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Zhu K, Wang A, Wu J, Yuan F, Guan D, Jin C, Zhang Y, Gong C. Effects of nitrogen additions on mesophyll and stomatal conductance in Manchurian ash and Mongolian oak. Sci Rep 2020; 10:10038. [PMID: 32572068 PMCID: PMC7308411 DOI: 10.1038/s41598-020-66886-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/28/2020] [Indexed: 12/02/2022] Open
Abstract
The response of plant CO2 diffusion conductances (mesophyll and stomatal conductances, gm and gsc) to soil drought has been widely studied, but few studies have investigated the effects of soil nitrogen addition levels on gm and gsc. In this study, we investigated the responses of gm and gsc of Manchurian ash and Mongolian oak to four soil nitrogen addition levels (control, low nitrogen, medium nitrogen and high nitrogen) and the changes in leaf anatomy and associated enzyme activities (aquaporin (AQP) and carbonic anhydrase (CA)). Both gm and gsc increased with the soil nitrogen addition levels for both species, but then decreased under the high nitrogen addition level, which primarily resulted from the enlargements in leaf and mesophyll cell thicknesses, mesophyll surface area exposed to intercellular space per unit leaf area and stomatal opening status with soil nitrogen addition. Additionally, the improvements in leaf N content and AQP and CA activities also significantly promoted gm and gsc increases. The addition of moderate levels of soil nitrogen had notably positive effects on CO2 diffusion conductance in leaf anatomy and physiology in Manchurian ash and Mongolian oak, but these positive effects were weakened with the addition of high levels of soil nitrogen.
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Affiliation(s)
- Kai Zhu
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Anzhi Wang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Jiabing Wu
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Fenghui Yuan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
| | - Dexin Guan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
| | - Changjie Jin
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Yushu Zhang
- The Institute of Atmospheric Environment, China Meteorological Administration, Shenyang, 110166, China
| | - Chunjuan Gong
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Fusaro L, Palma A, Salvatori E, Basile A, Maresca V, Asadi Karam E, Manes F. Functional indicators of response mechanisms to nitrogen deposition, ozone, and their interaction in two Mediterranean tree species. PLoS One 2017; 12:e0185836. [PMID: 28973038 PMCID: PMC5626521 DOI: 10.1371/journal.pone.0185836] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 09/20/2017] [Indexed: 11/18/2022] Open
Abstract
The effects of nitrogen (N) deposition, tropospheric ozone (O3) and their interaction were investigated in two Mediterranean tree species, Fraxinus ornus L. (deciduous) and Quercus ilex L. (evergreen), having different leaf habits and resource use strategies. An experiment was conducted under controlled condition to analyse how nitrogen deposition affects the ecophysiological and biochemical traits, and to explore how the nitrogen-induced changes influence the response to O3. For both factors we selected realistic exposures (20 kg N ha-1 yr-1 and 80 ppb h for nitrogen and O3, respectively), in order to elucidate the mechanisms implemented by the plants. Nitrogen addition resulted in higher nitrogen concentration at the leaf level in F. ornus, whereas a slight increase was detected in Q. ilex. Nitrogen enhanced the maximum rate of assimilation and ribulose 1,5-bisphosphate regeneration in both species, whereas it influenced the light harvesting complex only in the deciduous F. ornus that was also affected by O3 (reduced assimilation rate and accelerated senescence-related processes). Conversely, Q. ilex developed an avoidance mechanism to cope with O3, confirming a substantial O3 tolerance of this species. Nitrogen seemed to ameliorate the harmful effects of O3 in F. ornus: the hypothesized mechanism of action involved the production of nitrogen oxide as the first antioxidant barrier, followed by enzymatic antioxidant response. In Q. ilex, the interaction was not detected on gas exchange and photosystem functionality; however, in this species, nitrogen might stimulate an alternative antioxidant response such as the emission of volatile organic compounds. Antioxidant enzyme activity was lower in plants treated with both O3 and nitrogen even though reactive oxygen species production did not differ between the treatments.
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Affiliation(s)
- Lina Fusaro
- Sapienza University of Rome, Department of Environmental Biology, Rome, Italy
| | - Adriano Palma
- Sapienza University of Rome, Department of Environmental Biology, Rome, Italy
| | | | - Adriana Basile
- University of Naples “Federico II”, Biology Department, Naples, Italy
| | - Viviana Maresca
- University of Naples “Federico II”, Biology Department, Naples, Italy
| | - Elham Asadi Karam
- Shahid Bahonar University of Kerman, Biology Department, Kerman, Iran
| | - Fausto Manes
- Sapienza University of Rome, Department of Environmental Biology, Rome, Italy
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Cha S, Chae HM, Lee SH, Shim JK. Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla. PLoS One 2017; 12:e0171197. [PMID: 28182638 PMCID: PMC5300125 DOI: 10.1371/journal.pone.0171197] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 01/18/2017] [Indexed: 11/29/2022] Open
Abstract
The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition.
