrial exotics. Vegetation was surveyed before (spring) and after (late summer) the managed flood in the experimental billabong and in three control billabongs. Floodplain water levels were continuously monitored. Wet conditions caused two of the control billabongs to also flood, but to a lesser extent than the experimental billabong. We therefore assessed vegetation changes relative to flooding duration. With increasing flooding duration, the cover of wetland vegetation (amphibious and aquatic species) increased and the cover of terrestrial and exotic vegetation decreased, with these effects largest in the deliberately flooded billabong. Flooding durations greater than 20 days generally resulted in increased cover of wetland plants and restricted the growth of terrestrial plants. Reinstatement of more appropriate flooding regimes can thus promote native wetland plants, while suppressing terrestrial exotic species. Our study also provides evidence for the use of modest water allocations to augment the benefits of natural flooding in the maintenance and restoration of native wetland plant communities. [ABSTRACT FROM AUTHOR]

The shift from aerobic to anaerobic respiration is crucial for soybean response to flooding stress; however, the regulatory mechanism in action at the initial stage of flooding stress has not been fully elucidated. To identify this mechanism in soybean, proteomic analysis of S-nitrosylated proteins was performed with emphasis on nitric oxide (NO)-mediated regulation in soybean seedlings. Removal of NO by addition of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) partially restored seedling growth. After 3, 9, and 24 h of flooding stress, the S-nitrosylation status of 364, 188, and 186 proteins was altered relative to the corresponding status before flooding, respectively. Abundance of S-nitrosylated forms of 2, 186, and 162 proteins differed between the untreated control and flooded soybean plants after 3, 9, and 24 h of flooding stress, respectively. After flooding for 3 h, development, stress, and glycolysis/fermentation categories were identified as the top categories including proteins for which abundance of S-nitrosylated forms increased. Visualization of changes in S-nitrosylation profile by pathway mapping indicated a characteristic pattern in glycolysis/fermentation. Western blot analysis confirmed that S-nitrosylated status of alcohol dehydrogenase increased with flooding. These results suggest that S-nitrosylation comprises rapid molecular processes that change the abundance of the active form of alcohol dehydrogenase. [ABSTRACT FROM AUTHOR]

This is an institutional study of the policy instruments that respond to flood for agricultural producers and their community. Two case studies in Saskatchewan and Alberta, Canada were conducted through a review of secondary sources and semi-structured qualitative interviews to assess instruments based on the perceptions of agricultural producers and people involved in flood governance. Recent changes reducing federal government emergency training services for local responders have occurred at the same time that federal government disaster assistance payments to provinces and local communities have increased dramatically. Financial instruments are of key importance but increased attention should be paid to management instruments including participatory resilient emergency flood planning. Fragmentation in flood instruments and planning, together with a myopic time frame that does not include climate change considerations, leaves the study communities and agricultural producers vulnerable. Disparate communities not operating cohesively as districts leave one case study area vulnerable. These deficiencies are remediable by implementing appropriate missing instruments and comprehensive institutional flood planning. [ABSTRACT FROM AUTHOR]

The physiology of fatherhood is a growing field of study, and variability in hormonal mediators of reproductive effort (e.g. testosterone, cortisol) can predict variability in paternal investment. Studies often find that lower testosterone levels are associated with increased paternal investment, though most studies are conducted under relatively stable ecological conditions. In this paper, we examine parental physiological correlates of crop loss and family health problems among Tsimane forager-horticulturalists following a catastrophic flood in lowland Bolivia. Immediately after a devastating 2014 flood that impacted >75% of Tsimane communities, we conducted structured interviews examining crop losses and morbidity, and collected saliva specimens from 421 parents (n = 292 households) to analyze cortisol and testosterone. Over 98% of interviewees reported horticultural losses, with the average family losing 88% of their crops, while 80% of families reported flood-induced injuries or illnesses. Controlling for age, body mass index, and time of specimen collection, men's testosterone was negatively associated with both absolute cropland losses (Std. β = −0.16, p = 0.037), and percent of cropland lost (Std. β = −0.16, p = 0.040). Female testosterone was not associated with crop losses. Using the same control variables, both male and female cortisol was negatively associated with a composite measure of child health burden (fathers: Std. β = −0.34, p < 0.001; mothers: Std. β = −0.23, p = 0.037). These results are discussed in the cultural context of a strong sexual division of labor among Tsimane; we highlight the physiological and psychosocial costs of experiencing a natural disaster, especially for paternal caregivers in a nutritionally and pathogenically stressed subsistence population where cultigens provide the majority of calories in the diet. [ABSTRACT FROM AUTHOR]

Flooding frequency is predicted to increase during the next decades in Europe. Therefore, it is important to understand how short-term disturbance events affect soil biota providing essential ecosystem functions and uncover factors modulating their response such as plant community composition. Here we report on the response of soil microarthropod communities (Collembola and Acari) to a severe summer flood in 2013, which affected major parts of central Europe. Collembola and Acari density and Collembola and Oribatida richness were strongly affected by the flood, but they recovered within three months. Effects of plant community composition on soil microarthropods disappeared after the flood, presumably due to homogenization of the field, but the effects of plant community were in a stage of being reasserted three months after the flood. Widespread, surface living and generalistic microarthropod species recolonized the field quickly. Prostigmata and Oribatida were more resilient or recovered to flooding than Astigmata and Gamasida. Long-term impacts, however, remain unknown and deserve further investigation. [ABSTRACT FROM AUTHOR]

In discussions of human-environmental dynamics and climate change, treatments of water usually focus on the problem of drought. Monsoon environments constitute a different set of parameters for landscape interactions because of seasonal episodes of water abundance. In this paper, we evaluate the microscale management of routine and anticipated high-water events for the ancient Indian subcontinent, where people used the monsoon cycle to engage in rice farming that in turn supported the growth of cities. Rice production would have encompassed two fluctuating inputs: rural labor, which may have become scarce when villagers left farmlands to become city dwellers; and water, the quantity of which varies dramatically on both a seasonal basis because of the monsoon and on an occasional basis because of tropical cyclones. The abundance of water (even with its risks of overabundance) encompassed numerous logistical challenges but also permitted high productivity within short distances of urban centers. The case study of the ancient city of Sisupalgarh in eastern India illustrates that high levels of productivity per land area enabled city residents to engage in short-distance economies for food production, while maintaining regional contacts through durable-goods trade to mitigate occasional episodes of crop failure in times of major flooding. [ABSTRACT FROM AUTHOR]

