Measurement of vulnerability to water stress-induced cavitation in grapevine: a comparison of four techniques applied to a long-vesseled species
Measurement of vulnerability to water stress-induced cavitation in grapevine: a comparison of four techniques applied to a long-vesseled species
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DOI：
10.1111/j.1365-3040.2010.02160.x
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发表时间：
2010-09-01
影响因子：
7.3
通讯作者：
Mcelrone, Andrew J.
中科院分区：
文献类型：
--
作者：
Choat, Brendan;Drayton, William M.;Mcelrone, Andrew J.
在木本植物中，葡萄藤通常被描述为非常容易受到水分胁迫引起的空化，在轻微的张力下形成栓子。然而，我们发现，本地栓塞从未超过30%，尽管低木质部水势（PSI（x））为现场生长的葡萄干。自体栓塞测量值与先前报告之间的差异导致我们使用四种单独的方法和每种方法的改变（即节段长度和测量前冲洗/不冲洗以去除栓塞）来评估易损性曲线生成。脱水，脱水和空气注入的方法，这依赖于在分离的茎的水力传导率（PLC）的百分比损失的测量，进行了比较与非侵入性监测木质部空化与核磁共振（NMR）成像。短节段空气注入和冲洗的离心杆分别在Psi（x）为-0.5和-1.5 MPa时达到> 90 PLC，而脱水和长节段空气注入测量表明在Psi（x）> -2.0 MPa时没有显著的栓塞。NMR观察结果与脱水和长段空气注入方法一致，表明大多数容器在Psi（x）> -1.5 MPa时仍然充满水。我们的研究结果表明，葡萄茎远不如以前报道的那样容易受到水分胁迫引起的空化，脱水和长段注气技术更适合于长导管的物种和器官。
Among woody plants, grapevines are often described as highly vulnerable to water-stress induced cavitation with emboli forming at slight tensions. However, we found native embolism never exceeded 30% despite low xylem water potentials (Psi(x)) for stems of field grown vines. The discrepancy between native embolism measurements and those of previous reports led us to assess vulnerability curve generation using four separate methods and alterations (i.e. segment length and with/without flushing to remove embolism prior to measurement) of each. Centrifuge, dehydration and air-injection methods, which rely on measurement of percentage loss of hydraulic conductivity (PLC) in detached stems, were compared against non-invasive monitoring of xylem cavitation with nuclear magnetic resonance (NMR) imaging. Short segment air-injection and flushed centrifuge stems reached > 90 PLC at Psi(x) of-0.5 and -1.5 MPa, respectively, whereas dehydration and long-segment air-injection measurements indicated no significant embolism at Psi(x) > -2.0 MPa. Observations from NMR agreed with the dehydration and long segment air-injection methods, showing the majority of vessels were still water-filled at Psi(x) > -1.5 MPa. Our findings show V. vinifera stems are far less vulnerable to water stress-induced cavitation than previously reported, and dehydration and long segment air-injection techniques are more appropriate for long-vesseled species and organs.