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Quiroz MP, Blanco V, Zoffoli JP, Ayala M. Study of Mineral Composition and Quality of Fruit Using Vascular Restrictions in Branches of Sweet Cherry. Plants (Basel) 2023; 12:1922. [PMID: 37653839 PMCID: PMC10223680 DOI: 10.3390/plants12101922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/17/2023] [Accepted: 01/31/2023] [Indexed: 09/02/2023]
Abstract
Calcium (Ca) and carbohydrate (CHO) supply in sweet cherry have been associated with fruit quality at harvest and during storage. There is little published information integrating CHO and Ca availability and distribution in sweet cherry and their effects on fruit quality. Accordingly, in the 2019-20 season, vascular restrictions were imposed on the phloem (girdling, G, stopping phloem flow) and xylem (transverse incision, S, cutting 50% of xylem cross-section area) of individual vertical branches of the sweet cherry combination 'Lapins'/Colt trained as Kym Green Bush system to modify mineral and CHO composition in fruit and associate such changes with quality at harvest and storage. The girdling to the phloem was used to induce changes in CHO distribution. The transverse incision to the xylem was a tool to modify Ca distribution. Five treatments (TR) were implemented: TR1-CTL = Control (without vascular restriction), TR2-G, at its base, TR3-G + G: at its base, and G further up at the change of year between the second and the third years of growth TR4--S and TR5-S + G. The vegetative (i.e., shoot and leaf growth), reproductive (i.e., fruit set and yield) development and stomatal conductance were monitored. Each branch was divided into the upper (1-and 2-year-old wood) and the lower (3-and 4-year-old wood) segments of the restriction applied. The quality and mineral composition (Ca, Mg, K, and N) of fruit borne on each segment were measured at harvest. The upper segment of TR3-G + G branches were harvested 10 d before the lower segment. The fruit from the upper segment of TR3-G + G was the largest, the sweetest, and had the higher titratable acidity concentration. However, fruits of this segment were the softest, had the lowest Ca concentrations, and had the highest ratios of N:Ca and K:Ca, compared with the other TRs. TR3-G + G branches developed the highest number of lateral current season shoots including shoots below the second girdling in the lower segment of the branch. This vegetative flow of growth would explain the mineral unbalance produced in the fruit from the upper segment of the branch. TR2-G did not register changes in fruit quality and mineral concentration compared with TR1-CTL. Surprisingly, the fruit from the branches with xylem restriction did not show changes in Ca concentration, suggesting that the xylem stream was enough to supply the fruit in branches without lateral shoot development. Fruit firmness was positively related to fruit Ca concentration and negatively related to the ratios of K:Ca and N:Ca.
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Affiliation(s)
- María Paz Quiroz
- Departmatento de Fruticultura y Enología, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago P.O. Box 78204360, Chile
| | - Víctor Blanco
- Department of Horticulture, Tree Fruit Research and Extension Center, Washington State University, Wenatchee, WA 98801, USA
| | - Juan Pablo Zoffoli
- Departmatento de Fruticultura y Enología, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago P.O. Box 78204360, Chile
| | - Marlene Ayala
- Departmatento de Fruticultura y Enología, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago P.O. Box 78204360, Chile
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Xie S, Li D, Liu Z, Wang Y, Ren Z, Li C, Cheng Q, Liu J, Zhang L, Zhang L, Hu D. Foliar Fertilizer Application Alters the Effect of Girdling on the Nutrient Contents and Yield of Camellia oleifera. Life (Basel) 2023; 13. [PMID: 36836950 DOI: 10.3390/life13020591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 02/23/2023] Open
Abstract
Improving the economic benefits of Camellia oleifera is a major problem for C. oleifera growers, and girdling and foliar fertilizer have significant effects on improving the economic benefits of plants. This study explains the effects of girdling, girdling + foliar fertilizer on nutrient distribution, and the economic benefits of C. oleifera at different times. It also explains the N, P, and K contents of roots, leaves, fruits, and flower buds (sampled in March, May, August, and October 2021) and their economic benefits. The results showed girdling promoted the accumulation of N and K in leaves in March 2021 (before spring shoot emergence) but inhibited the accumulation of P, which led to the accumulation of P in roots and that of N in fruits in August 2021 (fruit expansion period). Foliar fertilizer application after girdling replenished the P content of leaves in March 2021, and P continued to accumulate in large quantities at the subsequent sampling time points. The N and P contents of the root system decreased in March. In October (fruit ripening stage), girdled shrubs showed higher contents of N and K in fruits and flower buds, and consequently lower relative contents of N and K in roots and leaves but higher content of P in leaves. Foliar fertilizer application slowed down the effects of girdling on nutrient accumulation in fruits and flower buds. Spraying foliar fertilizer decreased the N:P ratio in the flower buds and fruits of girdled plants. Thus, foliar fertilizer spray weakened the effects of girdling on the nutrient content and economic benefits of C. oleifera. In conclusion, girdling changed the nutrient accumulation pattern in various organs of C. oleifera at different stages, increased leaf N:K ratio before shoot emergence, reduced root K content at the fruit expansion stage and the N:K ratio of mature fruit, and promoted economic benefits.
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Peng Y, Gu X, Zhou Q, Huang J, Liu Z, Zhou Y, Zheng Y. Molecular and physiologic mechanisms of advanced ripening by trunk girdling at early veraison of 'Summer Black' grape. Front Plant Sci 2022; 13:1012741. [PMID: 36330263 PMCID: PMC9623158 DOI: 10.3389/fpls.2022.1012741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Although the effects of girdling on grape berry development have been widely studied, the underlying mechanisms are poorly understood, especially at the molecular level. This study investigated the effect of trunk girdling on grape (Vitis L.) berry maturation. Girdling was performed on 5-year-old 'Summer Black' grapevines at early veraison, and transcriptional and physiologic analyses were performed. Trunk girdling promoted sugar accumulation and color development in berries and accelerated berry ripening by 25 days. Genes related to sucrose cleavage and polysaccharide degradation were upregulated at the transcriptional level, which was associated with increased monosaccharide accumulation and berry softening. Anthocyanin biosynthesis and accumulation were also enhanced by trunk girdling through the upregulation of anthocyanin biosynthesis genes including phenylalanine ammonia-lyase and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT). The increased expression of two VvUFGT genes was accompanied by the upregulation of VvMYBA2 under girdling. The upregulation of genes involved in ethylene biosynthesis and hormone (abscisic acid and brassinosteroid) responses and downregulation of genes involved in indoleacetic acid biosynthesis and response may have also promoted berry ripening in the girdling group. A total of 120 differentially expressed transcription factor genes from 29 gene families including MYB, ERF, and MYB-related were identified in the girdling group, which may participate in the regulation of berry development and ripening. These results provide molecular-level insight into the positive effects of trunk girdling on berry development in grapes.
