| 引用本文: | 刘云洁,张含含,常胜朝,等.臭椿夜间树干液流变化特征及环境驱动因素分析[J].灌溉排水学报,2023,42(2):9-15. |
| LIU Yunjie,ZHANG Hanhan,CHANG Shengzhao,et al.臭椿夜间树干液流变化特征及环境驱动因素分析[J].灌溉排水学报,2023,42(2):9-15. |
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| 摘要: |
| 【目的】研究树木夜间液流可以更全面地了解其水分利用与环境的关系，本试验针对臭椿夜间液流与环境因子的关系开展研究，以深入揭示臭椿水分利用特征。【方法】采用热扩散式探针法（TDP）对河北保定地区臭椿（6—8月）树干液流密度、相关环境因子和树干径向的变化进行监测，分析了臭椿夜间液流的变化特征及其影响因素。【结果】臭椿夜间液流量占日总液流的12.1%,20:00—00:00（T1）时段液流密度大于00:00—05:00（T2）时段，T1时段液流量占总夜间液流的65%，T2时段占35%；臭椿T2时段液流密度同饱和水气压差、风速极显著正相关（P<0.01），T1时段液流密度同饱和水气压差、风速相关性较低；晴天臭椿夜间液流密度大于雨天，且雨天过后的晴天液流密度明显增大；臭椿夜间液流量与冠幅极显著正相关（P<0.01），与胸径显著正相关（P<0.05），日尺度下树干径向微变化与液流密度变化具有较好的线性关系（R2=0.672），T1时段树干膨胀幅度大于T2时段。【结论】液流和树干径向微变化共同反映臭椿的水分利用状况，臭椿夜间液流受环境因子和其生物学结构综合影响，T1时段主要进行补水，T2时段存在明显蒸腾，且补水大于蒸腾。 |
| 关键词: 臭椿；夜间液流；蒸腾；补水；树干径向微变化 |
| DOI：10.13522/j.cnki.ggps.2022107 |
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| Sap Flow at Night in the Stems of Ailanthus Altissima and Its Determinants |
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LIU Yunjie, ZHANG Hanhan, CHANG Shengzhao, ZHOU Xinqi, MA Changming
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1. College of Forestry, Hebei Agricultural University, Baoding 071000, China; 2. She County Forestry Development Service Center, Handan 056000, China; 3. Hejian City Natural Resources and Planning Department, Cangzhou 061000, China
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| Abstract: |
| 【Background and objective】Water ascent in plants is driven by hydraulic gradient regulated by stomatal opening and closure as well as soil water content; it is generally assumed to be approximately zero at night. However, recent findings reveal that stomata could partly open and sap continues to flow at night, making stems function as capacitors regulating transpiration in daytime. The purpose of this paper is to investigate the diurnal change in sap flow and its determinants. 【Method】We take Ailanthus altissima as the model plant and measure sap flow through its stems, as well as variation in stem diameter, using a diffusion probe (TDP) from June to August in an urban area. We also measure environmental factors which we anticipate to affect root water uptake by the tree. 【Result】Sap flow does occur at night; it contributes 12.1% to the total daily sap flow, of which 65% is from 20:00 to 00:00 (T1) and 35% from 00:00 to 05:00 (T2). The night sap flow rate is positively correlated to the vapor pressure deficit and wind speed, but the correlation is more significant in T2 (P<0.01) than in T1, and greater in sunny days than in rainy days. It is also found that sap flow at night is positively correlated with canopy width (P<0.01) and stem diameter at the breast height (P<0.05), and that it increases linearly with daily variation in stem diameter (R2=0.672). Stems expand more radially in T1 than in T2.【Conclusion】Night sap flow results in radial expansion of the stem of A. altissima, which is impacted jointly by environmental factors and plant traits. |
| Key words: Ailanthus altissima; night sap flow; night transpiration; night rehydration; radial micro-variation in the stem |