Ethnomedicinal plants play a very important role in the life of human beings. Bihar is a state where 80% people depend on plants and plants part for their diseases and their treatment. The studies indicate the value of traditional system of medicines, economically useful plants and possible effects of climate changes on medicinal plants. It is true that climate changes are causing noticeable effect on life cycles and distribution of the plant species in Saran district. Medicinal plants are widely used at present. A large no. of people in Bihar is directly dependent on the healthcare treatment by medicinal plants that is why it is a matter of concern in Bihar. It is very necessary to improve our understanding about the effects on medicinal plants by various researched and stems in present article. To know the present condition of medicinal plants and the effect of climatic changes on them in Saran district, Bihar. [ABSTRACT FROM AUTHOR]

Wheat is planted through the broadcast method on 7.8 million ha and irrigated through low-efficiency flood basin irrigation methods. With decreased water availability, there is a need to adopt water use efficient planting techniques. The current paper uses two-year trials data set as well as farmer survey data to demonstrate benefits of ridge-furrow planting wheat and farmer perception regarding the technology in Pakistan. During 2014–15 and 2015–16, ridge-furrow planting of wheat was compared with farmer practice of planting on flat surface through broadcasting at 162 sites located in 15 districts of Pakistan. In a survey, 134 farmers shared their experiences about ridge-furrow planting. Data collected from field trials and demonstrations showed that better tillering and crop growth contributed towards 12% higher wheat grain yield with ridge-furrow planting in comparison with the farmer practice of flat planting in all 15 districts during both years. Furrow-irrigated ridge planting of wheat helped farmers in saving of 30–35% water in comparison with farmer practice. Farmers adopting ridge-furrow wheat planting earned USD 100.63 per hectare more profit than nonadopter farmers. Adoption of this technology on one million hectare can help in saving 1 million acre foot of water and produce additional 0.36 million tons of wheat per year. [ABSTRACT FROM AUTHOR]

Abiotic stresses in plants are often transient, and the recovery phase following stress removal is critical. Flooding, a major abiotic stress that negatively impacts plant biodiversity and agriculture, is a sequential stress where tolerance is strongly dependent on viability underwater and during the postflooding period. Here we show that in Arabidopsis thaliana accessions (Bay-0 and Lp2-6), different rates of submergence recovery correlate with submergence tolerance and fecundity. A genome-wide assessment of ribosome-associated transcripts in Bay-0 and Lp2-6 revealed a signaling network regulating recovery processes. Differential recovery between the accessions was related to the activity of three genes: RESPIRATORY BURST OXIDASE HOMOLOG D, SENESCENCE-ASSOCIATED GENE113, and ORESARA1, which function in a regulatory network involving a reactive oxygen species (ROS) burst upon desubmergence and the hormones abscisic acid and ethylene. This regulatory module controls ROS homeostasis, stomatal aperture, and chlorophyll degradation during submergence recovery. This work uncovers a signaling network that regulates recovery processes following flooding to hasten the return to prestress homeostasis. [ABSTRACT FROM AUTHOR]

Vegetation response to flooding across large dryland areas such as Australia's Murray Darling Basin (MDB) is not understood synoptically and with locally relevant detail. We filled this knowledge gap by quantifying vegetation dynamics, defined here as greening and browning due to changing chlorophyll content and leaf area index, in response to flooding and rainfall across the floodplains of the entire MDB. We quantified vegetation and flooding dynamics using the same data source, namely 26 years of high resolution, wall-to-wall satellite data, in a top down statistical modeling approach, where we controlled for rainfall. Our time series (1986–2011) covered a period of extreme hydroclimatic variability, including the South East Australian Millennium Drought, thus providing a research opportunity to investigate how the relationship between vegetation and flooding changed during wet and dry periods. Our results showed that besides rainfall, flooding plays a key role in driving floodplain vegetation dynamics, yet the role of flooding varied across the MDB floodplains. We quantified a change in the relationship of how vegetation responds to rainfall and flooding with an unprecedented level of spatial detail. The change in the relationships coincided primarily with the onset of the Millennium Drought, yet local and regional differences in the timing of the change did occur, suggesting that the beginning of the Millennium Drought did not impact all floodplain areas at the same time. Our synoptic while locally relevant quantification of the changing response of vegetation to rainfall and flooding is a first step to help underpin Australia's investment into environmental water allocations. [ABSTRACT FROM AUTHOR]

Flooding negatively affects the growth of soybean, whereas the plant-derived smoke enhances seedling growth of crops. To clarify the mechanism underlying the recovery from flooding stress, proteomic analysis was performed based on morphological results. Growth of soybean seedlings was inhibited under flooding stress, but it recovered after water removal following treatment with plant-derived smoke. Sucrose/starch metabolism and glycolysis were suppressed in smoke-treated flooded soybean compared to flooded soybean. The protein abundance and gene expression of O -fucosyltransferase family proteins related to the cell wall were higher in smoke-treated flooded soybean than in flooded soybean. Protein abundance and gene expression of peptidyl-prolyl cis-trans isomerase and Bowman-Birk proteinase isoinhibitor D-II were lower in smoke-treated flooded soybean than in flooded soybean. Taken together, these results suggest that plant-derived smoke enhances soybean growth during recovery from flooding stress through the balance of sucrose/starch metabolism and glycolysis. Furthermore, the accumulation of cell-wall related protein might be an important factor contributing to recovery of soybean from flooding stress. Biological significance Flooding negatively affects the growth of soybean, whereas the plant-derived smoke enhances the seedling growth of crops. To clarify the mechanism underlying the recovery from flooding stress, proteomic analysis of soybean with different treatments including normal conditions, flooding stress, and flooding stress in the presence of plant-derived smoke was performed in this study. Growth of soybean seedlings was inhibited under flooding stress, however, it recovered with plant-derived smoke treatment during recovery from flooding stress. Sucrose/starch metabolism and glycolysis were suppressed in smoke-treated flooded soybean compared to flooded soybean, which suggests altered sucrose/starch metabolism and glycolysis contribute to soybean growth recovery from flood stress. Furthermore, the protein abundance and gene expression of O-fucosyltransferase family proteins related to the cell wall was higher in smoke-treated flooded soybean than in flooded soybean, which might be an important factor contributing to the recovery of soybean from flooding stress. [ABSTRACT FROM AUTHOR]