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Affiliation(s)
- Sangsub Cha
- Department of Life Science, Chung-Ang University, Seoul, Korea
| | - Hee-Myung Chae
- Department of Life Science, Chung-Ang University, Seoul, Korea
| | - Sang-Hoon Lee
- Department of Life Science, Chung-Ang University, Seoul, Korea
| | - Jae-Kuk Shim
- Department of Life Science, Chung-Ang University, Seoul, Korea
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Tanis SR, Mccullough DG. Host Resistance of Five Fraxinus Species to Agrilus planipennis (Coleoptera: Buprestidae) and Effects of Paclobutrazol and Fertilization. Environ Entomol 2015; 44:287-299. [PMID: 26313182 DOI: 10.1093/ee/nvu005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/20/2014] [Indexed: 06/04/2023]
Abstract
Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) has killed millions of Fraxinus spp. trees in North America. While all Fraxinus species assessed to date can be colonized, A. planipennis attraction to host trees varies among species and with tree health. We established a plantation of 105 trees (21 trees each of four North American species Fraxinus americana L., Fraxinus nigra Marshall, Fraxinus pennsylvanica Marshall, Fraxinus quadrangulata Michaux, and the Asian species, Fraxinus mandshurica Ruprecht), and determined whether resistance to A. planipennis could be enhanced by fertilizer or paclobutrazol applications. Differences among species overshadowed most treatment effects. In 2010, A. planipennis survival over 14 d was 53% when beetles were caged with F. nigra, 30-32% when beetles were caged with F. americana, F. pennsylvanica, or F. mandshurica, and only 14% for beetles caged with F. quadrangulata. In 2011, beetle survival was lower for beetles caged with F. quadrangulata (33%) than F. americana (72%) or F. mandshurica (80%). In 2010 and 2011, leaf weight consumed by beetles was the same among Fraxinus species. However, beetles caged on F. quadrangulata consumed less leaf area than that by beetles caged with other ash species. In 2011, when trees were exposed to wild A. planipennis, larval density (per m(2)) was highest on F. nigra (235.9 ± 36.41) and F. pennsylvanica (220.1 ± 39.77), intermediate on F. americana (40.7 ± 11.61), and lowest on F. quadrangulata and F. mandshurica (2.0 ± 0.98 and 1.5 ± 0.67, respectively). Results indicate F. quadrangulata and F. mandshurica were relatively resistant to A. planipennis, F. nigra and F. pennsylvanica were highly vulnerable, and F. americana was intermediate.
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Affiliation(s)
| | - Deborah G Mccullough
- Department of Forestry and Department of Entomology, Michigan State University, East Lansing, MI 48824.Corresponding author, e-mail:
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Fini A, Guidi L, Giordano C, Baratto MC, Ferrini F, Brunetti C, Calamai L, Tattini M. Salinity stress constrains photosynthesis in Fraxinus ornus more when growing in partial shading than in full sunlight: consequences for the antioxidant defence system. Ann Bot 2014; 114:525-38. [PMID: 25006177 PMCID: PMC4204663 DOI: 10.1093/aob/mcu130] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/12/2014] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS A major challenge in plant ecophysiology is understanding the effects of multiple sub-optimal environmental conditions on plant performance. In most Mediterranean areas soil salinity builds up during the summer because of low availability of soil water coupled with hot temperatures. Although sunlight and soil salinity may strongly interact in determining a plant's performance, this has received relatively little attention. METHODS Two-year-old seedlings of Fraxinus ornus were grown outdoors in pots during a Mediterranean summer in either 45 % (shaded plants) or 100 % (sun plants) sunlight irradiance and were supplied with either deionized water or deionized water plus 75 mm NaCl. Morpho-anatomical traits, water and ionic relations, gas exchange and photosystem II performance, concentrations of individual carotenoids, activity of antioxidant enzymes, concentrations of ascorbic acid and individual polyphenols were measured in leaves. Leaf oxidative stress and damage were estimated by in vivo analysis of stable free radicals and ultrastructural analyses. KEY RESULTS Leaf concentrations of potentially toxic ions did not markedly differ in shaded or sun plants in response to salinity. Leaves of sun plants displayed superior water use efficiency compared with leaves of shaded plants, irrespective of salinity treatment, and had both better stomatal control and higher CO2 carboxylation efficiency than leaves of shaded plants. In the salt-treated groups, the adverse effects of excess midday irradiance were greater in shade than in sun plants. The activity of enzymes responsible for detoxifying hydrogen peroxide decreased in shaded plants and increased in sun plants as a result of salinity stress. In contrast, the activity of guaiacol peroxidase and the concentration of phenylpropanoids increased steeply in response to salinity in shaded plants but were unaffected in sun plants. CONCLUSIONS It is concluded that salinity may constrain the performance of plants growing under partial shading more severely than that of plants growing under full sun during summer. The results suggest co-ordination within the antioxidant defence network aimed at detoxifying salt-induced generation of reactive oxygen species.
