Antecedent Drought Condition Affects Responses of Plant Physiology and Growth to Drought and Post-drought Recovery

Antecedent environmental conditions may have a substantial impact on plant response to drought and recovery dynamics. Saplings of Eucalyptus camaldulensis were exposed to a range of long-term water deficit pre-treatments (antecedent conditions) designed to reduce carbon assimilation to approximately 50 (A50) and 10% (A10) of maximum photosynthesis of well-watered plants (A100). Thereafter, water was withheld from all plants to generate three different levels of water stress before re-watering. Our objective was to assess the role of antecedent water limitations in plant physiology and growth recovery from mild to severe drought stress. Antecedent water limitations led to increased soluble sugar content and depletion of starch in leaves of A50 and A10 trees, but there was no significant change in total non-structural carbohydrate concentration (NSC; soluble sugar and starch), relative to A100 plants. Following re-watering, A50 and A10 trees exhibited faster recovery of physiological processes (e.g., photosynthesis and stomatal conductance) than A100 plants. Nonetheless, trees exposed to the greatest water stress (−5.0 MPa) were slowest to fully recover photosynthesis (Amax) and stomatal conductance (gs). Moreover, post-drought recovery of photosynthesis was primarily limited by gs, but was facilitated by biochemistry (Vcmax and Jmax). During recovery, slow regrowth rates in A50 and A10 trees may result from insufficient carbon reserves as well as impaired hydraulic transport induced by the antecedent water limitations, which was dependent on the intensity of drought stress. Therefore, our findings suggest that antecedent water stress conditions, as well as drought severity, are important determinants of physiological recovery following drought release.

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Morphological, Physiological and Biochemical Responses of Poplar Plants to Drought Stress

Journal of AgriSearch ◽

10.21921/jas.5.3.7 ◽

2018 ◽

Vol 5 (03) ◽

Author(s):

ARADHNA KUMARI ◽

IM KHAN ◽

ANIL KUMAR SINGH ◽

SANTOSH KUMAR SINGH

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biochemical Parameters ◽

Sugar Content ◽

Soluble Sugar ◽

Field Capacity ◽

Drought Event ◽

Total Biomass ◽

Biochemical Responses ◽

Physiological And Biochemical

Poplar clone Kranti was selected to assess the morphological, physiological and biochemical responses under drought at different levels of water stress, as it is a common clone used to be grown in Uttarakhand for making paper and plywood. The cuttings of Populus deltoides L. (clone Kranti) were exposed to four different watering regimes (100, 75, 50 and 25% of the field capacity) and changes in physiological and biochemical parameters related with drought tolerance were recorded. Alterations in physiological (i.e. decrease in relative water content) and biochemical parameters (i.e. increase in proline and soluble sugar content and build-up of malondialdehyde by-products) occurred in all the three levels of water stress, although drought represented the major determinant. Drought treatments (75%, 50% and 25% FC) decreased plant height, radial stem diameter, harvest index, total biomass content and RWC in all the three watering regimes compared to control (100% FC). Biochemical parameters like proline, soluble sugar and MDA content increased with severity and duration of stress, which helped plants to survive under severe stress. It was analyzed that for better wood yield poplar seedlings should avail either optimum amount of water (amount nearly equal to field capacity of soil) or maximum withdrawal up to 75% of field capacity up to seedling establishment period (60 days). Furthermore, this study manifested that acclimation to drought stress is related with the rapidity, severity, and duration of the drought event of the poplar species.

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Different Drought-Tolerant Mechanisms in Quinoa (Chenopodium quinoa Willd) and Djulis (Chenopodium formosanum Koidz.) Based on Physiological Analysis

Plants ◽

10.3390/plants10112279 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2279

Author(s):

Pin-Hua Lin ◽

Yun-Yang Chao

Keyword(s):