Climate change models predict temporal and spatial shifts in precipitation resulting in more frequent incidents of flooding, particularly in regions with poor soil drainage. In these flooding conditions, crop losses are inevitable due to exposure of plants to hypoxia and the spread of root rot diseases. Improving the tolerance of bean cultivars to flooding is crucial to minimize crop losses. In this experiment, we evaluated the phenotypic responses of 277 genotypes from the Andean Diversity Panel to flooding at germination and seedling stages. A randomized complete block design, with a split plot arrangement, was employed for phenotyping germination rate, total weight, shoot weight, root weight, hypocotyl length, SPAD index, adventitious root rate, and survival score. A subset of genotypes (n = 20) were further evaluated under field conditions to assess correlations between field and greenhouse data and to identify the most tolerant genotypes. A genome-wide association study (GWAS) was performed using ~203 K SNP markers to understand the genetic architecture of flooding tolerance in this panel. Survival scores between field and greenhouse data were significantly correlated (r = 0.55, P = 0.01). Subsequently, a subset of the most tolerant and susceptible genotypes were evaluated under pathogenic Pythium spp. pressure. This experiment revealed a potential link between flooding tolerance and Pythium spp. resistance. Several tolerant genotypes were identified that could be used as donor parents in breeding pipelines, especially ADP-429 and ADP-604. Based on the population structure analysis, a subpopulation consisting of 20 genotypes from the Middle American gene pool was detected that also possessed the highest root weight, hypocotyl length, and adventitious root development under flooding conditions. Genomic regions associated with flooding tolerance were identified including a region on Pv08/3.2Mb, which is associated with germination rate and resides in vicinity of SnRK1.1, a central gene involved in response of plants to hypoxia. Furthermore, a QTL at Pv07/4.7Mb was detected that controls survival score of seedlings under flooding conditions. The association of these QTL with the survivability traits including germination rate and survival score, indicates that these loci can be used in marker-assisted selection breeding to improve flooding tolerance in the Andean germplasm. [ABSTRACT FROM AUTHOR]

Summary: Rice (Oryza sativa L.) has two ecotypes, upland and lowland rice, that have been observed to show different tolerance levels under flooding stress. In this study, two rice cultivars, upland (Up221, flooding‐intolerant) and lowland (Low88, flooding‐tolerant), were initially used to study their molecular mechanisms in response to flooding germination. We observed that variations in the OsCBL10 promoter sequences in these two cultivars might contribute to this divergence in flooding tolerance. Further analysis using another eight rice cultivars revealed that the OsCBL10 promoter could be classified as either a flooding‐tolerant type (T‐type) or a flooding‐intolerant type (I‐type). The OsCBL10 T‐type promoter only existed in japonica lowland cultivars, whereas the OsCBL10 I‐type promoter existed in japonica upland, indica upland and indica lowland cultivars. Flooding‐tolerant rice cultivars containing the OsCBL10 T‐type promoter have shown lower Ca2+ flow and higher α‐amylase activities in comparison to those in flooding‐intolerant cultivars. Furthermore, the OsCBL10 overexpression lines were sensitive to both flooding and hypoxic treatments during rice germination with enhanced Ca2+ flow in comparison to wild‐type. Subsequent findings also indicate that OsCBL10 may affect OsCIPK15 protein abundance and its downstream pathways. In summary, our results suggest that the adaptation to flooding stress during rice germination is associated with two different OsCBL10 promoters, which in turn affect OsCBL10 expression in different cultivars and negatively affect OsCIPK15 protein accumulation and its downstream cascade. [ABSTRACT FROM AUTHOR]

Abstract: Floods and salinization of agricultural land adversely impact global rice production. We investigated whether gas films on leaves of submerged rice delay salt entry during saline submergence. Two‐week‐old plants with leaf gas films (+GF) or with gas films experimentally removed (−GF) were submerged in artificial floodwater with 0 or 50 m m NaCl for up to 16 d. Gas films were present >9 d on GF plants after which gas films were diminished. Tissue ion analysis (Na+, Cl− and K+) showed that gas films caused some delay of Na+ entry, as leaf Na+ concentration was 36–42% higher in −GF leaves than +GF leaves on days 1–5. However, significant net uptakes of Na+ and Cl−, and K+ net loss, occurred despite the presence of gas films, indicating the likely presence of some leaf‐to‐floodwater contact, so that the gas layer must not have completely separated the leaf surfaces from the water. Natural loss and removal of gas films resulted in severe declines in growth, underwater photosynthesis, chlorophylla and tissue porosity. Submergence was more detrimental to leaf PN and growth than the additional effect of 50 m m NaCl, as salt did not significantly affect underwater PN at 200 μ m CO2 nor growth. [ABSTRACT FROM AUTHOR]

