Differential photosynthetic performance and photoprotection mechanisms of three Mediterranean evergreen oaks under severe drought stress

2009 ◽  
Vol 36 (5) ◽  
pp. 453 ◽  
Author(s):  
José Javier Peguero-Pina ◽  
Domingo Sancho-Knapik ◽  
Fermín Morales ◽  
Jaume Flexas ◽  
Eustaquio Gil-Pelegrín
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Oxidative Damage ◽  
Dark Respiration ◽  
Photosynthetic Electron Transport ◽  
High Water ◽  
Quercus Suber ◽  
Photochemical Quenching ◽  
Severe Drought ◽  
Evergreen Oaks

The ability of three Mediterranean oaks (Quercus coccifera L., Quercus ilex ssp. ballota (Desf.) Samp and Quercus suber L.) to cope with intense drought was investigated. Water stress reduced stomatal conductance and photosynthesis in these species. Drought-mediated changes in photosynthetic-related parameters allowed the characterisation of the specific photo-protective mechanisms. Specifically, Q. suber downregulated photosynthetic electron transport rates (ETR) closing PSII reaction centres (i.e. decreasing photochemical quenching) and through an antheraxanthin (A) + zeaxanthin (Z)-mediated diminished intrinsic PSII efficiency (Φexc.). These changes were lower in Q. coccifera and Q. ilex ssp. ballota, which decreased further ETR photo-inactivating PSII centres (evidenced by their low predawn Fv/Fm ratios at high water stress). The predawn Fv/Fm ratio decreased in Q. coccifera largely due to Fm decreases, whereas in Q. ilex ssp. ballota Fv/Fm decreases were due to F0 increases, below –4 MPa. These Fv/Fm decreases were well correlated with increases in the A + Z photo-protective pigments. An analysis of dark respiration and photorespiration as alternative electron sinks under intense drought stress also revealed interspecific differences. The largest imbalance between electrons generated and consumed increased potentially oxidative damage in Q. suber. Subsequently, only Q. suber showed loss of chlorophyll, which is one of the main targets of oxidative damage. Data suggest that Q. coccifera and Q. ilex ssp. ballota seem more able than Q. suber to withstand highly xeric conditions. Therefore, our results question the consideration of Mediterranean evergreen oaks as a homogeneous physiological group.

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

2019 ◽  
Vol 13 ◽  
pp. 03007 ◽  
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.

scholarly journals Genotypic Variability in Photosynthesis, Water Use, and Light Absorption among Red and Freeman Maple Cultivars in Response to Drought Stress

2003 ◽  
Vol 128 (3) ◽  
pp. 337-342 ◽  
Author(s):  
William L. Bauerle ◽  
Jerry B. Dudley ◽  
Lawrence W. Grimes
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Light Absorption ◽  
Acer Rubrum ◽  
Stress Conditions ◽  
Photochemical Quenching ◽  
Red Maple ◽  
Psii Efficiency ◽  
Fluorescence Measurements ◽  
Water Stress Condition