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Affiliation(s)
- Alessio Fini
- Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, I-50019, Sesto Fiorentino, Florence, Italy
| | - Lucia Guidi
- Department of Agricultural, Food and Agro-Environmental Sciences, University of Pisa, Via del Borghetto 80, I-56124, Pisa, Italy
| | - Cristiana Giordano
- The National Research Council of Italy, Centre for Electron Microscopy (Ce.M.E.), Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Florence Italy
| | - Maria Camilla Baratto
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, I-53100 Siena, Italy
| | - Francesco Ferrini
- Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, I-50019, Sesto Fiorentino, Florence, Italy
| | - Cecilia Brunetti
- Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, I-50019, Sesto Fiorentino, Florence, Italy The National Research Council of Italy, Department of Biology, Agriculture and Food Sciences, Institute for Plant Protection, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Florence Italy
| | - Luca Calamai
- Department of Agri-Food and Environmental Science, University of Florence, Viale delle Idee 30, I-50019, Sesto Fiorentino, Florence, Italy
| | - Massimiliano Tattini
- The National Research Council of Italy, Department of Biology, Agriculture and Food Sciences, Institute for Plant Protection, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Florence Italy
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Cleary MR, Andersson PF, Broberg A, Elfstrand M, Daniel G, Stenlid J. Genotypes of Fraxinus excelsior with different susceptibility to the ash dieback pathogen Hymenoscyphus pseudoalbidus and their response to the phytotoxin viridiol - a metabolomic and microscopic study. Phytochemistry 2014; 102:115-25. [PMID: 24709032 DOI: 10.1016/j.phytochem.2014.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 03/03/2014] [Accepted: 03/06/2014] [Indexed: 05/26/2023]
Abstract
Eight European ash (Fraxinus excelsior) genotypes with different known susceptibility to Hymenoscyphus pseudoalbidus were tested against the phytotoxin viridiol and their response described at the microscopic and metabolomic level. All ash genotypes were sensitive to the toxin and necrosis was detectable after 24h. Among the three viridiol concentrations used in the experiment, the lowest concentration (14.7μM) yielded markedly lower mean damage scores compared to those resulting from seedlings tested at higher dosages. The highest damage scores were associated with the susceptible ash clones S-101, S-106 and S-125, but also with resistant clone R-104. Three resistant clones (R-131, R-121, and R-118) had lower mean damage scores compared to susceptible clones. Wilting of leaves was more common 48h after treatment and more pronounced on seedlings with high damage scores. The resulting lesions generally lacked browning of tissue and displayed only surface disruption of cells in direct contact with the toxin. A delay in symptom development was evident on all five resistant clones tested with the two higher concentrations of viridiol. LC-HRMS and MS/MS analyses of ash seedling extracts suggest several secoiridoid compounds as well as compounds related to abscisic acid (ABA) to be produced in response to viridiol. ABA-cysteine and xanthoxin were found at significantly higher concentrations in susceptible clones compared to resistant clones after treatment with viridiol, suggesting a primary role of ABA in response to stress. The results observed in this study suggest that genetic resistance to H. pseudoalbidus among ash genotypes may be explained, in part, by the varied response to phytotoxins produced by the fungus.
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Affiliation(s)
- M R Cleary
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Almas allé 5, PO Box 7026, SE-750 07 Uppsala, Sweden.
| | - P F Andersson
- Department of Chemistry and Biotechnology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Almas allé 5, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - A Broberg
- Department of Chemistry and Biotechnology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Almas allé 5, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - M Elfstrand
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Almas allé 5, PO Box 7026, SE-750 07 Uppsala, Sweden
| | - G Daniel
- Department of Forest Products, Swedish University of Agricultural Sciences, Vallvägen 9C, PO Box 7008, 750-07 Uppsala, Sweden
| | - J Stenlid
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Almas allé 5, PO Box 7026, SE-750 07 Uppsala, Sweden
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Donnarumma F, Capuana M, Vettori C, Petrini G, Giannini R, Indorato C, Mastromei G. Isolation and characterisation of bacterial colonies from seeds and in vitro cultures of Fraxinus spp. from Italian sites. Plant Biol (Stuttg) 2011; 13:169-76. [PMID: 21143738 DOI: 10.1111/j.1438-8677.2010.00334.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Culturable bacteria were isolated from seeds, embryos and contaminated in vitro cultures of ash (Fraxinus excelsior L., F. ornus L. and F. angustifolia L.) and were identified using morphological and molecular analyses. Fourteen morphologically distinct isolates were recovered from seeds of Fraxinus spp. 16S rDNA sequencing categorised these isolates into ten separate genera. Three strains isolated from contaminated in vitro cultures, Pantoea agglomerans, Staphylococcus succinus and Aerococcus viridans, were used for comparative analysis with isolates from seeds. Antibiotic sensitivity testing of the isolated contaminants, including phytotoxicity of antibiotics on in vitro cultures of ash, was also investigated. Phytotoxic effects on explants immersed in ampicillin or cultured on medium containing ampicillin were negligible, however tetracycline, either alone or in combination with other antibiotics, had phytotoxic effects. We conclude that ampicillin is a suitable antibiotic to limit the growth of contaminating bacteria during the in vitro culture of ash.
