Waterlogging Stress Research Articles

Waterlogging tolerance and wood properties of transgenic Populus alba × glandulosa expressing Vitreoscilla hemoglobin gene (Vgb)

Because overexpression of Vitreoscilla hemoglobin gene (Vgb) gene in plants can enhance tolerance to waterlogging, here Vgb was inserted into Populus alba × glandulosa to investigate its expression and effects on growth and physiological responses to waterlogging stress in the transgenic poplars. Southern blotting and RT-PCR analysis of Vgb-transgenic P. alba × glandulosa showed that the Vgb gene was integrated into the genome of the V13-81 and V13-85 transgenic lines and expressed. In greenhouse waterlogging stress tests, mortality of the transgenic poplar was significant lower than that of nontransgenic plants with increasing treatment time from 2 to 22 days. The transgenic plants had higher chlorophyll content and less chloroplast damage than in the control plants. Additionally, starch accumulation increased, and growth was enhanced in the transgenic plants, suggesting that the Vgb-expressing lines had improved energy reserves. Field trials of the transgenic poplar suggested that Vgb expression promotes growth and influences wood quality. Taken together, our results suggest that the expression of Vgb can increase the accumulation of chlorophyll and starch in the transgenic poplar, improve its ability to endure flooding, and improve growth and wood quality of the transgenic plants.

Unlocking the mystery of plants’ survival capability under waterlogging stress

Waterlogging is a major abiotic stress affecting crop plants throughout the world, which hampers crop growth and causes yield loss. There are various types of responses in plants under this stress through the combined operation of different signaling and physiological pathways. However, the correlation between these pathways is extremely limited and not well described in the published papers. Therefore, the complex waterlogging stress-tolerance mechanisms need to be presented most coherently for a comprehensive understanding of this stress. Here, we present sequential responses in plants under oxygen-deprivation stress. The regulation of the N-end rule pathway may be treated as the initial signaling in plants after facing waterlogging stress, but still, it remains a controversial topic. All the pathways under waterlogging stress are directly or indirectly related to glycolysis, tricarboxylic acid (TCA) cycle, programmed cell death (PCD) and removal of reactive oxygen species (ROS). Scientists may consider alanine aminotransferase as the main controlling switch for surviving of plants under waterlogging stress. Triggering the genes responsible for alanine aminotransferase may act as a crucial one to develop a waterlogging tolerant plant due to its ability to control anaerobic fermentation, TCA cycle and efficient utilization of carbons.

Foliar treatment of potassium nitrate modulates the fermentative and sucrose metabolizing pathways in contrasting maize genotypes under water logging stress.

The effect of potassium nitrate on the status of fermentative and sucrose metabolizing pathways was studied in two maize (Zea mays L.) genotypes, viz., LM 5 (relatively susceptible to flooding) and I 167 (relatively tolerant to flooding) under water logging stress. The higher increase in pyruvate decarboxylase, alcohol dehydrogenase and aldehyde dehydrogenase activities in the hypoxic roots of I 167 seedlings over LM 5 showed the former's efficient tolerance mechanism towards anaerobic conditions. Foliar application of KNO3 reduced these enzymatic activities in the roots of both the genotypes. The shoots of I 167 seedlings also showed a parallel increase in alcohol dehydrogenase and pyruvate decarboxylase activities under water logging stress. These enzymatic activities, however, remained unaffected in shoots of water logged LM 5 seedlings. There was a higher decrease in acid and alkaline invertase activities in the hypoxic roots of I 167 seedlings. KNO3 treatment led to higher acid invertase activity in roots of I 167 seedlings than those of LM 5. Sucrose synthase (synthesis) and sucrose phosphate synthase activities decreased, but sucrose synthase (breakdown) activity increased in the roots of both the genotypes, during water logging. KNO3 increased sucrose synthesizing activities with a parallel increase in the sucrose content of the roots. Sucrose synthesis was comparatively unaffected in I 167 shoots under water logging stress while LM 5 shoots showed higher reduction in its sucrose synthase (synthesis) and sucrose phosphate synthase activities. It may thus be concluded that KNO3 induced a network of reactions for improving water logging tolerance. The nitrate ions acted as an alternate electron acceptor and thus reduced the activities of fermentative enzymes. It promoted the funneling of sugars into the glycolytic pathway by inducing the activities of acid and alkaline invertases in the roots and shoots of maize genotypes. It also directed the hexoses towards biosynthetic pathway by increasing the activities of sucrose synthesizing enzymes.

