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Zhu H, Wu Y, Zheng Y. Effects of heat shock on photosynthesis-related characteristics and lipid profile of Cycas multipinnata and C. panzhihuaensis. BMC PLANT BIOLOGY 2022; 22:442. [PMID: 36109687 PMCID: PMC9476270 DOI: 10.1186/s12870-022-03825-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Cycas multipinnata and C. panzhihuaensis are two attractive ornamental tree species. With the global climate change, the temperature in the natural habitats of both the species shows a marked rising trend. However, how the two species respond to extreme high temperatures are not clear. Chlorophyll fluorescence parameters, chlorophyll content, chloroplast ultrastructure and lipid metabolism in the two species were determined following plant exposure to heat stress. RESULTS The results demonstrated that the photosynthetic efficiency decreased significantly in both the species following heat shock and recovery, but to a greater extent in C. panzhihuaensis. Compared to the control, chlorophyll content of C. multipinnata did not change significantly following heat stress and recovery. However, chlorophyll content of C. panzhihuaensis increased significantly after 1 d of recovery in comparison with the control. Chloroplast ultrastructures of C. panzhihuaensis were more severely affected by heat shock than C. multipinnata. C. multipinnata and C. panzhihuaensis followed a similar change trend in the amounts of most of the lipid categories after heat stress. However, only the amounts of lysophospholipids and fatty acyls differed significantly between the two species following heat treatment. Additionally, the unsaturation levels of the major lipid classes in C. multipinnata were significantly lower than or equal to those in C. panzhihuaensis. CONCLUSIONS C. multipinnata was less affected by extremely high temperatures than C. panzhihuaensis. The differential stability of chlorophyll and chloroplast ultrastructure and the differential adjustment of lipid metabolism might contribute to the different responses to heat shock between the two species.
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Affiliation(s)
- Huan Zhu
- Key Laboratory of State Forestry and Grassland Administration for Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, 650233, Yunnan, China
| | - Yangyang Wu
- Key Laboratory of State Forestry and Grassland Administration for Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, 650233, Yunnan, China
| | - Yanling Zheng
- Key Laboratory of State Forestry and Grassland Administration for Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, 650233, Yunnan, China.
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2
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He X, Hao J, Fan S, Liu C, Han Y. Role of Spermidine in Photosynthesis and Polyamine Metabolism in Lettuce Seedlings under High-Temperature Stress. PLANTS 2022; 11:plants11101385. [PMID: 35631810 PMCID: PMC9146551 DOI: 10.3390/plants11101385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 01/10/2023]
Abstract
High temperature is a huge threat to lettuce production in the world, and spermidine (Spd) has been shown to improve heat tolerance in lettuce, but the action mechanism of Spd and the role of polyamine metabolism are still unclear. The effects of Spd and D-arginine (D-arg) on hydroponic lettuce seedlings under high-temperature stress by foliar spraying of Spd and D-arg were investigated. The results showed that high-temperature stress significantly inhibited the growth of lettuce seedlings, with a 33% decrease in total fresh weight and total dry weight; photosynthesis of lettuce seedlings was inhibited by high-temperature stress, and the inhibition was greater in the D-arg treatment, while the Spd recovery treatment increased net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), stomatal limit value (Ls), and intercellular CO2 concentration (Ci). High-temperature stress significantly reduced the maximum photochemical efficiency (Fv/Fm), photochemical quenching coefficient (qP), electron transport rate (ETR), and photochemical efficiency of PSII (ΦPSII), increased the non-photochemical burst coefficient (NPQ) and reduced the use of light energy, which was alleviated by exogenous Spd. The increase in polyamine content may be due to an increase in polyamine synthase activity and a decrease in polyamine oxidase activity, as evidenced by changes in the expression levels of genes related to polyamine synthesis and metabolism enzymes. This evidence suggested that D-arg suppressed endogenous polyamine levels in lettuce and reduced its tolerance, whereas exogenous Spd promoted the synthesis and accumulation of polyamines in lettuce and increased its photosynthetic and oxidative stress levels, which had an impact on the tolerance of lettuce seedlings.
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Affiliation(s)
- Xin He
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; (X.H.); (J.H.)
| | - Jinghong Hao
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; (X.H.); (J.H.)
| | - Shuangxi Fan
- Beijing Vocational College of Agriculture, Beijing 102442, China;
| | - Chaojie Liu
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; (X.H.); (J.H.)
- Correspondence: (C.L.); (Y.H.)
| | - Yingyan Han
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; (X.H.); (J.H.)
- Correspondence: (C.L.); (Y.H.)
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3
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Jiang D, Lu B, Liu L, Duan W, Meng Y, Li J, Zhang K, Sun H, Zhang Y, Dong H, Bai Z, Li C. Exogenous melatonin improves the salt tolerance of cotton by removing active oxygen and protecting photosynthetic organs. BMC PLANT BIOLOGY 2021; 21:331. [PMID: 34246235 PMCID: PMC8272334 DOI: 10.1186/s12870-021-03082-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 05/26/2021] [Indexed: 05/23/2023]
Abstract
BACKGROUND As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0-500 μM MT treatments with salt stress induced by treatment with 150 mM NaCl. RESULTS Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). CONCLUSIONS Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.
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Affiliation(s)
- Dan Jiang
- State Key Laboratory of North China Crop Improvement and Regulation/College of Life Science, Hebei Agricultural University, Baoding, 071001, Hebei, China
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Bin Lu
- College of Landscape and Tourism, Hebei Agricultural University, Baoding, 071001, China
| | - Liantao Liu
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Wenjing Duan
- State Key Laboratory of North China Crop Improvement and Regulation/College of Life Science, Hebei Agricultural University, Baoding, 071001, Hebei, China
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Yanjun Meng
- State Key Laboratory of North China Crop Improvement and Regulation/College of Life Science, Hebei Agricultural University, Baoding, 071001, Hebei, China
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Jin Li
- State Key Laboratory of North China Crop Improvement and Regulation/College of Life Science, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Ke Zhang
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Hongchun Sun
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Yongjiang Zhang
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China
| | - Hezhong Dong
- Cotton Research Center/Key Laboratory of Cotton Breeding and Cultivation in Huang-huai-hai Plain, Ministry of Agriculture, Shandong Academy of Agricultural Sciences, Jinan, 250100, Shandong, China
| | - Zhiying Bai
- State Key Laboratory of North China Crop Improvement and Regulation/College of Life Science, Hebei Agricultural University, Baoding, 071001, Hebei, China.
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China.
| | - Cundong Li
- State Key Laboratory of North China Crop Improvement and Regulation/Key Laboratory of Crop Growth regulation of Hebei Province/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China.
