Canadian Geotechnical Journal, Ahead of Print.
Root water uptake induces additional soil suction by soil water extraction. However, induced soil suction restricts root water uptake when beyond a threshold (st) and tends to stop water uptake at a limiting suction (sl). This process is called root–soil hydraulic interactions, whose relationship with plant morphology (e.g., plant height, leaf area, and root length) is unclear. This study aims to investigate the effects of plant morphology on response of the sink term (water uptake intensity; WUI) to soil suction for Schefflera heptaphylla. Laboratory tests were conducted on 26 individuals in five different height groups. A new empirical model was derived to consider effects of plant morphology on root water uptake distribution in the full soil suction range. The locations of maximum root length density (RLD) and WUI for taller individuals were relatively deeper and farther from centreline. Before soil suction reached st, water uptake length ability (WULA) remained at a maximum level, positively related to LR ratio (ratio between leaf area, LA, and root length, RL), but less affected by plant height. For taller plants, the decreasing rate of st with LR ratio was larger, while the decreasing rate of WULA with soil suction beyond st appeared smaller. sl appeared independent of height, LA, and RL.

中文翻译：

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植物形态对七叶鹅掌柴根-土壤水力相互作用的影响

《加拿大岩土工程杂志》，预印本。
吸收根水会通过提取土壤水而吸引更多的土壤。但是，当超过阈值（st）时，诱导的土壤吸力会限制根系吸水，并且在极限吸力（s1）处往往会阻止吸水。这个过程称为根-土水力相互作用，其与植物形态（例如，植物高度，叶面积和根长）的关系尚不清楚。这项研究旨在调查植物形态对七叶鹅掌柴的下沉期（吸水强度； WUI）对土壤吸力的响应的影响。对五个不同身高组的26个人进行了实验室测试。得出了一个新的经验模型来考虑植物形态对整个土壤吸力范围内根系水分吸收分布的影响。较高的个体的最大根长密度（RLD）和WUI的位置相对较深，离中心线较远。在土壤吸力达到st之前，水分吸收长度能力（WULA）保持在最高水平，与LR比率（叶面积LA与根长RL之间的比率）成正相关，但受植物高度的影响较小。对于较高的植物，随着LR比的增加，st的降低速率较大，而土壤吸力超过st的WULA的降低速率显得较小。sl出现与高度，LA和RL无关。随着LR比的增加，st的下降率变大，而土壤吸力超过st的WULA的下降率变小。sl出现与高度，LA和RL无关。随着LR比的增加，st的下降率变大，而土壤吸力超过st的WULA的下降率变小。sl出现与高度，LA和RL无关。