Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity
Copyright © 2015 Elsevier Masson SAS. All rights reserved.
| Veröffentlicht in: | Plant physiology and biochemistry : PPB. - 1991. - 93(2015) vom: 15. Aug., Seite 44-55 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2015
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| Zugriff auf das übergeordnete Werk: | Plant physiology and biochemistry : PPB |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Anthocyanins Antioxidative enzymes Flavonoids High light intensity Sugar distribution UV-B radiation Variegation Antioxidants mehr... |
| Zusammenfassung: | Copyright © 2015 Elsevier Masson SAS. All rights reserved. We studied the specific effects of high photosynthetically active radiation (PAR, 400-700 nm) and ecologically relevant UV-B radiation (0.90 W m(-2)) on antioxidative and phenolic metabolism by exploiting the green-white leaf variegation of Pelargonium zonale plants. This is a suitable model system for examining "source-sink" interactions within the same leaf. High PAR intensity (1350 μmol m(-2) s(-1)) and UV-B radiation induced different responses in green and white leaf sectors. High PAR intensity had a greater influence on green tissue, triggering the accumulation of phenylpropanoids and flavonoids with strong antioxidative function. Induced phenolics, together with ascorbate, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) provided efficient defense against potential oxidative pressure. UV-B-induced up-regulation of non-phenolic H2O2 scavengers in green leaf sectors was greater than high PAR-induced changes, indicating a UV-B role in antioxidative defense under light excess; on the contrary, minimal effects were observed in white tissue. However, UV-B radiation had greater influence on phenolics in white leaf sections compared to green ones, inducing accumulation of phenolic glycosides whose function was UV-B screening rather than antioxidative. By stimulation of starch and sucrose breakdown and carbon allocation in the form of soluble sugars from "source" (green) tissue to "sink" (white) tissue, UV-B radiation compensated the absence of photosynthetic activity and phenylpropanoid and flavonoid biosynthesis in white sectors |
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| Beschreibung: | Date Completed 10.03.2016 Date Revised 30.09.2020 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1873-2690 |
| DOI: | 10.1016/j.plaphy.2015.01.008 |