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Jupa R, Rosell JA, Pittermann J. Bark structure is coordinated with xylem hydraulic properties in branches of five Cupressaceae species. PLANT, CELL & ENVIRONMENT 2024; 47:1439-1451. [PMID: 38234202 DOI: 10.1111/pce.14824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/27/2023] [Accepted: 01/08/2024] [Indexed: 01/19/2024]
Abstract
The properties of bark and xylem contribute to tree growth and survival under drought and other types of stress conditions. However, little is known about the functional coordination of the xylem and bark despite the influence of selection on both structures in response to drought. To this end, we examined relationships between proportions of bark components (i.e. thicknesses of tissues outside the vascular cambium) and xylem transport properties in juvenile branches of five Cupressaceae species, focusing on transport efficiency and safety from hydraulic failure via drought-induced embolism. Both xylem efficiency and safety were correlated with multiple bark traits, suggesting that xylem transport and bark properties are coordinated. Specifically, xylem transport efficiency was greater in species with thicker secondary phloem, greater phloem-to-xylem thickness ratio and phloem-to-xylem cell number ratio. In contrast, species with thicker bark, living cortex and dead bark tissues were more resistant to embolism. Thicker phellem layers were associated with lower embolism resistance. Results of this study point to an important connection between xylem transport efficiency and phloem characteristics, which are shaped by the activity of vascular cambium. The link between bark and embolism resistance affirms the importance of both tissues to drought tolerance.
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Affiliation(s)
- Radek Jupa
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California, USA
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California, USA
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Jupa R, Pokorná K. Bark wounding triggers gradual embolism spreading in two diffuse-porous tree species. TREE PHYSIOLOGY 2024; 44:tpad132. [PMID: 37930242 PMCID: PMC10849750 DOI: 10.1093/treephys/tpad132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Xylem transport is essential for the growth, development and survival of vascular plants. Bark wounding may increase the risk of xylem transport failure by tension-driven embolism. However, the consequences of bark wounding for xylem transport are poorly understood. Here, we examined the impacts of the bark wounding on embolism formation, leaf water potential and gas exchange in the terminal branches of two diffuse-porous tree species (Acer platanoides L. and Prunus avium L.). The effects of bark removal were examined on field-grown mature trees exposed to increased evaporative demands on a short-term and longer-term basis (6 h vs 6 days after bark wounding). Bark removal of 30% of branch circumference had a limited effect on the xylem hydraulic conductivity when embolized vessels were typically restricted to the last annual ring near the bark wound. Over the 6-day exposure, the non-conductive xylem area had significantly increased in the xylem tissue underneath the bark wound (from 22-29% to 51-52% of the last annual ring area in the bark wound zone), pointing to gradual yet relatively limited embolism spreading to deeper xylem layers over time. In both species, the bark removal tended to result in a small but non-significant increase in the percent loss of hydraulic conductivity compared with control intact branches 6 days after bark wounding (from 6 to 8-10% in both species). The bark wounding had no significant effects on midday leaf water potential, CO2 assimilation rates, stomatal conductance and water-use efficiency of the leaves of the current-year shoot, possibly due to limited impacts on xylem transport. The results of this study demonstrate that bark wounding induces limited but gradual embolism spreading. However, the impacts of bark wounding may not significantly limit water delivery to distal organs and leaf gas exchange at the scale of several days.
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Affiliation(s)
- Radek Jupa
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno CZ-62500, Czech Republic
| | - Kamila Pokorná
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, Brno CZ-62500, Czech Republic
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Nie W, Dong Y, Liu Y, Tan C, Wang Y, Yuan Y, Ma J, An S, Liu J, Xiao W, Jiang Z, Jia Z, Wang J. Climatic responses and variability in bark anatomical traits of 23 Picea species. FRONTIERS IN PLANT SCIENCE 2023; 14:1201553. [PMID: 37528988 PMCID: PMC10388546 DOI: 10.3389/fpls.2023.1201553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/26/2023] [Indexed: 08/03/2023]
Abstract
In woody plants, bark is an important protective tissue which can participate in photosynthesis, manage water loss, and transport assimilates. Studying the bark anatomical traits can provide insight into plant environmental adaptation strategies. However, a systematic understanding of the variability in bark anatomical traits and their drivers is lacking in woody plants. In this study, the bark anatomical traits of 23 Picea species were determined in a common garden experiment. We analyzed interspecific differences and interpreted the patterns in bark anatomical traits in relation to phylogenetic relationships and climatic factors of each species according to its global distribution. The results showed that there were interspecific differences in bark anatomical traits of Picea species. Phloem thickness was positively correlated with parenchyma cell size, possibly related to the roles of parenchyma cells in the radial transport of assimilates. Sieve cell size was negatively correlated with the radial diameter of resin ducts, and differences in sieve cells were possibly related to the formation and expansion of resin ducts. There were no significant phylogenetic signals for any bark anatomical trait, except the tangential diameter of resin ducts. Phloem thickness and parenchyma cell size were affected by temperature-related factors of their native range, while sieve cell size was influenced by precipitation-related factors. Bark anatomical traits were not significantly different under wet and dry climates. This study makes an important contribution to our understanding of variability in bark anatomical traits among Picea species and their ecological adaptations.