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Chaudhary S, Devi P, Bhardwaj A, Jha UC, Sharma KD, Prasad PVV, Siddique KHM, Bindumadhava H, Kumar S, Nayyar H. Identification and Characterization of Contrasting Genotypes/Cultivars for Developing Heat Tolerance in Agricultural Crops: Current Status and Prospects. FRONTIERS IN PLANT SCIENCE 2020; 11:587264. [PMID: 33193540 PMCID: PMC7642017 DOI: 10.3389/fpls.2020.587264] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 09/14/2020] [Indexed: 05/19/2023]
Abstract
Rising global temperatures due to climate change are affecting crop performance in several regions of the world. High temperatures affect plants at various organizational levels, primarily accelerating phenology to limit biomass production and shortening reproductive phase to curtail flower and fruit numbers, thus resulting in severe yield losses. Besides, heat stress also disrupts normal growth, development, cellular metabolism, and gene expression, which alters shoot and root structures, branching patterns, leaf surface and orientation, and anatomical, structural, and functional aspects of leaves and flowers. The reproductive growth stage is crucial in plants' life cycle, and susceptible to high temperatures, as reproductive processes are negatively impacted thus reducing crop yield. Genetic variation exists among genotypes of various crops to resist impacts of heat stress. Several screening studies have successfully phenotyped large populations of various crops to distinguish heat-tolerant and heat-sensitive genotypes using various traits, related to shoots (including leaves), flowers, fruits (pods, spikes, spikelets), and seeds (or grains), which have led to direct release of heat-tolerant cultivars in some cases (such as chickpea). In the present review, we discuss examples of contrasting genotypes for heat tolerance in different crops, involving many traits related to thermotolerance in leaves (membrane thermostability, photosynthetic efficiency, chlorophyll content, chlorophyll fluorescence, stomatal activity), flowers (pollen viability, pollen germination, fertilization, ovule viability), roots (architecture), biomolecules (antioxidants, osmolytes, phytohormones, heat-shock proteins, other stress proteins), and "omics" (phenomics, transcriptomics, genomics) approaches. The traits linked to heat tolerance can be introgressed into high yielding but heat-sensitive genotypes of crops to enhance their thermotolerance. Involving these traits will be useful for screening contrasting genotypes and would pave the way for characterizing the underlying molecular mechanisms, which could be valuable for engineering plants with enhanced thermotolerance. Wherever possible, we discussed breeding and biotechnological approaches for using these traits to develop heat-tolerant genotypes of various food crops.
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Affiliation(s)
| | - Poonam Devi
- Department of Botany, Panjab University, Chandigarh, India
| | | | | | - Kamal Dev Sharma
- Department of Agricultural Biotechnology, Chaudhary Sarwan Kumar Himachal Pradesh (CSK HP) Agricultural University, Palampur, India
| | | | | | - H. Bindumadhava
- World Vegetable Center, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, India
| | - Shiv Kumar
- International Center for Agriculture Research in the Dry Areas (ICARDA), Rabat, Morocco
| | - Harsh Nayyar
- Department of Botany, Panjab University, Chandigarh, India
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Bidabadi SS, VanderWeide J, Sabbatini P. Exogenous melatonin improves glutathione content, redox state and increases essential oil production in two Salvia species under drought stress. Sci Rep 2020; 10:6883. [PMID: 32327687 PMCID: PMC7181808 DOI: 10.1038/s41598-020-63986-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/08/2020] [Indexed: 01/05/2023] Open
Abstract
This research was conducted to understand the influence of foliar applied melatonin (0, 50, 100, 150 and 200 μM) on two Salvia species (Salvia nemorosa L., and Salvia reuterana Boiss) under conditions of water stress. Water stress was applied using a reduced irrigation strategy based on re-watering at 80%, 60% and 40% of the field capacity (FC). Increasing water stress, while significantly enhancing malondialdehyde (MDA), H2O2, electrolyte leakage, oxidized glutathione (GSSG), and total glutathione (GT), reduced glutathione (GSH), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) activities, which led to a marked reduction in fluorescence (Fv/Fm). Foliar application of melatonin alleviated the oxidative stress by increasing GT, CAT, POD, SOD and GR activities and reducing GSSG. In particular, melatonin heightened GSH content as well as the ratio of GSH/GSSG when compared to non-sprayed water stressed plants. Melatonin-treated plants had significantly lower SOD and POD activities than control plants under drought stress, while the CAT activity was enhanced with the foliar treatment. Essential oil yield of both Salvia species increased with the decrease in irrigation from 80% to 60% FC but diminished with the more severe water deficit (40% FC). Essential oil components of Salvia nemorosa were β- caryophyllene, germacrene- B, spathulenol, and cis- β- farnesene, while (E) - β- ocimene, α- gurjnnene, germacrene-D, hexyl acetate and aromadendrene was the major constituents of Salvia reuterana. When plants were subjected to water deficit, melatonin treatment increased the concentration and composition of the essential oil. In particular, melatonin treatments improved the primary oil components in both species when compared to non-melatonin treated plants. In conclusion, reduced irrigation regimes as well as melatonin treatments resulted in a significant improvement of essential oil production and composition in both Salvia species.
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Affiliation(s)
- Siamak Shirani Bidabadi
- Department of Horticulture, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Joshua VanderWeide
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
| | - Paolo Sabbatini
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA.
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6
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Zhao Q, Chen W, Bian J, Xie H, Li Y, Xu C, Ma J, Guo S, Chen J, Cai X, Wang X, Wang Q, She Y, Chen S, Zhou Z, Dai S. Proteomics and Phosphoproteomics of Heat Stress-Responsive Mechanisms in Spinach. FRONTIERS IN PLANT SCIENCE 2018; 9:800. [PMID: 29997633 PMCID: PMC6029058 DOI: 10.3389/fpls.2018.00800] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/24/2018] [Indexed: 05/02/2023]
Abstract
Elevated temperatures limit plant growth and reproduction and pose a growing threat to agriculture. Plant heat stress response is highly conserved and fine-tuned in multiple pathways. Spinach (Spinacia oleracea L.) is a cold tolerant but heat sensitive green leafy vegetable. In this study, heat adaptation mechanisms in a spinach sibling inbred heat-tolerant line Sp75 were investigated using physiological, proteomic, and phosphoproteomic approaches. The abundance patterns of 911 heat stress-responsive proteins, and phosphorylation level changes of 45 phosphoproteins indicated heat-induced calcium-mediated signaling, ROS homeostasis, endomembrane trafficking, and cross-membrane transport pathways, as well as more than 15 transcription regulation factors. Although photosynthesis was inhibited, diverse primary and secondary metabolic pathways were employed for defense against heat stress, such as glycolysis, pentose phosphate pathway, amino acid metabolism, fatty acid metabolism, nucleotide metabolism, vitamin metabolism, and isoprenoid biosynthesis. These data constitute a heat stress-responsive metabolic atlas in spinach, which will springboard further investigations into the sophisticated molecular mechanisms of plant heat adaptation and inform spinach molecular breeding initiatives.