Cultivars of red (Acer rubrum L.) and Freeman maple (Acer ×freemanii E. Murray) are popular ornamental plants which are commonly placed in a variety of landscapes. To date, little information quantifies the capacity to tolerate and recover from drought among cultivars of red and Freeman maple. The objective of this study was to compare the effects of water stress on the physiology of five different maple cultivars of marketable size including four red maple genotypes, `Summer Red', `October Glory' (October Glory), `Autumn Flame', and `Franksred' (Red Sunset), as well as one hybridized Freeman maple genotype, `Jeffersred' (Autumn Blaze). Two-year-old cloned genotypes of red and Freeman maple were subjected to two treatments: irrigated daily to container capacity or irrigation withheld for one drought and recovery cycle. Light absorption, gas exchange, and chlorophyll fluorescence measurements were conducted under well-watered and drought stress conditions that approached 0.070 m3·m-3. Compared to well-watered conditions, drought stress conditions of 0.090 m3·m-3 had a significant main effect that reduced the amount of light absorption in four of the five genotypes. Additionally, absorption among genotypes was different under both well-watered and water stress conditions. Over the course of drought stress and a recovery phase, net photosynthesis and stomatal conductance were different among genotypes. Maximum photosystem II (PSII) efficiency of dark-adapted leaves (Fv/Fm) was lowered by the water stress condition. The efficiency of excitation capture by open PSII reaction centers (Fv`/Fm') was variable among genotypes. Photochemical quenching was higher in Autumn Blaze, October Glory, and `Summer Red' under drought conditions, which corresponded with a low degree of closure of PSII centers. Additionally, the fraction of excess excitation energy was also lower. Lastly, water deficit caused an increase in PSII efficiency in all genotypes except Autumn Blaze. This research demonstrated physiological variation among commercially available red and Freeman maple genotypes that may be selected for drought tolerance based on site moisture characteristics.

scholarly journals Overexpression of MdATG8i Enhances Drought Tolerance by Alleviating Oxidative Damage and Promoting Water Uptake in Transgenic Apple

2021 ◽  
Vol 22 (11) ◽  
pp. 5517
Author(s):  
Xin Jia ◽  
Xiaoqing Gong ◽  
Xumei Jia ◽  
Xianpeng Li ◽  
Yu Wang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Oxidative Damage ◽  
Water Uptake ◽  
Transcript Level ◽  
Root Water Uptake ◽  
Plant Responses ◽  
Severe Drought ◽  
Root Hydraulic Conductivity ◽  
Drought Conditions

Water deficit adversely affects apple (Malus domestica) productivity on the Loess Plateau. Autophagy plays a key role in plant responses to unfavorable environmental conditions. Previously, we demonstrated that a core apple autophagy-related protein, MdATG8i, was responsive to various stresses at the transcript level. Here, we investigated the function of this gene in the response of apple to severe drought and found that its overexpression (OE) significantly enhanced drought tolerance. Under drought conditions, MdATG8iOE apple plants exhibited less drought-related damage and maintained higher photosynthetic capacities compared with the wild type (WT). The accumulation of ROS (reactive oxygen species) was lower in OE plants under drought stress and was accompanied by higher activities of antioxidant enzymes. Besides, OE plants accumulated lower amounts of insoluble or oxidized proteins but greater amounts of amino acids and flavonoid under severe drought stress, probably due to their enhanced autophagic activities. Particularly, MdATG8iOE plants showed higher root hydraulic conductivity than WT plants did under drought conditions, indicating the enhanced ability of water uptake. In summary, the overexpression of MdATG8i alleviated oxidative damage, modulated amino acid metabolism and flavonoid synthesis, and improved root water uptake, ultimately contributing to enhanced drought tolerance in apple.

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

2021 ◽  
Vol 4 ◽  
Author(s):  
Ximeng Li ◽  
Jingting Bao ◽  
Jin Wang ◽  
Chris Blackman ◽  
David Tissue
Keyword(s):  
Plant Physiology ◽  
Water Stress ◽  
Drought Stress ◽  
Stomatal Conductance ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Severe Drought ◽  
Substantial Impact ◽  
Drought Recovery ◽  
Water Limitations

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.

scholarly journals Effect of water stress and AM fungi on the growth performance of pea

2020 ◽  
Vol 4 (1) ◽  
pp. 36-43
Author(s):  
Jaya Thakur ◽  
Bharat Shinde
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Root Length ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Dry Weight ◽  
High Water ◽  
Fresh Weight ◽  
Number Of Leaves ◽  
Mycorrhizal Plants