Drought Stress ◽

Water Content ◽

Sugar Content ◽

Soluble Sugar ◽

Soluble Sugars ◽

Chenopodium Quinoa ◽

Proline Content ◽

Severe Drought ◽

Drought Treatment ◽

Total Soluble Sugar

The purpose of this experiment is to study the effects of treatment with 90% (28.5% volumetric water content (VWC)), 75% (24% VWC), 50% (16% VWC), and 25% (8% VWC) of water requirements on the growth of two djulis (Chenopodium formosana Koidz) varieties (red: RP and yellow: OR) and one quinoa (Chenopodium quinoa Willd) varieties (PI). The results showed that drought stress (8% VWC) significantly reduced plant growth and relative water content, and increased H2O2 and MDA content in C. formosana and C. quinoa. The most significant increase in these parameters was detected in the OR variety. The antioxidant enzymes, such as SOD, APX, and GR activities of PI variety under drought treatment (8% VWC), are significantly increased, while GR activity of C. formosana also increased significantly. Additionally, C. formosana and PI variety remained at a stable AsA/DHA ratio, but the GSH/GSSG ratio decreased during drought treatment. Moreover, drought stress increased total soluble sugars and proline content in the PI variety. However, C. formosana proline content was extremely significantly enhanced, and only the OR variety increased the total soluble sugar content at the same time during the vegetative growth period. In summary, C. formosana and C. quinoa have different drought tolerance mechanisms to adapt to being cultivated and produced under severe drought conditions.

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Production, Optimization, Characterization and Drought Stress Resistance by β-Glucan-Rich Heteropolysaccharide From an Endophytic Fungi Colletotrichum alatae LCS1 Isolated From Clubmoss (Lycopodium clavatum)

Frontiers in Fungal Biology ◽

10.3389/ffunb.2021.796010 ◽

2022 ◽

Vol 2 ◽

Author(s):

Hiran Kanti Santra ◽

Debdulal Banerjee

Keyword(s):

Drought Stress ◽

Stress Tolerance ◽

Endophytic Fungi ◽

Sugar Content ◽

Soluble Sugar ◽

Production Optimization ◽

Severe Drought ◽

Therapeutic Effects ◽

Lycopodium Clavatum ◽

First Time

Endophytic entities are ubiquitous in nature with all-square bioactivity ranging from therapeutic effects toward animals to growth promoting attributes and stress tolerance activities in case of green plants. In the present study, the club moss Lycopodium clavatum for the first time has been subjected for the isolation of endophytic fungi. An exopolysaccharide (EPS) extracted from Colletotrichum alatae LCS1, an endophytic fungi isolated from L. clavatum Linn., was characterized as a β-glucan heteropolymer (composed of mannose, rhamnose, arabinose, glucose, galactose, and fucose) which plays a pivotal role in obliterating the drought stress in rice seedlings (Oryza sativa) when applied at an amount of 20, 50, and 100 ppm. The fresh weight contents of rice tissue (39%), total chlorophyll (33%), proline (41%), soluble sugar content (26%) along with antioxidant enzymes such as catalase, peroxidase, and super-oxide dismutase increased (in comparison to control of non-EPS treated seedlings) while malondialdehyde content had reduced markedly after 30 days of regular treatment. The drought resistance of rice seedling was observed at peak when applied at 50 ppm dosage. Vital parameters for EPS production like fermentation duration (5 days), medium pH (6), nutrient (carbon (glucose-7 g%/l), nitrogen (yeast extract-0.4 g%/l), and mineral (NaCl-0.10 g%/l) sources, oxygen requirements (O2 vector or liquid alkane-n-hexane, n-heptane, n-hexadecane), and headspace volume (250 ml Erlenmeyer flask- 50 ml medium, 200 ml-headspace volume) were optimized to obtain an enhanced EPS yield of 17.38 g/L−59% higher than the preoptimized one. The present study, for the first time, reported the β-glucan rich heteropolysaccharide from Colletotrichum origin which is unique in structure and potent in its function of drought stress tolerance and could enhance the sustainable yield of rice cultivation in areas facing severe drought stress.

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Exploration of physiological and biochemical processes of canola with exogenously applied fertilizers and plant growth regulators under drought stress

PLoS ONE ◽

10.1371/journal.pone.0260960 ◽

2021 ◽

Vol 16 (12) ◽

pp. e0260960

Author(s):

Muhammad Mahran Aslam ◽

Fozia Farhat ◽

Mohammad Aquil Siddiqui ◽

Shafquat Yasmeen ◽

Muhammad Tahir Khan ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Stomatal Conductance ◽