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Affiliation(s)
- Yanjie Peng
- College of Life Science, Leshan Normal University, Leshan, China
- Institution of Biodiversity Conservation and Utilization in Mount Emei, Leshan Normal University, Leshan, China
| | - Xingjia Gu
- College of Life Science, Leshan Normal University, Leshan, China
| | - Qi Zhou
- Justices, Equity, Diversity, and Inclusion Department, California Association of Resource Conservation Districts, Folsom, CA, United States
| | - Jiao Huang
- College of Life Science, Leshan Normal University, Leshan, China
- Institution of Biodiversity Conservation and Utilization in Mount Emei, Leshan Normal University, Leshan, China
| | - Zhong Liu
- College of Life Science, Leshan Normal University, Leshan, China
- Institution of Biodiversity Conservation and Utilization in Mount Emei, Leshan Normal University, Leshan, China
| | - Yong Zhou
- College of Life Science, Leshan Normal University, Leshan, China
- Institution of Biodiversity Conservation and Utilization in Mount Emei, Leshan Normal University, Leshan, China
- Academy of Mount Emei, Leshan Normal University, Leshan, China
| | - Ying Zheng
- Research Institution of Industrial Crop, Leshan Academy of Agricultural Sciences, Leshan, China
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Amico Roxas A, Orozco J, Guzmán-Delgado P, Zwieniecki MA. Spring phenology is affected by fall non-structural carbohydrate concentration and winter sugar redistribution in three Mediterranean nut tree species. Tree Physiol 2021; 41:1425-1438. [PMID: 34383074 DOI: 10.1093/treephys/tpab014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 07/03/2020] [Accepted: 01/26/2021] [Indexed: 06/13/2023]
Abstract
Deciduous trees mostly rely on non-structural carbohydrates (NSC-soluble carbohydrates and starch) stored prior to dormancy to sustain both spring bloom and the initial phase of spring growth prior to the transition of leaves from sink to source. Winter management of NSC, their loss due to respiration, reallocation patterns and remobilization during spring, seems to be key to a timely and synchronous bloom. To assess tree dependence on NSC during dormancy, we tested whether the interruption of local branch NSC accumulation prior to dormancy by defoliation and the interruption of NSC translocation by phloem girdling influence spring phenology in three major deciduous Mediterranean nut crop species: Prunus dulcis (Mill.) D.A Webb, a hybrid between Pistacia integerrima (J. L. Stewart ex Brandis) and P. atlantica Desf. (referred to as P. integerrima), and Juglans regia L. Defoliation treatments had different effects on NSC concentration in different species depending on the time of application. However, despite the significant initial impact (increase or decrease of NSC concentration), with time this impact diminished resulting in overall similar concentrations between control and defoliated branches suggesting the presence of NSC reallocation during dormancy. Phloem girdling in P. dulcis and P. integerrima resulted in reduced export activity and greater NSC concentrations, while in J. regia girdling resulted in lower NSC concentrations, indicating that this species requires a net import of NSC during dormancy. Bud break was distinctly delayed by both defoliation and phloem girdling in all the three species, providing evidence of the significant roles that fall NSC accumulation and winter NSC management play in priming trees for spring growth resumption.
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Affiliation(s)
- Adele Amico Roxas
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Jessica Orozco
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Paula Guzmán-Delgado
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Hilman B, Muhr J, Helm J, Kuhlmann I, Schulze ED, Trumbore S. The size and the age of the metabolically active carbon in tree roots. Plant Cell Environ 2021; 44:2522-2535. [PMID: 34096615 DOI: 10.1111/pce.14124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 03/16/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
Little is known about the sources and age of C respired by tree roots. Previous research in stems identified two functional pools of non-structural carbohydrates (NSC): an "active" pool supplied directly from canopy photo-assimilates supporting metabolism and a "stored" pool used when fresh C supplies are limited. We compared the C isotope composition of water-soluble NSC and respired CO2 for aspen roots (Populus tremula hybrids) cut off from fresh C supply after stem-girdling or prolonged incubation of excised roots. We used bomb radiocarbon to estimate the time elapsed since C fixation for respired CO2 , water-soluble NSC and structural α-cellulose. While freshly excised roots (mostly <2.9 mm in diameter) respired CO2 fixed <1 year previously, the age increased to 1.6-2.9 year within a week after root excision. Freshly excised roots from trees girdled ~3 months ago had respiration rates and NSC stocks similar to un-girdled trees but respired older C (~1.2 year). We estimate that over 3 months NSC in girdled roots must be replaced 5-7 times by reserves remobilized from root-external sources. Using a mixing model and observed correlations between Δ14 C of water-soluble C and α-cellulose, we estimate ~30% of C is "active" (~5 mg C g-1 ).
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Affiliation(s)
- Boaz Hilman
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Jan Muhr
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
- Department of Bioclimatology, Georg-August University Göttingen, Göttingen, Germany
| | - Juliane Helm
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Iris Kuhlmann
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Ernst-Detlef Schulze
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Susan Trumbore
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
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Rademacher T, Fonti P, LeMoine JM, Fonti MV, Basler D, Chen Y, Friend AD, Seyednasrollah B, Eckes-Shephard AH, Richardson AD. Manipulating phloem transport affects wood formation but not local nonstructural carbon reserves in an evergreen conifer. Plant Cell Environ 2021; 44:2506-2521. [PMID: 34043242 DOI: 10.1111/pce.14117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 01/23/2021] [Revised: 05/16/2021] [Accepted: 05/18/2021] [Indexed: 06/12/2023]
Abstract
How variations in carbon supply affect wood formation remains poorly understood in particular in mature forest trees. To elucidate how carbon supply affects carbon allocation and wood formation, we attempted to manipulate carbon supply to the cambial region by phloem girdling and compression during the mid- and late-growing season and measured effects on structural development, CO2 efflux and nonstructural carbon reserves in stems of mature white pines. Wood formation and stem CO2 efflux varied with a location relative to treatment (i.e., above or below the restriction). We observed up to twice as many tracheids formed above versus below the treatment after the phloem transport manipulation, whereas the cell-wall area decreased only slightly below the treatments, and cell size did not change relative to the control. Nonstructural carbon reserves in the xylem, needles and roots were largely unaffected by the treatments. Our results suggest that low and high carbon supply affects wood formation, primarily through a strong effect on cell proliferation, and respiration, but local nonstructural carbon concentrations appear to be maintained homeostatically. This contrasts with reports of decoupling of source activity and wood formation at the whole-tree or ecosystem level, highlighting the need to better understand organ-specific responses, within-tree feedbacks, as well as phenological and ontogenetic effects on sink-source dynamics.
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Affiliation(s)
- Tim Rademacher
- School of Informatics, Computing, and Cyber Security, Northern Arizona University, Flagstaff, Arizona, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Patrick Fonti
- Swiss Federal Research Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - James M LeMoine
- School of Informatics, Computing, and Cyber Security, Northern Arizona University, Flagstaff, Arizona, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - Marina V Fonti
- Swiss Federal Research Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Institute of Ecology and Geography, Siberian Federal University, Krasnoyarsk, Russian Federation
| | - David Basler
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Yizhao Chen
- Department of Geography, University of Cambridge, Cambridge, UK
| | - Andrew D Friend
- Department of Geography, University of Cambridge, Cambridge, UK
| | - Bijan Seyednasrollah
- School of Informatics, Computing, and Cyber Security, Northern Arizona University, Flagstaff, Arizona, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | | | - Andrew D Richardson
- School of Informatics, Computing, and Cyber Security, Northern Arizona University, Flagstaff, Arizona, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
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Lievre DL, Anderson R, Boldingh H, Cooney J, Seelye R, Gould N, Hunter D, Jensen D, Pereira T, Wohlers M, Clearwater M, Richardson A. Modifying Carbohydrate Supply to Fruit during Development Changes the Composition and Flavour of Actinidia chinensis var. chinensis 'Zesy002' Kiwifruit. Plants (Basel) 2021; 10:1328. [PMID: 34209861 PMCID: PMC8309063 DOI: 10.3390/plants10071328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 11/26/2022]
Abstract
Consumer acceptance of fruit is determined by size, flavour and ripeness. In this study we investigated how altering the carbohydrate supply to Actinidia chinensis var. chinensis 'Zesy002' kiwifruit altered the balance between growth and accumulation of metabolites. Canes were phloem girdled and fruit thinned to a leaf-to-fruit ratio (L:F) of either 2 (Low carbohydrate) or 6 (High carbohydrate) at either 38 (Early) or 86 (Late) days after anthesis (DAA) and compared with ungirdled control canes with a L:F of 3. Fruit growth, metabolite accumulation, cytokinin concentrations and maturation were monitored and the sensory attributes of ripe fruit were assessed. The final weight of Early-High and Late-High carbohydrate fruit was 38% and 16% greater compared with control fruit. High carbohydrate fruit had increased starch, soluble sugar and cytokinin concentrations and fruit began to mature earlier and those with a Low carbohydrate had decreased concentrations and matured later compared with control fruit. Control fruit were described by consumers as more acidic and under-ripe compared with those from Early-High carbohydrate canes, but as sweeter than those from Low carbohydrate canes. This study showed that carbohydrate supply can have a major impact on the growth, sugar accumulation and maturity of 'Zesy002' fruit sinks.
