Trends in wood density and structure are linked to prevention of xylem implosion by negative pressure
Trends in wood density and structure are linked to prevention of xylem implosion by negative pressure
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DOI：
10.1007/s004420100628
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发表时间：
2001-02-01
期刊：
影响因子：
2.7
通讯作者：
McCulloch, KA
中科院分区：
文献类型：
--
作者：
Hacke, UG;Sperry, JS;McCulloch, KA
木材密度 (D-t) 是机械性能的良好预测指标，通常被视为与对重力、风、雪和其他环境力的支撑有关。相比之下，我们展示了 D-t 和木材结构的变化与木质部管道中的负压对内爆的支持之间的惊人程度的联系。植物越耐旱，木质部压力在没有空化的情况下变得越负，木质部导管壁上的内部负载就越大。因此，D-t 与抗气蚀性相关。这种趋势与通过负压维持内爆的安全系数一致：按比例缩放管道壁跨度 (b) 和厚度 (t)，以便 (t/b)(2) 与避免壁塌陷所需的空化阻力成正比。出乎意料的是，D-t 的趋势可能与木质部管道的支持和植物的支持一样多或更多地相关。
Wood density (D-t), an excellent predictor of mechanical properties, is typically viewed in relation to support against gravity, wind, snow, and other environmental forces. In contrast, we show the surprising extent to which variation in D-t and wood structure is linked to support against implosion by negative pressure in the xylem pipeline. The more drought-tolerant the plant, the more negative the xylem pressure can become without cavitation, and the greater the internal load on the xylem conduit walls. Accordingly, D-t was correlated with cavitation resistance. This trend was consistent with the maintenance of a safety factor from implosion by negative pressure: conduit wall span (b) and thickness (t) scaled so that (t/b)(2) was proportional to cavitation resistance as required to avoid wall collapse. Unexpectedly, trends in D-t may be as much or more related to support of the xylem pipeline as to support of the plant.