Overexpression of Barley Transcription Factor HvERF2.11 in Arabidopsis Enhances Plant Waterlogging Tolerance

Waterlogging stress significantly affects the growth, development, and productivity of crop plants. However, manipulation of gene expression to enhance waterlogging tolerance is very limited. In this study, we identified an ethylene-responsive factor from barley, which was strongly induced by waterlogging stress. This transcription factor named HvERF2.11 was 1158 bp in length and encoded 385 amino acids, and mainly expressed in the adventitious root and seminal root. Overexpression of HvERF2.11 in Arabidopsis led to enhanced tolerance to waterlogging stress. Further analysis of the transgenic plants showed that the expression of AtSOD1, AtPOD1 and AtACO1 increased rapidly, while the same genes did not do so in non-transgenic plants, under waterlogging stress. Activities of antioxidant enzymes and alcohol dehydrogenase (ADH) were also significantly higher in the transgenic plants than in the non-transgenic plants under waterlogging stress. Therefore, these results indicate that HvERF2.11 plays a positive regulatory role in plant waterlogging tolerance through regulation of waterlogging-related genes, improving antioxidant and ADH enzymes activities.

Impacts and management strategies for crop production in waterlogged or flooded soils: A review

AbstractGlobally, flooding is one of the most damaging abiotic stresses, besides drought, that affects 17 million km2 of land surface annually. Recent research indicates that climate change is resulting in more extreme weather events, such as flooding or soil waterlogging, that negatively affect crop production. Therefore, it is imperative to understand how flooding stress affects crops and to develop improved production practices that make cropping systems more resilient and able to cope with extreme weather events. This review paper summarizes the current state of knowledge on the impacts of flooding or soil waterlogging on crop production losses, nitrogen (N) losses, and provides potential management strategies to reduce these losses. The factors affecting the extent of flooding injury in plants as well as plant adaptations under waterlogging stress are also discussed briefly. For the purpose of this review, “flooding” refers to the situation when all or part of the plant is submerged under water, whereas “soil waterlogging” refers to the situation where soil pores are saturated with water. Soil waterlogging also promotes soil N losses through runoff, leaching, and denitrification. Potential management practices that can be used to mitigate soil waterlogging stress include the use of flood‐tolerant varieties, adjusting management practices, improving drainage, and practicing adaptive nutrient management strategies. However, these might be site‐ or crop‐specific management practices and they should be validated for their economic viability before developing future management plans that promote sustainable crop yields from waterlogged soils.

A Comprehensive Transcriptomics Analysis Reveals Long Non-Coding RNA to be Involved in the Key Metabolic Pathway in Response to Waterlogging Stress in Maize.

Waterlogging stress (WS) in a dynamic environment seriously limits plant growth, development, and yield. The regulatory mechanism underlying WS conditions at an early stage in maize seedlings is largely unknown. In the present study, the primary root tips of B73 seedlings were sampled before (0 h) and after (2 h, 4 h, 6 h, 8 h, 10 h, and 12 h) WS and then subjected to transcriptome sequencing, resulting in the identification of differentially expressed protein-coding genes (DEpcGs) and long non-coding RNAs (DElncRs) in response to WS. These DEpcGs were classified into nine clusters, which were significantly enriched in several metabolic pathways, such as glycolysis and methionine metabolism. Several transcription factor families, including AP2-EREBP, bZIP, NAC, bHLH, and MYB, were also significantly enriched. In total, 6099 lncRNAs were identified, of which 3190 were DElncRs. A co-expression analysis revealed lncRNAs to be involved in 11 transcription modules, 10 of which were significantly associated with WS. The DEpcGs in the four modules were enriched in the hypoxia response pathways, including phenylpropanoid biosynthesis, MAPK signaling, and carotenoid biosynthesis, in which 137 DElncRs were also co-expressed. Most of the co-expressed DElncRs were co-localized with previously identified quantitative trait loci associated with waterlogging tolerance. A quantitative reverse transcription-polymerase chain reaction analysis of DEpcG and DElncR expression among the 32 maize genotypes after 4 h of WS verified significant expression correlations between them as well as significant correlation with the phenotype of waterlogging tolerance. Moreover, the high proportion of hypoxia response elements in the promoter region increased the reliability of the DElncRs identified in this study. These results provide a comprehensive transcriptome in response to WS at an early stage of maize seedlings and expand our understanding of the regulatory network involved in hypoxia in plants.