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Affiliation(s)
- Qi Zhao
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
- Key Laboratory of Forest Plant Ecology, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Wenxin Chen
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Jiayi Bian
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Hao Xie
- Key Laboratory of Forest Plant Ecology, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Ying Li
- Key Laboratory of Forest Plant Ecology, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Chenxi Xu
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Jun Ma
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Siyi Guo
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, Kaifeng, China
| | - Jiaying Chen
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Xiaofeng Cai
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Xiaoli Wang
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Quanhua Wang
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Yimin She
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Sixue Chen
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
- Plant Molecular and Cellular Biology Program, Department of Biology, Genetics Institute, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, United States
| | - Zhiqiang Zhou
- Key Laboratory of Forest Plant Ecology, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
- *Correspondence: Shaojun Dai, Zhiqiang Zhou,
| | - Shaojun Dai
- Development Center of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
- Key Laboratory of Forest Plant Ecology, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
- *Correspondence: Shaojun Dai, Zhiqiang Zhou,
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Zheng X, Tan DX, Allan AC, Zuo B, Zhao Y, Reiter RJ, Wang L, Wang Z, Guo Y, Zhou J, Shan D, Li Q, Han Z, Kong J. Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress. Sci Rep 2017; 7:41236. [PMID: 28145449 PMCID: PMC5286529 DOI: 10.1038/srep41236] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 12/19/2016] [Indexed: 12/16/2022] Open
Abstract
Within the chloroplasts reactive oxygen species (ROS) are generated during photosynthesis and stressful conditions. Excessive ROS damages chloroplasts and reduces photosynthesis if not properly detoxified. In this current study, we document that chloroplasts produce melatonin, a recently-discovered plant antioxidant molecule. When N-acetylserotonin, a substrate for melatonin synthesis, was fed to purified chloroplasts, they produced melatonin in a dose-response manner. To further confirm this function of chloroplasts, the terminal enzyme for melatonin synthesis, N-acetylserotonin-O-methyltransferase (ASMT), was cloned from apple rootstock, Malus zumi. The in vivo fluorescence observations and Western blots confirmed MzASMT9 was localized in the chloroplasts. A study of enzyme kinetics revealed that the Km and Vmax of the purified recombinant MzASMT9 protein for melatonin synthesis were 500 μM and 12 pmol/min·mg protein, respectively. Arabidopsis ectopically-expressing MzASMT9 possessed improved melatonin level. Importantly, the MzASMT9 gene was found to be upregulated by high light intensity and salt stress. Increased melatonin due to the highly-expressed MzASMT9 resulted in Arabidopsis lines with enhanced salt tolerance than wild type plants, as indicated by reduced ROS, lowered lipid peroxidation and enhanced photosynthesis. These findings have agricultural applications for the genetic enhancement of melatonin-enriched plants for increasing crop production under a variety of unfavorable environmental conditions.
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Affiliation(s)
- Xiaodong Zheng
- College of Horticulture, China Agricultural University, Beijing, China
| | - Dun X. Tan
- Department of Cellular & Structural Biology, The UT Health Science Center, San Antonio, TX, USA
| | - Andrew C. Allan
- Plant & Food Research, Private Bag 92169, Auckland, New Zealand
| | - Bixiao Zuo
- College of Horticulture, China Agricultural University, Beijing, China
| | - Yu Zhao
- College of Horticulture, China Agricultural University, Beijing, China
| | - Russel J. Reiter
- Department of Cellular & Structural Biology, The UT Health Science Center, San Antonio, TX, USA
| | - Lin Wang
- College of Horticulture, China Agricultural University, Beijing, China
| | - Zhi Wang
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yan Guo
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jingzhe Zhou
- College of Horticulture, China Agricultural University, Beijing, China
| | - Dongqian Shan
- College of Horticulture, China Agricultural University, Beijing, China
| | - Qingtian Li
- College of Horticulture, China Agricultural University, Beijing, China
| | - Zhenhai Han
- College of Horticulture, China Agricultural University, Beijing, China
| | - Jin Kong
- College of Horticulture, China Agricultural University, Beijing, China
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Meng JF, Xu TF, Wang ZZ, Fang YL, Xi ZM, Zhang ZW. The ameliorative effects of exogenous melatonin on grape cuttings under water-deficient stress: antioxidant metabolites, leaf anatomy, and chloroplast morphology. J Pineal Res 2014; 57:200-12. [PMID: 25039750 DOI: 10.1111/jpi.12159] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 07/08/2014] [Indexed: 01/15/2023]
Abstract
Grapes are an important economic crop and are widely cultivated around the world. Most grapes are grown in arid or semi-arid regions, and droughts take a heavy toll in grape and wine production areas. Developing effective drought-resistant cultivation measures is a priority for viticulture. Melatonin, an indoleamine, mediates many physiological processes in plants. Herein, we examined whether exogenously applied melatonin could improve the resistance of wine grape seedlings grown from cuttings to polyethylene glycol-induced water-deficient stress. The application of 10% polyethylene glycol (PEG) markedly inhibited the growth of cuttings, caused oxidative stress and damage from H2 O2 and O2∙-, and reduced the potential efficiency of Photosystem II and the amount of chlorophyll. Application of melatonin partially alleviated the oxidative injury to cuttings, slowed the decline in the potential efficiency of Photosystem II, and limited the effects on leaf thickness, spongy tissue, and stoma size after application of PEG. Melatonin treatment also helped preserve the internal lamellar system of chloroplasts and alleviated the ultrastructural damage induced by drought stress. This ameliorating effect may be ascribed to the enhanced activity of antioxidant enzymes, increased levels of nonenzymatic antioxidants, and increased amount of osmoprotectants (free proline). We conclude that the application of melatonin to wine grapes is effective in reducing drought stress.
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Affiliation(s)
- Jiang-Fei Meng
- College of Enology, Northwest A&F University, Yangling, China
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9
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Wang X, Cai J, Liu F, Dai T, Cao W, Wollenweber B, Jiang D. Multiple heat priming enhances thermo-tolerance to a later high temperature stress via improving subcellular antioxidant activities in wheat seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 74:185-92. [PMID: 24308988 DOI: 10.1016/j.plaphy.2013.11.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/02/2013] [Indexed: 05/21/2023]
Abstract
Seedlings of winter wheat (Triticum aestivum L.) were firstly twice heat-primed at 32/24 °C, and subsequently subjected to a more severe high temperature stress at 35/27 °C. The later high temperature stress significantly decreased plant biomass and leaf total soluble sugars concentration. However, plants experienced priming (PH) up-regulated the Rubisco activase B encoding gene RcaB, which was in accordance with the higher photosynthesis rate in relation to the non-primed plants (NH) under the later high temperature stress. In relation to NH, the major chlorophyll a/b-binding protein gene Cab was down-regulated in PH plants, implying a reduction of the light absorption to protect the photosystem II from excitation energy under high temperature stress. At the same time, under the later high temperature stress PH plants showed significantly higher actual photochemical efficiency, indicating an improvement of light use efficiency due to the priming pre-treatment. Under the later high temperature stress, PH could be maintained a better redox homeostasis than NH, as exemplified by the higher activities of superoxide dismutase (SOD) in chloroplasts and glutathione reductase (GR), and of peroxidase (POD) in mitochondria, which contributed to the lower superoxide radical production rate and malondialdehyde concentration in both chloroplasts and mitochondria. The improved antioxidant capacity in chloroplasts and mitochondria was related to the up-regulated expressions of Cu/Zn-SOD, Mn-SOD and GR in PH. Collectively, heat priming effectively improved thermo-tolerance of wheat seedlings subjected to a later high temperature stress, which could be largely ascribed to the enhanced anti-oxidation at the subcellular level.
