scholarly journals Antioxidant Enzymatic Activity and Osmotic Adjustment as Components of the Drought Tolerance Mechanism in Carex duriuscula

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 436
Author(s):  
Peichen Hou ◽  
Feifei Wang ◽  
Bin Luo ◽  
Aixue Li ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Osmotic Adjustment ◽  
Soluble Sugars ◽  
Soil Drought ◽  
Arid Environments ◽  
Ros Scavenging ◽  
Efficient Operation ◽  
Ambient Temperatures ◽  
Relative Contribution ◽  
Leaves And Roots

Drought stress is a major environmental constraint for plant growth. Climate-change-driven increases in ambient temperatures resulted in reduced or unevenly distributed rainfalls, leading to increased soil drought. Carex duriuscula C. A. Mey is a typical drought-tolerant sedge, but few reports have examined the mechanisms conferring its tolerant traits. In the present study, the drought responses of C. duriuscula were assessed by quantifying activity of antioxidant enzymes in its leaf and root tissues and evaluating the relative contribution of organic and inorganic osmolyte in plant osmotic adjustment, linking it with the patterns of the ion acquisition by roots. Two levels of stress—mild (MD) and severe (SD) drought treatments—were used, followed by re-watering. Drought stress caused reduction in a relative water content and chlorophyll content of leaves; this was accompanied by an increase in the hydrogen peroxide (H2O2) and superoxide (O2−) contents in leaves and roots. Under MD stress, the activities of catalase (CAT), peroxidase (POD), and glutathione peroxidase (GPX) increased in leaves, whereas, in roots, only CAT and POD activities increased. SD stress led to an increase in the activities of CAT, POD, superoxide dismutase (SOD), and GPX in both tissues. The levels of proline, soluble sugars, and soluble proteins in the leaves also increased. Under both MD and SD stress conditions, C. duriuscula increased K+, Na+, and Cl− uptake by plant roots, which resulted in an increased K+, Na+, and Cl− concentrations in leaves and roots. This reliance on inorganic osmolytes enables a cost-efficient osmotic adjustment in C. duriuscula. Overall, this study revealed that C. duriuscula was able to survive arid environments due to an efficient operation of its ROS-scavenging systems and osmotic adjustment mechanisms.

scholarly journals Overexpression of a Voltage-Dependent Anion-Selective Channel (VDAC) Protein-Encoding Gene, MsVDAC, from Medicago sativa Confers Cold and Drought Tolerance to Transgenic Tobacco

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1706
Author(s):  
Mei Yang ◽  
Xinhang Duan ◽  
Zhaoyu Wang ◽  
Hang Yin ◽  
Junrui Zang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Cold Stress ◽  
Medicago Sativa ◽  
Transgenic Tobacco ◽  
Soluble Sugars ◽  
Ros Scavenging ◽  
Osmotic Homeostasis ◽  
Voltage Dependent ◽  
Stress Responsive Genes

Voltage-dependent anion channels (VDACs) are highly conserved proteins that are involved in the translocation of tRNA and play a key role in modulating plant senescence and multiple pathways. However, the functions of VDACs in plants are still poorly understood. Here, a novel VDAC gene was isolated and identified from alfalfa (Medicago sativa L.). MsVDAC localized to the mitochondria, and its expression was highest in alfalfa roots and was induced in response to cold, drought and salt treatment. Overexpression of MsVDAC in tobacco significantly increased MDA, GSH, soluble sugars, soluble protein and proline contents under cold and drought stress. However, the activities of SOD and POD decreased in transgenic tobacco under cold stress, while the O2− content increased. Stress-responsive genes including LTP1, ERD10B and Hxk3 were upregulated in the transgenic plants under cold and drought stress. However, GAPC, CBL1, BI-1, Cu/ZnSOD and MnSOD were upregulated only in the transgenic tobacco plants under cold stress, and GAPC, CBL1, and BI-1 were downregulated under drought stress. These results suggest that MsVDAC provides cold tolerance by regulating ROS scavenging, osmotic homeostasis and stress-responsive gene expression in plants, but the improved drought tolerance via MsVDAC may be mainly due to osmotic homeostasis and stress-responsive genes.