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Affiliation(s)
- Danielle Le Lievre
- School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; (D.L.L.); (M.C.)
| | - Rachelle Anderson
- Te Puke Research Centre, The New Zealand Institute for Plant & Food Research Limited (PFR), 412 No. 1 Road, RD2, Te Puke 3182, New Zealand; (R.A.); (N.G.)
| | - Helen Boldingh
- PFR, Ruakura Research Centre, Private Bag 3105, Hamilton 3240, New Zealand; (H.B.); (J.C.); (R.S.); (D.J.); (T.P.)
| | - Janine Cooney
- PFR, Ruakura Research Centre, Private Bag 3105, Hamilton 3240, New Zealand; (H.B.); (J.C.); (R.S.); (D.J.); (T.P.)
| | - Richard Seelye
- PFR, Ruakura Research Centre, Private Bag 3105, Hamilton 3240, New Zealand; (H.B.); (J.C.); (R.S.); (D.J.); (T.P.)
| | - Nick Gould
- Te Puke Research Centre, The New Zealand Institute for Plant & Food Research Limited (PFR), 412 No. 1 Road, RD2, Te Puke 3182, New Zealand; (R.A.); (N.G.)
| | - Denise Hunter
- PFR, Mt Albert Research Centre, Private Bag 92169, Auckland 1142, New Zealand; (D.H.); (M.W.)
| | - Dwayne Jensen
- PFR, Ruakura Research Centre, Private Bag 3105, Hamilton 3240, New Zealand; (H.B.); (J.C.); (R.S.); (D.J.); (T.P.)
| | - Trisha Pereira
- PFR, Ruakura Research Centre, Private Bag 3105, Hamilton 3240, New Zealand; (H.B.); (J.C.); (R.S.); (D.J.); (T.P.)
| | - Mark Wohlers
- PFR, Mt Albert Research Centre, Private Bag 92169, Auckland 1142, New Zealand; (D.H.); (M.W.)
| | - Mike Clearwater
- School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; (D.L.L.); (M.C.)
| | - Annette Richardson
- PFR, Kerikeri Research Centre, 121 Keri Downs Road, RD1, Kerikeri 0294, New Zealand
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Oberhuber W, Landlinger-Weilbold A, Schröter DM. Triggering Bimodal Radial Stem Growth in Pinus sylvestris at a Drought-Prone Site by Manipulating Stem Carbon Availability. Front Plant Sci 2021; 12:674438. [PMID: 34122490 PMCID: PMC8193578 DOI: 10.3389/fpls.2021.674438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
A bimodal radial growth (RG) pattern, i.e., growth peaks in spring and autumn, was repeatedly found in trees in the Mediterranean regions, where summer drought causes reduction or cessation of cambial activity. In a dry inner Alpine valley of the Eastern Alps (Tyrol, Austria, 750 m asl), Pinus sylvestris shows unimodal RG with onset and cessation of cambial activity in early April and late June, respectively. A resumption of cambial activity after intense summer rainfall was not observed in this region. In a field experiment, we tested the hypothesis that early cessation of cambial activity at this drought-prone site is an adaptation to limited water availability leading to an early and irreversible switch of carbon (C) allocation to belowground. To accomplish this, the C status of young P. sylvestris trees was manipulated by physical blockage of phloem transport (girdling) 6 weeks after cessation of cambial cell division. Influence of manipulated C availability on RG was recorded by stem dendrometers, which were mounted above the girdling zone. In response to blockage of phloem flow, resumption of cambial activity was detected above girdling after about 2 weeks. Although the experimentally induced second growth surge lasted for the same period as in spring (c. 2 months), the increment was more than twice as large due to doubling of daily maximum RG rate. After girdling, wood anatomical traits above girdling no longer showed any significant differences between earlywood and latewood tracheids indicating pronounced effects of C availability on cell differentiation. Below girdling, no reactivation of cambial activity occurred, but cell wall thickness of last formed latewood cell was reduced due to lack of C supply after girdling. Intense RG resumption after girdling indicates that cessation of cambial activity can be reversed by manipulating C status of the stem. Hence, our girdling study yielded strong support for the hypothesis that belowground organs exert high C sink strengths on the drought-prone study site. Furthermore, this work highlights the need of in-depth experimental studies in order to understand the interactions between endogenous and exogenous factors on cambial activity and xylem cell differentiation more clearly.
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Affiliation(s)
- Walter Oberhuber
- Department of Botany, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
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Wang X, An M, Wang K, Fan H, Shi J, Chen K. Effects of Organic Polymer Compound Material on K + and Na + Distribution and Physiological Characteristics of Cotton Under Saline and Alkaline Stresses. Front Plant Sci 2021; 12:636536. [PMID: 34122466 PMCID: PMC8194489 DOI: 10.3389/fpls.2021.636536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 04/29/2021] [Indexed: 05/05/2023]
Abstract
Soil salinization and alkalization greatly restrict crop growth and yield. In this study, NaCl (8 g kg-1) and Na2CO3 (8 g kg-1) were used to create saline stress and alkaline stress on cotton in pot cultivation in the field, and organic polymer compound material (OPCM) and stem girdling were applied before cotton sowing and at flowering and boll-forming stage, respectively, aiming to determine the effects of OPCM on K+ and Na+ absorption and transport and physiological characteristics of cotton leaf and root. The results showed that after applying the OPCM, the Na+ content in leaf of cotton under saline stress and alkaline stress were decreased by 7.72 and 6.49%, respectively, the K+/Na+ ratio in leaf were increased by 5.65 and 19.10%, respectively, the Na+ content in root were decreased by 9.57 and 0.53%, respectively, the K+/Na+ ratio in root were increased by 65.77 and 55.84%, respectively, and the transport coefficients of K+ and Na+ from leaf to root were increased by 39.59 and 21.38%, respectively. The activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), and the relative electrical conductivity (REC) in cotton leaf were significantly increased, while the content of malondialdehyde (MDA) was decreased; but the changes in those in root were not significant. The boll weights were increased by 11.40 and 13.37%, respectively, compared with those for the control. After stem girdling, the application of OPCM still promoted the ion transport of cotton organs; moreover, the CAT activity in root was increased by 25.09% under saline stress, and the SOD activity in leaf and CAT in root were increased by 42.22 and 6.91%, respectively under alkaline stress. Therefore, OPCM can significantly change the transport of K+ and Na+ to maintain the K+ and Na+ homeostasis in leaf and root, and regulate physiological and biochemical indicators to alleviate the stress-induced damage. Besides, the regulation effect of OPCM on saline stress was better than that on alkaline stress.
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Raiol-Junior LL, Cifuentes-Arenas JC, de Carvalho EV, Girardi EA, Lopes SA. Evidence That ' Candidatus Liberibacter asiaticus' Moves Predominantly Toward New Tissue Growth in Citrus Plants. Plant Dis 2021; 105:34-42. [PMID: 33201785 DOI: 10.1094/pdis-01-20-0158-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
'Candidatus Liberibacter asiaticus' (Las) is an unculturable, phloem-limited, insect-transmitted bacterium associated with the Asiatic form of huanglongbing (HLB), the most destructive citrus disease. In Asia and the Americas, it is transmitted by the Asian citrus psyllid (Diaphorina citri Kuwavama). Despite considerable research, little is known about the processes involved in plant infection and colonization by Las. This study was conducted to determine whether the basal portion (below girdling) of the plant is an important route for Las to move laterally from a point of inoculation on a branch to pathogen-free branches elsewhere in the canopy, and to quantify the influence of actively growing tissues on vertical upward (acropetally) or downward (basipetally) movement of Las. Nongirdled and fully or partially girdled stems of potted plants of 'Pera' sweet orange, graft-inoculated above or below girdling, were sampled in distinct regions and assessed by qPCR, 6 months postinoculation. Las invaded all regions of partially and nongirdled plants but remained restricted to the inoculated regions of fully girdled plants, evidence that in planta bacterium movement is limited to the phloem. In fully girdled plants, starch accumulated above the girdling site, probably because of changes in flow of phloem sap. To study the influence of actively growing tissues, inoculated 'Valencia' sweet orange plants were kept intact or were top- or root-pruned to force production of new tissues, and sampled at 15-day intervals. Las migrated rapidly and most predominantly toward newly developing root and leaf tissues. The rapid and predominant movement of Las to newly developed shoots and roots would explain failures of canopy heat treatments and pruning to cure HLB-affected trees, and reinforces the need to protect rapidly growing new shoots from feeding by D. citri in order to minimize transmission and spread of the pathogen by the vector within and between orchards.
