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.

Photosynthesis, carbon partitioning and metabolite content during drought stress in peach seedlings

1998 ◽  
Vol 25 (2) ◽  
pp. 197 ◽  
Author(s):  
A. J. Escobar-Gutiérrez ◽  
B. Zipperlin ◽  
F. Carbonne ◽  
A. Moing ◽  
J.P. Gaudillére
Keyword(s):  
Drought Stress ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Short Term ◽  
Phloem Sap ◽  
Mature Leaves ◽  
Key Enzyme

Photosynthesis, metabolic carbon partitioning and the contribution of sorbitol to the osmotic potential of mature peach (Prunus persica (L.) Batsch) leaves and phloem sap were examined in plants undergoing two levels of a short term drought stress. The relationship between osmotic potential at full turgor and water potential showed that neither mild nor severe drought stress induced a significant active osmotic adjustment in mature leaves. The osmotic potential of leaves at full turgor was -1.9 MPa; sorbitol was the major organic component (20%). Leaf sucrose and starch contents were significantly reduced by drought. The partitioning of newly-fixed carbon was also affected by stress. These changes appeared to originate from the inhibition of photosynthesis induced by drought stress. At low photosynthetic rates, the turnover of organic ions was low, and sorbitol synthesis was favoured over that of sucrose. Water stress did not affect the in vitro activity of sucrose phosphate synthase (EC 2.4.1.14), the key enzyme in sucrose synthesis. The in vitro activity of aldose-6-phosphate reductase (EC 1.1.1.200), the key enzyme in sorbitol synthesis, tended to increase linearly in response to drought stress. It is concluded that, contrary to some other polyol-synthesising species, peach did not seem to benefit from sorbitol synthesis during short term drought stress for active osmotic adjustment in mature leaves. However, in phloem sap, increases in sucrose and especially sorbitol concentration were observed in stressed plants.

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 The Role of Carbohydrates in Active Osmotic Adjustment in Apple under Water Stress

1992 ◽  
Vol 117 (5) ◽  
pp. 816-823 ◽  
Author(s):  
Zhongchun Wang ◽  
Gary W. Stutte
Keyword(s):  
Water Stress ◽  
Malus Domestica ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Soluble Sugars ◽  
Sugar Alcohol ◽  
Apple Trees ◽  
Mature Leaves ◽  
Leaf Osmotic Potential

Greenhouse grown 2-year-old potted `Jonathan' apple trees (Malus domestica Borkh.) were subjected to various levels of water stress in February. Midday leaf water potential (ψW), leaf osmotic potential (ψS), soluble sugars, and starch contents of mature leaves were measured throughout the development of water stress to determine whether active osmotic adjustment could be detected and whether carbohydrates were involved. Active adjustments of 0.6 MPa were observed 3 and 5 days, respectively, after water stress was initiated. Leaf turgor potential (ψP) could not be maintained through the osmotic adjustment when ψW dropped below -1.6 MPa. Sorbitol, glucose, and fructose concentrations increased while sucrose and starch levels decreased significantly as water stress developed, strongly suggesting that sugar alcohol and monosaccharide are the most important osmotica for adjustment. Sorbitol was a primary carbohydrate in the cell sap and accounted for > 50% of total osmotic adjustment. The partitioning of newly fixed W-labeled photosynthates in mature leaves was not affected by water stress immediately after the 30-min 14CO2 treatment. All the W-labeled carbohydrates decreased in the labeled leaves very rapidly after 14CO2 labeling. The decrease in 14C-sorbitol was greater than the decrease in other carbohydrates under both well-watered and stressed conditions. After 24 hours of water stress, however, the percentage of 14C-sorbitol increased while the percentages of sucrose, starch, glucose, and fructose decreased significantly with increasing levels of stress. The ratio of 14C-sorbitol in leaves with ψW = -3.5 MPa to leaves with ψW = -0.5 MPa was significantly higher than that of 14C-sucrose, 14C-glucose, W-fructose, or 14C-starch.

Osmotic Adjustment in Water Stressed Grapevine Leaves in Relation to Carbon Assimilation

1993 ◽  
Vol 20 (3) ◽  
pp. 309 ◽  
Author(s):  
ML Rodrigues ◽  
MM Chaves ◽  
R Wendler ◽  
MM David ◽  
WP Quick ◽  
...  
Keyword(s):  
Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Soluble Sugars ◽  
Carbon Assimilation ◽  
Dry Weight ◽  
Leaf Water ◽  
Soluble Carbohydrates ◽  
Water Fraction ◽  
The Difference

The response of grapevine plants to severe water deficit (predawn leaf water potential of - 1.13 MPa), imposed at a rate of about 0.16 MPa day-1 was studied in terms of leaf water relations characteristics, stomatal behaviour and gas exchange. Carbohydrate status of leaves was also analysed in order to assess the contribution of soluble sugars as osmotic solutes during drought. Pressure/volume analysis showed an active osmotic adjustment in water-stressed leaves, which decreased osmotic potential at full turgor by 0.45 MPa and the apoplastic water fraction showed a reduction of 19% as compared to the well- watered plants. Cell wall elasticity was not significantly affected by water stress, and turgor loss point in stressed leaves was reached at lower water potential and relative water content values than in the well-watered controls. Photosynthesis was markedly reduced in water-stressed plants. However, well-watered and water-stressed leaves had similar concentrations of glucose and fructose. The concentrations of sucrose and starch decreased in water-stressed leaves. This accounted for a marked decrease in the ratio of leaf dry weight to area in droughted plants. The changes in concentrations of soluble carbohydrates could not account for the difference in osmotic potential between water-stressed and well-watered leaves.