Physiological, anatomical and antioxidant responses to salinity in the Mediterranean pastoral grass plant Stipa lagascae

2017 ◽  
Vol 68 (9) ◽  
pp. 872 ◽  
Author(s):  
Raoudha Abdellaoui ◽  
Fayçal Boughalleb ◽  
Zohra Chebil ◽  
Maher Mahmoudi ◽  
Azaiez Ouled Belgacem
Keyword(s):  
Glutathione Reductase ◽  
Ascorbate Peroxidase ◽  
Osmotic Adjustment ◽  
Perennial Grass ◽  
Soluble Sugars ◽  
Ros Scavenging ◽  
Total Soluble Sugars ◽  
Chlorophyll Pigments ◽  
Moderate Salinity ◽  
Stipa Lagascae

Soil and water salinity is a major environmental problem in the dry Mediterranean regions, affecting rangeland production. This study investigated the effects of salinity on the wild perennial grass (Poaceae) species Stipa lagascae R. & Sch., a potential forage plant that could be used to rehabilitate degraded rangelands in dry areas. In a laboratory, 3-month-old S. lagascae seedlings were subjected to increasing salt treatments (0–400 mm NaCl) for 45 days. Physiological and biochemical parameters such as leaf water potential (Ψw), leaf relative water content (RWC), proline, total soluble sugars, Na+, K+ and Ca2+ contents, and catalase, ascorbate peroxidase and glutathione reductase activities were measured. Total soluble sugars and proline concentrations increased and Ψw and RWC decreased with increasing salt concentrations. Lower salt concentrations induced a non-significant degradation of chlorophyll pigments. Shoot Na+ content increased with a salinity level, whereas shoot K+ and Ca2+ concentrations decreased and the K+ : Na+ ratio was lower. The salinity threshold, above which S. lagascae showed signs of damage, occurred at 300 mm. Plants have evolved reactive oxygen species (ROS) scavenging enzymes including catalase, ascorbate peroxidase and glutathione reductase, which provide cells with an efficient mechanism to neutralise ROS. The tolerance strategies of S. lagascae to moderate salinity seem to include osmotic adjustment through total soluble sugars and proline accumulation, and highly inducible antioxidative defence. Further investigations are necessary to study the effect of salt stress on distribution of ions (Na+, K+, Ca2+, Mg2+, Cl–, NO3–, SO42–) and osmotic adjustment. Photosynthesis and water-use efficiency parameters could be also useful tools.

scholarly journals Physiological Acclimation of Dicranostigma henanensis to Soil Drought Stress and Rewatering

2021 ◽  
Vol 90 ◽  
Author(s):  
Ning Wang ◽  
Hao Chen ◽  
Lei Wang
Keyword(s):  
Drought Stress ◽  
Soil Water ◽  
Stress Gradient ◽  
Thiobarbituric Acid ◽  
Soil Drought ◽  
Photosynthetic Parameters ◽  
Arid Environments ◽  
Weighting Method ◽  
Relative Electrical Conductivity ◽  
Strong Ability