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Affiliation(s)
- F Donnarumma
- Dipartimento di Biologia Evoluzionistica, Università di Firenze, Firenze, Italy
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Paoletti E, Contran N, Bernasconi P, Günthardt-Goerg MS, Vollenweider P. Erratum to "Structural and physiological responses to ozone in Manna ash (Fraxinus ornus L.) leaves of seedlings and mature trees under controlled and ambient conditions". Sci Total Environ 2010; 408:2014-2024. [PMID: 20238440 DOI: 10.1016/j.scitotenv.2010.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Leaf-level microscopical symptom structure and physiological responses were investigated in seedlings experimentally exposed to ozone (O3) in indoor chambers (150 ppb, 8 hd(-1) per 7 weeks), and field trees of Manna ash (Fraxinus ornus) exposed to ambient O3 (max 93 ppb per one growing season). Ozone-induced leaf injury, including leaf reddening and stippling, was observed in both seedlings and mature trees, but the morphology of injury in the stipples differed, being hypersensitive-like (HR-like) in the chamber seedlings and accelerated cell senescence (ACS) in the field trees. In both exposure conditions, the main structural impact of O3 was on the mesophyll and especially the upper assimilating cell layers. The main physiological impact was on carbon assimilation and on stomatal sluggishness. These effects were not due to stomatal structural injury and were more severe in juvenile compared to mature trees because of environmental (water availability, light) and constitutional (gas exchange capacity) factors and differences in the cell physiology processes (HR-like vs. ACS) triggered by ozone stress. Given the plasticity of plant responses to ozone stress, dose/response relationships for tree seedlings in the indoor chambers cannot be extrapolated to mature trees unless ambient conditions are closely simulated.
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Affiliation(s)
- Elena Paoletti
- Institute Plant Protection, National Council of Research, Via Madonna del Piano 10, Sesto Fiorentino, Florence, Italy.
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Cicek E, Yilmaz F, Yilmaz M. Effect of N and NPK fertilizers on early field performance of narrow-leaved ash, Fraxinus angustifolia. J Environ Biol 2010; 31:109-114. [PMID: 20648820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The effect of fertilization in the first growing season on early survival and growth of narrow-leaved ash (NLA) (Fraxinus angustifolia ssp. oxycarpa) was evaluated throughout the first 3 years of growth in Adapazari, Turkey. A randomized complete block design with four replications was established to investigate fertilization effects. Granular N urea [46%, (NH2)2CO, NH2-N] and NPK (15/15/15%; NH3-N, P2O5, K2O) fertilizers were applied in mid-May of the first growing season. Fertilization treatments per tree were control, 67 g NPK (equal to 10/10/10 g N/P2O5 /K2O tree(-1)), 133 g NPK (20/20/20 g N/P2O5 /K2O tree(-1)), 33 g urea N (15 g N tree(-1)) and 54 g urea N (25 g N tree(-1)). After three growing seasons under these fertilizer treatments, 98% of trees were still viable. Compared to the control treatment, fertilization had a large and positive effect on diameter and height growth during the first 3 years of growth. However, since there were no significant differences among the fertilized plots in terms of tree diameter and height growth, addition of P and K to the fertilizer regime was not beneficial. The results show that N fertilization in the first growing season has the potential to improve early field growth of narrow-leaved ash.
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Affiliation(s)
- Emrah Cicek
- Faculty of Forestry, Duzce University, Duzce - 81620, Turkey.
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Jiang S, Xu K, Zhao N, Zheng SX, Ren YP, Gao YB, Gu S. Ethylene evolution changes in tilted Fraxinus mandshurica Rupr. var. japonica maxim. seedlings in relation to tension wood formation. J Integr Plant Biol 2009; 51:707-713. [PMID: 19566649 DOI: 10.1111/j.1744-7909.2009.00835.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The effects of ethylene on tension wood formation were studied in 3-year-old Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings in two separate experiments. In experiment 1, ethylene evolution of buds and stems was measured using gas chromatography after 0, 2, 4, 7, 14, and 21 d of treatment; in experiment 2, both aminoethoxyvinylglycine (AVG) and AgNO3 were applied to the horizontally-placed stems, and the cell numbers on sites of applications were measured after 40 d. Ethylene evolution from buds was found to be much greater in tilted seedlings than in upright ones. The cell numbers of wood fibers in shoots and 1-year-old stems were reduced in treatments with 12.5 x 10(-7)micromol/L AVG, 12.5 x 10(-8)micromol/L AVG, and 11.8 x 10(-8)micromol/L AgNO3; whereas the horizontal and vertical diameters were reduced by treatment of 12.5 x 10(-7)micromol/L AVG. Ethylene evolutions of shoots and 1-year-old stems were inhibited greatly in comparison with the control by applying 12.5 x 10(-7)micromol/L AVG. The formation of a gelatinous layer of wood fibers was affected by neither AVG nor AgNO3 application. These results suggest that ethylene regulates the quantity of wood production, but does not affect G-layer formation in F. mandshurica Rupr. var. japonica Maxim. seedlings.