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Affiliation(s)
| | | | | | - Eduardo A Girardi
- Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), Cruz das Almas BA, Brazil
| | - Silvio A Lopes
- Fundo de Defesa da Citricultura (Fundecitrus), Araraquara SP, Brazil
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11
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Parker TC, Clemmensen KE, Friggens NL, Hartley IP, Johnson D, Lindahl BD, Olofsson J, Siewert MB, Street LE, Subke JA, Wookey PA. Rhizosphere allocation by canopy-forming species dominates soil CO 2 efflux in a subarctic landscape. New Phytol 2020; 227:1818-1830. [PMID: 32248524 DOI: 10.1111/nph.16573] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 01/22/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
In arctic ecosystems, climate change has increased plant productivity. As arctic carbon (C) stocks predominantly are located belowground, the effects of greater plant productivity on soil C storage will significantly determine the net sink/source potential of these ecosystems, but vegetation controls on soil CO2 efflux remain poorly resolved. In order to identify the role of canopy-forming species in belowground C dynamics, we conducted a girdling experiment with plots distributed across 1 km2 of treeline birch (Betula pubescens) forest and willow (Salix lapponum) patches in northern Sweden and quantified the contribution of canopy vegetation to soil CO2 fluxes and belowground productivity. Girdling birches reduced total soil CO2 efflux in the peak growing season by 53%, which is double the expected amount, given that trees contribute only half of the total leaf area in the forest. Root and mycorrhizal mycelial production also decreased substantially. At peak season, willow shrubs contributed 38% to soil CO2 efflux in their patches. Our findings indicate that C, recently fixed by trees and tall shrubs, makes a substantial contribution to soil respiration. It is critically important that these processes are taken into consideration in the context of a greening arctic because productivity and ecosystem C sequestration are not synonymous.
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Affiliation(s)
- Thomas C Parker
- Biological and Environmental Sciences, University of Stirling, Stirling,, FK9 4LA, UK
| | - Karina E Clemmensen
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, SE-75007, Sweden
| | - Nina L Friggens
- Biological and Environmental Sciences, University of Stirling, Stirling,, FK9 4LA, UK
| | - Iain P Hartley
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter,, EX4 4RJ, UK
| | - David Johnson
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PT, UK
| | - Björn D Lindahl
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, SE-75007, Sweden
| | - Johan Olofsson
- Department of Ecology and Environmental Sciences, Umeå University, Umeå, SE-901 87, Sweden
| | - Matthias B Siewert
- Department of Ecology and Environmental Sciences, Umeå University, Umeå, SE-901 87, Sweden
| | - Lorna E Street
- School of Geosciences, University of Edinburgh, Edinburgh,, EH9 3FF, UK
| | - Jens-Arne Subke
- Biological and Environmental Sciences, University of Stirling, Stirling,, FK9 4LA, UK
| | - Philip A Wookey
- Biological and Environmental Sciences, University of Stirling, Stirling,, FK9 4LA, UK
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Du W, Pan ZY, Hussain SB, Han ZX, Peng SA, Liu YZ. Foliar Supplied Boron Can Be Transported to Roots as a Boron-Sucrose Complex via Phloem in Citrus Trees. Front Plant Sci 2020; 11:250. [PMID: 32211005 PMCID: PMC7076173 DOI: 10.3389/fpls.2020.00250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/18/2020] [Indexed: 05/07/2023]
Abstract
Although foliar boron (B) fertilization is regarded as an efficient way to remedy B deficiency, the mechanisms of foliar B transport from leaves to roots are still unclear. In this study, performed with 1-year-old "Newhall" navel orange (Citrus sinensis) grafted on trifoliate orange (Poncirus trifoliata) plants, we analyzed the B concentration in leaves and roots, B-sucrose complex in the phloem sap after foliar application of 10B, girdling, and/or shading treatments. Results indicated that 10B concentration was significantly increased in roots after foliar 10B treatment. On the other hand, both girdling the scion stem and shading over the plants with a black plastic net significantly reduced the B and 10B concentration in roots. LC-MS analysis revealed that foliar 10B-treated plants had higher concentration of sucrose and some sugar alcohols in the phloem sap as compared to foliar water-treated plants. Combining with the analysis in the artificial mixture of B and sucrose, a higher peak intensity of the 10B-sucrose complex was found in the phloem sap of foliar 10B-treated plants compared to the control plants. Taken together, it is concluded that foliar B can be long distance transported from leaves to roots via phloem, at least by forming a B-sucrose complex in citrus plants.
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Affiliation(s)
- Wei Du
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Zhi-Yong Pan
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Syed Bilal Hussain
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Zhong-Xing Han
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Shu-Ang Peng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Yong-Zhong Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
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Yin DS, Wu HB, Zhang JY, Ge WZ, Zhou ZJ, Shen HL. [Effects of girdling and defoliation on the growth of female cones and branches and nutrient content in different tissues and organs of Pinus koraiensis.]. Ying Yong Sheng Tai Xue Bao 2019; 30:3671-3680. [PMID: 31833679 DOI: 10.13287/j.1001-9332.201911.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
To explore the nutrient source and supply-demand relationship of the female cone deve-lopment and new shoot growth of Pinus koraiensis, reproductive mother branches were experimentally girdled, defoliated, and under the combination of both treatments. The effects of different treatments on the female cones development, branch growth and the content of carbohydrate (NSC), nitrogen (N) and phosphorus (P) in different tissues and organs were measured. The results showed that girdling significantly affected female cone development, new shoot growth, and the contents of NSC, N and P in different tissues and organs, while defoliation treatment had limited effect. The NSC content in the mother branch xylem and phloem after girdling were significantly lower than that of the control (CK, ungirdling+0% defoliation), and decreased significantly with the increases of the degree of defoliation. The NSC content in mother branch xylem and phloem of girdling+100% defoliation was 59.0% and 64.8% lower than that of CK, respectively. The deficiency of NSC resulted in the death of mother branches and new shoots and the abortion of female cone. Under girdling treatment, the contents of N and P in xylem and phloem of mother branches of 0%, 50% and 100% defoliation treatment were significantly higher than that of CK. The contents of N and P in xylem of mother branches were 17.3%, 18.2% and 24.3% and 17.9%, 7.1% and 3.6% higher than those of CK, respectively. The contents of N and P in phloem of mother branches was 39.3%, 35.2% and 48.9% and 31.0%, 28.2% and 14.8% higher than those of CK, respectively. The female cone development and new shoot growth of P. koraiensis consumed a large amount of NSC, N and P. The carbohydrates and mineral nutrients manufactured or stored in the mother branches could not meet the needs of female cone development and new shoot growth, and thus they need to be imported from other tissues.