Abstract The adaptability of plants to drought not only includes their ability to resist drought stress, but also their ability to recover after stress is relieved. In this study, a weighting method was used to control the soil water content to produce a soil water stress gradient. The effects of drought and rewatering on the changes in osmotic adjustment substance content, antioxidant enzyme activity, and photosynthetic characteristics of potted Dicranostigma henanensis seedlings were measured on Day 28 after the imposition of watering treatments and Day 7 after rewatering. During the drought stress process, the relative electrical conductivity, thiobarbituric acid, water use efficiency, and proline content displayed a continuously increasing trend. Further, the net photosynthetic rate, stomatal conductance, and transpiration rate constantly decreased, while the chlorophyll content first increased and then decreased. After rehydration, superoxide dismutase (EC 1.15.1.1) activity and photosynthetic parameters quickly recovered to the CK level (soil moisture is 75%–80% of the maximum water holding capacity in the field), indicating that D. henanensis plants have a strong ability to repair the damage caused by drought stress. In particular, the photosynthetic machinery may have sophisticated regulation and repair mechanisms, which may be associated with its stable photosystem. Collectively, our findings demonstrate that the D. henanensis plant has a strong ability to adapt to arid environments, and therefore could be an excellent ornamental flower for landscaping in arid and semiarid areas.

scholarly journals The nature of the progression of drought stress drives differential metabolomic responses in Populus deltoides

2019 ◽  
Vol 124 (4) ◽  
pp. 617-626 ◽  
Author(s):  
Timothy James Tschaplinski ◽  
Paul E Abraham ◽  
Sara S Jawdy ◽  
Lee E Gunter ◽  
Madhavi Z Martin ◽  
...  
Keyword(s):  
Drought Stress ◽  
Secondary Metabolism ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Populus Deltoides ◽  
Soluble Sugars ◽  
Acute Onset ◽  
Gas Chromatography Mass Spectrometry ◽  
Primary Metabolism ◽  
Populus Species

Abstract Background and Aims The use of woody crops for Quad-level (approx. 1 × 1018 J) energy production will require marginal agricultural lands that experience recurrent periods of water stress. Populus species have the capacity to increase dehydration tolerance by lowering osmotic potential via osmotic adjustment. The aim of this study was to investigate how the inherent genetic potential of a Populus clone to respond to drought interacts with the nature of the drought to determine the degree of biochemical response. Methods A greenhouse drought stress study was conducted on Populus deltoides ‘WV94’ and the resulting metabolite profiles of leaves were determined by gas chromatography–mass spectrometry following trimethylsilylation for plants subjected to cyclic mild (–0.5 MPa pre-dawn leaf water potential) drought vs. cyclic severe (–1.26 MPa) drought in contrast to well-watered controls (–0.1 MPa) after two or four drought cycles, and in contrast to plants subjected to acute drought, where plants were desiccated for up to 8 d. Key Results The nature of drought (cyclic vs. acute), frequency of drought (number of cycles) and the severity of drought (mild vs. severe) all dictated the degree of osmotic adjustment and the nature of the organic solutes that accumulated. Whereas cyclic drought induced the largest responses in primary metabolism (soluble sugars, organic acids and amino acids), acute onset of prolonged drought induced the greatest osmotic adjustment and largest responses in secondary metabolism, especially populosides (hydroxycinnamic acid conjugates of salicin). Conclusions The differential adaptive metabolite responses in cyclic vs. acute drought suggest that stress acclimation occurs via primary metabolism in response to cyclic drought, whereas expanded metabolic plasticity occurs via secondary metabolism following severe, acute drought. The shift in carbon partitioning to aromatic metabolism with the production of a diverse suite of higher order salicylates lowers osmotic potential and increases the probability of post-stress recovery.

scholarly journals Diethyl Aminoethyl Hexanoate Priming Ameliorates Seed Germination via Involvement in Hormonal Changes, Osmotic Adjustment, and Dehydrins Accumulation in White Clover Under Drought Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Jawad Hassan ◽  
Wan Geng ◽  
Weihang Zeng ◽  
Muhammad Ali Raza ◽  
Imran Khan ◽  
...  
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
White Clover ◽  
Osmotic Adjustment ◽  
Soluble Sugars ◽  
Seed Vigor ◽  
Starch Degradation ◽  
Diethyl Aminoethyl Hexanoate ◽  
The Impact ◽  
Seeds Germination

