Differential response of plant transpiration to uptake of rainwater-recharged soil water for dominant tree species in the semiarid Loess Plateau
<p>Establishing whether uptake of rainwater-recharged soil water (RRS) can increase plant transpiration in response to rainfall pulses requires an investigation to evaluate plant adaptability, especially in water-limited regions where rainwater is the only replenishable soil water source. In t...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-10-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://hess.copernicus.org/articles/26/4995/2022/hess-26-4995-2022.pdf |
| Summary: | <p>Establishing whether uptake of rainwater-recharged soil water (RRS) can increase plant transpiration in response to rainfall pulses requires an investigation to evaluate plant adaptability, especially in water-limited regions where rainwater is the only replenishable soil water source. In this study, the
water sources from RRS and three soil layers, the predawn leaf water potential (<span class="inline-formula">Ψ<sub>pd</sub></span>), the midday leaf water potential (<span class="inline-formula">Ψ<sub>m</sub></span>), the gradient of leaf water potential (<span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span>), and the plant transpiration in response to rainfall pulses were analyzed for two dominant tree species, <i>Hippophae rhamnoides</i> subsp. <i>sinensis</i> and <i>Populus tomentosa</i>, in pure and mixed plantations during the growing period (June–September). Mixed afforestation significantly enhanced <span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span>, RRS uptake proportion (RUP), and the relative response of daily normalized sap flow (SF<span class="inline-formula"><sub>R</sub></span>) and reduced the water source proportion from the deep soil layer (100–200 cm) for both species (<span class="inline-formula"><i>P</i><0.05</span>). In pure and mixed plantations, the large <span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span> was consistent with high SF<span class="inline-formula"><sub>R</sub></span>
for <i>H. rhamnoides</i> and the small <span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span> was consistent with low SF<span class="inline-formula"><sub>R</sub></span> for <i>P. tomentosa</i> in response to rainfall pulses. Therefore, <i>H. rhamnoides</i> and <i>P. tomentosa</i> exhibited anisohydric and isohydric behavior, respectively, and the former plant species was more sensitive to rainfall pulses than <i>P. tomentosa</i>. Furthermore, in pure plantations, the SF<span class="inline-formula"><sub>R</sub></span> was significantly affected by RUP and <span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span> for <i>H. rhamnoides</i> and significantly influenced by <span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span> for <i>P. tomentosa</i> (<span class="inline-formula"><i>P</i><0.05</span>). However, the SF<span class="inline-formula"><sub>R</sub></span> was significantly influenced by RUP and <span class="inline-formula">Ψ<sub>pd</sub>−Ψ<sub>m</sub></span> for both species in the mixed plantation. These results indicate that mixed afforestation enhanced the influence of RRS uptake on plant transpiration for these different rainfall-pulse-sensitive plants. This study provides insights into suitable plantation species selection and management considering the link between RRS uptake and plant transpiration in water-limited regions.</p> |
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| ISSN: | 1027-5606 1607-7938 |