夜间不同环境稳定性条件下杨树水分生理过程的生物物理控制

doi:10.11707/j.1001-7488.LYKX20240136

摘要/Abstract

摘要：

目的: 以杨树人工林生态系统为研究对象，研究环境因子与内源性昼夜节律对树木叶片水分生理和树干液流的生物物理调控机制，旨在揭示树木水分生理过程（叶片气孔导度、叶片蒸腾、叶片水势和树干液流）在夜间对不同环境稳定性条件的响应模式和影响因素。方法: 对位于北京市顺义区潮白河沿岸的欧美杨人工林，在生长季期间选定7个晴朗的昼夜，连续监测3棵样树的叶片气体交换和叶片水势。同时，使用热扩散探针技术监测样树的树干液流密度变化，同步记录环境因子变化，并使用日落后历时量化昼夜节律的影响。结果: 1）夜间出现树木气孔开放的现象，叶片蒸腾和液流同步发生。夜间环境稳定（v=0且?VPD ≤0.1 kPa）条件下，树木水分生理指标主要受大气和土壤温度影响（P<0.05），且较弱。夜间液流与叶片气孔导度显著负相关（P<0.01），表明液流主要用于茎干补水。2）夜间环境波动（v>0或?VPD≥0.1 kPa）条件下，叶片气孔导度和树干液流密度受大气温度（T_a）和VPD的正向调控，与空气湿度（RH）显著负相关(P<0.05)，且T_a为主导影响因素。叶水势主要受T_a、土壤含水量（SWC）和温度（ST）的共同影响。夜间液流与叶片气孔导度、蒸腾速率和水势显著正相关（R²=0.67）。3）日间环境波动较强，叶片水分生理指标与树干液流密度的相关性显著高于夜间，但叶片气孔导度与VPD呈负相关，且气孔导度与液流密度之间表现出解耦现象（P=0.078）。4）以日落后历时为表征的昼夜节律对树木水分生理指标的作用方式随夜间环境稳定性变化而不同。在夜间环境稳定条件下，日落后历时显著影响叶片气孔导度、叶片水势和叶片蒸腾（P<0.01）；而在夜间环境波动条件下，该因子对叶片水分生理指标的影响程度均有所降低且对气孔导度和叶片水势的影响不显著（P₁=0.066, P₂=0.08），说明夜间环境波动影响了昼夜节律对树木水分生理过程的作用方式和程度。结论: 在夜间不同环境稳定性条件下，树木水分生理的生物物理过程和调控机制有显著差异，当环境因子波动较小时，树木水分生理过程受昼夜节律调控形成了显著的夜间模式，此时应考虑其对植物水分的影响。本研究强调了昼夜节律在调控林木水利用中的关键作用，并建议制定基于时间和环境稳定性的灌溉策略，以优化水分管理和应对气候变化。

关键词: 环境稳定性, 昼夜差异, 树干液流, 叶片水分生理, 昼夜节律

Abstract:

Objective: In the context to the global trend of decreasing surface wind speeds, known as "atmospheric stilling", differences in diurnal environmental stability primarily driven by vapor pressure deficit (VPD) and wind speed (v) are becoming increasingly pronounced. However, the biophysical control mechanisms of tree water physiological processes under different environmental stability conditions remain unclear. In this study, an ecological system of poplar plantations was targeted and the biophysical regulation mechanisms of environmental factors and endogenous circadian rhythms on leaf water physiology and trunk sap flow in trees were investigated. This study aims to explore the response patterns and influencing factors of tree water-related physiological processes, such as leaf stomatal conductance, leaf-level transpiration rate, leaf water potential, and trunk sap flow, under different nighttime environmental conditions. Method: The research was conducted in a Populus × euramericana plantation along the Chaobai River in Shunyi District, Beijing. During the growing season, gas exchange at the leaf-level and leaf water potential were measured continuously over seven clear day-night cycles on three sample trees. Simultaneously, sap flux density in the sample trees was monitored using heat diffusion probe technology, with concurrent recording changes in environmental factor, and the impact of diurnal rhythms was quantified using hours after dusk. Result: 1) Nighttime stomatal opening was observed, with synchronized occurrences of leaf transpiration and sap flux. Under stable nocturnal conditions (v=0 and ΔVPD ≤0.1 kPa), tree water physiological indicators were primarily influenced by air and soil temperatures (P<0.05), albeit relatively weak. There was a significant negative correlation between nocturnal sap flux and leaf stomatal conductance (P<0.01), indicating that sap flux was mainly used for stem water replenishment. 2) Under fluctuating nighttime environmental conditions (v>0 or ΔVPD ≥0.1 kPa), leaf stomatal conductance and sap flux density were positively regulated by air temperature (T_a) and VPD, and negatively correlated with relative humidity (RH), with T_a being the dominant factor. Leaf water potential was mainly influenced by T_a, soil water content (SWC), and soil temperature (ST). Nighttime sap flux density showed significant positive correlations with leaf stomatal conductance, transpiration rate, and water potential (R²=0.67). 3) Daytime environmental conditions fluctuated strongly, showing a significantly higher correlation between leaf water physiological indicators and sap flux density compared to nighttime. However, there was a negative correlation between leaf stomatal conductance and VPD, and there was a decoupling phenomenon between stomatal conductance and sap flux density (P=0.078). 4) The impact of the circadian rhythm, as characterized by hours after dusk, varied with changes in nighttime environmental stability. Under stable nocturnal conditions, duration after dusk significantly affected leaf stomatal conductance, leaf water potential, and transpiration (P<0.01). Under fluctuating nocturnal conditions, the influence of this factor on leaf water physiological indicators were reduced, with no significant impact on stomatal conductance and leaf water potential (P₁=0.066, P₂=0.08), indicating that nocturnal environmental fluctuations affected the manner and extent to which the circadian rhythm influenced tree water-related physiological processes. Conclusion: Under varying nighttime environmental stability conditions, there are significant differences in the biophysical processes and regulatory mechanisms of tree water physiology. When environmental fluctuations are minimal, tree water physiology processes are regulated by circadian rhythms, forming a pronounced nocturnal pattern. At this time, its impact on plant hydration should be considered. This research emphasizes the pivotal role of circadian rhythms in controlling forest water usage and recommends formulating irrigation strategies based on temporal factors and environmental stability to optimize water management and adapt to climate change. Furthermore, this study provides theoretical support for understanding forest hydrological cycles and assessing the adaptability of riparian plantations to climate change.