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Affiliation(s)
- Sha Jiang
- College of Life Sciences, Nankai University, Tianjin 300071, China
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Paoletti E, Contran N, Bernasconi P, Günthardt-Goerg MS, Vollenweider P. Structural and physiological responses to ozone in Manna ash (Fraxinus ornus L.) leaves of seedlings and mature trees under controlled and ambient conditions. Sci Total Environ 2009; 407:1631-1643. [PMID: 19136142 DOI: 10.1016/j.scitotenv.2008.11.061] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 11/24/2008] [Accepted: 11/24/2008] [Indexed: 05/27/2023]
Abstract
Leaf-level microscopical symptom structure and physiological responses were investigated in seedlings experimentally exposed to ozone (O3) in indoor chambers (150 ppb, 8 h d(-1)/7 weeks), and field trees of Manna ash (Fraxinus ornus) exposed to ambient O3 (max 93 ppb/one growing season). Ozone-induced leaf injury, including leaf reddening and stippling, was observed in both seedlings and mature trees, but the morphology of injury in the stipples differed, being hypersensitive-like (HR-like) in the chamber seedlings and accelerated cell senescence (ACS) in the field trees. In both exposure conditions, the main structural impact of O3 was on the mesophyll and especially the upper assimilating cell layers. The main physiological impact was on carbon assimilation and on stomatal sluggishness. These effects were not due to stomatal structural injury and were more severe in juvenile compared to mature trees because of environmental (water availability, light) and constitutional (gas exchange capacity) factors and differences in the cell physiology processes (HR-like vs. ACS) triggered by ozone stress. Given the plasticity of plant responses to ozone stress, dose/response relationships for tree seedlings in the indoor chambers cannot be extrapolated to mature trees unless ambient conditions are closely simulated.
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Affiliation(s)
- Elena Paoletti
- Institute Plant Protection, National Council of Research, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Florence, Italy.
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Paoletti E, Contran N, Manning WJ, Castagna A, Ranieri A, Tagliaferro F. Protection of ash (Fraxinus excelsior) trees from ozone injury by ethylenediurea (EDU): roles of biochemical changes and decreased stomatal conductance in enhancement of growth. Environ Pollut 2008; 155:464-472. [PMID: 18331769 DOI: 10.1016/j.envpol.2008.01.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Accepted: 01/24/2008] [Indexed: 05/26/2023]
Abstract
Treatments with ethylenediurea (EDU) protect plants from ozone foliar injury, but the processes underlying this protection are poorly understood. Adult ash trees (Fraxinus excelsior), with or without foliar ozone symptoms in previous years, were treated with EDU at 450 ppm by gravitational trunk infusion in May-September 2005 (32.5 ppm h AOT40). At 30-day intervals, shoot growth, gas exchange, chlorophyll a fluorescence, and water potential were determined. In September, several biochemical parameters were measured. The protective influence of EDU was supported by enhancement in the number of leaflets. EDU did not contribute its nitrogen to leaf tissue as a fertiliser, as determined from lack of difference in foliar N between treatments. Both biochemical (increase in ascorbate-peroxidase and ascorbic acid, and decrease in apoplastic hydrogen peroxide) and biophysical (decrease in stomatal conductance) processes regulated EDU action. As total ascorbic acid increased only in the asymptomatic trees, its role in alleviating O(3) effects on leaf growth and visible injury is controversial.
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Affiliation(s)
- Elena Paoletti
- IPP-CNR, Via Madonna del Piano 10, Sesto Fiorentino, I-50019 Florence, Italy.
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Jiang S, Xu K, Wang YZ, Ren YP, Gu S. Role of GA3, GA4 and uniconazole-P in controlling gravitropism and tension wood formation in Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings. J Integr Plant Biol 2008; 50:19-28. [PMID: 18666948 DOI: 10.1111/j.1744-7909.2007.00552.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
GA(3) and GA(4) (gibberellins) play an important role in controlling gravitropism and tension wood formation in woody angiosperms. In order to improve our understanding of the role of GA(3) and GA(4) on xylem cell formation and the G-layer, we studied the effect of GA(3) and GA(4) and uniconazole-P, which is an inhibitor of GA biosynthesis, on tension wood formation by gravity in Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings. Forty seedlings were divided into two groups; one group was placed upright and the other tilted. Each group was further divided into four sub-groups subjected to the following treatments: 3.43 x 10(-9) micromol acetone as control, 5.78 x 10(-8) micromol gibberellic acid (GA(3)), 6.21 x 10(-8) micromol GA(4), and 6.86 x 10(-8) micromol uniconazole-P. During the experimental period, GAs-treated seedlings exhibited negative gravitropism, whereas application of uniconazole-P inhibited negative gravitropic stem bending. GA(3) and GA(4) promoted wood fibers that possessed a gelatinous layer on the upper side, whereas uniconazole-P inhibited wood formation but did not inhibit the differentiation of the gelatinous layer in wood fibers on the upper side. These results suggest that: (i) both the formation of gelatinous fibers and the quantity of xylem production are important for the negative gravitropism in horizontally-positioned seedlings; (ii) GA(3) and GA(4) affect wood production more than differentiation of the gelatinous layer in wood fibers; G-layer development may be regulated by other hormones via the indirect-role of GA(3) and GA(4) in horizontally-positioned F. mandshurica seedlings rather than the direct effect of GAs; and (iii) the mechanism for upward wood stem bending is different to the newly developed shoot bending in reaction to gravity in this species.