SALICYLIC ACID INDUCES PHYSIOLOGICAL AND BIOCHEMICAL CHANGES IN PEONY UNDER WATERLOGGING STRESS

In this study, the effects of salicylic acid to antioxidative activity and photosynthetic characteristics in waterlogging stress of two peony cultivars (‘Fengdanbai’ and ‘Mingxing’) were investigated. 4-year-old peony grown in different levels of waterlogging stress and then different concentration prepared SA (0.0, 0.1, 0.5 and 1.0 mmol L–1) sprayed on fresh leaves of peony. The antioxidative enzymes activities include superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), chlorophyll content, relative conductivity and MDA content were measured in leaves about different waterlogging treatment, the photosynthetic characteristics were also measured using photosynthetic measurement system. The results showed that waterlogging stress decreased the chlorophyll content in all peony cultivars leaves, but with SA treatment can inhibit the decrease of chlorophyll content. Relative conductivity increased as the extension of waterlogging time in two cultivars. SA treatment could effectively inhibit the increase of relative conductivity, and 0.5 mmol L–1 of SA was the most suitable concentration. SOD, POD, CAT activity increased first and then decreased in different waterlogging condition, SA significantly increased the activity of various enzymes. MDA content was increase as the expansion of waterlogging time in two cultivars. SA inhibits the increase of MDA content. Of all concentration of SA, 0.5 mmol L–1 was the best concentration to inhibit the waterlogging stress. For the photosynthetic characteristics, the net assimilation rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and intercellular CO2 (Ci) were decreased under different waterlogging condition. SA treatment can increase Pn, Gs, Tr and Ci of peony.

Morpho-anatomical and physiological characteristics responses of a paried near-isogenic lines of waxy corn to waterlogging

Waterlogging stress is one of the most natural stress, which due to excessive rainfall or low-lying terrain, and limits crop growth and yield. Our objective was to study the morpho-anatomical and physiological characteristics of a paired near-isogenic lines of waxy corn under waterlogging stress. This experiment was implemented in pots with a paired of near-isogenic lines differing in waterlogging tolerance: Zz-R (waterlogging-resistant) and Zz-S (waterlogging-sensitive). Root morphology features, anaerobic respiratory enzyme activity, and tissue anatomical characteristics were measured at 0, 2, 4, 6 and 8d in the control and waterlogging conditions. The result indicated that waterlogging induced a decrease in the root length, volume and surface areas of the two waxy corn inbred lines, the total root length, root volume, and root surface area of the Zz-R showed less reduction than the Zz-S. Waterlogging stress influenced significantly by the parenchyma cells in cortex of root between Zz-R and Zz-S. Zz-R can also maintain a higher level of anaerobic respiratory enzyme activity under waterlogging stress. The different reaction between the paired near-isogenic lines may be responsible for higher tolerance of Zz-R than Zz-S. These results can provide a certain theoretical basis of the resistance evaluation and breeding to the resistant varieties.

Waterlogging tolerance of five soybean genotypes through different physiological and biochemical mechanisms

Waterlogging is a serious environmental threat that limits crop growth and yield in low-lying, rainfed areas in many regions across the globe. Here we investigated the effects of waterlogging and subsequent re-oxygenation on the physiology and biochemistry of three soybean [Glycine max (L.) Merrill] genotypes (PELBR10-6000, PELBR11-6028, and PELBR11-6042) and two cultivars (TEC IRGA 6070 and BMX Potência). Plants were grown under greenhouse conditions until the V4 stage when they were subjected to waterlogging for seven days. The water was then drained and plants were allowed to recover for another seven days. Overall, all genotypes suppressed waterlogging stress with distinct mechanisms. Waterlogged PELBR10-6000 surpassed control plant levels of CO2 assimilation rate and readily responded to the energy lack induced by hypoxia by activating the fermentative enzymes and alanine aminotransferase. Similar mechanisms were observed in BMX Potência, which restored metabolism to control levels at the end of the recovery. PELBR11-6028 and PELBR11-6042 activated the antioxidant defenses, and TEC IRGA 6070 did not delay flowering.