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Affiliation(s)
- Xiao Wang
- National Engineering and Technology Center for Information Agriculture, Key Laboratory of Crop Physiology and Ecology in Southern China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China; Aarhus University, Faculty of Science and Technology, Institute of Agroecology, Research Centre Flakkebjerg, DK 4200 Slagelse, Denmark
| | - Jian Cai
- National Engineering and Technology Center for Information Agriculture, Key Laboratory of Crop Physiology and Ecology in Southern China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Fulai Liu
- University of Copenhagen, Faculty of Sciences, Department of Plant and Environmental Sciences, Højbakkegaard Allé 13, DK-2630 Taastrup, Denmark
| | - Tingbo Dai
- National Engineering and Technology Center for Information Agriculture, Key Laboratory of Crop Physiology and Ecology in Southern China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Weixing Cao
- National Engineering and Technology Center for Information Agriculture, Key Laboratory of Crop Physiology and Ecology in Southern China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Bernd Wollenweber
- Aarhus University, Faculty of Science and Technology, Institute of Agroecology, Research Centre Flakkebjerg, DK 4200 Slagelse, Denmark
| | - Dong Jiang
- National Engineering and Technology Center for Information Agriculture, Key Laboratory of Crop Physiology and Ecology in Southern China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
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10
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Protection of phosphatidylcholine to photosystem II membrane during heat treatment. Sci Bull (Beijing) 2013. [DOI: 10.1007/bf03325672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Hui R, Li X, Chen C, Zhao X, Jia R, Liu L, Wei Y. Responses of photosynthetic properties and chloroplast ultrastructure of Bryum argenteum from a desert biological soil crust to elevated ultraviolet-B radiation. PHYSIOLOGIA PLANTARUM 2013; 147:489-501. [PMID: 22901234 DOI: 10.1111/j.1399-3054.2012.01679.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/24/2012] [Accepted: 06/18/2012] [Indexed: 06/01/2023]
Abstract
Our understanding of plant responses to enhanced ultraviolet-B (UV-B) radiation has improved over recent decades. However, research on cryptogams is scarce and it remains controversial whether UV-B radiation causes changes in physiology related to photosynthesis. To investigate the effects of supplementary UV-B radiation on photosynthesis and chloroplast ultrastructure in Bryum argenteum Hedw., specimens were cultured for 10 days under four UV-B treatments (2.75, 3.08, 3.25 and 3.41 W m(-2) ), simulating depletion of 0% (control), 6%, 9% and 12% of stratospheric ozone at the latitude of Shapotou, a temperate desert area of northwest China. Analyses showed malondialdehyde content significantly increased, whereas chlorophyll (Chl) fluorescence parameters and Chl contents decreased with increased UV-B intensity. These results corresponded with changes in thylakoid protein complexes and chloroplast ultrastructure. Overall, enhanced UV-B radiation leads to significant decreases in photosynthetic function and serious destruction of the chloroplast ultrastructure of B. argenteum. The degree of negative influences increased with the intensity of UV-B radiation. These results may not only provide a potential mechanism for supplemental UV-B effects on photosynthesis of moss crust, but also establish a theoretical basis for further studies of adaptation and response mechanisms of desert ecosystems under future ozone depletion.
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Affiliation(s)
- Rong Hui
- Shapotou Desert Research and Experiment Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, P. R. China
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12
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Response of Mature, Developing and Senescing Chloroplasts to Environmental Stress. PLASTID DEVELOPMENT IN LEAVES DURING GROWTH AND SENESCENCE 2013. [DOI: 10.1007/978-94-007-5724-0_28] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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13
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Chen HX, Li WJ, An SZ, Gao HY. Characterization of PSII photochemistry and thermostability in salt-treated Rumex leaves. JOURNAL OF PLANT PHYSIOLOGY 2004; 161:257-64. [PMID: 15077623 DOI: 10.1078/0176-1617-01231] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A study was conducted, using chlorophyll fluorescence, rapid fluorescence induction kinetics, and polyphasic fluorescence transients, to determine the effect of salt treatment and heat stress on PSII photochemistry in Rumex leaves. Salt treatment was accomplished by adding NaCl solutions of different concentrations ranging from 50 to 200 mmol/L. Heat stress was induced by exposing the plant leaves to temperatures ranging from 29 to 47 degrees C. The control plants were grown without NaCl treatment. The data acquired in this study showed that NaCl treatment alone had no effect on the maximal photochemistry of PSH or the polyphasic rise of chlorophyll fluorescence. However, the NaCl treatment modified heat stress on PSII photochemistry in Rumex leaves, which was manifested by a lesser heat-induced decrease in photochemical quenching (qP), efficiency of excitation energy capture by open PSII reaction centers (Fv'/Fm'), and quantum yield of PSII electron transport (phiPSII). The data also showed that NaCl treatment compromised the impact of heat stress on the capacity of transferring electrons from Q(A)- to Q(B). Furthermore, the NaCl treatment promoted heat resistance of O2-evolving complex (OEC). In summary, NaCl treatment enhanced the thermostability of PSII.
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Affiliation(s)
- Hua-Xin Chen
- Department of Plant Science, Shandong Agricultural University, Taian, Shandong, 271018, PR China
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14
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Gounaris K, Brain AP, Quinn PJ, Williams W. Structural and functional changes associated with heat-induced phase-separations of non-bilayer lipids in chloroplast thylakoid membranes. FEBS Lett 2001. [DOI: 10.1016/0014-5793(83)80117-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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15
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Carpentier R. Effect of High-Temperature Stress on the Photosynthetic Apparatus. BOOKS IN SOILS, PLANTS, AND THE ENVIRONMENT 1999. [DOI: 10.1201/9780824746728.ch14] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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16
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Čajánek M, Štroch M, Lachetová I, Kalina J, Spunda V. Characterization of the photosystem II inactivation of heat-stressed barley leaves as monitored by the various parameters of chlorophyll a fluorescence and delayed fluorescence. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1998. [DOI: 10.1016/s1011-1344(98)00197-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Rainwater DT, Gossett DR, Millhollon EP, Hanna HY, Banks SW, Lucas MC. The relationship between yield and the antioxidant defense system in tomatoes grown under heat stress. Free Radic Res 1996; 25:421-35. [PMID: 8902541 DOI: 10.3109/10715769609149065] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Four putative heat-tolerant tomato (Lycopersicum esculentum) cultivars (Tamasabro, Heat Wave, LHT-24, and Solar Set) and one putative heat-sensitive tomato cultivar (Floradade) were grown in the field under non-stress (average daily temperature of 26 degrees C) and heat-stress (average daily temperature of 34 degrees C) conditions. At anthesis, approximately five weeks after being transplanted to the field, leaf samples were collected for antioxidant analyses. Yield was determined by harvesting ripe fruit seven weeks after the collection of leaf samples. Heat stress resulted in a 79.1% decrease in yield for the heat-sensitive Floradade, while the fruit yield in the heat-tolerant cultivars Heat Wave, LHT-24, Solar Set, and Tamasabro was reduced 51.5%, 22.1%, 43.8%, and 34.8% respectively. When grown under heat stress, antioxidant activities were also greater in the heat-tolerant cultivars. Superoxide dismutase (SOD) activity increased up to 9-fold in the heat-tolerant cultivars but decreased 83.1% in the heat-sensitive Floradade. Catalase, peroxidase, and ascorbate peroxidase activity increased significantly in all cultivars. Only Heat Wave showed a significant increase in glutathione reductase in response to heat stress but all heat-tolerant cultivars exhibited significantly lower oxidized ascorbate/reduced ascorbate ratios, greater reduced glutathione/oxidized glutathione rations, and greater alpha-tocopherol concentrations compared to the heat-sensitive cultivar Floridade. These data indicate that the more heat-tolerant cultivars had an enhanced capacity for scavenging active oxygen species and a more active ascorbate-glutathione cycle and suggest a strong correlation between the ability to up-regulate the antioxidant defense system and the ability of tomatoes to produce greater yields when grown under heat stress.