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Affiliation(s)
- Dong-Sheng Yin
- Forestry Research Institute of Heilongjiang Province, Harbin 150081, China
| | - Hai-Bo Wu
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Jian-Ying Zhang
- Forestry Research Institute of Heilongjiang Province, Harbin 150081, China
| | - Wen-Zhi Ge
- Forestry Research Institute of Heilongjiang Province, Harbin 150081, China
| | - Zhi-Jun Zhou
- Forestry Research Institute of Heilongjiang Province, Harbin 150081, China
| | - Hai-Long Shen
- School of Forestry, Northeast Forestry University, Harbin 150040, China
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Lachenbruch B, Zhao JP. Effects of phloem on canopy dieback, tested with manipulations and a canker pathogen in the Corylus avellana/Anisogramma anomala host/pathogen system. Tree Physiol 2019; 39:1086-1098. [PMID: 30938425 DOI: 10.1093/treephys/tpz027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [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: 10/23/2018] [Revised: 02/18/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Canker pathogens cause necrosis of the phloem, but in many host/pathogen systems, they also cause canopy dieback, which implicates xylem, not phloem dysfunction. We hypothesize that this dieback distal to the canker is caused by water stress resulting from the lack of a phloem-to-xylem connection, which in a healthy plant would allow delivery of nonstructural carbohydrates (NSCs) and water inward to aid in xylem embolism refilling. We tested several components of this hypothesis in the host/pathogen system Corylus avellana L./Anisogramma anomala (Peck) E. Müll (Eastern filbert blight). Cankers were non-girdling and usually ≥0.1 m long. As expected, healthy controls had higher specific conductivity (Ks) than diseased stems, but unexpectedly, had similar moisture content (m.c.), showing that the lower Ks did not result from more embolisms in the diseased stems. Moreover, manipulations that removed cambium and phloem to simulate a canker, or that shaded stems to lower NSCs, did not result in lower Ks or m.c. than controls. The outer millimeter of xylem adjacent to a canker had infrequent tyloses and/or fungal hyphae in many but not all samples, and dye studies showed little xylem water transport in that region, but the incidence of these blockages was insufficient to cause the observed 19% decrease in Ks. Healthy stems had higher m.c. than diseased stems above the canker (or analogous) location and were longer for the same leaf weight, suggestive of water stress in the upper portion of diseased stems. These results suggest that dieback distal to cankers in this system results from the bottleneck in water transport in the region adjacent to a canker, but did not find evidence to support the requirement of a phloem-to-xylem connection for continued water transport.
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Affiliation(s)
- B Lachenbruch
- Department of Forest Ecosystems & Society, Oregon State University, OR
| | - Jia-Ping Zhao
- State Key Laboratory of Tree Genetics and Breeding, Forestry Institute of New Technology, Chinese Academy of Forestry, Beijing, China
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15
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Aubrey DP, Teskey RO. Stored root carbohydrates can maintain root respiration for extended periods. New Phytol 2018; 218:142-152. [PMID: 29281746 DOI: 10.1111/nph.14972] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/29/2017] [Indexed: 05/17/2023]
Abstract
Tight coupling between below-ground autotrophic respiration and the availability of recently assimilated carbon (C) has become a paradigm in the ecophysiological literature. Here, we show that stored carbohydrates can decouple respiration from assimilation for prolonged periods by mobilizing reserves from transport roots to absorptive roots. We permanently disrupted the below-ground transfer of recently assimilated C using stem girdling and root trenching and measured soil CO2 efflux for over 1 yr in longleaf pine (Pinus palustris), a species that has large reserves of stored carbohydrates in roots. Soil CO2 efflux was not influenced by girdling or trenching through the 14-month observation period. Stored carbohydrate concentrations in absorptive roots were not affected by the disrupted supply of current photosynthate for over 1 yr; however, carbohydrate concentrations in transport roots decreased. Our results indicate that root respiration can be decoupled from recent canopy assimilation and that stored carbohydrates can be mobilized from transport roots to absorptive roots to maintain respiration for over 1 yr. This refines the current paradigm that canopy assimilation and below-ground respiration are tightly coupled and provides evidence of the mechanism and dynamics responsible for decoupling the above- and below-ground processes.
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Affiliation(s)
- Doug P Aubrey
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Robert O Teskey
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
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16
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Rainer-Lethaus G, Oberhuber W. Phloem Girdling of Norway Spruce Alters Quantity and Quality of Wood Formation in Roots Particularly Under Drought. Front Plant Sci 2018; 9:392. [PMID: 29636766 PMCID: PMC5881222 DOI: 10.3389/fpls.2018.00392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/12/2018] [Indexed: 05/31/2023]
Abstract
Carbon (C) availability plays an essential role in tree growth and wood formation. We evaluated the hypothesis that a decrease in C availability (i) triggers mobilization of C reserves in the coarse roots of Picea abies to maintain growth and (ii) causes modification of wood structure notably under drought. The 6-year-old saplings were subjected to two levels of soil moisture (watered versus drought conditions) and root C status was manipulated by physically blocking phloem transport in the stem at three girdling dates (GDs). Stem girdling was done before the onset of bud break [day of the year (doy) 77], during vigorous aboveground shoot and radial stem growth (GD doy 138), and after cessation of shoot growth (GD doy 190). The effect of blockage of C transport on root growth, root phenology, and wood anatomical traits [cell lumen diameter (CLD) and cell wall thickness (CWT)] in earlywood (EW) and latewood (LW) was determined. To evaluate changes in belowground C status caused by girdling, non-structural carbohydrates (soluble sugars and starch) in coarse roots were determined at the time of girdling and after the growing season. Although fine root mass significantly decreased in response to blockage of phloem C transport, the phenology of root elongation growth was not affected. Surprisingly, radial root growth and CLD of EW tracheids in coarse roots were strikingly increased in drought-stressed trees, when girdling occurred before bud break or during aboveground stem growth. In watered trees, the growth response to girdling was less distinct, but the CWT of EW significantly increased. Starch reserves in the roots of girdled trees significantly decreased in both soil moisture treatments and at all GDs. We conclude that (i) radial growth and wood development in coarse roots of P. abies saplings are not only dependent on current photosynthates, and (ii) blockage of phloem transport induces physiological changes that outweigh drought effects imposed on root cambial activity and cell differentiation.
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Affiliation(s)
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
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17
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Mitchell PJ, McAdam SAM, Pinkard EA, Brodribb TJ. Significant contribution from foliage-derived ABA in regulating gas exchange in Pinus radiata. Tree Physiol 2017; 37:236-245. [PMID: 28399262 DOI: 10.1093/treephys/tpw092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 04/21/2016] [Accepted: 08/20/2016] [Indexed: 06/07/2023]
Abstract
The complex regulatory system controlling stomata involves physical and chemical signals that affect guard cell turgor to bring about changes in stomatal conductance (gs). Abscisic acid (ABA) closes stomata, yet the mechanisms controlling foliar ABA status in tree species remain unclear. The importance of foliage-derived ABA in regulating gas exchange was evaluated under treatments that affected phloem export through girdling and reduced water availability in the tree species, Pinus radiata (D. Don). Branch- and whole-plant girdling increased foliar ABA levels leading to declines in gs, despite no change in plant water status. Changes in gs were largely independent of the more transient increases in foliar non-structural carbohydrates (NSC), suggesting that gradual accumulation of foliar ABA was the primary mechanism for reductions in gs and assimilation. Whole-plant girdling eventually reduced root NSC, hindering root water uptake and decreasing foliar water potential, causing a dramatic increase in ABA level in leaves and concentrations in the xylem sap of shoots (4032 ng ml-1), while root xylem sap concentrations remained low (43 ng ml-1). Contrastingly, the drought treatment caused similar increases in xylem sap ABA in both roots and shoots, suggesting that declines in water potential result in relatively consistent changes in ABA along the hydraulic pathway. ABA levels in plant canopies can be regulated independently of changes in root water status triggered by changes by both phloem export and foliar water status.
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Affiliation(s)
| | - Scott A M McAdam
- School of Biological Sciences, University of Tasmania, College Rd, Hobart, Tasmania 7005, Australia
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18
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Abstract
Plant susceptibility to herbivore attack is determined not just by the suite of defenses present in different tissues of the plant, but also by the capabilities of the herbivore for tolerating, circumventing, or disarming the defenses. This article reviews the elaborate behaviors exhibited by leaf-chewing insects that appear to function specifically to deactivate hostplant defenses. Shortcomings in our understanding and promising areas for future research are highlighted. Behaviors covered include vein cutting, trenching, girdling, leaf clipping, and application of fluids from exocrine glands. Many of these behaviors have a widespread distribution, having evolved independently in multiple insect lineages. Insects utilizing the behaviors include significant agricultural, horticultural, and forestry pests, as well as numerous species important in natural ecosystems. Behavioral, ecological, and phylogenetic studies have documented the importance of the behaviors and their ancient history, but the molecular analysis of how the behaviors affect plant physiology has scarcely begun.