Plant Growth ◽

Stability Index ◽

Leaf Temperature ◽

Membrane Stability Index ◽

Chemical Fertilizers ◽

Chlorophyll Contents ◽

Water Contents

Environmental stresses may alter the nutritional profile and economic value of crops. Chemical fertilizers and phytohormones are major sources which can enhance the canola production under stressful conditions. Physio-biochemical responses of canola altered remarkably with the use of nitrogen/phosphorus/potassium (N/P/K) fertilizers and plant growth regulators (PGRs) under drought stress. The major aim of current study was to evaluate nutritional quality and physio-biochemical modulation in canola (Brassica napus L.) from early growth to seed stage with NPK and PGRs in different water regimes. To monitor biochemical and physiological processes in canola, two season field experiment was conducted as spilt plot under randomized complete block design (RCBD) with four treatments (Control, Chemical fertilizers [N (90 kg/ha), P and K (45 kg ha-1)], PGRs; indole acetic acid (IAA) 15g ha-1, gibberellic acid (GA3) 15g ha-1 and the combination of NPK and PGRs] under different irrigations regimes (60, 100, 120, 150 mm evaporations). Water stress enhanced peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO), soluble sugar, malondialdehyde (MDA), proline contents as well as leaf temperature while substantially reduced leaf water contents (21%), stomatal conductance (50%), chlorophyll contents (10–67%), membrane stability index (24%) and grain yield (30%) of canola. However, the combined application of NPK and PGR further increased the enzymatic antioxidant pool, soluble sugars, along with recovery of leaf water contents, chlorophyll contents, stomatal conductance and membrane stability index but decreased the proline contents and leaf temperature at different rate of evaporation. There is positive interaction of applied elicitors to the water stress in canola except leaf area. The outcomes depicted that the combination of NPK with PGRs improved the various morpho-physiological as well as biochemical parameters and reduced the pressure of chemical fertilizers cost about 60%. It had also reduced the deleterious effect of water limitation on the physiology and grain yield and oil contents of canola in field experiments.

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Phedimus Aizoon L. Responds to Drought Stress: Growth, Physiological Changes and Mechanism of Drought Resistance

10.21203/rs.3.rs-132688/v1 ◽

2020 ◽

Author(s):

Yuhang Liu ◽

Zhongqun He ◽

Yongdong Xie ◽

Lihong Su ◽

Ruijie Zhang ◽

...

Keyword(s):

Drought Stress ◽

Drought Resistance ◽

Soluble Sugar ◽

Severe Drought ◽

Physiological Changes ◽

Moderate Drought ◽

Negative Effect ◽

Mda Content ◽

Maximum Water ◽

Mild Drought

Abstract A pot experiment was conducted to investigate the growth, physiological changes and mechanism of drought resistance of Phedimus aizoon L. under different levels of water content .CK: 75% ~ 80% of the MWHC (maximum water holding capacity), Mild drought: 55% ~ 60%, Moderate drought: 40% ~ 45%, Severe drought: 20% ~ 25%.We observed that the plants grew normally in the first two treatments, even the mild drought promoted the growth of the roots. In the last two treatments, drought stress had a significant negative effect on plant growth, at the same time, Phedimus aizoon L. also made positive physiological response to cope with the drought: The aboveground part of the plant (leaf, plant height, stem diameter) was smaller, the waxy layer of the leaves was thickened, the stomata of the leaves were closed during the day, and only a few stomata were opened at night, which proved that the dark reaction cycle metabolism mode of the plant was transformed from C3 cycle to CAM pathway. The activity of antioxidant enzymes (SOD, POD and CAT) was continuously increased to alleviate the damage caused by drought. To ensure the relative stability of osmotic potential, the contents of osmoregulation substances such as proline, soluble sugar, soluble protein and trehalose increased correspondingly. But plants have limited regulatory power, with aggravation of drought stress degree and extension of stress time, the MDA content and electrolyte leakage of leaves increased continuously. Observed under electron microscope,the morphology of chloroplast and mitochondria changed and the membrane structure was destroyed. The plant's photosynthetic and respiratory mechanisms are destroyed and the plant gradually die.

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Summer drought stress: differential effects on cane anatomy and non-structural carbohydrate content in overwintering Cabernet Sauvignon and Syrah vines

BIO Web of Conferences ◽

10.1051/bioconf/20191303007 ◽

2019 ◽

Vol 13 ◽

pp. 03007 ◽

Cited By ~ 2

Author(s):

Rachele Falchi ◽

Elisa Petrussa ◽

Marco Zancani ◽

Valentino Casolo ◽

Paola Beraldo ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biochemical Characterization ◽