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18
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Allakhverdiev SI, Feyziev YM, Ahmed A, Hayashi H, Aliev JA, Klimov VV, Murata N, Carpentier R. Stabilization of oxygen evolution and primary electron transport reactions in photosystem II against heat stress with glycinebetaine and sucrose. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1996; 34:149-57. [PMID: 22872909 DOI: 10.1016/1011-1344(95)07276-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The protective action of co-solutes, such as sucrose and glycinebetaine, against the thermal inactivation of photosystem II function was studied in untreated and Mn-depleted photosystem II preparations. It was shown that, in addition to the reactions that depend on the oxygen evolving activity of the photosystem, those that implicate more intimately the reaction center itself are protected by high concentrations of osmolytes. However, the temperature required to inhibit oxygen evolution totally in the presence of osmolytes is lower than that required to eliminate reactions, such as P680 (primary electron donor in photosystem II) photo-oxidation and pheophytin photo reduetion, which only involve charge separation and primary electron transport processes. The energy storage measured from the thermal dissipation yield during photoacoustic experiments and the yield of variable fluorescence are also protected to a significant degree (up to 30%) at temperatures at which oxygen evolution is totally inhibited. It is suggested that a cyclic electron transport reaction around photosystem II may be preserved under these conditions and may be responsible for the energy storage measured at relatively high temperatures. This interpretation is also supported by thermoluminescence data involving the recombination between reduced electron acceptors and oxidized electron donors at - 30 and - 55 °C. The data also imply that a high concentration of osmolyte allows the stabilization of the photosystem core complex together with the oxygen-evolving complex. The stabilization effect is understood in terms of the minimization of protein-water interactions as proposed by the theory of Arakawa and Timasheff (Biophys. J., 47 (1985) 411--414).
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19
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Chen Q, Osteryoung K, Vierling E. A 21-kDa chloroplast heat shock protein assembles into high molecular weight complexes in vivo and in Organelle. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36821-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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20
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Havaux M, Strasser RJ. ANTAGONISTIC EFFECTS OF RED AND FAR-RED LIGHTS ON THE STABILITY OF PHOTOSYSTEM II IN PEA LEAVES EXPOSED TO HEAT. Photochem Photobiol 1992. [DOI: 10.1111/j.1751-1097.1992.tb04285.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Bilger W, Schreiber U. Chlorophyll luminescence as an indicator of stress-induced damage to the photosynthetic apparatus. Effects of heat-stress in isolated chloroplasts. PHOTOSYNTHESIS RESEARCH 1990; 25:161-171. [PMID: 24420347 DOI: 10.1007/bf00033158] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/1989] [Accepted: 05/04/1990] [Indexed: 06/03/2023]
Abstract
A brief review is given of investigations on stres-induced alterations of ms-to s-luminescence yield of chlorophyll in plants. Three different approaches are considered: phytoluminography, luminescence-temperature curves, and luminescence induction curves. The remainder of this article presents new results of the effect of heat stress on luminescence induction curves of isolated chloroplasts. Three parameters with widely different heat resistances were resolved from induction curves. A fast valinomycin sensitive transient, L'i, with a 50% inhibition temperature of 33 to 34°C was correlated with the magnitude of the light-induced membrane potential after heat pretreatment. A slower nigericin sensitive transient, L'm, with a 50% inhibition temperature of 39 to 40°C was mainly correlated with the light-induced proton gradient. An uncoupler resistant part of the induction curve, L0, was enhanced by heat stress (half maximum after pretreatment at 46°C) and was correlated with the degree of inhibition of oxygen evolution. Since L0 was also raised by other treatments impairing the oxygen evolving enzyme system, and since this rise was inhibited by DCMU and hydroxylamine, this type of luminescence was ascribed to the intrinsic backreaction. We conclude that luminescence induction curves can serve as an useful indicator of the intactness of the membrane potential, the proton gradient, and the oxygen evolving enzyme system in isolated chloroplasts after heat stress.
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Affiliation(s)
- W Bilger
- Institut für Botanik und Pharmazeutische Biologie der Universität Würzburg, Mittlerer Dallenbergweg 64, 87, Würzburg, FRG
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22
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Al-Khatib K, Wiest SC. Heat-induced reversible and irreversible alterations in the structure of phaseolus vulgaris thylakoid proteins. J Therm Biol 1990. [DOI: 10.1016/0306-4565(90)90008-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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24
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Yordanov I, Goltsev V, Stoyanova T, Venediktov P. High-temperature damage and acclimation of the photosynthetic apparatus : I. Temperature sensitivity of some photosynthetic parameters of chloroplasts isolated from acclimated and non-acclimated bean leaves. PLANTA 1987; 170:471-477. [PMID: 24233010 DOI: 10.1007/bf00402981] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/1986] [Accepted: 11/28/1986] [Indexed: 06/02/2023]
Abstract
The thermosensitivity of delayed fluorescence, the relative values of variable chlorophyll fluorescence and the degree of quenching of 9-aminoacridine fluorescene were studied in the chloroplasts from heat-acclimated and non-acclimated (treated 6 h at 52,5°C) young bean plants. The temperature sensitivity of each parameter studied was defined by that temperature at which chloroplast activity decreased by 50% (T50) of its maximum value. There was appreciable increase in the thermostability of membrane energization in chloroplasts isolated from acclimated and non-acclimated plants compared with the controls. The photosynthetic parameters differed according to the suspending medium and the preacclimation treatment. When chloroplast were suspended in phosphate buffer with the addition of stabilizing compounds (2 M sucrose or 0.5% human serum albumin) the thermostability of the thylakoid membranes increased, as was evident by the increases in T50 of about 8-10° C (sucrose) and 2-5° C (human serum albumin) for all the parameters investigated. Photoinduced quenching of 9-aminoacridine fluorescence decreased to some extent in the presence of protective compounds, but in chloroplasts from acclimated plants the T50 was practically equal to that for their long-lived luminescence under the same conditions. At the thylakoid membrane level, acclimation was clearly manifested as an increased thermostability of photoinduced proton-gradient formation.