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Affiliation(s)
- Wen Nie
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Yao Dong
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Yifu Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Cancan Tan
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Ya Wang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Yanchao Yuan
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Jianwei Ma
- Research Institute of Forestry of Xiaolong Mountain, Gansu Provincial Key Laboratory of Secondary Forest Cultivation, Tianshui, China
| | - Sanping An
- Research Institute of Forestry of Xiaolong Mountain, Gansu Provincial Key Laboratory of Secondary Forest Cultivation, Tianshui, China
| | - Jianfeng Liu
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Wenfa Xiao
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Zeping Jiang
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Zirui Jia
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Junhui Wang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
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Petrík P, Petek-Petrik A, Mukarram M, Schuldt B, Lamarque LJ. Leaf physiological and morphological constraints of water-use efficiency in C 3 plants. AOB PLANTS 2023; 15:plad047. [PMID: 37560762 PMCID: PMC10407996 DOI: 10.1093/aobpla/plad047] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 07/05/2023] [Indexed: 08/11/2023]
Abstract
The increasing evaporative demand due to climate change will significantly affect the balance of carbon assimilation and water losses of plants worldwide. The development of crop varieties with improved water-use efficiency (WUE) will be critical for adapting agricultural strategies under predicted future climates. This review aims to summarize the most important leaf morpho-physiological constraints of WUE in C3 plants and identify gaps in knowledge. From the carbon gain side of the WUE, the discussed parameters are mesophyll conductance, carboxylation efficiency and respiratory losses. The traits and parameters affecting the waterside of WUE balance discussed in this review are stomatal size and density, stomatal control and residual water losses (cuticular and bark conductance), nocturnal conductance and leaf hydraulic conductance. In addition, we discussed the impact of leaf anatomy and crown architecture on both the carbon gain and water loss components of WUE. There are multiple possible targets for future development in understanding sources of WUE variability in plants. We identified residual water losses and respiratory carbon losses as the greatest knowledge gaps of whole-plant WUE assessments. Moreover, the impact of trichomes, leaf hydraulic conductance and canopy structure on plants' WUE is still not well understood. The development of a multi-trait approach is urgently needed for a better understanding of WUE dynamics and optimization.
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Affiliation(s)
- Peter Petrík
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU), Kreuzeckbahnstraße 19, 82467 Garmisch-Partenkirchen, Germany
| | - Anja Petek-Petrik
- Institute of Botany, Czech Academy of Sciences, Lidická 971, 602 00 Brno, Czech Republic
| | - Mohammad Mukarram
- Department of Phytology, Faculty of Forestry, Technical University in Zvolen, T.G. Masaryka 24, 960 01 Zvolen, Slovakia
| | - Bernhard Schuldt
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden (TUD), Pienner Str. 7, 01737 Tharandt, Germany
| | - Laurent J Lamarque
- Département des Sciences de l’environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G8Z 4M3, Canada
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Lintunen A, Salmon Y, Hölttä T, Suhonen H. Inspection of gas bubbles in frozen Betula pendula xylem with micro‐CT: Conduit size, water status and bark permeability affect bubble characteristics. PHYSIOLOGIA PLANTARUM 2022. [PMCID: PMC9540547 DOI: 10.1111/ppl.13749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bubbles of gas trapped in the xylem during freezing are a major cause of damage for trees growing at high altitudes or latitudes, as the bubbles may cause embolism during thawing. Yet the factors controlling bubble formation upon freeze–thaw cycles remain poorly understood. Especially the size of the bubbles formed in the ice is crucial for winter embolism formation. We used high‐resolution X‐ray microtomography combined with freezing experiments to investigate the size and shape of 68,343 gas bubbles in frozen conduits in branches of Betula pendula. We also studied how conduit size, tree water status (−0.2 MPa vs. −0.6 MPa) and bark permeability to gases (decreased by Vaseline‐coating) affect the gas bubbles characteristics. High‐resolution X‐ray images allowed us to detect gas bubbles down to 1.0 μm in diameter and revealed that not only small spherical gas bubbles but also gaseous volumes of various shapes and sizes were found from the frozen xylem indicating that gas bubbles may have started to grow already during the freezing propagation. Most of the gas bubbles were found in fibers, but the rare gas bubbles found in the vessels were larger than those in the fibers. Bubble volume increased with conduit volume in both fibers and vessels, but conduit size alone could not explain gas bubble volume. Low water potential and restriction of gas escape from the branch seem to cause more, larger, and less spherical bubbles and thus increase the risk of embolism formation. These findings open new research avenues for further studies of winter embolism formation.
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Affiliation(s)
- Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, Faculty of ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Heikki Suhonen
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
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