Tolerance Screening of Sugarcane Varieties Toward Waterlogging Stress

The aim of this research was to obtain the resistant plant toward waterlogging stress. The research used complete randomized block design (RBD) with two factors and three replications. The first factors of sugarcane variety are PS 8845, VMC 7616, BL, VMC 86550, PSJK 922 and PS 864. The second factor is the treatments of waterlogging on the level of treatment, that is, without waterlogging, 6, 9, and 12 weeks of waterlogging in bucket. The research results showed that the differences in resistance response of several tested varieties were seen in parameters of number of leaves, number of yellowing leaves, fresh weight of plant, plant height, stem diameter, root length, root’s branch, number of tillers, chlorophyll content, the rate of photosynthesis, stomatal density, shoot leaf size, and leaf angle. Quantitative data character were analysed using ANOVA and DMRT. The conclusion of this research were that PS 8845 and VMC 7616 variety can be recommended as a variety that is resistant to water logging stress. While variety PSJK 922 showed the worst response in condition of waterlogging stress.

Sedum mexicanum ‘Gold Mound’ exhibits better adaptive characters in contrast to S. spurium ‘Coccineum’ when subjugated to sustained waterlogging stress

<i>Sedum mexicanum</i> ‘Gold Mound’ exhibits better adaptive characters in contrast to <i>S. spurium</i> ‘Coccineum’ when subjugated to sustained waterlogging stress

Plant Growth Regulator-Brassinolide for Mitigating Field Waterlogging Stress on Maize

Aim: To assess the pleiotropic role of a plant growth regulator, commercially identified as brassinolide (BR) in mitigating waterlogging stress imposed on maize.&#x0D; Study Design: A factorial combination of two maize varieties [Ikom White (IKW) and Oba-98], two BR levels (0 and 250 ml) and two waterlogging stages of maize growth [control (WL0) and seedling stage (WL1)], arranged as a split-split plot in a randomized complete block design with three replications was used.&#x0D; Place and Duration of Study: Akpabuyo Local Government Area, Cross River State-Nigeria. A two-year field experiment was conducted during the dry seasons of December 2016 and December 2017.&#x0D; Methodology: Waterlogging test was conducted on plots by demarcating them with 3.6 by 1.7 m metal sheets buried to a depth of 60 cm to prevent lateral soil-water movement. Two maize seeds were sown at 25 cm within and 75 cm between rows. The BR (250 ml) was sprayed foliar at 21 DAS. The non-waterlogging plots served as control. Observations were made on growth and yield variables as well as the plant's physiological traits.&#x0D; Results: Waterlogging significantly reduced the growth attributes of maize and increased (p≤0.05) the leaf moisture content. The photosynthetically active radiation on maize plants was substantially reduced (p≤0.05) by the waterlogging stress. Dry matter yield (DMY) and nutrient uptake in the leaves, stems and grains were reduced (p≤0.05) at both silking and at harvest. The effect of the BR was greater in Oba-98 with higher nutrient contents, radiation absorption, dry matter and grain yields than IKW.&#x0D; Conclusion: Treatment of maize plants with BR could induce some tolerance of field waterlogging. Thus, for optimum efficiency in maize production under stressed soil condition of waterlogging, it is recommended that the foliar spray of BR at the 250 ml per plant rate be considered.