Abstract: The hydrology of riparian areas changes rapidly these years because of climate change‐mediated alterations in precipitation patterns. In this study, we used a large‐scale in situ experimental approach to explore effects of drought and flooding on plant taxonomic diversity and functional trait composition in riparian areas in temperate Europe. We found significant effects of flooding and drought in all study areas, the effects being most pronounced under flooded conditions. In near‐stream areas, taxonomic diversity initially declined in response to both drought and flooding (although not significantly so in all years) and remained stable under drought conditions, whereas the decline continued under flooded conditions. For most traits, we found clear indications that the functional diversity also declined under flooded conditions, particularly in near‐stream areas, indicating that fewer strategies succeeded under flooded conditions. Consistent changes in community mean trait values were also identified, but fewer than expected. This can have several, not mutually exclusive, explanations. First, different adaptive strategies may coexist in a community. Second, intraspecific variability was not considered for any of the traits. For example, many species can elongate shoots and petioles that enable them to survive shallow, prolonged flooding but such abilities will not be captured when applying mean trait values. Third, we only followed the communities for 3 years. Flooding excludes species intolerant of the altered hydrology, whereas the establishment of new species relies on time‐dependent processes, for instance the dispersal and establishment of species within the areas. We expect that altered precipitation patterns will have profound consequences for riparian vegetation in temperate Europe. Riparian areas will experience loss of taxonomic and functional diversity and, over time, possibly also alterations in community trait responses that may have cascading effects on ecosystem functioning. [ABSTRACT FROM AUTHOR]

The Blanco River, which flows through the limestone Balcones Canyonlands of central Texas (USA), experienced catastrophic flooding in May 2015 that resulted in significant biogeomorphic disturbance to its riparian corridor. High-resolution aerial and satellite imagery from pre- and post-flooding for a 55-km reach of river were used to map and categorize patterns of disturbance by degree of severity ranging from complete floodplain stripping to no disturbance. The most severe disturbance occurred within the floodway near the channel and decreased with lateral distance into the 100- and 500-year floodplains. Disturbance patterns previously identified in the literature including meander scour, parallel chute scour, convex bank erosion, and macroturbulent scour were all present following this event, as well as substantial disturbance proximal to tributary confluences. In the aftermath of this event, TreeFolks, a local nonprofit organization, engaged with the community to actively replant and restore the riparian corridor of the Blanco River on public and private lands. These reforestation efforts supplement the natural passive recovery of the riparian corridor, enabling the system to recover more quickly and be resilient to future flood events. [ABSTRACT FROM AUTHOR]

Black ash (Fraxinus nigra Marsh.) exhibits canopy dominance in regularly inundated wetlands, suggesting advantageous adaptation. Black ash mortality due to emerald ash borer (Agrilus planipennis Fairmaire) will alter canopy composition and site hydrology. Retention of these forested wetlands requires understanding black ash's ecohydrologic role. Our study examined the response of sap flux to water level and atmospheric drivers in three codominant species: black ash, red maple (Acer rubrum L.), and yellow birch (Betula alleghaniensis Britt.), in depressional wetlands in western Michigan, USA. The influence of water level on sap flux rates and response to vapor pressure deficit (VPD) was tested among species. Black ash had significantly greater sap flux than non-black ash at all water levels (80-160% higher). Black ash showed a significant increase (45%) in sap flux rates as water levels decreased. Black ash and red maple showed significant increases in response to VPD as water levels decreased (112% and 56%, respectively). Exploration of alternative canopy species has focused on the survival and growth of seedlings, but our findings show important differences in water use and response to hydrologic drivers among species. Understanding how a replacement species will respond to the expected altered hydrologic regimes of black ash wetlands following EAB infestation will improve species selection. [ABSTRACT FROM AUTHOR]

Saltmarsh plants are exposed tomultiple stresses including tidal inundation, salinity, wave action and sediment anoxia, which require specific root system adaptations to secure sufficient resource capture and firm anchorage in a temporary toxic environment. It is well known that many saltmarsh species develop large below-ground biomass (roots and rhizomes) but relations between fine roots, in particular, and the abiotic conditions in salt marshes are widely unknown. We studied fine root mass (<2mm in diameter), fine root depth distribution and fine root morphology in three typical communities (Spartina anglica-dominated pioneer zone, Atriplex portulacoides-dominated lowermarsh, Elytrigia atherica-dominated uppermarsh) across elevational gradients in two tidal saltmarshes of the German North Sea coast [a mostly sandy marsh on a barrier island (Spiekeroog), and a silty-clayey marsh on the mainland coast (Westerhever)]. Fine root mass in the 0-40 cm profile ranged between 750 and 2,500 g m-2 in all plots with maxima at both sites in the lower marsh with intermediate inundation frequency and highest plant species richness indicating an effect of biodiversity on fine root mass. Fine root mass and, even more, total fine root surface area (maximum 340 m2 m-2) were high compared to terrestrial grasslands, and were greater in the nutrient-poorer Spiekeroog marsh. Fine root density showed only a slight or no decrease toward 40 cm depth.We conclude that the standing fine root mass and morphology of these salt marshes is mainly under control of species identity and nutrient availability, but species richness is especially influential. The plants of the pioneer zone and lower marsh possess well adapted fine roots and large standing root masses despite the often water-saturated sediment. [ABSTRACT FROM AUTHOR]

The experiments concluded 48hrs for germination testing as most appropriate stress duration. Using paper roll for recording the traits was the best method than petri dish and towel method. Among the traits relative germination rate (RGR), relative seedling length (RSL), relative root length (RRL), relative root fresh weight (RRFW) and relative root dry weight (RRDW) were proved to be flooding-responsive. RSL was chosen as the major seed-flooding indicator due to higher heritability (h2), genotypic coefficient of variation (GCV), correlation with other indicators and easier measuring procedure, while RRL was considered as the subsidiary indicator. Thus, the RSL in paper roll after 48hrs seed-flooding was recognized as standard seed-flooding testing procedure and used to evaluate breeding materials. Among the 11 cultivars, the superior seed-floodingtolerant ones were M8206, NN1138-2 and ZXD, while ten best lines were evaluated from one hundred breeding lines. [ABSTRACT FROM AUTHOR]

Abstract: Extensive modelling studies on nitrogen (N) dynamics in flooded soil systems have been published. Consequently, many N dynamics models are available for users to select from. With the current research trend, inclined towards multidisciplinary research, and with substantial progress in understanding of N dynamics in flooded soil systems, the objective of this paper is to provide an overview of the modelling concepts and performance of 14 models developed to simulate N dynamics in flooded soil systems. This overview provides breadth of knowledge on the models, and, therefore, is valuable as a first step in the selection of an appropriate model for a specific application. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