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Affiliation(s)
- I Yordanov
- Institute of Plant Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
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25
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Santarius KA, Falsone G, Haddad H. Effects of the sesquiterpene lactone tetraesters thapsigargicin and thapsigargin, from roots of Thapsia garganica L., on isolated spinach chloroplasts. Toxicon 1987; 25:389-99. [PMID: 3617076 DOI: 10.1016/0041-0101(87)90072-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The effect of thapsigargicin and thapsigargin, extracted from the roots of Thapsia garganica L., on isolated photosynthetic membranes (thylakoids) and intact chloroplasts from spinach leaves (Spinacia oleracea L.) was investigated. Both sesquiterpene lactone tetraesters impair membranes and organelles in an identical, chlorophyll-dependent manner. In thylakoids these compounds primarily act as inhibitors of photophosphorylation. At lower sesquiterpene lactone tetraester/chlorophyll ratios, cyclic and non-cyclic photophosphorylation, ADP-stimulated electron transport and the photosynthetic control ratio progressively decreased with increasing concentrations of thapsigargicin and thapsigargin, whereas the state 4 electron flow, the coupling efficiency of photophosphorylation, the light-induced proton gradient, and the H+ flux across the membranes remained nearly unaffected. Half-maximal inhibition of photophosphorylation was obtained with 4-5 X 10(-7) moles sesquiterpene lactone tetraesters per mg chlorophyll. At higher sesquiterpene lactone tetraester/chlorophyll ratios, uncoupling of photophosphorylation from electron transport occurred. This was evident from stimulation of the state 4 electron flow, decline in the ADP/2e- ratio, increase in proton permeability and decrease in delta pH, whereas the uncoupled electron transport was only little impaired. In intact chloroplasts inhibition of HCO-3, 3-phosphoglycerate and oxaloacetate reduction by thapsigargicin and thapsigargin was not caused by inactivation of the photochemical reactions of the thylakoid membranes but were rather due to alterations in the permeability properties of the chloroplast envelope. This was concluded from similarities in the kinetics of these reactions. It is suggested that the highly lipid soluble sesquiterpene lactone tetraesters effectively disrupt the lipid-protein associations of biomembranes.
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26
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Thomas PG, Dominy PJ, Vigh L, Mansourian AR, Quinn PJ, Williams W. Increased thermal stability of pigment-protein complexes of pea thylakoids following catalytic hydrogenation of membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1986. [DOI: 10.1016/0005-2728(86)90104-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Weis E, Wamper D, Santarius KA. Heat sensitivity and thermal adaptation of photosynthesis in liverwort thalli. Oecologia 1986; 69:134-139. [DOI: 10.1007/bf00399049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/1985] [Indexed: 10/26/2022]
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28
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Thomas PG, Quinn PJ, Williams WP. The origin of photosystem-I-mediated electron transport stimulation in heat-stressed chloroplasts. PLANTA 1986; 167:133-9. [PMID: 24241743 DOI: 10.1007/bf00446380] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/1985] [Accepted: 08/27/1985] [Indexed: 05/09/2023]
Abstract
Exposure of isolated chloroplasts of pea (Pisum sativum L.) to temperatures above 35° C leads to a stimulation of photosystem-I-mediated electron transport from dichlorophenolindophenol to methyl viologen. The threshold temperature for this stimulation coincides closely with that for heat-induced inhibition of photosystem-II activity in such chloroplasts. This coincidence is explained in terms of a rearrangement of the thylakoid membrane resulting in the exposure of a new set of donor sites for dichlorophenolindophenol within the cytochrome f/b 6 complex of the electron-transport chain linking the two photosystems.
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Affiliation(s)
- P G Thomas
- Department of Biochemistry, King's College London (KQC), Campden Hill, W8 7AH, London, UK
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29
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Williams WP, Sen A, Fork DC. Selective photobleaching of PSI-related chlorophylls in heat-stressed pea chloroplasts. PHOTOSYNTHESIS RESEARCH 1986; 10:75-92. [PMID: 24435278 DOI: 10.1007/bf00024187] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/1985] [Revised: 08/05/1985] [Indexed: 06/03/2023]
Abstract
Measurements of electron transport activity point to the occurrence of major changes in the organisation of the photosynthetic apparatus of heat-stressed chloroplasts. One of the consequences of these changes is shown to be a greatly increased susceptibility of chlorophyll to photobleaching. Despite the fact that the threshold temperature for this photobleaching coincides closely with that for the inhibition of PSII activity, the bleached components were found to be specifically associated with PSI. This increased susceptibility of PSI pigments to photobleaching is shown to be a direct consequence of an interruption of the flow of reductants from PSII to PSI that would normally protect PSI from photooxidation.
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Affiliation(s)
- W P Williams
- Department of Plant Biology, Carnegie Institution of Washington, 290 Panama Street, 94305, Stanford, CA, USA
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30
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Barényi B, Krause GH. Inhibition of photosynthetic reactions by light : A study with isolated spinach chloroplasts. PLANTA 1985; 163:218-226. [PMID: 24249342 DOI: 10.1007/bf00393510] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/1984] [Accepted: 08/25/1984] [Indexed: 06/02/2023]
Abstract
Illumination of isolated intact chloroplasts of Spinacia oleracea L. for 10 min with 850 W m(-2) red light in the absence of substrate levels of bicarbonate caused severe inhibition of subsequently measured photosynthetic activities. The capacity of CO2-dependent O2 evolution and of non-cyclic electron transport were impaired to similar degrees. This photoinactivation was prevented by addition of bicarbonate which allowed normal carbon metabolism to proceed during preillumination. Photoinhibition of electron transport was observed likewise upon illumination of intact or broken chloroplasts when efficient electron acceptors were absent. Addition of uncouplers did not influence the extent of inhibition. Studies of partial electron-transport reactions indicated that the activity of both photosystems was affected by light. In addition, the water-oxidation system or its connection to photosystem II seemed to be impaired. Preillumination did not cause uncoupling of photophosphorylation. Chlorophyll-fluorescence data obtained at room temperature and at 77 K are consistent with the view that photosystem-II reaction centers were altered. Addition of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) or 1,4-diazabicyclo(2,2,2)octane to isolated thylakoids prior to preillumination substantially diminished photoinhibition. This result shows that reactive oxygen species were involved in the damage. It is concluded that bright light, which normally does not damage the photosynthetic apparatus, may exert the described destructive effects under conditions that restrict metabolic turnover of photosynthetic energy.
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Affiliation(s)
- B Barényi
- Botanisches Institut der Universität, Universitätsstrasse 1, D-4000, Düsseldorf 1, Germany
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31
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Krause GH, Weis E. Chlorophyll fluorescence as a tool in plant physiology : II. Interpretation of fluorescence signals. PHOTOSYNTHESIS RESEARCH 1984; 5:139-57. [PMID: 24458602 DOI: 10.1007/bf00028527] [Citation(s) in RCA: 234] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/1983] [Revised: 12/21/1983] [Indexed: 05/18/2023]
Affiliation(s)
- G H Krause
- Botanisches Institut der Universität Düsseldorf, Universitätsstraße 1, D-4000, Düsseldorf 1, Germany (F.R.G.)
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32
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33
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The Influence of Leaf-aging on the Heat-sensitivity and Heat-hardening of the Photosynthetic Apparatus in Phaseolus vulgaris. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0044-328x(84)80095-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Venediktov PS, Krivoshejeva AA. Effects of pH and deuterium oxide on the heat-inactivation temperature of chloroplasts. PLANTA 1984; 160:200-203. [PMID: 24258500 DOI: 10.1007/bf00402854] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/1983] [Accepted: 10/18/1983] [Indexed: 06/02/2023]
Abstract
The inactivation temperature for Hill activity and for the long-lived delayed fluorescence of isolated Pisum sativum L. chloroplasts was found to depend on pH, the maximal value being in the pH region 5-7. Salts increase the inactivation temperature by 4-7°C. Effects of D2O and some other substances that modify the thermostability of chloroplasts are dependent on pH. It is concluded that thermal denaturation of proteins is the most probable mechanism for heat inactivation of chloroplasts.