The Variation induction of Glycine max through low dose gamma irradiation produces genetic and physiological alteration as source of tolerant variants in waterlogging conditions

Abstract. Saputro TB, Muslihatin W, Wahyuni DK, Nurhidayati T, Wardhani FO, Rosalia E. 2019. Variation induction of Glycine max through low dose gamma irradiation produces genetic and physiological alteration as source of tolerant variants in waterlogging conditions. Biodiversitas 20: 3299-3308. Soybean (Glycine max L.) is the main food commodity that contains high proteins, oils, and carbohydrates. Waterlogging is considered as the dominant factor and major constraint responsible for the decrements of soybean production in Indonesia. The development of promising G.max that tolerates waterlogging is essentially needed. In this study, induction of variation was conducted by gamma rays irradiation with doses of 25Gy, 50Gy, 75Gy, and 100Gy. The mutant or variants lines were then selected under waterlogging conditions with 100%, 150%, 200%, and 250% of field capacity. The results showed that, in 250% waterlogging condition, plants irradiated with 25Gy shows the best performance in amount of roots, adventitious roots and number of pods parameters, while plants irradiated with 50Gy have the highest growth indicated by amount of root nodules, plant heights, dry weights, leaf area, and chlorophyll contents. The genotypes then were assayed by the Inter Simple Sequence Repeats (ISSR) to confirm that the mutants differ compared to its wild type. Out of 10 ISSR primers, seven primers showed polymorphic patterns. The best primer to differentiate the mutant lines and its wild type is primer ISSR1 [ (AC)8G] that able to generate the highest level of polymorphism with 44.0%. The comparison of protein profiles among the mutant lines showed that proteins with molecular weight 53,78 KDa; 43,12 KDa; and 20,62 Kda are all overexpressed for plants irradiated at 25Gy and treated with 250% waterlogging stress. All those three proteins are predicted as 1-amino cyclopropane-1-carboxylate synthase (ACS), Alcohol-dehydrogenase (ADH), and Superoxide dismutase (SOD) respectively.

Sodium Azide Priming Enhances Waterlogging Stress Tolerance in Okra (Abelmoschus esculentus L.)

Waterlogging stress adversely affects crop growth and yield worldwide. Effect of sodium azide priming on waterlogging stress tolerance of okra plants was investigated. The study was conducted as a field experiment using two weeks old plants grown from 0%, 0.02%, and 0.05% sodium azide (NaN3)-treated seeds. The waterlogging conditions applied were categorized into control, one week, and two weeks. Different growth and reproductive parameters were investigated. Activity and expression of antioxidant enzymes, root anatomy, and soil chemical analysis were also studied. Results showed that sodium azide priming inhibited germination. The germination percentages recorded were 92.50, 85.00, and 65.00 for 0%, 0.02%, and 0.05% NaN3-treated seeds, respectively, nine days after planting. Waterlogging conditions depressed plant height ten weeks after planting. Under waterlogging conditions, NaN3 promoted plant height and number of leaves formed. NaN3 also supported the survival of plants and formation of adventitious roots under waterlogging conditions. Waterlogging conditions negatively affected the redox potential, organic C, N, and P concentrations in the soil but enhanced Soil pH, Fe, Mn, Zn, and SO4. Under waterlogging conditions, NaN3 increased the average number of flower buds, flowers, and fruits produced in comparison to control. Moreover, NaN3 highly stimulated the development of aerenchyma which in turn enhanced the survival of okra plants under waterlogging conditions. NaN3 priming also enhanced the activities and gene expression level of antioxidant enzymes (ascorbate peroxidase, APX; catalase, CAT) under waterlogging conditions. In conclusion, this study demonstrated that NaN3 priming could improve waterlogging stress tolerance in okra.

Waterlogging Tolerance at Germination in Field Pea: Variability, Genetic Control, and Indirect Selection.