River flooding has become a major issue in the last decades, placing at risk wide portions of the planet. Modeled scenarios are the most helpful tools to reduce flood hazard; nevertheless they can lead to significant over- or underestimation of flood discharge and peak flood level if field attributes, especially floodplain roughness, are not carefully surveyed and reasonably included in their design. Besides, floodplains provide optimal habitats for invasive species, which can form dense stands, influencing roughness and flow velocity considerably. The floodplains of the Tisza River and its tributaries (Hungary) are highly invaded by invasive plants, however their existence is not considered during flood modeling. Among these plants Amorpha fruticosa has the greatest impact and creates impenetrable shrubbery on the floodplain, having 5–10 branches sprouting from its stump. The aim of this study is to give a precise and field-based estimation of vegetation density and floodplain roughness of different vegetation categories along the floodplain of the Tisza River, to overcome inaccuracies caused by the use of reference values. Through the Parallel Photographic Method, digital images are used to create photo mosaics and derive accurate estimates of vegetation density and floodplain roughness. Further, the role of invasive A. fruticosa in increasing vegetation density of the floodplain is also investigated. Results confirm a considerable underestimation of vegetation density and floodplain roughness (average difference: 0.04–0.06) by using simple reference values, as invasive Amorpha contributes for 55% of vegetation density on average, and on abandoned fields it constitutes 100% of the woody vegetation. These values suggest that modeled flood water levels can be remarkably underestimated if density of invasive species is not considered. The results of this study stress the importance of including field-based assessments of vegetation characteristics and the influence of invasive species in river modeling, to generate realistic predictions and address effective flood hazard strategies. [ABSTRACT FROM AUTHOR]

Soybean ( Glycine max [L.] Merr.) cultivars are generally sensitive to flooding stress. The plant growth is severely affected and grain yield is largely reduced in the flooded field. It is important to develop flood-tolerant soybean cultivars for grain production in regions of heavy rainfalls worldwide. In this study, a total of 722 soybean genotypes were evaluated for flooding tolerance at R1 stages (first flower at any node) in the 5-year flooding screening tests. Differential soybean genotypes exhibited diverse responses to flooding stress with that plant foliar damage score ( FDS) and plant survival rate ( PSR) ranged from 1.9 to 8.8 and 3.4% to 81.7%, respectively ( p < .0001). Based on our standard of flooding evaluation, most genotypes were sensitive to flooding with 6.0 of average FDS and 38.7% of PSR. Fifty-two soybean genotypes showed flooding tolerance and 11 genotypes were with consistent flooding tolerance during 4- to 5-year continual evaluations. In the meantime, six genotypes were identified with consistent high sensitivity to flooding. The group analysis showed that genotypes from different sources had distinguishable responses to flooding stress ( p < .0001). The interacting analysis of year and flooding tolerance indicated that FDS and PSR means were significantly different among 5 years due to weather temperature and flooding treatment time influences of each year ( p < .0001). Furthermore, five breeding lines with high-yielding and flood-tolerant traits were developed using selected consistent flood-tolerant and high-yielding genotypes through conventional breeding approach. [ABSTRACT FROM AUTHOR]

Mechanized transplanting of rice could decrease costs and use of labor in the peak of transplanting periods. Self-propelled rice transplanter requires an ideal field condition as well as optimal inundation of non-puddled soil before transplanting. Hence, self-propelled rice transplanters (four rows walking type, model DP480 except clay loam soil during the Boro season in 2013-2014 where six rows riding type rice transplanter, model S3-680) was evaluated in clay loam, loam and sandy loam soil during the irrigated dry season (Boro) in 2012-2013 and 2013-2014. Tillage treatments in a strip plot design were stripped, zero and conventional tillage and irrigation treatments as inundation periods before transplanting as sub-plots were 12, 18 and 24 hours (hrs). Soil penetration resistance decreased with the increased of inundation period in both the seasons and three soil types. Field capacity of both the walking (0.11 to 0.14 ha hr-1) and the riding type rice transplanter (0.21 to 0.22 ha hr-1) had not varied significantly with the tillage options. Averaged of two seasons, strip tillage gave higher field capacity for 12 hrs inundation period in clay loam soil and 18 hrs inundation period in loam and sandy loam soil whereas zero and conventional tillage gave higher for 24, 18 and 24 hrs inundation period and 18, 12 and 18 hrs inundation period in clay loam, loam and sandy loam soil, respectively. The non-puddled strip and zero tillage reduced fuel consumption by 22% to 13% and 8% to 13% for transplanting in clay loam and sandy loam soil compared to conventional tillage, respectively. However, strip tillage reduced the percentage of missing hills (9.7%) compared to zero (13.0%) and conventional tillage (10.7%) while percentage of missing hills, averaged of two seasons and three soil types, decreased 13.7% to 9.2% with the increased of inundation periods 12 to 24 hrs. The highest percentage of picker missing hills was observed in zero tillage irrespective of seasons and soil types. However, zero tillage also gave higher percentage of damage hills compared to conventional and strip tillage. Floating hills decreased with the increased of inundation periods in non-puddled strip and zero tillage. Conventional tillage increased the buried hills significantly in both the seasons. Strip tillage gave higher grain yield compared to zero and conventional tillage in both the seasons except clay loam soil during the Boro season in 2012-13 where zero tillage gave a higher grain yield. However, 18 hrs inundation periods for strip (6.1 t ha-1), 24 hrs for zero (6.0 t ha-1) and conventional (5.9 t ha-1) tillage gave the highest grain yields. Finally, it can be stated that non-puddled minimum tillage (strip and zero) is a resource saving technique while 18 hrs inundation prior to transplant for strip and 24 hrs inundation for zero tillage showed more benefited for rice production. [ABSTRACT FROM AUTHOR]

