Optical observations of embolism in three conifers overestimate the vulnerability of stem xylem to hydraulic dysfunction.

IF 5.6 2区生物学 Q1 PLANT SCIENCES

Journal of Experimental Botany Pub Date : 2025-02-28 DOI:10.1093/jxb/eraf075

Adriano Losso, Feng Feng, Barbara Beikircher, Stefan Mayr

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引用次数: 0

Abstract

Hydraulic failure due to drought stress is a major cause of forest decline. Therefore, many techniques have been developed to test the vulnerability of trees to drought-induced xylem embolism, each with advantages and limitations. We quantified drought vulnerability using the optical vulnerability (OV) and ultrasonic acoustic emission (UAE) techniques by performing simultaneous measurements on branches of three conifers (Picea abies, Pinus sylvestris and Pinus cembra). Results were compared with vulnerability curves obtained using the flow-centrifuge (FC) technique. With respect to the OV method, the light transmission properties of the samples were analyzed to determine the xylem fraction observed. OV vulnerability thresholds were 0.3-1.4MPa higher than those obtained with UAE and FC, which were similar overall. Xylem depths observed by OV were limited to peripheral 0.15-0.20mm, as no light transmission was detected deeper. Light transmission was higher in saturated than in dry xylem. Results suggest that xylem embolism detection by OV is limited to thin, peripheral xylem layers, and that vulnerability thresholds may differ from thicker samples (>0.4mm) measured with UAE and FC. Therefore, OV may not accurately reflect the general vulnerability of thick branches, as only peripheral xylem layers are analyzed. Changes in light transmission during dehydration must be considered.

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三种针叶树的栓塞光学观察高估了茎木质部对水力功能障碍的脆弱性。

干旱造成的水力衰竭是森林退化的主要原因。因此，已经开发了许多技术来测试树木对干旱诱导木质部栓塞的脆弱性，每种技术都有其优点和局限性。利用光学易损性（OV）和超声声发射（UAE）技术，对云杉（Picea abies）、西尔松（Pinus sylvestris）和松（Pinus cembra） 3种针叶树的枝条进行了同时测量，量化了干旱易损性。结果与流式离心（FC）技术得到的易损性曲线进行了比较。用OV法分析样品的透光性能，确定观察到的木质部分数。OV的漏洞阈值比UAE和FC的漏洞阈值高0.3-1.4MPa，两者总体相似。OV观测到的木质部深度限制在外围0.15-0.20mm，因为深层没有光透射。饱和木质部的透光率高于干燥木质部。结果表明，OV检测木质部栓塞仅限于薄的外周木质部层，并且脆弱性阈值可能不同于用UAE和FC测量的较厚的样品（>0.4mm）。因此，OV可能不能准确地反映粗枝的一般脆弱性，因为只分析了周围木质部层。必须考虑脱水过程中光透射的变化。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Experimental Botany 生物-植物科学

CiteScore

12.30

自引率

4.30%

发文量

450

审稿时长

1.9 months

期刊介绍： The Journal of Experimental Botany publishes high-quality primary research and review papers in the plant sciences. These papers cover a range of disciplines from molecular and cellular physiology and biochemistry through whole plant physiology to community physiology. Full-length primary papers should contribute to our understanding of how plants develop and function, and should provide new insights into biological processes. The journal will not publish purely descriptive papers or papers that report a well-known process in a species in which the process has not been identified previously. Articles should be concise and generally limited to 10 printed pages.