In the Eastern Gangetic Plain of South Asia field pea (Pisum sativum L.) is often grown as a relay crop where soil waterlogging (WL) causes germination failure. To assess if selection for WL tolerance is feasible, we studied the response to WL stress at germination stage in a recombinant inbred line (RIL) population from a bi-parental cross between WL-contrasting parents and in a diversity panel to identify extreme phenotypes, understand the genetics of WL tolerance and find traits for possible use in indirect selection. The RIL population and the diversity panel were screened to test the ability of germination under both waterlogged and drained soils. A total of 50, most WL tolerant and sensitive, genotypes from each of both the RIL and the diversity panel were further evaluated to assay testa integrity/leakage in CaSO4 solution. Morphological characterization of both populations was undertaken. A wide range of variation in the ability to germination in waterlogged soil was observed in the RIL population (6–93%) and the diversity panel (5–100%) with a high broad-sense heritability (H2 > 85%). The variation was continuously distributed indicating polygenic control. Most genotypes with a dark colored testa (90%) were WL tolerant, whereas those with a light colored testa were all WL sensitive in both the RIL population and diversity panel. Testa integrity, measured by electrical conductivity of the leakage solute, was strongly associated with WL tolerance in the RIL population (rG = −1.00) and the diversity panel (rG = −0.90). Therefore, testa integrity can be effectively used in indirect selection for WL tolerance. Response to selection for WL tolerance at germination is confidently predicted enabling the adaptation of the ancient model pea to extreme precipitation events at germination.

The leaf-air temperature difference reflects the variation in water status and photosynthesis of sorghum under waterlogged conditions.

Waterlogging stress is one of the most important abiotic stresses limiting sorghum growth and development. Consequently, the responses of sorghum to waterlogging must be monitored and studied. This study investigated changes in the leaf water status, xylem exudation rate, leaf anatomical structure, leaf temperature and photosynthetic performance. Waterlogging-tolerant (Jinuoliang 01, abbreviated JN01) and waterlogging-sensitive (Jinza 31, abbreviated JZ31) sorghum cultivars were planted in pots. The experiment was carried out using a split block design with three replications. Waterlogging stress was imposed at the sorghum five-leaf stage. The leaf free water content (FWC) and relative water content (RWC) decreased under the waterlogged condition. The leaf thickness was thinner under the waterlogged condition, and the main changes occurred in the upper epidermal and mesophyll cells. Gas exchange parameters and the xylem exudation rate were also restrained by waterlogging; however, greater responses of these parameters were observed in JZ31. JZ31 had a higher leaf-air temperature difference (ΔT) than JN01. We found that changes in ΔT were always consistent with changes in the RWC and the gas exchange parameters. ΔT was significantly associated with the leaf RWC, photosynthetic rate (Pn) and transpiration rate (Tr). The results suggest that ΔT may be an indicator reflecting the water status in leaves and can be used to evaluate the tolerance of sorghum to waterlogging.

Effects of waterlogging stress on plant-pathogen interaction between &lt;i&gt;Fusarium poae&lt;/i&gt; and wheat/ barley

Waterlogging stress is one of the abiotic factors which causes damage to crops affecting yield components and grain quality of wheat and barley. On the other hand, Fusarium poae is one of the most common Fusarium species isolated from wheat and barley. The aim of this study was to evaluate the effects of waterlogging and F. poae on disease parameters, yield components and grain quality of durum and bread wheat and barley. The experiment was carried out using pots under greenhouse conditions. Four treatments were applied: control/control (W0F0), control/F. poae (W0F1), waterlogging/control (W1F0) and waterlogging/F. poae (W1F1). The results showed that incidence, severity and FHB index of F. poae were higher in W0F1 compared to W1F1 suggesting that waterlogging treatment would be generating no favorable conditions for fungal growth. Therefore, yield components and grain composition and quality were significantly affected by the Fusarium presence and waterlogging treatment which could induce changes in parameters mainly related to the industrial quality of wheat and barley. These results highlight the behavior of wheat and barley under the combination of abiotic and biotic stress.

A group VII ethylene response factor gene, ZmEREB180, coordinates waterlogging tolerance in maize seedlings.