The majority of rice ( Oryza sativa L.) produced in the southern USA is drill-seeded and grown under upland-like conditions because permanent flooding is established after the four-leaf stage. Therefore, rice during the seedling growth stage will be subjected to variable soil moisture content. A greenhouse experiment was conducted to evaluate the performance of 15 rice cultivars commonly grown in Mississippi of USA under early-season soil moisture stress. Twenty morpho-physiological parameters of rice seedlings subjected to three different levels (100%, 66% and 33% field capacity) of soil moisture, from 10 to 30 d after sowing, were measured. Significant moisture stress × treatment interaction ( P < 0.001) was observed for most of the parameters. Further, the total drought response index (TDRI) was developed to score the cultivars for drought tolerance with the variation from 26.88 to 36.21. Accordingly, the cultivars were classified into different groups of tolerance. The cultivars CL152 and CL142-AR were classified as the least and the most tolerant to drought based on TDRI and standard deviation, respectively. Even though both total root ( R 2 = 0.98) or shoot ( R 2 = 0.76) drought responses indices were positively correlated with TDRI, root traits were important in deriving the indices. Therefore, TDRI could be used to select cultivars for drought tolerance in a given environment and develop rice varieties with early-season drought tolerance. However, further research is needed to identify and characterize tolerance at other stages to assist breeding programs in rice. [ABSTRACT FROM AUTHOR]

A rice GWAS panel of 281 accessions of japonica rice was phenotypically characterized for 26 traits related to phenology, plant and seed morphology, physiology and yield for 2 years in field conditions under permanent flooding (PF) and limited water (LW). A genome-wide analysis uncovered a total of 160 significant marker-trait associations (MTAs), of which 32 were LW-specific, 59 were PF-specific, and 69 were in common between the two water management systems. LW-specific associations were identified for several agronomic traits including days to maturation, days from flowering to maturation, leaf traits, plant height, panicle and seed traits, hundred grain weight, yield and tillering. Significant MTAs were detected across all the 12 rice chromosomes, while clusters of effects influencing different traits under LW or in both watering conditions were, respectively, observed on chromosomes 4, 8, and 12 and on chromosomes 1, 3, 4, 5, and 8. The analysis of genes annotated in the Nipponbare reference sequence and included in the regions associated to traits related to plant morphology, grain yield, and physiological parameters allowed the identification of genes that were demonstrated to affect the respective traits. Among these, three (OsOFP2, Dlf1, OsMADS56) and seven (SUI1, Sd1, OsCOL4, Nal1, OsphyB, GW5, Ehd1) candidate genes were, respectively, identified to co-localize with LW-specific associations and associations in common between the two water treatments. For several LW-specific MTAs, or in common among the two treatments, positional co-localizations with previously identified QTLs for rice adaptation to water shortages were observed, a result that further supports the role of the loci identified in this work in conferring adaptation to LW. The most robust associations identified here could represent suitable targets for genomic selection approaches to improve yield-related traits under LW. [ABSTRACT FROM AUTHOR]

Electrophysiological signal in plant is a weak electrical signal, which can fluctuate with the change of environment. An amplification detection system was designed for plant electrical signal acquisition by using integrated op-amps (CA3140, AD620, and INA118), patch electrode, data acquisition card (NI USB-6008), computer, and shielded box. Plant electrical signals were also studied under pressure and flooding stress. The amplification detection system can make nondestructive acquisition for Aquatic Scindapsus and Guaibcn with high precision, high sensitivity, low power consumption, high common mode rejection ratio, and working frequency bandwidth. Stress experiments were conducted through the system; results show that electrical signals were produced in the leaf of Aquatic Scindapsus under the stress of pressure. Electrical signals in the up-leaf surface of Aquatic Scindapsus were stronger than the down-leaf surface. Electrical signals produced in the leaf of Guaibcn were getting stronger when suffering flooding stress. The more the flooding stress was severe, the faster the electrical signal changed, the longer the time required for returning to a stable state was, and the greater the electrical signal got at the stable state was. [ABSTRACT FROM AUTHOR]

Flooding is an abiotic stress that causes considerable reductions in crop growth and yield worldwide. Soybean ( Glycine max [L.] Merr.) cultivars are generally sensitive to flooding stress. The objective of this study was to develop an effective flooding tolerance screening method in the field. A total of 40 soybean genotypes were evaluated for flooding tolerance at V5 and R1 growth stages. At each stage, genotypes were exposed to different durations of flooding stress (3, 6, 9, 12 and 15 days). Plant foliar damage score ( FDS) and plant survival rate ( PSR) were used as the indicators of flooding tolerance. Soybeans were more sensitive to flooding at R1 growth stage than V5 growth stage. Length of flooding duration accounted for the variance of FDS and PSR. Soybean genotypes exposed to a 3-day flooding in either V5 or R1 growth stage, did not show obvious foliar damage, while genotypes exposed to a 12- or 15-day flooding showed significant foliar damage and plant death. The optimum flooding duration to screen for flooding tolerance in the field was determined to be 9 and 6 days for V5 and R1 growth stages, respectively, as distinguishable responses to flooding allowed genotypes to be classified as either being flooding tolerant or flooding sensitive. High correlation between FDS and PSR (.99, p < .0001) was observed. Similarly, FDS and PSR were highly correlated with grain yield (.95 and .95, p < .0001). The field screening method for flooding tolerance developed in our study will be favourable for selection of soybean flooding-tolerant germplasm. [ABSTRACT FROM AUTHOR]

The northeastern region of Bangladesh often experiences flash flooding during the pre-harvesting period of the boro rice crop, which is the major cereal crop in the country. In this study, our objective was to delineate the impact of the 2017 flash flood (that initiated on 27 March 2017) on boro rice using multi-temporal Landsat-8 OLI and MODIS data. Initially, we opted to use Landsat-8 OLI data for mapping the damages; however, during and after the flooding event the acquisition of cloud free images were challenging. Thus, we used this data to map the cultivated boro rice acreage considering the planting to mature stages of the crop. Also, in order to map the extent of the damaged boro area, we utilized MODIS data as their 16-day composites provided cloud free information. Our results indicated that both the cultivated and damaged boro area estimates based on satellite data had strong relationships while compared to the ground-based estimates (i.e., r2 values approximately 0.92 for both cases, and RMSE of 18,374 and 9380 ha for cultivated and damaged areas, respectively). Finally, we believe that our study would be critical for planning and ensuring food security for the country. [ABSTRACT FROM AUTHOR]