Key words: environmental stability, diurnal differences, sap flow, leaf water physiology, diurnal rhythms

中图分类号:

S718.43

王一君,陈立欣,陈左司南,张志强,许行,姚飞,陈胜楠. 夜间不同环境稳定性条件下杨树水分生理过程的生物物理控制[J]. 林业科学, 2024, 60(8): 95-108.

Yijun Wang,Lixin Chen,Zuosinan Chen,Zhiqiang Zhang,Hang Xu,Fei Yao,Shengnan Chen. Biophysical Control of Water Physiological Processes in Poplar under Various Nighttime Environmental Stability Conditions[J]. Scientia Silvae Sinicae, 2024, 60(8): 95-108.

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参考文献 0

	曹生奎, 冯　起, 司建华, 等. 植物叶片水分利用效率研究综述. 生态学报, 2009, 29 (7): 3882- 3892. doi: 10.3321/j.issn:1000-0933.2009.07.051
	Cao S K, Feng Q, Si J H, et al. Summary on the plant water use efficiency at leaf level. Acta Ecologica Sinica, 2009, 29 (7): 3882- 3892. doi: 10.3321/j.issn:1000-0933.2009.07.051
	范云翔, 邸　楠, 刘　洋, 等. 毛白杨茎干夜间液流时空动态及其环境影响因子. 植物生态学报, 2023, 47 (2): 262- 274.
	Fan Y X, Di N, Liu Y, et al. Spatiotemporal dynamics of nocturnal sap flow of Populus tomentosa and environmental impact factors. Journal of Plant Ecology, 2023, 47 (2): 262- 274.
	高惠璇. 两个多重相关变量组的统计分析(3)(偏最小二乘回归与PLS过程). 数理统计与管理, 2002, 21 (2): 58- 64.
	Gao H X. Statistical analyses for multiple correlation variables of two sets (3) (partial least-sguares regression and PLS procedure). Journal of Applied Statistics and Management, 2002, 21 (2): 58- 64.
	贾国栋, 陈立欣, 李瀚之, 等. 北方土石山区典型树种耗水特征及环境影响因子. 生态学报, 2018, 38 (10): 3441- 3452.
	Jia G D, Chen L X, Li H Z, et al. The effect of environmental factors on plant water consumption characteristics in a northern rocky mountainous area. Acta Ecologica Sinica, 2018, 38 (10): 3441- 3452.
	孔　喆, 陈胜楠, 律　江, 等. 欧美杨单株液流昼夜组成及其影响因素分析. 林业科学, 2020, 56 (3): 8- 20. doi: 10.11707/j.1001-7488.20200302
	Kong Z, Chen S N, Lü J, et al. Characteristics of Populus euramericana sap flow over day and night and its influencing factors. Scientia Silvae Sinicae, 2020, 56 (3): 8- 20. doi: 10.11707/j.1001-7488.20200302
	李光莹, 祖姆热提·于苏甫江, 董正武, 等. 古尔班通古特沙漠西南缘地区多枝柽柳(Tamarix ramosissima)生理特性对沙堆不同堆积阶段的响应. 生态学报, 2024, 44 (8): 1- 14.
	Li G Y, Zumrat·Yusufjan, Dong Z W, et al. Response of physiological characteristics of Tamarix ramosissima to different accumulation stages of cones in the southwestern margin of Gurbantungut Desert. Acta Ecologica Sinica, 2024, 44 (8): 1- 14.
	罗丹丹, 王传宽, 金　鹰. 植物水分调节对策: 等水与非等水行为. 植物生态学报, 2017, 41 (9): 1020- 1032. doi: 10.17521/cjpe.2016.0366
	Luo D D, Wang C K, Jin Y. Plant water-regulation strategies: isohydric versus anisohydric behavior. Journal of Plant Ecology, 2017, 41 (9): 1020- 1032. doi: 10.17521/cjpe.2016.0366
	罗丹丹, 王传宽, 金　鹰. 木本植物水力系统对干旱胁迫的响应机制. 植物生态学报, 2021, 45 (9): 925- 941. doi: 10.17521/cjpe.2021.0111
	Luo D D, Wang C K, Jin Y. Response mechanisms of hydraulic systems of woody plants to drought stress. Journal of Plant Ecology, 2021, 45 (9): 925- 941. doi: 10.17521/cjpe.2021.0111
	魏鸾葳, 陈左司南, 陈胜楠, 等. 降雨对河岸生态系统杨树树干液流及其环境控制的影响. 水土保持学报, 2023, 37 (4): 284- 293.
	Wei L W, Chen Z S N, Chen S N, et al. Effects of rainfall on sap flow and its environmental controls in a riparian poplar plantation ecosystem. Journal of Soil and Water Conservation, 2023, 37 (4): 284- 293.
	徐志彬. 2022. 北方三种常见针叶树种蒸腾耗水特征及其环境响应和生理控制. 北京: 北京林业大学.