Drought is a serious outcome of climate change reducing the productivity of forage species under arid and semi-arid conditions worldwide. Diethyl aminoethyl hexanoate (DA-6), a novel plant growth regulator, has proven to be involved in the amelioration of critical physiological functions in many agricultural crops under various abiotic stresses, but the role of the DA-6 in improving seed germination has never been investigated under drought stress. The present study was carried out to elucidate the impact of the DA-6 priming on seeds germination of white clover under drought stress. Results showed that seed priming with the DA-6 significantly mitigated the drought-induced reduction in germination percentage, germination vigor, germination index, seed vigor index, root length, shoot length, and fresh weight after 7 days of seed germination. The DA-6 significantly increased the endogenous indole-3-acetic acid, gibberellin, and cytokinin content with marked reduction in abscisic acid content in seedlings under drought stress. In addition, the DA-6 significantly accelerated starch catabolism by enhancing the activities of hydrolases contributing toward enhanced soluble sugars, proline content and ameliorated the antioxidant defense system to enhance the ability of reactive oxygen species scavenging under drought stress. Furthermore, exogenous DA-6 application significantly increased dehydrins accumulation and upregulated transcript levels of genes encoding dehydrins (SK2, Y2SK, or DHNb) during seeds germination under water deficient condition. These findings suggested that the DA-6 mediated seeds germination and drought tolerance associated with changes in endogenous phytohormones resulting in increased starch degradation, osmotic adjustment, antioxidants activity, and dehydrins accumulation during seed germination under water deficient condition.

Water loss prevention plays a greater role than ROS scavenging in dehydration tolerance of Kalanchoe tubiflora epiphyllous buds

2015 ◽  
Vol 62 (3) ◽  
pp. 153-159 ◽  
Author(s):  
Yin Ling Luo ◽  
Zhi Long Su ◽  
Xian Liang Cui ◽  
Qin Ying Lan
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Loss ◽  
Seedling Survival ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Ros Scavenging ◽  
Superoxide Anion Production ◽  
Kalanchoe Tubiflora ◽  
Epiphyllous Buds

Different plants and plant organs have various strategies to cope with drought stress.Kalanchoe tubifloraplants have a strong ability to prevent water loss and to scavenge reactive oxygen species. The epiphyllous bud of the plant serves as a reproduction unit and is able to generate plantlets even under conditions of extreme drought. The aim of this project was to study the antioxidant-stress response and osmoregulation ofK. tubifloraepiphyllous buds to dehydration and to compare the drought-tolerance mechanisms of the plant body and the epiphyllous buds. With the progression of bud dehydration, relative water content, seedling survival rate and dry weight per seedling decreased, and electrolyte leakage, hydrogen peroxide and malondialdehyde content and superoxide anion production rate increased. The activities of the antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase, dehydroascorbate reductase and glutathione reductase decreased under dehydration. The content of proline, soluble sugars and soluble protein increased in dehydrated buds proportionally with the extent of water loss. These data indicate that the drought-tolerance mechanism of theK. tubiflorabud was different from that of its mother plant. The buds invest more energy to prevent water loss during drought stress, and their antioxidant defense weakens.

Contrasting adaptations to drought stress in field-grown Ziziphus mauritiana and Prunus persica trees: water relations, osmotic adjustment and carbon isotope composition

2000 ◽  
Vol 27 (11) ◽  
pp. 985 ◽  
Author(s):  
Stefan K. Arndt ◽  
Wolfgang Wanek ◽  
Sean C. Clifford ◽  
Marianne Popp
Keyword(s):  
Drought Stress ◽  
Water Potential ◽  
Carbon Isotope ◽  
Leaf Water Potential ◽  
Osmotic Adjustment ◽  
Prunus Persica ◽  
Isotope Composition ◽  
Soluble Sugars ◽  
Carbon Isotope Composition ◽  
Ziziphus Mauritiana