The study was conducted to determine the effect of arbuscular mycorrhizal (AM) fungi inoculation on growth of pea grown under water stressed pot culture conditions. Water stress was given to the pea plants after 30 days at the interval of 4, 8 and 12 days. The data was collected at an interval of 15 days. Three replicates of each set were maintained. . The mixture of AM fungi used for current experiment included the species of Acaulospora denticulata, A. gerdemannii, Glomus macrocarpum, G. maculosum, G. fasciculatum and Scutellospora minuta. The mycorrhizal plants have shown more shoot and root length as compared to the control plants. The height of shoot and root was significantly decreased with the increase in drought stress. Mycorrhizal plants with low water stress showed enhanced shoot and root length than high water stress. The mycorrhizal plants have shown more number of leaves than control plants during drought stress. The number of leaves significantly reduced with the increase in drought stress. The leaves produced by the control plants were comparatively smaller than those of mycorrhizal plants. The dry weight of root and shoot of both control and mycorrhizal plants decreased with the increase in water stress. Mycorrhizal plants showed more dry weight of shoot and root as compared to control plants.  Plants inoculated with AM fungi produce more dry weight than the control plants. The fresh weight of both control and mycorrhizal plants has been decreased with the increase in water stress interval and also the fresh weight of root and shoot was observed higher in mycorrhizal plants as compared to those of control plants.

Adaptation to and recovery from drought stress at vegetative stages in wheat (Triticum aestivum) cultivars

2016 ◽  
Vol 43 (12) ◽  
pp. 1159 ◽  
Author(s):  
Muhammad Abid ◽  
Zhongwei Tian ◽  
Syed Tahir Ata-Ul-Karim ◽  
Feng Wang ◽  
Yang Liu ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Grain Yield ◽  
Dry Matter ◽  
Leaf Gas Exchange ◽  
Field Capacity ◽  
Severe Drought ◽  
Drought Intensity ◽  
Crop Growth Rate ◽  
Physiological Adaptations

Studying plants’ capability to adapt and recover from drought stress is essential because of the ever-changing nature of drought events. To evaluate the genotypically variable morpho-physiological adaptations to drought stress and recovery after re-watering, two wheat cultivars (Luhan-7 and Yangmai-16) were pot-cultured under three levels of water stress: severe (35–40% field capacity, FC) and moderate water deficits (55–60% FC) and well-watered conditions. Drought stress was applied at tillering (Feekes 2 stage) and jointing (Feekes 6 stage), respectively, followed by re-watering, and we observed changes in leaf characteristics, growth and physiological activities during water stress and rewatering periods as well as final grain yield traits at maturity. Results showed that drought stress adaptability associated with reduced leaf area, higher leaf thickness, chlorophyll, leaf dry matter and maintenance of leaf water potential were more strongly pronounced in Luhan-7 than in Yangmai-16. Under moderate stress both cultivars exhibited a small decrease in leaf gas-exchange and chlorophyll fluorescence activities, followed by rapid recovery. Under severe drought stress, Yangmai-16 displayed relatively less adaptability to drought, with a slower recovery after re-watering and a greater decrease in grain yield. It was concluded that even though crop growth rate completely recovered after re-watering, the final dry matter and grain yield outcomes were affected by pre-drought stress, and were dependant on the drought intensity, adaptability and recovery differences of the cultivars and growth stage. It was also concluded that genotypic variations in adaptability and recovery from drought stress are the indicators of drought tolerance and grain yield sustainability in wheat.

scholarly journals Physiological Mechanism of Drought-Resistant Rice Coping with Drought Stress

2020 ◽  
Author(s):  
Benfu Wang ◽  
Xiaolong Yang ◽  
Jianping Cheng ◽  
Liang Chen ◽  
Yuanyuan Jiang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Physiological Mechanism ◽  
Photochemical Quenching ◽  
Yield Reduction ◽  
Severe Drought ◽  
Physiological Basis ◽  
Moderate Drought ◽  
Drought Resistant ◽  
Mild Drought