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Affiliation(s)
- David E Dussourd
- Department of Biology, University of Central Arkansas, Conway, Arkansas, 72035;
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Henriksson N, Tarvainen L, Lim H, Tor-Ngern P, Palmroth S, Oren R, Marshall J, Näsholm T. Stem compression reversibly reduces phloem transport in Pinus sylvestris trees. Tree Physiol 2015; 35:1075-1085. [PMID: 26377876 DOI: 10.1093/treephys/tpv078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 03/13/2015] [Accepted: 07/28/2015] [Indexed: 06/05/2023]
Abstract
Manipulating tree belowground carbon (C) transport enables investigation of the ecological and physiological roles of tree roots and their associated mycorrhizal fungi, as well as a range of other soil organisms and processes. Girdling remains the most reliable method for manipulating this flux and it has been used in numerous studies. However, girdling is destructive and irreversible. Belowground C transport is mediated by phloem tissue, pressurized through the high osmotic potential resulting from its high content of soluble sugars. We speculated that phloem transport may be reversibly blocked through the application of an external pressure on tree stems. Thus, we here introduce a technique based on compression of the phloem, which interrupts belowground flow of assimilates, but allows trees to recover when the external pressure is removed. Metal clamps were wrapped around the stems and tightened to achieve a pressure theoretically sufficient to collapse the phloem tissue, thereby aiming to block transport. The compression's performance was tested in two field experiments: a (13)C canopy labelling study conducted on small Scots pine (Pinus sylvestris L.) trees [2-3 m tall, 3-7 cm diameter at breast height (DBH)] and a larger study involving mature pines (∼15 m tall, 15-25 cm DBH) where stem respiration, phloem and root carbohydrate contents, and soil CO2 efflux were measured. The compression's effectiveness was demonstrated by the successful blockage of (13)C transport. Stem compression doubled stem respiration above treatment, reduced soil CO2 efflux by 34% and reduced phloem sucrose content by 50% compared with control trees. Stem respiration and soil CO2 efflux returned to normal within 3 weeks after pressure release, and (13)C labelling revealed recovery of phloem function the following year. Thus, we show that belowground phloem C transport can be reduced by compression, and we also demonstrate that trees recover after treatment, resuming C transport in the phloem.
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Affiliation(s)
- Nils Henriksson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Lasse Tarvainen
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Hyungwoo Lim
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Pantana Tor-Ngern
- Department of Environmental Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Sari Palmroth
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, USA
| | - Ram Oren
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, USA
| | - John Marshall
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden Department of Forest, Rangeland, and Fire Sciences, University of Idaho, 875 Perimeter Drive, Moscow, ID 83844-1133, USA
| | - Torgny Näsholm
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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Brzostek ER, Dragoni D, Brown ZA, Phillips RP. Mycorrhizal type determines the magnitude and direction of root-induced changes in decomposition in a temperate forest. New Phytol 2015; 206:1274-82. [PMID: 25627914 DOI: 10.1111/nph.13303] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [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: 09/18/2014] [Accepted: 12/24/2014] [Indexed: 05/27/2023]
Abstract
Although it is increasingly being recognized that roots play a key role in soil carbon (C) dynamics, the magnitude and direction of these effects are unknown. Roots can accelerate soil C losses by provisioning microbes with energy to decompose organic matter or impede soil C losses by enhancing microbial competition for nutrients. We experimentally reduced belowground C supply to soils via tree girdling, and contrasted responses in control and girdled plots for three consecutive growing seasons. We hypothesized that decreases in belowground C supply would have stronger effects in plots dominated by ectomycorrhizal (ECM) trees rather than arbuscular mycorrhizal (AM) trees. In ECM-dominated plots, girdling decreased the activity of enzymes that break down soil organic matter (SOM) by c. 40%, indicating that, in control plots, C supply from ECM roots primes microbial decomposition. In AM-dominated plots, girdling had little effect on SOM-degrading enzymes, but increased the decomposition of AM leaf litter by c. 43%, suggesting that, in control plots, AM roots may intensify microbial competition for nutrients. Our findings indicate that root-induced changes in soil processes depend on forest composition, and that shifts in the distribution of AM and ECM trees owing to climate change may determine soil C gains and losses.
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Affiliation(s)
- Edward R Brzostek
- Department of Biology, West Virginia University, Morgantown, WV, 26506, USA
| | - Danilo Dragoni
- Department of Geography, Indiana University, Bloomington, IN, 47405, USA
| | - Zachary A Brown
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
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Hanssens J, DE Swaef T, Steppe K. High light decreases xylem contribution to fruit growth in tomato. Plant Cell Environ 2015; 38:487-98. [PMID: 25039478 DOI: 10.1111/pce.12411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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: 08/27/2012] [Accepted: 06/27/2014] [Indexed: 05/09/2023]
Abstract
Recently, contradicting evidence has been reported on the contribution of xylem and phloem influx into tomato fruits, urging the need for a better understanding of the mechanisms involved in fruit growth. So far, little research has been performed on quantifying the effect of light intensity on the different contributors to the fruit water balance. However, as light intensity affects both transpiration and photosynthesis, it might be expected to induce important changes in the fruit water balance. In this study, tomato plants (Solanum lycopersicum L.) were grown in light and shade conditions and the fruit water balance was studied by measuring fruit growth of girdled and intact fruits with linear variable displacement transducers combined with a model-based approach. Results indicated that the relative xylem contribution significantly increased when shading lowered light intensity. This resulted from both a higher xylem influx and a lower phloem influx during the daytime. Plants from the shade treatment were able to maintain a stronger gradient in total water potential between stem and fruits during daytime, thereby promoting xylem influx. It appeared that the xylem pathway was still functional at 35 days after anthesis and that relative xylem contribution was strongly affected by environmental conditions.
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Affiliation(s)
- Jochen Hanssens
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Gent, Belgium
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Abstract
For almost a century the plant hormone auxin has been central to theories on apical dominance, whereby the growing shoot tip suppresses the growth of the axillary buds below. According to the classic model, the auxin indole-3-acetic acid is produced in the shoot tip and transported down the stem, where it inhibits bud growth. We report here that the initiation of bud growth after shoot tip loss cannot be dependent on apical auxin supply because we observe bud release up to 24 h before changes in auxin content in the adjacent stem. After the loss of the shoot tip, sugars are rapidly redistributed over large distances and accumulate in axillary buds within a timeframe that correlates with bud release. Moreover, artificially increasing sucrose levels in plants represses the expression of BRANCHED1 (BRC1), the key transcriptional regulator responsible for maintaining bud dormancy, and results in rapid bud release. An enhancement in sugar supply is both necessary and sufficient for suppressed buds to be released from apical dominance. Our data support a theory of apical dominance whereby the shoot tip's strong demand for sugars inhibits axillary bud outgrowth by limiting the amount of sugar translocated to those buds.
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Affiliation(s)
- Michael G. Mason
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - John J. Ross
- School of Plant Science, University of Tasmania, Sandy Bay, TAS 7005, Australia; and
| | - Benjamin A. Babst
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973-5000
| | | | - Christine A. Beveridge
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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Bloemen J, Agneessens L, Van Meulebroek L, Aubrey DP, McGuire MA, Teskey RO, Steppe K. Stem girdling affects the quantity of CO2 transported in xylem as well as CO2 efflux from soil. New Phytol 2014; 201:897-907. [PMID: 24400900 DOI: 10.1111/nph.12568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [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: 07/31/2013] [Accepted: 09/26/2013] [Indexed: 05/24/2023]
Abstract
There is recent clear evidence that an important fraction of root-respired CO2 is transported upward in the transpiration stream in tree stems rather than fluxing to the soil. In this study, we aimed to quantify the contribution of root-respired CO2 to both soil CO2 efflux and xylem CO2 transport by manipulating the autotrophic component of belowground respiration. We compared soil CO2 efflux and the flux of root-respired CO2 transported in the transpiration stream in girdled and nongirdled 9-yr-old oak trees (Quercus robur) to assess the impact of a change in the autotrophic component of belowground respiration on both CO2 fluxes. Stem girdling decreased xylem CO2 concentration, indicating that belowground respiration contributes to the aboveground transport of internal CO2 . Girdling also decreased soil CO2 efflux. These results confirmed that root respiration contributes to xylem CO2 transport and that failure to account for this flux results in inaccurate estimates of belowground respiration when efflux-based methods are used. This research adds to the growing body of evidence that efflux-based measurements of belowground respiration underestimate autotrophic contributions.