Drought resistance strategies of Ziziphus mauritiana Lamk. and peach (Prunus persica L.) were studied, focusing on changes in leaf water potential, carbon isotope composition, and solute and stress metabolite contents during an annual cycle under natural rainfed conditions at a field site in Zimbabwe. After a 100-d drought period, leaf water potential (yleaf) of peach trees decreased to –2.0 MPa, whereas yleaf of Z. mauritiana remained constant at –0.7 MPa. Values for the natural abundance of 13 C (d13 C) of bulk peach leaves as well as of total water-soluble compounds and soluble sugars of leaves increased gradually, resulting in significantly higher values as drought stress developed, indicative of increased water use efficiency (WUE). By the end of the dry season, both leaves and roots of peach exhibited osmotic adjustment, with significant accumulation of monosaccharide sugars, anions and cations in the leaves. Sorbitol and oxalate accounted for the greatest proportion of solute increases during drought, while foliar sucrose content decreased. In roots, soluble sugars such as sorbitol, glucose and fructose all increased, whereas root starch content decreased. For Z. mauritiana leaves, neither d13 C values nor soluble sugar concentrations changed markedly during the study period, and Z. mauritiana plants showed no osmotic adjustment during the dry season. Data indicate that the two species exhibited different strategies for coping with soil moisture deficits under field conditions. Although Z. mauritiana exhibited the capacity for osmotic adjustment in glasshouse experiments, the trees avoided drought stress in this investigation, which is an indication of a root system that has access to deeper moist soil layers. In contrast, the increased WUE in peach is likely due to stomatal control of water loss with onset of drought stress. The observed active osmotic adjustment to maintain turgor is in contrast to glasshouse studies, where no osmotic adjustment was found, and emphasizes the importance of field studies where stress develops more slowly.

scholarly journals Osmoregulants Involved in Osmotic Adjustment for Differential Drought Tolerance in Different Bentgrass Genotypes

2015 ◽  
Vol 140 (6) ◽  
pp. 605-613 ◽  
Author(s):  
Nanqing Liu ◽  
Yixin Shen ◽  
Bingru Huang
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Osmotic Adjustment ◽  
Soluble Sugars ◽  
Creeping Bentgrass ◽  
Genetic Variations ◽  
Agrostis Stolonifera ◽  
Turf Quality ◽  
Relative Water ◽  
Highly Correlated

Compatible solute accumulation regulating osmotic adjustment (OA) is associated with drought tolerance. The objectives of this study were to examine genetic variations in OA among a diverse group of bentgrass (Agrostis sp.) genotypes or lines with differential drought tolerance, and determine major types of organic osmoregulants contributing to OA and accounting for the genetic variations in drought tolerance. A wild type cultivar of creeping bentgrass [Agrostis stolonifera (Penncross)], a transgenic line of creeping bentgrass (SAGIPT41), and four hybrid bentgrass lines [Agrostis capillaris × Agrostis stolonifera (ColxCr14, ColxCr190, ColxCr481, and ColxCr679)] were exposed to drought stress by withholding irrigation for 17 days in growth chambers. Among genotypes, ColxCr14, ColxCr190, and SAGIPT41 showed superior drought tolerance, as manifested by higher turf quality (TQ) and leaf relative water content (RWC), as well as OA than ‘Penncross’, ColxCr679, and ColxCr481 under drought stress. SAGIPT41 leaves accumulated greater content of soluble sugars (glucose, sucrose, and fructose), proline, glycine betaine (GB), and spermine; ColxCr190 had higher content of soluble sugars and spermidine; and ColxCr14 accumulated more soluble sugars and GB, compared with the three drought-sensitive genotypes. Soluble sugars were predominant contributors to OA, followed by GB and proline, with all three forms of polyamine (PA) as minor contributors in bentgrass genotypes. The osmolytes highly correlated to OA and superior drought tolerance could be used as biomarkers to select for drought-tolerant germplasm of bentgrass and other cool-season turfgrass species.

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