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.

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.

scholarly journals Copper Chlorophyllin Impacts on Growth and Drought Stress Tolerance of Tomato Plants

HortScience ◽  
2019 ◽  
Vol 54 (12) ◽  
pp. 2195-2201 ◽  
Author(s):  
Xunzhong Zhang ◽  
Mike Goatley ◽  
Jamie Conner ◽  
Megan Wilkins ◽  
Inna Teshler ◽  
...  
Keyword(s):  
Drought Stress ◽  
Stress Tolerance ◽  
Osmotic Adjustment ◽  
Foliar Application ◽  
Soluble Sugars ◽  
Stress Conditions ◽  
Tomato Plants ◽  
Antioxidant Defense Capacity ◽  
Leaf Photosynthetic Rate ◽  
Paraffinic Oil

Plant-based pigments have been used as substances to improve crop yield and quality, but the mechanisms of their action on plant growth and stress tolerance are not well understood. The objective of this study was to investigate effects of two formulations of plant-based copper chlorophyllin (Cu-Chl) with and without synthetic paraffinic oil. These formulations, referred to as B18-0074 and B18-0075, were applied as a soil drench plus foliar or a foliar-only application. We investigated their impact on physiological responses of tomato plants under prolonged drought stress conditions. In addition, we examined photosynthetic impacts associated with the application of Cu-Chl formulations. B18-0074 increased leaf photosynthetic rate (Pn) by 8.8% with soil plus foliar application and 18.6% with foliar application relative to the control under drought stress at day 21. Similarly, B18-0075 increased Pn by 16.9% with soil plus foliar application and 24.6% with foliar application relative to the control under drought stress at day 21. The application of the two Cu-Chl–containing products increased leaf antioxidant enzyme catalase (CAT) and ascorbate peroxidase (APX) activity, as well as glutathione (GSH) content. The two products also increased leaf soluble sugars and proline content, indicating improvement of osmotic adjustment. Soil plus foliar and foliar application only of B18-0075 increased root biomass but did not consistently affect plant shoot growth. The results of this study suggest that application of Cu-Chl in combination with synthetic paraffinic oil may improve photosynthetic function, osmotic adjustment, antioxidant defense capacity, and root growth of tomato plant grown under drought stress conditions.

scholarly journals Effects of Trinexapac-ethyl on Drought Responses in Creeping Bentgrass Associated with Water Use and Osmotic Adjustment

2009 ◽  
Vol 134 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Xiuju Bian ◽  
Emily Merewitz ◽  
Bingru Huang
Keyword(s):  
Drought Stress ◽  
Water Content ◽  
Water Use ◽  
Osmotic Adjustment ◽  
Soluble Sugars ◽  
Photochemical Efficiency ◽  
Inorganic Ions ◽  
Creeping Bentgrass ◽  
Water Depletion ◽  
Plant Foliage

Understanding factors influencing drought resistance traits is important for improving turfgrass growth in water-limited environments. The objectives of this study were to examine effects of a plant growth regulator, trinexapac-ethyl (TE), on turf growth and water use for creeping bentgrass (Agrostis stolonifera L.) exposed to drought stress, and to determine changes in the accumulation of solutes involved in osmotic adjustment associated with TE application. Plant foliage of cultivar L-93 was sprayed with 1.95 mL·L−1 of TE at 0.113% a.i. 14 days before and at the initiation of drought stress. TE-treated and untreated plants were exposed to well-watered or drought stress conditions for 28 days in a growth chamber. TE-treated plants exhibited a reduced rate of water depletion from the soil as demonstrated by higher soil water content, lower evapotranspiration rates, and higher leaf relative water content during 28 days of drought stress compared with non-TE-treated plants. During the later phase of drought stress, TE-treated plants had a greater reduction in leaf ψS at full turgor or greater osmotic adjustment, which was associated with increased accumulation of soluble sugars and inorganic ions (Ca and K) in leaves of TE-treated plants. Proline content increased in response to drought stress, but was unaffected by TE application, suggesting that it may not contribute to the effects of TE on osmotic adjustment. TE-treated plants maintained significantly higher turf quality and leaf photochemical efficiency under drought stress. The results suggest that the promotive effects of TE application on turf growth during drought stress were associated with the reduction in water depletion or lower water use and increases in osmotic adjustment due to the accumulation of inorganic solutes and soluble sugars.

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