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Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio

Tree source-sink ratio has a predominant and complex impact on tree performance and can affect multiple physiological processes including vegetative and reproductive growth, water and nutrient use, photosynthesis, and productivity. In this study, we manipulated the branch level source-sink ratio by...

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Autores principales: Marino, Giulia, Guzmán-Delgado, Paula, Santos, Emily, Adaskaveg, Jaclyn A., Blanco-Ulate, Bárbara, Ferguson, Louise, Zwieniecki, Maciej A., Fernández-Suela, Eduardo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10436215/
https://www.ncbi.nlm.nih.gov/pubmed/37600173
http://dx.doi.org/10.3389/fpls.2023.1194177
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author Marino, Giulia
Guzmán-Delgado, Paula
Santos, Emily
Adaskaveg, Jaclyn A.
Blanco-Ulate, Bárbara
Ferguson, Louise
Zwieniecki, Maciej A.
Fernández-Suela, Eduardo
author_facet Marino, Giulia
Guzmán-Delgado, Paula
Santos, Emily
Adaskaveg, Jaclyn A.
Blanco-Ulate, Bárbara
Ferguson, Louise
Zwieniecki, Maciej A.
Fernández-Suela, Eduardo
author_sort Marino, Giulia
collection PubMed
description Tree source-sink ratio has a predominant and complex impact on tree performance and can affect multiple physiological processes including vegetative and reproductive growth, water and nutrient use, photosynthesis, and productivity. In this study, we manipulated the branch level source-sink ratio by reduction of photosynthetic activity (partial branch defoliation) or thinning branch fruit load early in the growing season (after fruit set) in pistachio (Pistacia vera) trees. We then characterized the leaf photosynthetic light response curves through leaf aging. In addition, we determined changes in leaf non-structural carbohydrates (NSC) and nitrogen (N) concentrations. In leaves with high source-sink ratios, there was a gradual decrease in maximum net photosynthetic rate (A(Nmax)) over the growing season, while in branches with low source-sink ratios, there was a sharp decline in A(Nmax) in the first two weeks of August. Branches with high-sink showed an up-regulation (increase) in photosynthesis toward the end of July (at 1,500 growing degree days) during the period of rapid kernel growth rate and increased sink strength, with A(Nmax) being about 7 μmol m(-1) s(-1) higher than in branches with low-sink. In August, low source-sink ratios precipitated leaf senescence, resulting in a drastic A(Nmax) decline, from 25 to 8 μmol m(-1) s(-1) (70% drop in two weeks). This reduction was associated with the accumulation of NSC in the leaves from 20 to 30 mg g(-1). The mechanisms of A(Nmax) reduction differ between the two treatments. Lower photosynthetic rates of 8-10 μmol m(-1) s(-1) late in the season were associated with lower N levels in high-sink branches, suggesting N remobilization to the kernels. Lower photosynthesis late in the season was associated with lower respiration rates in low-source branches, indicating prioritization of assimilates to storage. These results can facilitate the adaptation of management practices to tree crop load changes in alternate bearing species.
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spelling pubmed-104362152023-08-19 Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio Marino, Giulia Guzmán-Delgado, Paula Santos, Emily Adaskaveg, Jaclyn A. Blanco-Ulate, Bárbara Ferguson, Louise Zwieniecki, Maciej A. Fernández-Suela, Eduardo Front Plant Sci Plant Science Tree source-sink ratio has a predominant and complex impact on tree performance and can affect multiple physiological processes including vegetative and reproductive growth, water and nutrient use, photosynthesis, and productivity. In this study, we manipulated the branch level source-sink ratio by reduction of photosynthetic activity (partial branch defoliation) or thinning branch fruit load early in the growing season (after fruit set) in pistachio (Pistacia vera) trees. We then characterized the leaf photosynthetic light response curves through leaf aging. In addition, we determined changes in leaf non-structural carbohydrates (NSC) and nitrogen (N) concentrations. In leaves with high source-sink ratios, there was a gradual decrease in maximum net photosynthetic rate (A(Nmax)) over the growing season, while in branches with low source-sink ratios, there was a sharp decline in A(Nmax) in the first two weeks of August. Branches with high-sink showed an up-regulation (increase) in photosynthesis toward the end of July (at 1,500 growing degree days) during the period of rapid kernel growth rate and increased sink strength, with A(Nmax) being about 7 μmol m(-1) s(-1) higher than in branches with low-sink. In August, low source-sink ratios precipitated leaf senescence, resulting in a drastic A(Nmax) decline, from 25 to 8 μmol m(-1) s(-1) (70% drop in two weeks). This reduction was associated with the accumulation of NSC in the leaves from 20 to 30 mg g(-1). The mechanisms of A(Nmax) reduction differ between the two treatments. Lower photosynthetic rates of 8-10 μmol m(-1) s(-1) late in the season were associated with lower N levels in high-sink branches, suggesting N remobilization to the kernels. Lower photosynthesis late in the season was associated with lower respiration rates in low-source branches, indicating prioritization of assimilates to storage. These results can facilitate the adaptation of management practices to tree crop load changes in alternate bearing species. Frontiers Media S.A. 2023-08-02 /pmc/articles/PMC10436215/ /pubmed/37600173 http://dx.doi.org/10.3389/fpls.2023.1194177 Text en Copyright © 2023 Marino, Guzmán-Delgado, Santos, Adaskaveg, Blanco-Ulate, Ferguson, Zwieniecki and Fernández-Suela https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Plant Science
Marino, Giulia
Guzmán-Delgado, Paula
Santos, Emily
Adaskaveg, Jaclyn A.
Blanco-Ulate, Bárbara
Ferguson, Louise
Zwieniecki, Maciej A.
Fernández-Suela, Eduardo
Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
title Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
title_full Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
title_fullStr Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
title_full_unstemmed Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
title_short Interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
title_sort interactive effect of branch source-sink ratio and leaf aging on photosynthesis in pistachio
topic Plant Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10436215/
https://www.ncbi.nlm.nih.gov/pubmed/37600173
http://dx.doi.org/10.3389/fpls.2023.1194177
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