Carbon Allocation ◽

Starch Accumulation ◽

Cabernet Sauvignon ◽

Severe Drought ◽

Summer Drought ◽

Long Term Effects ◽

Experimental Conditions

Grapevines store non-structural carbohydrates (NSC) during late summer to sustain plant development at the onset of the following spring’s growth. Starch is the main stored carbohydrate, found in the wood-ray parenchyma of roots and canes. Although the relationship between hydraulic and plant photosynthetic performance is well-recognized, little research has been done on the long-term effects of drought in grapevines adopting different strategies to cope with water stress (i.e. isohydric and anisohydric). We performed our study by exposing two different grape cultivars (Syrah and Cabernet Sauvignon) to a short but severe drought stress, at two stages of the growing season (July and September). No marked differences in the physiological and hydraulic responses of the two varieties were found, probably due to our experimental conditions. However, anatomical and biochemical characterization of overwintering canes pointed out several interesting outcomes. We found a significant and parallel increase of starch and medullar ray number in both cultivars exposed to early water stress. We hypothesize that stressed vines limited their carbon allocation to growth, while shifting it to starch accumulation, with a most evident effect in the period of intense photosynthetic activity. We also speculate that a different aptitude to osmotic adjustment may underlay variation in starch increase and the specific involvement of bark NSC in the two cultivars.

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Exogenous Melatonin Modulates the Physiological and Biochemical Mechanisms of Drought Tolerance in Tartary Buckwheat (Fagopyrum tataricum (L.) Gaertn)

Molecules ◽

10.3390/molecules25122828 ◽

2020 ◽

Vol 25 (12) ◽

pp. 2828

Author(s):

Md. Shakhawat Hossain ◽

Jing Li ◽

Ashim Sikdar ◽

Mirza Hasanuzzaman ◽

Ferdinand Uzizerimana ◽

...

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Sugar Content ◽

Soluble Sugar ◽

Growth And Yield ◽

Tartary Buckwheat ◽

Arid Zones ◽

Enzymatic Antioxidants ◽

Fagopyrum Tataricum ◽

Exogenous Melatonin

Tartary buckwheat is one of the nutritious minor cereals and is grown in high-cold mountainous areas of arid and semi-arid zones where drought is a common phenomenon, potentially reducing the growth and yield. Melatonin, which is an amphiphilic low molecular weight compound, has been proven to exert significant effects in plants, under abiotic stresses, but its role in the Tartary buckwheat under drought stress remains unexplored. We evaluated the influence of melatonin supplementation on plant morphology and different physiological activities, to enhance tolerance to posed drought stress by scavenging reactive oxygen species (ROS) and alleviating lipid peroxidation. Drought stress decreased the plant growth and biomass production compared to the control. Drought also decreased Chl a, b, and the Fv/Fm ratio by 54%, 70%, and 8%, respectively, which was associated with the disorganized stomatal properties. Under drought stress, H2O2, O2•−, and malondialdehyde (MDA) contents increased by 2.30, 2.43, and 2.22-folds, respectively, which caused oxidative stress. In contrast, proline and soluble sugar content were increased by 84% and 39%, respectively. However, exogenous melatonin (100 µM) could improve plant growth by preventing ROS-induced oxidative damage by increasing photosynthesis, enzymatic antioxidants (superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase), secondary metabolites like phenylalanine ammonialyase, phenolics, and flavonoids, total antioxidant scavenging (free radical DPPH scavenging), and maintaining relative water content and osmoregulation substances under water stress. Therefore, our study suggested that exogenous melatonin could accelerate drought resistance by enhancing photosynthesis and antioxidant defense in Tartary buckwheat plants.

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Deciphering the Mechanisms of Microbe Mediated Drought Stress Alleviation in Wheat

10.21203/rs.3.rs-1100465/v1 ◽

2021 ◽

Author(s):

DEVENDRA SINGH ◽

Shobit Thapa ◽

Jagriti Yadav ◽

Dikchha SINGH ◽

Hillol Chakdar ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Plant Growth ◽