SummaryGroup VII ethylene response factors (ERFVIIs) play important roles in ethylene signalling and plant responses to flooding. However, natural ERFVII variations in maize (ZmERFVIIs) that are directly associated with waterlogging tolerance have not been reported. Here, a candidate gene association analysis of the ZmERFVII gene family showed that a waterlogging‐responsive gene, ZmEREB180, was tightly associated with waterlogging tolerance. ZmEREB180 expression specifically responded to waterlogging and was up‐regulated by ethylene; in addition, its gene product localized to the nucleus. Variations in the 5ʹ‐untranslated region (5ʹ‐UTR) and mRNA abundance of this gene under waterlogging conditions were significantly associated with survival rate (SR). Ectopic expression of ZmEREB180 in Arabidopsis increased the SR after submergence stress, and overexpression of ZmEREB180 in maize also enhanced the SR after long‐term waterlogging stress, apparently through enhanced formation of adventitious roots (ARs) and regulation of antioxidant levels. Transcriptomic assays of the transgenic maize line under normal and waterlogged conditions further provided evidence that ZmEREB180 regulated AR development and reactive oxygen species homeostasis. Our study provides direct evidence that a ZmERFVII gene is involved in waterlogging tolerance. These findings could be applied directly to breed waterlogging‐tolerant maize cultivars and improve our understanding of waterlogging stress.

The effects of persistent drought and waterlogging on the dynamics of nonstructural carbohydrates of Robinia pseudoacacia L. seedlings in Northwest China

BackgroundThe nonstructural carbohydrates (NSCs) of plants are posited to be crucial traits for the resistance and resilience of plants to climate change-induced drought and flooding. However, the potential effects of persistent drought and waterlogging on the dynamics of the NSCs and the underlying mechanisms are still poorly understood.MethodsWe measured the NSCs concentrations and pool size, photosynthetic rate and biomass of Robinia pseudoacacia L. seedlings for both 2015 and 2016 under five soil water treatments: 3%, 8%, 17%, 24% and 34% soil water content, representing extreme drought (ED), moderate drought (MD), the control group (CG), field capacity (FC) and waterlogging (WL) stresses, respectively. We observed the relationship between the pool size of NSCs and the survival of seedlings under water stress (drought and waterlogging) for 30 days in greenhouse.ResultsCompared with CG, the net photosynthetic rate decreased 91%, 67%, 34% and 71%, and the biomass decreased by 37%, 15%, 16% and 33% under ED, MD, FC and WL, respectively. The total NSC (TNSC) concentration was significantly increased by 154% under ED after 10 days and sharply decreased by 50% under ED after 30 days. The concentrations of soluble sugars (SS) were significantly increased by 100% under MD after 10 days and sharply decreased by 60% under ED after 30 days. Compared with GC, the response of NSCs, photosynthetic rate and biomass under ED were more dramatic than that under WL. The pool sizes of fructose and sucrose were larger under ED and WL, but the maximum pool size of starch occurred under the CG. The depletion of NSCs was not observed under ED at the end of the experiments in both 2015 and 2016.ConclusionsOur results indicate that the dynamics of NSCs is an important physiological feature of plant adaptation and resistance to drought and waterlogging. In addition, high sugars concentrations are beneficial for the plants during the short-term extreme drought and the longer term mild drought or waterlogging.

Effects of waterlogging stress on the physiological response and grain-filling characteristics of spring maize (Zea mays L.) under field conditions

A field experiment was implemented to discuss the effects of waterlogging and subsurface waterlogging stress on the grain yield, grain-filling characteristics, superoxide anion ( $${\text{O}}_{2}^{ \cdot - }$$ ) content, hydrogen peroxide (H2O2) content, malondialdehyde (MDA) content, antioxidant enzyme activity, proline, soluble protein content and SPAD value of the spring maize (Zea mays L.) hybrids “Demeiya1” (DMY1) and “Keyu16” (KY16). The waterlogging and subsurface waterlogging treatments were conducted for different durations (3, 6, and 9 days and 5, 10, and 15 days, respectively) at the seedling (V3), jointing (V6), and tasseling (VT) stages. The results showed that the most significant effects of waterlogging and subsurface waterlogging stress occurred at the V3 stage, followed by the V6 stage and then VT stage. Waterlogging and subsurface waterlogging caused a decline in grain filling, which resulted in a decline in grain weight and ultimately caused an obvious decrease in yield. The content of $${\text{O}}_{2}^{ \cdot - }$$ and H2O2 as well as MDA increased with the prolongation of the duration of waterlogging and subsurface waterlogging, which caused an up-regulation of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, as well as increased proline and soluble protein contents and decreased SPAD value. In addition, we also demonstrated that KY16 is more sensitive than DMY1 to waterlogging and subsurface waterlogging.