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Affiliation(s)
- Jasper Bloemen
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Coupure links 653, 9000, Gent, Belgium
| | - Laura Agneessens
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Coupure links 653, 9000, Gent, Belgium
| | - Lieven Van Meulebroek
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Doug P Aubrey
- Department of Biology, Georgia Southern University, PO Box 8042, Statesboro, GA, 30460-8042, USA
| | - Mary Anne McGuire
- Warnell School of Forestry and Natural Resources, University of Georgia, 180 East Green St, Athens, GA, 30602-2152, USA
| | - Robert O Teskey
- Warnell School of Forestry and Natural Resources, University of Georgia, 180 East Green St, Athens, GA, 30602-2152, USA
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Coupure links 653, 9000, Gent, Belgium
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24
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Abstract
In boreal forests, seedling establishment is limited by various factors including soil nitrogen (N) availability. Seedlings may absorb N from soil in a variety of inorganic and organic forms; however, the energy and thus carbohydrate requirements for uptake and assimilation of N vary with N source. We studied the importance of current photoassimilates for the acquisition and allocation of different N sources by Scots pine (Pinus sylvestris (L.)) seedlings. Girdling was used as a tool to impair phloem transport of photoassimilates, and hence gradually deprive roots of carbohydrates. Seedlings were cultivated in a greenhouse on equimolar N concentrations of one of the N sources-arginine, ammonium or nitrate-and then girdled prior to a pulse-chase uptake experiment with isotopically labeled N sources. Girdling proved to be efficient in decreasing levels of soluble sugars and starch in the roots. Uptake rate of arginine N was highest, intermediate for ammonium N and lowest for nitrate N. Moreover, the uptake of arginine N was unaffected by girdling, while the uptake of the two inorganic N sources decreased to 45-56% of the ungirdled controls. In arginine-treated seedlings, 95-96% of the acquired arginine N resided in the roots, whereas a significant shift in the N distribution toward the shoot was evident in girdled seedlings treated with inorganic N. This spatial shift was especially pronounced in nitrate-treated seedlings suggesting that the reduction and following incorporation into roots was limited by the availability of current photoassimilates. These results suggest that there are energetic benefits for seedlings to utilize organic N sources, particularly under circumstances where carbohydrate supply is limited. Hence, these putative benefits might be of importance for the survival and growth of seedlings when carbohydrate reserves are depleted in early growing season, or in light-limited environments, such as those sustained by continuous cover forestry systems.
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Affiliation(s)
- Linda Gruffman
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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25
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De Schepper V, Steppe K. Tree girdling responses simulated by a water and carbon transport model. Ann Bot 2011; 108:1147-54. [PMID: 21478174 PMCID: PMC3189833 DOI: 10.1093/aob/mcr068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [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: 12/26/2010] [Accepted: 02/10/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Girdling, or the removal of a strip of bark around a tree's outer circumference, is often used to study carbon relationships, as it triggers several carbon responses which seem to be interrelated. METHODS An existing plant model describing water and carbon transport in a tree was used to evaluate the mechanisms behind the girdling responses. Therefore, the (un)loading functions of the original model were adapted and became a function of the phloem turgor pressure. KEY RESULTS The adapted model successfully simulated the measured changes in stem growth induced by girdling. The model indicated that the key driving variables for the girdling responses were changes in turgor pressure due to local changes in sugar concentrations. Information about the local damage to the phloem system was transferred to the other plant parts (crown and roots) by a change in phloem pressure. After girdling, the loading rate was affected and corresponded to the experimentally observed feedback inhibition. In addition, the unloading rate decreased after girdling and even reversed in some instances. The model enabled continuous simulation of changes in starch content, although a slight underestimation was observed compared with measured values. CONCLUSIONS For the first time a mechanistic plant model enabled simulation of tree girdling responses, which have thus far only been experimentally observed and fragmentally reported in literature. The close agreement between measured and simulated data confirms the underlying mechanisms introduced in the model.
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Affiliation(s)
- Veerle De Schepper
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
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26
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Isogimi T, Matsushita M, Watanabe Y, Nakagawa M. Sexual differences in physiological integration in the dioecious shrub Lindera triloba: a field experiment using girdling manipulation. Ann Bot 2011; 107:1029-37. [PMID: 21385778 PMCID: PMC3080626 DOI: 10.1093/aob/mcr043] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 01/06/2011] [Accepted: 01/24/2011] [Indexed: 05/26/2023]
Abstract
BACKGROUND AND AIMS It is important to consider the modular level when verifying sexual dimorphism in dioecious plants. Nevertheless, between-sex differences in resource translocation among modules (i.e. physiological integration) have not been tested at the whole-plant level. In this study, sexual differences in physiological integration were examined among ramets, within a genet in the dioecious sprouting shrub Lindera triloba, by a field experiment with girdling manipulation. METHODS Female and male genets were randomly assigned to girdled or intact groups. Girdling of the main ramets was conducted in May 2009 by removing a ring of bark and cambium approx. 1 cm wide at a height of 80-100 cm. The effects of treatment and sex on ramet dynamics (mortality, recruitment and diameter growth) and inflorescence production during 1 year after girdling were examined. KEY RESULTS The diameter growth rate of main ramets of both sexes was lower at ground level (D(0)) but higher at breast height (dbh) in girdled than in intact groups. In sprouted ramets with a dbh of 0-2 cm, males in girdled groups had lower growth rates at D(0) than those of intact groups, whereas no girdling effect was found for females. The main ramets in girdled groups produced more inflorescences than intact groups, irrespective of sex, but male ramets showed a greater response to the treatment than females. CONCLUSIONS In L. triloba, physiological integration exists at the whole-plant level, and sprouted ramets are dependent on assimilates translocated from main ramets, but this dependence weakens as sprouted ramets get larger. Female sprouted ramets can grow in a physiologically independent manner from the main ramet earlier than those of males. This study highlights the importance of considering modular structures and physiological integration when evaluating sexual differences in demographic patterns of clonal plants.
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Affiliation(s)
- Tomohiro Isogimi
- Laboratory of Forest Ecology and Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan.
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27
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Kaiser C, Frank A, Wild B, Koranda M, Richter A. Negligible contribution from roots to soil-borne phospholipid fatty acid fungal biomarkers 18:2ω6,9 and 18:1ω9. Soil Biol Biochem 2010; 42:1650-1652. [PMID: 21633516 PMCID: PMC2928450 DOI: 10.1016/j.soilbio.2010.05.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 05/11/2010] [Accepted: 05/18/2010] [Indexed: 05/05/2023]
Abstract
The phospholipid fatty acid biomarkers 18:1ω9, 18:2ω6,9 and 18:3ω3,6,9 are commonly used as fungal biomarkers in soils. They have, however, also been found to occur in plant tissues, such as roots. Thus, the use of these PLFAs as fungal biomarkers in sieved soil, which may still contain small remains of roots, has been questioned. We used data from a recent beech tree girdling experiment to calculate the contribution of roots to these biomarkers and were able to demonstrate that not more than 0.61% of 18:1ω9 and 18:2ω6,9 in sieved soil samples originated from roots (but 4% of 18:3ω3,6,9). Additionally, the abundance of the biomarker 18:2ω6,9 in the soil was found to be highly correlated to ectomycorrhizal root colonization, which further corroborates its fungal origin. PLFA biomarkers were substantially reduced in vital roots from girdled trees compared to roots of control trees (by up to 76%), indicating that the major part of PLFAs measured in roots may actually originate from ectomycorrhizal fungi growing inside the roots. We calculated, that even a near to 50% reduction in fine root biomass - as observed in the girdling treatment - accounted for only 0.8% of the measured decrease of 18:2ω6,9. Our results demonstrate that both 18:1ω9 and 18:2ω6,9 are suitable biomarkers for detecting fungal dynamics in soils and that especially 18:2ω6,9 is a reliable biomarker to study mycorrhizal dynamics in beech forests.