Abstract Drought stress is one of major threats to rice production. The weakening of leaf photosynthesis due to drought is the main reason for the reduction of grain yield, but its mechanism is still obscure. The objectives of this study were to reveal the physiological mechanism of drought stress affecting photosynthetic capacity and grain yield. Pot experiments were conducted with three rice cultivars, Hanyou113 (HY113), Huanghuazhan (HHZ) and Zhonghan3 (ZH3) under four water management treatments (traditional flooding (CK), mild drought stress (LD), moderate drought stress (MD) and severe drought stress (HD)) in 2013 and 2014. Compared with CK, grain yield was significantly reduced by 14.9%, 30.8% and 12.8% in HY113, HHZ and ZH3 under mild drought stress, 32.9%, 33.7% and 22.9% in HY113, HHZ and ZH3 under moderate drought stress and 53.6%, 45.6% and 30.7% in HY113, HHZ and ZH3 under severe drought stress, respectively. The photosynthetic rate (Pn) decreased by 49.0% from 20.0 to 10.2 µmol m-2 s-1 in HY113, and 67.6% from 23.4 to 7.58 µmol m-2 s-1 in HHZ, and 39.3% from 23.4 to 14.2 in ZH3. The Pn of HHZ was similar to that of ZH3 under CK conditions. The yield reduction of drought-resistant cultivars was smaller than that of conventional cultivars. Maintaining leaf water potentia (LWP), Pn, photosystem II (PSII) original light energy conversion efficiency, non–photochemical quenching coefficient (NPQ), and increasing in the ratio of photochemical reaction energy in fluorescence and antioxidant enzyme activity, is the physiological basis to achieve a relatively high photosynthesis. These traits could be the target for breeder to developing drought-tolerant varieties.

scholarly journals Reaction of some rapeseed (Brassica napus L.) genotypes to different drought stress levels during germination and seedling growth stages

OCL ◽  
2019 ◽  
Vol 26 ◽  
pp. 23 ◽  
Author(s):  
Souhail Channaoui ◽  
Imane Saghouri El Idrissi ◽  
Hamid Mazouz ◽  
Abdelghani Nabloussi
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Seed Germination ◽  
Seedling Growth ◽  
Stress Level ◽  
Elongation Rate ◽  
Growth Stages ◽  
Severe Drought ◽  
Oilseed Crop ◽  
Stress Levels

Drought is a major abiotic stress that affects seed germination and plant growth in arid and semi-arid regions. Rapeseed is an oilseed crop adapted to Mediterranean area; however, it is reported that it is sensitive to water stress occurring during seed germination. In this study, we investigated how seed germination and early seedling growth of six rapeseed genotypes were influenced by different water stress levels. In addition to the control (absence of drought stress), three drought levels were simulated using three osmotic potentials of polyethylene glycol (PEG-6000), −9, −10 and −11 bars. A completely randomized design with three replications was used for this experiment. Germination percentage (GP), shoot length (SL), root length (RL), shoot elongation rate (SER) and root elongation rate (RER) were determined to evaluate the genotypes response to PEG-induced drought stress. Results showed drought stress, genotype and interaction stress × genotype had a significant effect on the studied parameters. GP decreased with the increase in stress level. The genotype ‛Nap9’ was the most interesting, having the highest GP values, namely 63.33, 62.67 and 28% under the stress levels −9, −10 and −11 bars, respectively. The genotype ‛H2M-5’, which ranked second with respect to this parameter, was statistically comparable to ‛Nap9’. Also, SL, RL, SER and RER decreased with the increase in drought stress level. However, the studied genotypes reacted differently to various water stress levels. Once again, the genotype ‛H2M-5’ exhibited the highest average RL and RER under all drought levels. Particularly, for severe drought conditions (−11 bars), ‛H2M-5’ had an average RL of 1.54 cm and RER of 0.36 cm/d. Field evaluation under controlled conditions is needed to confirm findings of the present experiment. The mutant ‛H2M-5’ could be a valuable and promising germplasm for developing a performant and adapted variety to be designed for harsh environments particularly characterized by early drought coinciding with germination and seedling growth stages.