Rising energy costs, decreasing soil depth, and best management practices that require on-farm water retention have led to interest in flood-tolerant bioenergy crops for production in the Everglades Agricultural Area (EAA) of Florida. Information on the effects of high water tables on sugarcane ( Saccharum spp. L.) is available; however, little is known about the bioenergy crops elephant grass ( Pennisetum purpureum Schumach.), energycane ( Saccharum spp. L.), and giant reed ( Arundo donax L.). The objective of this study was to evaluate the role of water-table depth on the yields, morphology, physiology, and early season growth of these three bioenergy species in relation to sugarcane. The species were grown in a greenhouse and subjected to three water management strategies, −40 or −16 cm constant water-table depths, and bi-weekly flooding with drainage to −40 cm. The experiment was conducted in plant-cane, first-ratoon, and successive plant-cane crop cycles. Periodic flooding relative to a −40 cm constant water table significantly reduced dry weights and leaf area index and increased aerenchyma development. Averaged among crops, dry weight declined by 32, 49, 37, and 52% while leaf area index (LAI) decreased by 31, 50, 46, and 57% for giant reed, elephant grass, energycane, and sugarcane, respectively, in response to flooding. Aerenchyma proportional area of the stalk increased by 52, 90, and 95% for elephant grass, energycane, and sugarcane, respectively, but aerenchyma in giant reed decreased by 11%. High yields and stalk populations for all water tables were observed in energycane and elephant grass. These two species show potential for bioenergy production in the EAA. Field trials are recommended to confirm production scale yield. [ABSTRACT FROM AUTHOR]

The world is currently experiencing dramatic increases in flood events impacting on natural vegetation and crops. Flooding often results in low O2 status in root tissues during waterlogging, but sometimes also in shoot tissues when plants become completely submerged. Plants possess a suite of traits enabling tissue aeration and/or adjusted metabolism during hypoxia or even in the absence of O2. This special issue of Functional Plant Biology presents key papers for plant scientists on the quest to further address and improve flood tolerance of terrestrial plants. The papers address low O2 responses in roots, shoots or whole plants in controlled laboratory conditions or in the field situation using natural wetland plants as models as well as economically important crops, such as rice, wheat and barley. The studies advance our understanding of low O2 responses in plant tissues as caused by O2 shortage during flooding. However, in most instances, submergence not only leads to hypoxic or anoxic tissues, but inundation in water also results in accumulation of CO2 and the important plant hormone ethylene. Thus, carefully designed laboratory studies are often needed to unravel the mechanistic relationships between a combined decline in O2 followed by increases in CO2 and ethylene at tissue as well as on the cellular level. [ABSTRACT FROM AUTHOR]

Global climate change is predicted to increase water precipitation fluctuations and lead to localized prolonged floods in agricultural fields and natural plant communities. Thus, understanding the genetic basis of submergence tolerance is crucial in order to improve plant survival under these conditions. In this study, we performed a quantitative trait locus (QTL) analysis in Arabidopsis to identify novel candidate genes for increased submergence tolerance by using Kas-1 and Col (gl1) parental accessions and their derived recombinant inbred lines (RILs). We measured survival after submergence in dark for a 13-day period and used median lethal time, LT50 values for the QTL analysis. A major QTL, the Come Quick, Drowning (CQD1) locus, was detected in 2 independent experiments on the lower arm of chromosome 5 involved in higher submergence tolerance in the parental accession Kas-1. For fine-mapping, we then constructed near isogenic lines (NILs) by backcrossing the CQD1 QTL region. We also analyzed QTL regions related to size, leaf number, flowering, or survival in darkness and none of the QTL related to these traits overlapped with CQD1. The submergence tolerance QTL, CQD1, region detected in this study includes genes that have potential to be novel candidates effecting submergence tolerance such as trehalose-6-phosphate phosphatase and respiratory burst oxidase protein D. Gene expression and functional analysis for these genes under submergence would reveal the significance of these novel candidates and provide new perspectives for understanding genetic basis of submergence tolerance. [ABSTRACT FROM AUTHOR]

Flooding regimes are a primary influence on the wetland plant community. Human-induced disturbance often changes the duration and frequency of flooding in wetlands, and has a marked influence on wetland plant composition and viability. Comprehensive studies of the environmental thresholds of wetland plants are required for the development of proper practices for wetland management and restoration after hydrological disturbance. This study provides a quantitative assessment of the establishment, growth, and community shifts in dominance of three emergent plant species ( Scirpus tabernaemontani, Typha orientalis, and Zizania latifolia) typical of South Korean wetlands, under five hydrological regimes (waterlogged, low-level standing water, high-level standing water, intensive periodic flooding, and intermittent flooding) over four growing seasons. A mesocosm experiment was conducted in the campus of Seoul National University, South Korea. The number and biomass of shoots of Z. latifolia responded positively to increased water level and flooding frequency, while that of the other plants did not. Zizania latifolia outcompeted S. tabernaemontani and T. orientalis irrespective of hydrological regime. This study suggests that Z. latifolia can outcompete the other two macrophytes in the field. This study will improve our ability to predict the dynamics of wetland vegetation and so facilitate the formulation of wetland management and restoration strategies. [ABSTRACT FROM AUTHOR]

Vietnam is reported to be one of the most vulnerable countries to future climate change, particularly in relation to sea-level rise and extreme climatic events. Agricultural adaptation and mitigation will be crucial for maintaining food and fibre production. Areas in Central Vietnam are prone to flooding, particularly in the lowland rice production areas. This article presents a case study of how small-scale rice farmers in the lowland areas of Le Thuy district, Quang Binh province, have transitioned into a ratoon system, locally referred to as ‘re-generated rice’, as a means of adapting to early flooding. While ratoon rice systems have been globally implemented, farmers in Le Thuy have adopted this system recently, based on their indigenous knowledge. The ratoon system was found to result in economic, social and environmental benefits for the surveyed households (N = 80), despite typically lower yields than the conventional system (approximately 70% of conventional). Through the sustainable livelihoods framework, findings show that the ratoon system is more economically efficient than the conventional and also allows farming households to spend more time on other income-generating, social or family activities, which is particularly important for balancing the gender division of labour. However, the new system tests the ability of the region to meet provincial level rice production targets, challenging conceptualizations of food security and livelihood security. [ABSTRACT FROM PUBLISHER]