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28
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Kaiser C, Koranda M, Kitzler B, Fuchslueger L, Schnecker J, Schweiger P, Rasche F, Zechmeister-Boltenstern S, Sessitsch A, Richter A. Belowground carbon allocation by trees drives seasonal patterns of extracellular enzyme activities by altering microbial community composition in a beech forest soil. New Phytol 2010; 187:843-58. [PMID: 20553392 PMCID: PMC2916209 DOI: 10.1111/j.1469-8137.2010.03321.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 04/23/2010] [Indexed: 05/17/2023]
Abstract
*Plant seasonal cycles alter carbon (C) and nitrogen (N) availability for soil microbes, which may affect microbial community composition and thus feed back on microbial decomposition of soil organic material and plant N availability. The temporal dynamics of these plant-soil interactions are, however, unclear. *Here, we experimentally manipulated the C and N availability in a beech forest through N fertilization or tree girdling and conducted a detailed analysis of the seasonal pattern of microbial community composition and decomposition processes over 2 yr. *We found a strong relationship between microbial community composition and enzyme activities over the seasonal course. Phenoloxidase and peroxidase activities were highest during late summer, whereas cellulase and protease peaked in late autumn. Girdling, and thus loss of mycorrhiza, resulted in an increase in soil organic matter-degrading enzymes and a decrease in cellulase and protease activity. *Temporal changes in enzyme activities suggest a switch of the main substrate for decomposition between summer (soil organic matter) and autumn (plant litter). Our results indicate that ectomycorrhizal fungi are possibly involved in autumn cellulase and protease activity. Our study shows that, through belowground C allocation, trees significantly alter soil microbial communities, which may affect seasonal patterns of decomposition processes.
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Affiliation(s)
- Christina Kaiser
- University of Vienna, Department of Chemical Ecology and Ecosystem Research, Vienna, Austria.
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29
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Abstract
Foliar and soil-drench insecticide treatments were used in attempts to manipulate infestation of cultivated sunflower plants, Helianthus annuus LeConte (Asterales: Asteraceae) by Dectes texanus LeConte, (Coleoptera: Cerambycidae) a serious pest of sunflowers in the High Plains of the USA. Seed yields were assessed on a per-plant basis for both oilseed and confection type sunflower hybrids in two years. Both insecticide treatments (foliar ë-cyhalothrin and soil-drench carbofuran) improved yield of oilseed sunflowers in 2004, but not in 2005. Yield of confection hybrids was improved by a systemic fungicide (thiophanate methyl) in 2005, but insecticides did not improve yield in either year. Both insecticide treatments gave good control of various stalk-boring insects such as Cylindrocopturus adspersus (Coleoptera: Curculionidae), Mordellistena sp. (Coleoptera: Mordellidae), and Pelochrista womanana (Lepidoptera: Tortricidae), but neither gave better than 50% control of D. texanus. Plants were sorted according to the presence or absence of D. texanus larvae and no reduction was found in total seed weight, seed size, or oil content as a result of infestation. However, mature larvae of D. texanus girdle stalks at the base in preparation for overwintering, a behavior that reduced stalk breakage force by 34-40%, leading to yield losses through lodging. At harvest in 2005, there were differences between cultivars and among treatments in the proportions of D. texanus larvae that had girdled their plants at harvest. It was concluded that further research aimed at reducing crop losses to D. texanus should focus on means of delaying stalk desiccation and/or deterioration, factors that appear to trigger girdling behavior.
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Affiliation(s)
- J P Michaud
- Kansas State University, Agricultural Research Center - Hays, Hays, KS 67601, USA.
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30
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LI CHUN, WEISS DAVID, GOLDSCHMIDT ELIEZERE. Girdling affects carbohydrate-related gene expression in leaves, bark and roots of alternate-bearing citrus trees. Ann Bot 2003; 92:137-43. [PMID: 12763756 PMCID: PMC4243633 DOI: 10.1093/aob/mcg108] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Effects of girdling on carbohydrate status and carbohydrate-related gene expression in citrus trees were investigated. Alternate-bearing 'Murcott' (a Citrus reticulata hybrid of unknown origin) trees were girdled during autumn (25 Sep. 2001) and examined 10 weeks later. Girdling brought about carbohydrate (soluble sugar and starch) accumulation in leaves and shoot bark above the girdle, in trees during their fruitless, 'off' year. Trees during their heavy fruit load, 'on' year did not accumulate carbohydrates above the girdle due to the high demand for carbohydrates by the developing fruit. Girdling caused a strong decline in soluble sugar and starch concentrations in organs below the girdle (roots), in both 'on' and 'off' trees. Expression of STPH-L and STPH-H (two isoforms of starch phosphorylase), Agps (ADP-glucose pyrophosphorylase, small subunit), AATP (plastidic ADP/ATP transporter), PGM-C (phosphoglucomutase) and CitSuS1 (sucrose synthase), all of which are associated with starch accumulation, was studied. It was found that gene expression is related to starch accumulation in all 'off' tree organs. RNA levels of all the genes examined were high in leaves and bark that accumulated high concentrations of starch, and low in roots with declining starch concentrations. It may be hypothesized that changes in specific sugars signal the up- and down-regulation of genes involved in starch synthesis.
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Affiliation(s)
- CHUN‐YAO LI
- The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - DAVID WEISS
- The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - ELIEZER E. GOLDSCHMIDT
- The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
- * For correspondence. E‐mail
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Sullivan TP, Klenner W. Influence of Diversionary Food on Red Squirrel Populations and Damage to Crop Trees in Young Lodgepole Pine Forest. Ecol Appl 1993; 3:708-718. [PMID: 27759310 DOI: 10.2307/1942102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study was designed to test the hypothesis that large-scale provision of diversionary food (sunflower seeds) would reduce red squirrel (Tamiasciurus hudsonicus) feeding damage to lodgepole pine (Pinus contorta) crop trees. Study areas with managed lodgepole pine stands were located near Vernon and Quesnel in south-central British Columbia, Canada. Large-scale applications of sunflower seeds were conducted on a manual basis in 1989, and by manual and aerial means in 1990, and an operational level by aerial means in 1991. Feeding damage to crop trees was assessed in control and treatment blocks. Populations of the red squirrel, northwestern chipmunk (Eutamias amoenus), and Columbian ground squirrel (Spermophilus columbianus) were sampled intensively by live-trapping on control and treatment blocks in 1990. Manual application of seed (clumped distribution) significantly reduced damage in the treatment block (11.3% of trees damaged) compared with the control (57.5% of trees damaged). Aerial application of seed (uniform distribution) also significantly reduced damage in replicated treatment vs. control blocks. Provision of diversionary food resulted in a temporary increase in the overall number of red squirrels caught on the treatment areas followed by a return to control levels within 6 wk. This increase was primarily the result of an increased number of transients in the trapped sample. The population density of resident (transients excluded) red squirrels did not increase when diversionary food was added. Similarly, we could not detect differences in reproduction, body masses, or survival of squirrels between control and food-supplemented areas. Northwestern chipmunks and Columbian ground squirrels also showed a temporary increase in density when food was added. Application of sunflower seed on an operational basis significantly reduced damage by squirrels in replicated study areas covering three different forest ecological zones. Provision of diversionary food is an effective strategy to protect intensively managed stands of lodgepole pine from red squirrel feeding damage.
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