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Affiliation(s)
- Sha Jiang
- College of Life Sciences, Nankai University, Tianjin 300071, China.
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Novak K, Cherubini P, Saurer M, Fuhrer J, Skelly JM, Kräuchi N, Schaub M. Ozone air pollution effects on tree-ring growth, delta(13)C, visible foliar injury and leaf gas exchange in three ozone-sensitive woody plant species. Tree Physiol 2007; 27:941-9. [PMID: 17403646 DOI: 10.1093/treephys/27.7.941] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We assessed the effects of ambient tropospheric ozone on annual tree-ring growth, delta(13)C in the rings, leaf gas exchange and visible injury in three ozone-sensitive woody plant species in southern Switzerland. Seedlings of Populus nigra L., Viburnum lantana L. and Fraxinus excelsior L. were exposed to charcoal-filtered air (CF) and non-filtered air (NF) in open-top chambers, and to ambient air (AA) in open plots during the 2001 and 2002 growing seasons. Ambient ozone exposures in the region were sufficient to cause visible foliar injury, early leaf senescence and premature leaf loss in all species. Ozone had significant negative effects on net photosynthesis and stomatal conductance in all species in 2002 and in V. lantana and F. excelsior in 2001. Water-use efficiency decreased and intercellular CO(2) concentrations increased in all species in response to ozone in 2002 only. The width and delta(13)C of the 2001 and 2002 growth rings were measured for all species at the end of the 2002 growing season. Compared with CF seedlings, mean ring width in the AA and NF P. nigra seedlings was reduced by 52 and 46%, respectively, in 2002, whereas in V. lantana and F. excelsior, ring width showed no significant reductions in either year. Although delta(13)C was usually more negative in CF seedlings than in AA and NF seedlings, with the exception of F. excelsior in 2001, ozone effects on delta(13)C were significant only for V. lantana and P. nigra in 2001. Among species, P. nigra exhibited the greatest response to ozone for the measured parameters as well as the most severe foliar injury and was the only species to show a significant reduction in ring width in response to ozone exposure, despite significant negative ozone effects on leaf gas exchange and the development of visible foliar injury in V. lantana and F. excelsior. Thus, significant ozone-induced effects at the leaf level did not correspond to reduced tree-ring growth or increased delta(13)C in all species, indicating that the timing of ozone exposure and severity of leaf-level responses may be important in determining the sensitivity of tree productivity to ozone exposure.
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Affiliation(s)
- Kristopher Novak
- Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland
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Contran N, Paoletti E. Visible foliar injury and physiological responses to ozone in Italian provenances of Fraxinus excelsior and F. ornus. ScientificWorldJournal 2007; 7 Suppl 1:90-7. [PMID: 17450285 PMCID: PMC5901263 DOI: 10.1100/tsw.2007.10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We compared leaf visible injury and physiological responses (gas exchange and chlorophyll a fluorescence) to high O3 exposure (150 nmol mol–1 h, 8 h day–1, 35–40 days) of two woody species of the same genus with different ecological features: the mesophilic green ash (Fraxinus excelsior) and the xerotolerant manna ash (F. ornus). We also studied how provenances from northern (Piedmont) and central (Tuscany) Italy, within the two species, responded to O3 exposure. Onset and extent of visible foliar injury suggested that F. excelsior was more O3 sensitive than F. ornus. The higher stomatal conductance in F. ornus than in F. excelsior suggested a larger potential O3 uptake, in disagreement to lower visible foliar injury. The higher carbon assimilation in F. ornus suggested a higher potential of O3 detoxification and/or repair. Contrasting geographical variations of ash sensitivity to O3 were recorded, as Piedmont provenances reduced gas exchange less than Tuscan provenances in F. excelsior and more in F. ornus. Visible injury was earlier and more severe in F. excelsior from Piedmont than from Tuscany, while the provenance did not affect visible injury onset and extent in F. ornus.
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Affiliation(s)
- Nicla Contran
- Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy.
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Paoletti E, Contran N, Manning WJ, Tagliaferro F. Ethylenediurea (EDU) affects the growth of ozone-sensitive and tolerant ash (Fraxinus excelsior) trees under ambient O3 conditions. ScientificWorldJournal 2007; 7 Suppl 1:128-33. [PMID: 17450289 PMCID: PMC5900486 DOI: 10.1100/tsw.2007.21] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Adult ash trees (Fraxinus excelsior L.), known to be sensitive or tolerant to ozone, determined by presence or absence of foliar symptoms in previous years, were treated with ethylenediurea (EDU) at 450 ppm by gravitational trunk infusion over the 2005 growing season (32.5 ppm h AOT40). Tree and shoot growth were recorded in May and September. Leaf area, ectomycorrhizal infection, and leaf and fine root biomass were determined in September. EDU enhanced shoot length and diameter, and the number and area of leaves, in both O3-sensitive and tolerant trees. However, no EDU effects were recorded at the fine root and tree level. Therefore, a potential for EDU protection against O3-caused growth losses of forest trees should be evaluated during longer-term experiments.