Physiological Responses on Sedum yvesii under Water Stress

2014 ◽  
Vol 1073-1076 ◽  
pp. 233-238
Author(s):  
Hong Zeng ◽  
Liu Qing Yang ◽  
Xiao Qing Zhu
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Chlorophyll Content ◽  
Water Saturation ◽  
Stress Gradient ◽  
Control Group ◽  
Severe Drought ◽  
Chlorophyll Content And Fluorescence ◽  
Water Saturation Deficit ◽  
Submergence Stress

In order to learn the reaction and adaptability to water stress of Sedum yvesii, the changes in physiology of leaf water saturation deficit (RWD), plasma membrane relative permeability, chlorophyll content and fluorescence parameters were studied in different moisture gradient of water stress. The results showed that: after 20 days for submergence stress, it had an effect on the normal growth of Sedum yvesii; after 30 days for severe drought stress and 10 days for extreme drought stress, it can severely inhibit the growth of Sedum yvesii, even lead to death, which embodied in the dramatic decline of chlorophyll content, Fv /Fm, Fv'/Fm', ETR and the increase of RWD, relative electrical conductivity. The indicators of slight drought stress and moderate drought stress group have little differences with the control group. They did not cause a significant effect on the growth of Sedum yvesii, indicating that Sedum yvesii has a strong ability to these two kinds of water stress gradient.

scholarly journals Monitoring of Salinity, Temperature, and Drought Stress in Grafted Watermelon Seedlings Using Chlorophyll Fluorescence

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu Kyeong Shin ◽  
Shiva Ram Bhandari ◽  
Jun Gu Lee
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Quantum Yield ◽  
Abiotic Stresses ◽  
Growth Parameters ◽  
Photochemical Quenching ◽  
Physiological Status ◽  
Severe Drought ◽  
Effective Quantum Yield ◽  
Salinity Levels

Chlorophyll fluorescence (CF) is used to measure the physiological status of plants affected by biotic and abiotic stresses. Therefore, we aimed to identify the changes in CF parameters in grafted watermelon seedlings exposed to salt, drought, and high and low temperatures. Grafted watermelon seedlings at the true three-leaf stage were subjected to salinity levels (0, 50, 100, 150, and 200 mM) and temperature [low (8°C), moderate (24°C), and high (40°C)] stresses for 12 days under controlled environmental conditions independently. Eight CF parameters were measured at 2-day intervals using the FluorCam machine quenching protocol of the FluorCam machine. The seedlings were also exposed to drought stress for 3 days independent of salinity and temperature stress; CF parameters were measured at 1-day intervals. In addition, growth parameters, proline, and chlorophyll content were evaluated in all three experiments. The CF parameters were differentially influenced depending on the type and extent of the stress conditions. The results showed a notable effect of salinity levels on CF parameters, predominantly in maximum quantum yield (Fv/Fm), non-photochemical quenching (NPQ), the ratio of the fluorescence decrease (Rfd), and quantum yield of non-regulated energy dissipation in PSII [Y(NO)]. High temperature had significant effects on Rfd and NPQ, whereas low temperature showed significant results in most CF parameters: Fv/Fm, Y(NO), NPQ, Rfd, the efficiency of excitation capture of open photosystem II (PSII) center (Fv′/Fm′), and effective quantum yield of photochemical energy conversion in PSII [Y(PSII)]. Only NPQ and Rfd were significantly influenced by severe drought stress. Approximately, all the growth parameters were significantly influenced by the stress level. Proline content increased with an increase in stress levels in all three experiments, whereas the chlorophyll (a and b) content either decreased or increased depending upon the stressor. The results provided here may be useful for understanding the effect of abiotic stresses on CF parameters and the selection of index CF parameters to detect abiotic stresses in grafted watermelon seedlings.

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