Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species
Compared to arid regions, forests in humid regions can be more vulnerable to drought as they are not used to, and thus not adapted to, water stress. Therefore, it is vital to understand the drought responses of woodland species in humid areas. Xylem structures and functions of species growing in the...
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MDPI AG
2022-09-01
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| Online Access: | https://www.mdpi.com/1999-4907/13/10/1564 |
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| author | Jiang-Bo Xie Bo-Na Zhang Zhong-Yuan Wang |
| author_facet | Jiang-Bo Xie Bo-Na Zhang Zhong-Yuan Wang |
| author_sort | Jiang-Bo Xie |
| collection | DOAJ |
| description | Compared to arid regions, forests in humid regions can be more vulnerable to drought as they are not used to, and thus not adapted to, water stress. Therefore, it is vital to understand the drought responses of woodland species in humid areas. Xylem structures and functions of species growing in the humid regions are the key to their drought responses. Two Cupressaceae species (including three taxa: <i>Sequoia sempervirens</i>, <i>Taxodium distichum</i> and its variety <i>Taxodium distichum</i> var. <i>imbricatum</i>) grown in a mesic common garden were targeted, and their xylem hydraulic function (hydraulic conductivity, <i>K</i><sub>s</sub>; cavitation resistance, <i>P</i><sub>50</sub>), anatomical structure (tracheid and pit structure), and mechanical support (wood density, WD; tracheid thickness-to-span ratio, <i>Ttob</i>) were measured. Likewise, we analyzed the differences in hydraulic function and anatomical structure of xylem in branches and roots, and the quantitative relationship between xylem water transport, anatomical structure, and mechanical support. Our results showed that roots had a higher hydraulic conductivity and a weaker cavitation resistance than branches. There was no safety–efficiency trade-off in the branches and roots within species. Tracheid mechanical support had a trade-off relationship with <i>K</i><sub>s</sub> or <i>P</i><sub>50</sub> (negative correlation appeared in branch <i>K</i><sub>s</sub> ~ WD and root <i>K</i><sub>s</sub> ~ <i>Ttob</i> of <i>S. sempervirens</i>, root <i>P</i><sub>50</sub> ~ <i>Ttob</i> of <i>T. distichum</i> var. <i>imbricatum</i>, and branch <i>P</i><sub>50</sub> ~ WD). There was no trade-off in anatomical structure, which led to no safety–efficiency trade-off in xylem function. Our results suggest that the two species exhibit both low efficiency and low safety in xylem, and that there is no safety–efficiency trade-off in branches and roots. The reason behind this is that the structural demand for high safety and high efficiency differs (i.e., the root <i>K</i><sub>s</sub> of <i>S. sempervirens</i> was strongly controlled by <i>D</i><sub>h</sub>; in contrast, the root <i>P</i><sub>50</sub> of <i>S. sempervirens</i> was strongly determined by tracheid density, <i>N</i>). Namely, the structural basis for a safety–efficiency trade-off does not exist and therefore trade-offs cannot be achieved. |
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| language | English |
| last_indexed | 2024-03-09T20:12:36Z |
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| spelling | doaj.art-685260932b5d4a84a36e43a640c580ba2023-11-24T00:09:15ZengMDPI AGForests1999-49072022-09-011310156410.3390/f13101564Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae SpeciesJiang-Bo Xie0Bo-Na Zhang1Zhong-Yuan Wang2State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, 666 Wu-Su Street, Lin-An District, Hangzhou 311300, ChinaState Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, 666 Wu-Su Street, Lin-An District, Hangzhou 311300, ChinaState Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, 666 Wu-Su Street, Lin-An District, Hangzhou 311300, ChinaCompared to arid regions, forests in humid regions can be more vulnerable to drought as they are not used to, and thus not adapted to, water stress. Therefore, it is vital to understand the drought responses of woodland species in humid areas. Xylem structures and functions of species growing in the humid regions are the key to their drought responses. Two Cupressaceae species (including three taxa: <i>Sequoia sempervirens</i>, <i>Taxodium distichum</i> and its variety <i>Taxodium distichum</i> var. <i>imbricatum</i>) grown in a mesic common garden were targeted, and their xylem hydraulic function (hydraulic conductivity, <i>K</i><sub>s</sub>; cavitation resistance, <i>P</i><sub>50</sub>), anatomical structure (tracheid and pit structure), and mechanical support (wood density, WD; tracheid thickness-to-span ratio, <i>Ttob</i>) were measured. Likewise, we analyzed the differences in hydraulic function and anatomical structure of xylem in branches and roots, and the quantitative relationship between xylem water transport, anatomical structure, and mechanical support. Our results showed that roots had a higher hydraulic conductivity and a weaker cavitation resistance than branches. There was no safety–efficiency trade-off in the branches and roots within species. Tracheid mechanical support had a trade-off relationship with <i>K</i><sub>s</sub> or <i>P</i><sub>50</sub> (negative correlation appeared in branch <i>K</i><sub>s</sub> ~ WD and root <i>K</i><sub>s</sub> ~ <i>Ttob</i> of <i>S. sempervirens</i>, root <i>P</i><sub>50</sub> ~ <i>Ttob</i> of <i>T. distichum</i> var. <i>imbricatum</i>, and branch <i>P</i><sub>50</sub> ~ WD). There was no trade-off in anatomical structure, which led to no safety–efficiency trade-off in xylem function. Our results suggest that the two species exhibit both low efficiency and low safety in xylem, and that there is no safety–efficiency trade-off in branches and roots. The reason behind this is that the structural demand for high safety and high efficiency differs (i.e., the root <i>K</i><sub>s</sub> of <i>S. sempervirens</i> was strongly controlled by <i>D</i><sub>h</sub>; in contrast, the root <i>P</i><sub>50</sub> of <i>S. sempervirens</i> was strongly determined by tracheid density, <i>N</i>). Namely, the structural basis for a safety–efficiency trade-off does not exist and therefore trade-offs cannot be achieved.https://www.mdpi.com/1999-4907/13/10/1564climate changehumid areaCupressaceaehydraulic efficiencycavitation resistance |
| spellingShingle | Jiang-Bo Xie Bo-Na Zhang Zhong-Yuan Wang Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species Forests climate change humid area Cupressaceae hydraulic efficiency cavitation resistance |
| title | Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species |
| title_full | Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species |
| title_fullStr | Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species |
| title_full_unstemmed | Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species |
| title_short | Relationships between Xylem Transport, Anatomical, and Mechanical Traits at Organ Level of Two Cupressaceae Species |
| title_sort | relationships between xylem transport anatomical and mechanical traits at organ level of two cupressaceae species |
| topic | climate change humid area Cupressaceae hydraulic efficiency cavitation resistance |
| url | https://www.mdpi.com/1999-4907/13/10/1564 |
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