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New Phytologist:木质化组织光合作用的糖减少木质部空穴化

已有 3068 次阅读 2017-9-20 08:54 |个人分类:每日摘要|系统分类:论文交流|关键词:学者

Sugars from woody tissue photosynthesis reduce xylem vulnerability to cavitation

First author:Niels J. F. De Baerdemaeker; Affiliations: Ghent University (根特大学): Ghent, Belgium

Corresponding author: Niels J. F. De Baerdemaeker

Reassimilation (重新同化) of internal CO2 via woody tissue photosynthesis has a substantial effect on tree carbon income and wood production. However, little is known about its role in xylem vulnerability to cavitation (木质部空穴化) and its implications in drought-driven tree mortality (死亡).

Young trees of Populus nigra (黑杨) were subjected to light exclusion at the branch and stem levels. After 40 d, measurements of xylem water potential (水势), diameter variation and acoustic emission (AE; 声发射) were performed in detached (分离的) branches to obtain acoustic vulnerability curves (脆弱性曲线) to cavitation following bench-top dehydration (台式脱水).

Acoustic vulnerability curves and derived AE50 values (i.e. water potential at which 50% of cavitation-related acoustic emissions occur) differed significantly between light-excluded and control branches (AE50,light-excluded = −1.00 ± 0.13 MPa; AE50,control = −1.45 ± 0.09 MPa; P = 0.007) denoting higher vulnerability to cavitation in light-excluded trees.

Woody tissue photosynthesis represents an alternative and immediate source of nonstructural carbohydrates (NSC; 非结构性的碳水化合物) that confers lower xylem vulnerability to cavitation via sugar-mediated mechanisms. Embolism repair (栓塞修复) and xylem structural changes could not explain this observation as the amount of cumulative AE and basic wood density did not differ between treatments. We suggest that woody tissue assimilates might play a role in the synthesis of xylem surfactants (表面活性剂) for nanobubble (纳米气泡) stabilization under tension.


通讯:Niels J. F. De Baeqrdemaeker (http://www.plantecology.ugent.be/people/)

doi: 10.1111/nph.14787

Journal: New Phytologist
First Published data: September 18, 2017.

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