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Secchi F, Pagliarani C, Cavalletto S, Petruzzellis F, Tonel G, Savi T, Tromba G, Obertino MM, Lovisolo C, Nardini A, Zwieniecki MA. Chemical inhibition of xylem cellular activity impedes the removal of drought-induced embolisms in poplar stems - new insights from micro-CT analysis. New Phytol 2021; 229:820-830. [PMID: 32890423 DOI: 10.1111/nph.16912] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [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: 07/01/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
In drought-stressed plants a coordinated cascade of chemical and transcriptional adjustments occurs at the same time as embolism formation. While these processes do not affect embolism formation during stress, they may prime stems for recovery during rehydration by modifying apoplast pH and increasing sugar concentration in the xylem sap. Here we show that in vivo treatments modifying apoplastic pH (stem infiltration with a pH buffer) or reducing stem metabolic activity (infiltration with sodium vanadate and sodium cyanide; plant exposure to carbon monoxide) can reduce sugar accumulation, thus disrupting or delaying the recovery process. Application of the vanadate treatment (NaVO3, an inhibitor of many ATPases) completely halted recovery from drought-induced embolism for up to 24 h after re-irrigation, while partial recovery was observed in vivo in control plants using X-ray microcomputed tomography. Our results suggest that stem hydraulic recovery in poplar is a biological, energy-dependent process that coincides with accumulation of sugars in the apoplast during stress. Recovery and damage are spatially coordinated, with embolism formation occurring from the inside out and refilling from the outside in. The outside-in pattern highlights the importance of xylem proximity to the sugars within the phloem to the embolism recovery process.
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Affiliation(s)
- Francesca Secchi
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Chiara Pagliarani
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, Torino, 10135, Italy
| | - Silvia Cavalletto
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, University of Trieste, via Giorgieri 10, Trieste, 34127, Italy
| | - Giulia Tonel
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Tadeja Savi
- Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU, Gregor-Mendel-Straße 33, Vienna, 1180, Austria
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, Basovizza, Trieste, 34149, Italy
| | - Maria Margherita Obertino
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Claudio Lovisolo
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, University of Trieste, via Giorgieri 10, Trieste, 34127, Italy
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
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