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Affiliation(s)
- Elena Paoletti
- IPP-CNR, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Florence, Italy.
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Paoletti E, Manning WJ, Spaziani F, Tagliaferro F. Gravitational infusion of ethylenediurea (EDU) into trunks protected adult European ash trees (Fraxinus excelsior L.) from foliar ozone injury. Environ Pollut 2007; 145:869-73. [PMID: 16769164 DOI: 10.1016/j.envpol.2006.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 05/02/2006] [Accepted: 05/03/2006] [Indexed: 05/10/2023]
Abstract
Adult ash trees (Fraxinus excelsior L.), known to be sensitive or insensitive to ozone, determined by presence or absence of foliar symptoms in previous years, were treated with ethylenediurea (EDU) at 450 ppm by gravitational trunk infusion on six occasions at 21-day intervals in summer 2005 at Turin, Italy. At the end of the season, foliar ozone injury on EDU-treated trees was not complete, but was greatly and significantly reduced when compared to results from trees infused with water. Significant symptom reduction occurred at any crown level in the treated trees suggesting that EDU protected whole crowns. Gravitational infusion of EDU resulted in protection from ozone injury for ozone-sensitive ash trees. The amount of EDU needed to provide protection is assumed to be in the range 13-26 mg m(-2) leaf.
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Affiliation(s)
- E Paoletti
- IPP-CNR, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Florence, Italy.
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Abstract
The gaseous environment surrounding parenchyma in woody tissue is low in O2 and high in CO2, but it is not known to what extent this affects respiration or might play a role in cell death during heartwood formation. Sapwood respiration was measured in two conifers and three angiosperms following equilibration to levels of O2 and CO2 common within stems, using both inner and outer sapwood to test for an effect of age. Across all species and tissue ages, lowering the O2 level from 10% to 5% (v/v) resulted in about a 25% decrease in respiration in the absence of CO2, but a non-significant decrease at 10% CO2. The inhibitory effect of 10% CO2 was smaller and only significant at 10% O2, where it reduced respiration by about 14%. Equilibration to a wider range of gas combinations in Pinus strobus L. showed the same effect: 10% CO2 inhibited respiration by about 15% at both 20% and 10% O2, but had no net effect at 5% O2. In an extreme treatment, 1% O2+20% CO2 increased respiration by over 30% relative to 1% O2 alone, suggesting a shift in metabolic response to high CO2 as O2 decreases. Although an increase in respiration would be detrimental under limiting O2, this extreme gas combination is unlikely to exist within most stems. Instead, moderate reductions in respiration under realistic O2 and CO2 levels suggest that within-stem gas composition does not severely limit respiration and is unlikely to cause the death of xylem parenchyma during heartwood formation.
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Affiliation(s)
- Rachel Spicer
- Rowland Institute at Harvard, 100 Edwin H. Land Boulevard, Cambridge, MA 02142, USA.
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Novak K, Schaub M, Fuhrer J, Skelly JM, Hug C, Landolt W, Bleuler P, Kräuchi N. Seasonal trends in reduced leaf gas exchange and ozone-induced foliar injury in three ozone sensitive woody plant species. Environ Pollut 2005; 136:33-45. [PMID: 15809106 DOI: 10.1016/j.envpol.2004.12.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Accepted: 12/13/2004] [Indexed: 05/24/2023]
Abstract
Seasonal trends in leaf gas exchange and ozone-induced visible foliar injury were investigated for three ozone sensitive woody plant species. Seedlings of Populus nigra L., Viburnum lantana L., and Fraxinus excelsior L. were grown in charcoal-filtered chambers, non-filtered chambers and open plots. Injury assessments and leaf gas exchange measurements were conducted from June to October during 2002. All species developed typical ozone-induced foliar injury. For plants exposed to non-filtered air as compared to the charcoal-filtered air, mean net photosynthesis was reduced by 25%, 21%, and 18% and mean stomatal conductance was reduced by 25%, 16%, and 8% for P. nigra, V. lantana, and F. excelsior, respectively. The timing and severity of the reductions in leaf gas exchange were species specific and corresponded to the onset of visible foliar injury.
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Affiliation(s)
- K Novak
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland.