Sugar Content ◽

Pcr Analysis ◽

Stress Alleviation ◽

Microbial Inoculation ◽

Water Stress Condition ◽

Plant Growth Promoting ◽

Plant Growth Promoting Microbes

Abstract Drought stress adversely influences the crop plants. Herein, present research was designed to elucidate the role of plant growth promoting microbes for amelioration of water stress in wheat. A pot experiment was conducted for screening the microorganisms on the basis of plant growth, chlorophyll and proline content under water stress. Bacillus sp. BT3 and Klebsiella sp. HA9 were found more promising strains that positively influenced the plant growth, chlorophyll and proline status of seedlings under water stress condition. Further, Bacillus sp. BT-3 and Klebsiella sp. HA9 along with check strain (BioNPK) were used for elucidating their detailed effect on morphological, biochemical, physiological and molecular traits to mitigate drought stress in wheat. Microbial inoculation significantly enhanced plant growth, biomass, relative water content, chlorophyll content and root morphological parameters over the uninoculated water stressed (30% FC) control. Likewise, sugar content, protein content and antioxidant enzymes were also significantly enhanced due to microbial inoculation under water stress (30% FC). Microbial inoculation significantly decreased proline, glycine betaine, lipid peroxidation, peroxide and superoxide radicals in wheat over the uninoculated water stressed (30%FC) control. Quantitative real-time (qRT)- PCR analysis revealed that Bacillus sp. BT-3, Klebsiella sp. HA9 and BioNPK inoculation significantly upregulated stress responsive genes (DHN, DREB, L15 and TaABA-8OH) over the uninoculated water stressed (30% F.C.) control. The study reports the potential of Bacillus sp. BT3 and Klebsiella sp. HA9 along with BioNPK in water stress alleviation in wheat which could be recommended as effective biofertilizers.

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IS ABSCISIC ACID INVOLVED IN THE DROUGHT RESPONSES OF BRAZILIAN GREEN DWARF COCONUT?

Experimental Agriculture ◽

10.1017/s0014479708007436 ◽

2009 ◽

Vol 45 (2) ◽

pp. 189-198 ◽

Cited By ~ 9

Author(s):

F. P. GOMES ◽

M. A. OLIVA ◽

M. S. MIELKE ◽

A-A. F. DE ALMEIDA ◽

H. G. LEITE ◽

...

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Stomatal Conductance ◽

Gas Exchange ◽

Water Potential ◽

Water Use ◽

Severe Drought ◽

Use Efficiency ◽

Recovery Cycles ◽

Mild Drought

SUMMARYAbscisic acid (ABA) accumulation in leaves of drought-stressed coconut palms and its involvement with stomatal regulation of gas exchange during and after stress were investigated. Two Brazilian Green Dwarf coconut ecotypes from hot/humid and hot/dry environments were submitted to three consecutive drying/recovery cycles under greenhouse conditions. ABA accumulated in leaflets before significant changes in pre-dawn leaflet water potential (ΨPD) and did not recover completely in the two ecotypes after 8 days of rewatering. Stomatal conductance was influenced by ABA under mild drought and by ΨPD under severe drought. There were no significant differences between the ecotypes for most variables measured. However, the ecotype from a hot/dry environment showed higher water use efficiency after repeated cycles of water stress.

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Interactive Effects of Cinnamic Acid and Water Stress on Wheat Seedlings

International Journal of Plant and Environment ◽

10.18811/ijpen.v4i01.11616 ◽

2018 ◽

Vol 4 (01) ◽

pp. 105-112

Author(s):

N. B. Singh ◽

Nimisha Amist

Keyword(s):

Water Stress ◽

Nitrate Reductase ◽

Cinnamic Acid ◽

Reductase Activity ◽

Sugar Content ◽

Soluble Sugar ◽

Interactive Effects ◽

Guaiacol Peroxidase ◽

Seedling Height ◽

Wheat Seedlings

In the present study we compared the effects of allelochemical with water stress (WS) on growth, biochemical parameters and responses of antioxidative enzymes in wheat seedlings. The wheat seedlings were treated with 0.5, 1.0 and 1.5 mM concentrations of cinnamic acid (CA) with and without water stress by withholding water supply for 5 days. Leaf water status, photosynthetic pigments, protein content, amount of proline and nitrate reductase (NR) and antioxidant enzymes activities were examined. CA resulted in reduction of seedling height with drastic decrease in stressed seedlings. The combined treatments CA+WS further decreased the seedling height. The same result was registered for seedlings dry weight, relative water content and pigment and protein contents. Total soluble sugar content and nitrate reductase activity were variedly affected under all treatments. Proline content and lipid peroxidation increased. Activity of superoxide dismutase increased significantly (less than 0.05) while catalase P activity was lower in all treatments. Ascorbate peroxidase and guaiacol peroxidase activities were higher as compared with catalase which showed protection of wheat seedlings from oxidative stress. Water stress elevated the toxic effect of allelochemical.

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