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Affiliation(s)
- P S Venediktov
- Biophysics Department, Faculty of Biology, M.V. Lomonosov State University, Lenin Hills, 117234, Moscow, USSR
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35
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Immobilization of photosynthetically active intact chloroplasts in a crosslinked albumin matrix. Biotechnol Lett 1983. [DOI: 10.1007/bf01386655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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36
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Weigel HJ. The effect of high temperatures on leaf cells of Valerianella: relative heat stability of the tonoplast membrane of mesophyll vacuoles. PLANTA 1983; 159:398-403. [PMID: 24258291 DOI: 10.1007/bf00392074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/1982] [Accepted: 06/11/1983] [Indexed: 06/02/2023]
Abstract
The effect of short-term heat stress on the tonoplast membrane of lamb's lettuce (Valerianella locusta (L.) Betcke) mesophyll vacuoles has been investigated. The maintainance of a proton concentration difference (δpH) across the tonoplast membrane served as a criterion for the integrity of the vacuoles. After heat treatment, δpH was measured at room temperature using the fluorescent amine, 9-aminoacridine. It was found with this method that thermal damage to isolated vacuoles mainly occurred in the temperature range above 50°C. Compared with this results, the photosynthetic functions of isolated lettuce protoplasts proved to be markedly more thermolabile, e.g. photosynthetic CO2 fixation and light-induced chlorophyll fluorescence were drastically reduced at temperatures between 40° and 50°C. Heating of whole leaves and protoplasts and subsequent isolation of vacuoles showed that tonoplast-membrane integrity is not affected by heat stress in situ up to 45°C. Measurement of 9-aminoacridine fluorescence in protoplasts, which allowed conclusions to be drawn regarding the integrity of the tonoplast membrane in its natural cytoplasmic environment, revealed that heat treatment up to 55°C did not significantly affect vacuolar compartmentation. The data provide evidence that the tonoplast membrane is relatively heat stable compared with photosynthetic membranes.
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Affiliation(s)
- H J Weigel
- Botanisches Institut der Universität Düsseldorf, Universitätsstrasse 1, D-4000, Düsseldorf, Federal Republic of Germany
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37
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Weis E. The influence of metal cations and pH on the heat sensitivity of photosynthetic oxygen evolution and chlorophyll fluorescence in spinach chloroplasts. PLANTA 1982; 154:41-47. [PMID: 24275915 DOI: 10.1007/bf00385494] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/1981] [Accepted: 10/12/1981] [Indexed: 06/02/2023]
Abstract
The heat-sensitivity of photosynthetic oxygen evolution of thylakoids isolated from spinach increases by increasing the pH above neutral value. The temperature for inactivation (transition temperature) is lowered from about 45° C (pH 6.0-7.4) to 33°C (pH 8.5). Similar results are obtained with intact chloroplasts. At pH 7.0 the transition temperature of washed thylakoids decreases by lowering the salt concentration below 20 mM with monovalent cations (Li(+), Na(+), K(+)) and below 3-4 mM with divalent cations (Mg(2+), Ca(2+), Sr(2+)). Illumination decreases the heat-sensitivity of oxygen evolution in intact chloroplasts, but even increases the heat-sensitivity in uncoupled chloroplasts. In intact chloroplasts the transition temperature of the heat-induced rise in chlorophyll fluorescence yield (Fo; see Schreiber and Armond 1978) decreases from 44° C to 38° C when the pH of the suspending medium is increased from 6.5 to 8.5. At 20° C, Fo is almost insensitive to pH (6.0-8.5). At 40° C, however, Fo is constant between 6.0 and 7.0, but strongly increases by increasing the pH above neutral value. The results are discussed in terms of a close relation between electrostatic forces at the thylakoid membrane and thermal sensitivity of photosynthetic apparatus. It is suggested that the heat-sensitivity of the photosystem II complex partially depends on the ionization state of fixed groups having alkaline pK. The "packed volume" of thylakoids suspended in a low salt medium increases when the temperature is increased above 30° C (pH 7.0) and above 20° C (pH 8.0), respectively. This result suggests a heat-induced increase in surface charge density of the thylakoid membrane.
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Affiliation(s)
- E Weis
- Botanisches Institut der Universität, Universitätsstraße 1, D-4000, Düsseldorf, Federal Republic of Germany
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Stabilization of the Morphology and the Photosynthetic Function of Isolated Intact Chloroplasts with Glutaraldehyde. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0044-328x(82)80014-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Klosson RJ, Krause GH. Freezing injury in cold-acclimated and unhardened spinach leaves : II. Effects of freezing on chlorophyll fluorescence and light scattering reactions. PLANTA 1981; 151:347-352. [PMID: 24301977 DOI: 10.1007/bf00393289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/1980] [Accepted: 11/14/1980] [Indexed: 06/02/2023]
Abstract
Leaves from cold-acclimated and from unhardened spinach plants (Spinacia oleracea L.) were subjected to a freezing/thawing procedure in which varying minimum temperatures were reached. Subsequently, the chlorophyll fluorescence induction signal (Kautsky phenomenon) and the light-induced apparent absorbance changes at 535 nm (light-scattering changes indicative of the proton gradient, and absorbance changes induced by the membrane potential) of the leaves were studied to obtain information on the course and mechanism of frost damage to the photosynthetic apparatus. Membrane energization as indicated by these signals was related in a complex way to the inactivation of CO2 assimilation due to the progressing impact of freezing: In the absence of CO2, the maximum energization of the thylakoids was progressively decreased. According to altered fluorescence signals, the electron transport system was affected in parallel. In the presence of CO2, energization frequently appeared increased when the leaves had been partially damaged, i.e., when the CO2 assimilation rates were lowered. The results suggest that the primary frost injury in chloroplasts of intact leaves consists of an inhibition of the energy conserving photosynthetic processes and, in addition, of a partial inactivation of the carbon reduction cycle. The pattern of freezing injury was no different in frost-hardened and unhardened leaves.
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Affiliation(s)
- R J Klosson
- Botanisches Institut der Universität Düsseldorf, Universitätsstraße 1, D-4000, Düsseldorf 1, Germany
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Weis E. Reversible heat-inactivation of the calvin cycle: A possible mechanism of the temperature regulation of photosynthesis. PLANTA 1981; 151:33-39. [PMID: 24301667 DOI: 10.1007/bf00384234] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/1980] [Accepted: 09/25/1980] [Indexed: 06/02/2023]
Abstract
Photosynthetic CO2 fixation rates in leaves and intact chloroplasts of spinach measured at 18°-20° C are substantially decreased by pretreatment at temperatures exceeding 20° C. Mild heating which causes 80% inhibition of CO2 fixation does not affect phosphoglyceroacid reduction and causes increases in the ATP/ADP ratio and the light-induced transthylakoid proton gradient. The inactivation of the CO2 fixation is completely reversible with half-times of recovery in the order of 15-20 min. Comparison of steady-state patterns of (14)C labeled Calvin cycle intermediates of heat-treated and control samples reveals a large increase in the ribulose-1,5-bisphosphate/phosphoglyceroacid ratio and a large decrease in the phosphoglyceroacid/triosephosphate ratio. It is concluded that inactivation of CO2 fixation occurring at elevated temperatures is caused by inhibition of the ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39). Measurements of light-induced light scattering changes of thylakoids and of the light-induced electrochromic absorption shift show that these signals are affected by mild heating in a way which is strictly correlated with the inactivation of the CO2 fixation. It is proposed that the function of the ribulose-1,5-bisphosphate carboxylase in vivo requires a form of activation that involves properties of the thylakoid membrane which are affected by the heat treatment. The fact that these changes in thylakoid membrane properties and of ribulose-1,5-bisphosphate carboxylase activity are already affected at elevated temperatures which can still be considered physiological, and the reversible nature of these changes, suggest that they may play a role in temperature regulation of the overall photosynthetic process.