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Tonon G, Kevers C, Faivre-Rampant O, Grazianil M, Gaspar T. Effect of NaCl and mannitol iso-osmotic stresses on proline and free polyamine levels in embryogenic Fraxinus angustifolia callus. J Plant Physiol 2004; 161:701-8. [PMID: 15266717 DOI: 10.1078/0176-1617-01096] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
With the aim to differentiate the ionic and osmotic components of salt stress, short and long-term changes in free polyamines and proline induced by iso-osmotic concentrations of NaCl (0.1 mol/L and 0.2 mol/L) and mannitol (0.2 mol/L and 0.4 mol/L) were determined in Fraxinus angustifolia callus. The peculiarities of the short-term responses were: i) a very early (30 min) and temporary increase in Putrescine (Pu) and Spermine (Spm) as a consequence of salt treatment, and ii) a continuous accumulation of Spermidine (Spd) and Spm in response to mannitol. The changes of Proline (Pro) were quite limited both in the short and in the long term, and generally occurred later than Polyamine (PAs) changes took place, suggesting a regulatory mechanism of PAs metabolism on Pro biosynthesis. In the long-term, no drastic accumulations of Pro or PAs in response to NaCl and mannitol were observed, suggesting that their physiological role is unlikely to be that of osmo-compatible solutes in this plant system. The salt induced a higher callus growth inhibition effect than did mannitol and this inhibition was associated with the reduction of endogenous levels of PAs, especially Pu. However, while a diverging time course was observed under lethal salt concentration (0.2 mol/L NaCl), a high parallelism in the endogenous changes of Pro and Pu was observed under all non-lethal conditions (control--0.2 and 0.4 mol/L mannitol--0.1 mol/L NaCl). Therefore the synchronous changes of Pro and Pu can be considered as a physiological trait associated with cell survival. These results indicate a strong metabolic co-ordination between PAs and Pro pathways and suggest that the metabolic fluxes through these pathways start competing only when the stress level is high enough to be lethal for cells.
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Affiliation(s)
- Giustino Tonon
- Università di Bologna, Dipartimento di Colture Arboree, Via Fanin 46, IT-40127 Bologna, Italy.
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Schaub M, Skelly JM, Steiner KC, Davis DD, Pennypacker SP, Zhang J, Ferdinand JA, Savage JE, Stevenson RE. Physiological and foliar injury responses of Prunus serotina, Fraxinus americana, and Acer rubrum seedlings to varying soil moisture and ozone. Environ Pollut 2003; 124:307-320. [PMID: 12713930 DOI: 10.1016/s0269-7491(02)00462-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Sixteen black cherry (Prunus serotina, Ehrh.), 10 white ash (Fraxinus americana, L.) and 10 red maple (Acer rubrum, L.) 1-year old seedlings were planted per plot in 1997 on a former nursery bed within 12 open-top chambers and six open plots. Seedlings were exposed to three different ozone scenarios (ambient air: 100% O3; non-filtered air: 98% ambient O3; charcoal-filtered air: 50% ambient O3) within each of two different water regimes (nine plots irrigated, nine plots non-irrigated) during three growing seasons. During the 1998 and 1999 growing season, leaf gas exchange, plant water relations, and foliar injury were measured. Climatic data,ambient- and chamber-ozone-concentrations were monitored. We found that seedlings grown under irrigated conditions had similar (in 1998) but significantly higher gas exchange rates (in 1999) than seedlings grown within non-irrigated plots among similar ozone exposures. Cherry and ash had similar ozone uptake but cherry developed more ozone-induced injury (< 34% affected leaf area, LAA) than ash (<5% LAA), while maple rarely showed foliar injury, indicating the species differed in ozone sensitivity. Significantly more severe injury on seedlings grown under irrigated conditions than seedlings grown under non-irrigated conditions demonstrated that soil moisture altered seedling responses to ambient ozone exposures.
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Affiliation(s)
- M Schaub
- Graduate Ecology Program, Pennsylvania State University, University Park, PA 16802, USA
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Gerosa G, Marzuoli R, Bussotti F, Pancrazi M, Ballarin-Denti A. Ozone sensitivity of Fagus sylvatica and Fraxinus excelsior young trees in relation to leaf structure and foliar ozone uptake. Environ Pollut 2003; 125:91-8. [PMID: 12804831 DOI: 10.1016/s0269-7491(03)00094-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
During the summer of 2001, 2-year-old Fraxinus excelsior and Fagus sylvatica plants were subjected to ozone-rich environmental conditions at the Regional Forest Nursery at Curno (Northern Italy). Atmospheric ozone concentrations and stomatal conductance were measured, in order to calculate the foliar fluxes by means of a one-dimensional model. The foliar structure of both species was examined (thickness of the lamina and of the individual tissues, leaf mass per area, leaf density) and chlorophyll a fluorescence was determined as a response parameter. Stomatal conductance was always greater in Fraxinus excelsior, as was ozone uptake, although the highest absorption peaks did not match the peaks of ozone concentration in the atmosphere. The foliar structure can help explain this phenomenon: Fraxinus excelsior has a thicker mesophyll than Fagus sylvatica (indicating a greater photosynthesis potential) and a reduced foliar density. This last parameter, related to the apoplastic fraction, suggests a greater ability to disseminate the gases within the leaf as well as a greater potential detoxifying capacity. As foliar symptoms spread, the parameters relating to chlorophyll a fluorescence also change. PI (Performance Index, Strasser, A., Srivastava, A., Tsimilli-Michael, M., 2000. The fluorescence transient as a tool to characterize and screen photosynthetic samples. In: Yunus, M., Pathre, U., Mohanty, P., (Eds.) Probing Photosynthesis: Mechanisms, Regulation and Adaptation. Taylor & Francis, London, UK, pp. 445-483.) has proved to be a more suitable index than Fv/Fm (Quantum Yield Efficiency) to record the onset of stress conditions.
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Affiliation(s)
- Giacomo Gerosa
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Via Celoria 2, 20133, Milan, Italy
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