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Matos IS, McDonough S, Johnson BC, Kalantar D, Rohde J, Sahu R, Wang J, Fontao A, To J, Carlos S, Garcia L, Boakye M, Forbes H, Blonder BW. Negative allometry of leaf xylem conduit diameter and double-wall thickness: implications for implosion safety. New Phytol 2024. [PMID: 38641796 DOI: 10.1111/nph.19771] [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: 12/11/2023] [Accepted: 03/25/2024] [Indexed: 04/21/2024]
Abstract
Xylem conduits have lignified walls to resist crushing pressures. The thicker the double-wall (T) relative to its diameter (D), the greater the implosion safety. Having safer conduits may incur higher costs and reduced flow, while having less resistant xylem may lead to catastrophic collapse under drought. Although recent studies have shown that conduit implosion commonly occurs in leaves, little is known about how leaf xylem scales T vs D to trade off safety, flow efficiency, mechanical support, and cost. We measured T and D in > 7000 conduits of 122 species to investigate how T vs D scaling varies across clades, habitats, growth forms, leaf, and vein sizes. As conduits become wider, their double-cell walls become proportionally thinner, resulting in a negative allometry between T and D. That is, narrower conduits, which are usually subjected to more negative pressures, are proportionally safer than wider ones. Higher implosion safety (i.e. higher T/D ratios) was found in asterids, arid habitats, shrubs, small leaves, and minor veins. Despite the strong allometry, implosion safety does not clearly trade off with other measured leaf functions, suggesting that implosion safety at whole-leaf level cannot be easily predicted solely by individual conduits' anatomy.
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Affiliation(s)
- Ilaine Silveira Matos
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Samantha McDonough
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Breanna Carrillo Johnson
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Diana Kalantar
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - James Rohde
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Roshni Sahu
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Joyce Wang
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Adrian Fontao
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Jason To
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Sonoma Carlos
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Lisa Garcia
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Mickey Boakye
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Holly Forbes
- University of California Botanical Garden, Berkeley, CA, 94720, USA
| | - Benjamin Wong Blonder
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
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Taneda H, Terashima I. Co-ordinated development of the leaf midrib xylem with the lamina in Nicotiana tabacum. Ann Bot 2012; 110:35-45. [PMID: 22589329 PMCID: PMC3380598 DOI: 10.1093/aob/mcs102] [Citation(s) in RCA: 4] [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: 01/31/2012] [Accepted: 03/30/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS The water-transport capacity of leaf venation is positively related to the leaf-lamina area, because the number and diameter of vein-xylem conduits are controlled to match the lamina area. This study aimed to investigate how this co-ordinated relationship between the leaf-lamina area and vein-xylem characteristics is achieved by examining the midrib xylem of tobacco leaves. METHODS The changes in the midrib-xylem characteristics over time were quantified using leaves with four different final lamina areas. The measured data were fitted to sigmoidal functions. From the constants of the fitted curves, the final values in mature leaves, maximal developmental rates (V(Dev)) and developmental duration (T(Dev)) were estimated for each of the xylem characteristics. Whether it is the lamina or the midrib xylem that drives the co-ordinated development was examined by lamina removal from unfolding leaves. The effects of the application of 0·1 % IAA (indole-3-acetic acid) to leaves with the laminas removed were also analysed. KEY RESULTS For both the leaf lamina and the midrib-xylem characteristics, the differences in final values among leaves with different lamina areas were more strongly associated with those in V(Dev). Notably, the V(Dev) values of the midrib-xylem characteristics were related to those of the leaf-lamina area. By lamina removal, the conduit diameter was reduced but the number of conduits did not significantly change. By IAA application, the decrease in the conduit diameter was halted, and the number of conduits in the midrib xylem increased. CONCLUSIONS According to the results, the V(Dev) values of the lamina area and the midrib-xylem characteristics changed in a co-ordinated manner, so that the water-transport capacity of the midrib xylem was positively related to the leaf-lamina area. The results also suggest that IAA derived from the leaf lamina plays a crucial role in the development of the leaf venation.
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Affiliation(s)
- Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan.
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