Water background significantly affects the reflectance of partially flooded vegetation. However, the flooded background effects on the reflectance anisotropy have not been fully understood. This paper explores the water background effects on the anisotropic reflectance of rice canopy through multi-angle measurements. Seasonal multi-angle reflectance was measured for different view zenith angles (VZA) (−60°–60° with 15° interval) in a flooded paddy rice site. Wavelengths of 550 nm, 660 nm, 850 nm and 1640 nm were extracted to show the canopy anisotropic characteristics. Two canopy anisotropic indices, the anisotropic factor (ANIF) and the anisotropy index (ANIX), were examined for both non-flooded and flooded canopies in key phenology phases. Results show that the reflectance anisotropy of rice canopy is significantly weakened by a shallow layer (≈10 cm) of water. For VZA > 15°, background water decreases the canopy reflectance by up to 28% and weakens the anisotropic properties when LAI < 4.0 and the fraction of vegetation cover (fCover) <80%. The background water shows barely no effect on canopy reflectance when LAI > 5.0. 1640 nm shows the strongest anisotropy when LAI < 2.0, whereas 660 nm shows more significant anisotropy when LAI > 3.0. The backward observations show stronger scattering than the forward observations for the same VZA. The data from this study can be used as input for biophysical models and as validation data for remote sensing products. [ABSTRACT FROM AUTHOR]

Background: Tolerance to complete submergence is recognized in a limited number of Asian rice ( Oryza sativa L.) varieties, most of which contain submergence-inducible SUB1A on the polygenic SUBMERGENCE-1 ( SUB1) locus. It has been shown that the SUB1 locus encodes two Ethylene-Responsive Factor ( ERF) genes, SUB1B and SUB1C, in all O. sativa varieties. These genes were also found in O rufipogon and O nivara, wild relatives of O. sativa. However, detailed analysis of the polygenic locus in other Oryza species has not yet been made. Findings: Chromosomal location, phylogenetic, and gene structure analyses have revealed that the SUB1 locus is conserved in the long arm of chromosome 9 in most Oryza species. We also show that the SUB1A-like gene of O. nivara is on chromosome 1 and that Leersia perrieri, a grass-tolerant to deep-flooding, presents three ERF genes in the SUB1 locus. Conclusion: We provide here a deeper insight into the evolutionary origin and variation of the SUB1 locus and raise the possibility that an association of these genes with flooding tolerance in L. perrieri may exist. [ABSTRACT FROM AUTHOR]

Sugarcane (Saccharumspp.) is an economical crop in the tropical and subtropical countries. However, because of global climate change, flooding has become problematic, particularly during the rainy season, in Thailand. We investigated the effects of floods on three commercial sugarcane cultivars, namely NiF8, U-thong 6 (UT6), and U-thong 9 (UT9), as well asErianthus spp. Growth was assessed using a pot experiment in a glasshouse with two treatments: (1) control and (2) 60 d of flooding followed by 30 d of normal conditions. In comparison with control, during prolonged flooding,Erianthusshowed greatly decreased CO2assimilation, whereas NiF8, UT6, and UT9 showed slightly declined CO2assimilation. Growth in plants subjected to 60 d of flooding was less influenced by floods while sucrose content was not affected except in UT6. During flooding, some roots died, resulting in plants compensating adventitious roots to offset the negative effects of root death and to assist them in maintaining their growth, which appeared from the submerged nodes, with different characteristics for each cultivar. However, 30 d after draining, roots remained damaged, while adventitious roots died, resulting in lesser growth as compared with the control, but it did not significantly affect sucrose content and sugar yield. This study suggests that sugarcane plants need to produce the adventitious roots to compensate their roots’ death during flooding and require time to recover their root system after flooding for obtaining the optimum yield and quality at harvest. [ABSTRACT FROM PUBLISHER]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To explore the regeneration properties of a Populus euphratica Oliv. forest under unstable environmental conditions, we performed replicate censuses to determine the sapling dynamics of a P. euphratica population in the vicinity of the Ejina Oasis (Inner Mongolia). Even when the stands were established on riverside flatland, we detected slight variations in ground levels and salt concentrations. Due to leaching by flood water, the salinity of topsoil was lower in the riverbed than on the riverbank. Newly recruited saplings grew on riverbanks with high-salinity soil. Saplings were distributed over a wide area via fluctuating water levels, and those growing where salt levels were relatively low were able to grow more easily and become canopy trees. Small individuals comprise a sapling bank on the forest floor that is relatively stable. The dieback of larger saplings results in few reaching a height of more than 2 m. The growth of saplings (including new recruits) is balanced by the death of smaller saplings and the dieback of larger saplings. Individual saplings persist for about 4 years on the forest floor. In summary, hydrological events coupled with soil conditions may drive vegetation distribution patterns in riparian areas in arid regions. P. euphratica forests regenerate via a sapling bank rather than a seed bank. Yearly fluctuations in water flow facilitate the spread of the sapling bank, which guarantees regeneration of the forest. Dieback through partial defoliation is a mechanism used by saplings to escape adverse conditions, thereby maintaining a stable state in arid regions. [ABSTRACT FROM AUTHOR]

The Kosi flood of 18th August, 2008 is the single calamity in the annals of India to date, that was formally declared as a 'National Calamity'! Two most affected districts were selected covering 160 randomly selected respondents. Data were subjected to descriptive statistical analysis and the results indicated noteworthy change in habitat pattern from kachha to semi-pucca types housing during the period 2008 to 2013-2014. Consequently, area under paddy had witnessed a substantial decrease because floodwater ramification had resulted in deterioration of land quality. The lesson learnt from study can be replicated in other flood affected regions of India and across the globe. [ABSTRACT FROM AUTHOR]