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Affiliation(s)
- E Weis
- Botanisches Institut der Universität, Universitätsstraße 1, Gebäude 26.13, D-4000, Düsseldorf, Germany
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Santarius KA, Crea AE, Falsone G. Effects of a 4-deoxyphorbol triester from the latex sap of Euphorbia biglandulosa Desf. on isolated spinach chloroplasts. Toxicon 1981; 19:383-92. [PMID: 7245219 DOI: 10.1016/0041-0101(81)90043-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Weis E. Reversible Effects of High, Sublethal Temperatures on Light-Induced Light Scattering Changes and Electrochromic Pigment Absorption Shift in Spinach Leaves. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0044-328x(81)80051-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Santarius KA, Müller M. Investigations on heat resistance of spinach leaves. PLANTA 1979; 146:529-38. [PMID: 24318323 DOI: 10.1007/bf00388828] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/1979] [Accepted: 05/10/1979] [Indexed: 05/18/2023]
Abstract
Exposure of spinach plants to high temperature (35° C) increased the heat resistance of the leaves by about 3° C. This hardening process occurred within 4 to 6 h, whereas dehardening at 20°/15° C required 1 to 2 days. At 5° C dehardening did not take place. Hardening and dehardening occurred in both the dark and the light. The hardiness was tested by exposure of the leaves to heat stress and subsequent measurements of chlorophyll fluorescence induction and light-induced absorbance changes at 535 nm on the leaves and of the photosynthetic electron transport in thylakoids isolated after heat treatment. Heat-induced damage to both heat-hardened and non-hardened leaves seemed to consist primarily in a breakdown of the membrane potential of the thylakoids accompanied by partial inactivation of electron transport through photosystem II. The increase in heat resistance was not due to temperature-induced changes in lipid content and fatty acid composition of the thylakoids, and no conspicuous changes in the polypeptide composition of the membranes were observed. Prolonged heat treatment at 35° C up to 3 days significantly decreased the total lipid content and the degree of unsaturation of the fatty acids of membrane lipids without further increase in the thermostability of the leaves. Intact chloroplasts isolated from heat-hardened leaves retained increased heat resistance. When the stroma of the chloroplasts was removed, the thermostability of the thylakoids was decreased and was comparable to the heat resistance of chloroplast membranes obtained from non-hardened control plants. Compartmentation studies demonstrated that the content of soluble sugars within the chloroplasts and the whole leaf tissue decreased as heat hardiness increased. This indicated that in spinach leaves, sugars play no protective role in heat hardiness. The results suggest that changes in the ultrastructure of thylakoids in connection with a stabilizing effect of soluble non-sugar stroma compounds are responsible for acclimatization of the photosynthetic apparatus to high temperature conditions. Changes in the chemical composition of the chloroplast membranes did not appear to play a role in the acclimatization.
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Affiliation(s)
- K A Santarius
- Botanisches Institut, Universität Düsseldorf, Universitätsstraße 1, D-4000, Düsseldorf, Federal Republic of Germany
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Bauer H, Senser M. Photosynthesis of Ivy Leaves (Hedera helix L.) after Heat Stress II. Activity of Ribulose Bisphosphate Carboxylase, Hill Reaction, and Chloroplast Ultrastructure. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0044-328x(79)80047-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Salinity Dependent Resistance of Dunaliella parva against Extreme Temperatures I. Salinity and Thermoresistance. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/s0044-328x(78)80175-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Krause GH, Thorne SW, Lorimer GH. Glycolate synthesis by intact chloroplasts. Studies with inhibitors of photophosphorylation. Arch Biochem Biophys 1977; 183:471-9. [PMID: 921273 DOI: 10.1016/0003-9861(77)90382-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Krause GH. Light-induced movement of magnesium ions in intact chloroplasts. Spectroscopic determination with Eriochrome Blue SE. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 460:500-10. [PMID: 880298 DOI: 10.1016/0005-2728(77)90088-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The metallochromic indicator Eriochrome Blue SE was used to measure light-induced internal movement of Mg2+ in intact chloroplasts. By dual-wave-length spectroscopy (measuring wavelength 554 nm, reference 592 nm) a light-induced, dark-reversible absorbance increase of Eriochrome Blue in samples of isolated intact chloroplasts was observed. The light/dark difference spectrum of Eriochrome Blue between 550 and 590 nm (reference wavelength 562 nm) indicated that this absorbance increase was caused by an increased concentration of free Mg2+ in a neutral or slightly alkaline chloroplast compartment. The signal was seen only with intact, but not with broken, envelope-free chloroplasts, which had lost most of their divalent cations. This is interpreted to show that the indicator responds to an increase of Mg2+ concentration in the chloroplast stroma, which represents an efflux of Mg2+ from the intra-thylakoid space caused by light-dependent proton pumping. As calculated from corrected values of the absorbance increase of Eriochrome Blue, the light-induced internal release of Mg2+ was close to 100 nequiv per mg chlorophyll at pH 7.6 and 250 nequiv at pH 7.1. This corresponds to a light-dependent increase in the concentration of free Mg2+ in the stroma of about 2 and 5 mM, respectively.
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Schreiber U, Berry JA. Heat-induced changes of chlorophyll fluorescence in intact leaves correlated with damage of the photosynthetic apparatus. PLANTA 1977; 136:233-8. [PMID: 24420396 DOI: 10.1007/bf00385990] [Citation(s) in RCA: 146] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/1977] [Accepted: 06/19/1977] [Indexed: 05/10/2023]
Abstract
Methods were developed to measure chlorophyll fluorescence yield of intact leaf tissue during heat treatment under varying conditions of light intensity and photosynthetic activity. Fluorescence yield of a dark-adapted leaf increases by 2- to 3-fold with an increase of temperature into the region where heat-damage occurs. The temperatures of the fluorescence transition correlate well with the temperatures where quantum yield of CO2 fixation is irreversibly depressed. Fluorescence-temperature (F-T) curves allow ranking of different species according to their heat sensitivity. Within a single species acclimation to different growth temperatures is reflected by shifts of the transition temperatures in the F-T curves. When F-T curves are recorded in the steady light states at increasing light intensities, substantial shifts (up to 6°C) of transition temperatures to higher values are observed. Quantum yield measurements of CO2 fixation confirm that hight-light conditions protect from heat-damage. It is suggested that chlorophyll acts as an intrinsic fluorescence probe of the thylakoid membrane and responds to the same changes which cause irreversible denaturation of photosynthetic enzymes.
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Affiliation(s)
- U Schreiber
- Department of Plant Biology, Carnegie Institution of Washington, 94305, Stanford, CA, USA
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