	Xu Z B. 2022. Environmental responses and physiological controls of transpiration of three common coniferous tree species in North China. Beijing: Beijing Forestry University. ［in Chinese］
	Bai Y, Li X Y, Liu S M, et al. Modelling diurnal and seasonal hysteresis phenomena of canopy conductance in an oasis forest ecosystem. Agricultural and Forest Meteorology, 2017, 246, 98- 110. doi: 10.1016/j.agrformet.2017.06.006
	Barbour M M, Buckley T N. 2007. The stomatal response to evaporative demand persists at night in Ricinus communis plants with high nocturnal conductance. Plant, Cell & Environment, 30(6): 711–721.
	Barbour M M, Cernusak L A, Whitehead D, et al. Nocturnal stomatal conductance and implications for modelling δ¹⁸O of leaf-respired CO₂ in temperate tree species. Functional Plant Biology, 2005, 32 (12): 1107- 1121. doi: 10.1071/FP05118
	Battin T J, Lauerwald R, Bernhardt E S, et al. River ecosystem metabolism and carbon biogeochemistry in a changing world. Nature, 2023, 613 (7944): 449- 459. doi: 10.1038/s41586-022-05500-8
	Buckley T N. 2019. How do stomata respond to water status? New Phytologist, 224(1): 21–36.
	Bucci S J, Scholz F G, Goldstein G, et al. Processes preventing nocturnal equilibration between leaf and soil water potential in tropical savanna woody species. Tree Physiology, 2004, 24 (10): 1119- 1127. doi: 10.1093/treephys/24.10.1119
	Caird M A, Richards J H & Donovan L A, 2007. Nighttime stomatal conductance and transpiration in C₃ and C₄ plants. Plant Physiology, 143(1): 4–10.
	Chen Z S N, Zhang Z Q, Sun G, et al. Biophysical controls on nocturnal sap flow in plantation forests in a semi-arid region of northern China. Agricultural and Forest Meteorology, 2020, 284, 107904. doi: 10.1016/j.agrformet.2020.107904
	Chowdhury F I, Arteaga C, Alam M S, et al. Drivers of nocturnal stomatal conductance in C₃ and C₄ plants. Science of the Total Environment, 2022, 814, 151952. doi: 10.1016/j.scitotenv.2021.151952
	Clearwater M J, Meinzer F C, Andrade J L, et al. Potential errors in measurement of nonuniform sap flow using heat dissipation probes. Tree Physiology, 1999, 19 (10): 681- 687. doi: 10.1093/treephys/19.10.681
	Cochard H, Coll L, Le Roux X, et al. Unraveling the effects of plant hydraulics on stomatal closure during water stress in walnut. Plant Physiology, 2002, 128 (1): 282- 290. doi: 10.1104/pp.010400
	Cunningham S C. Stomatal sensitivity to vapour pressure deficit of temperate and tropical evergreen rainforest trees of Australia. Trees, 2004, 18 (4): 399- 407.
	Daley M J, Phillips N G. Interspecific variation in nighttime transpiration and stomatal conductance in a mixed New England deciduous forest. Tree Physiology, 2006, 26 (4): 411- 419. doi: 10.1093/treephys/26.4.411
	Dawson T E, Burgess S S O, Tu K P, et al. Nighttime transpiration in woody plants from contrasting ecosystems. Tree Physiology, 2007, 27 (4): 561- 575. doi: 10.1093/treephys/27.4.561
	Dodd A N, Salathia N, Hall A, et al. Plant circadian clocks increase photosynthesis, growth, survival, and competitive advantage. Science, 2005, 309 (5734): 630- 633. doi: 10.1126/science.1115581
	Farquhar G D, Sharkey T D. Stomatal conductance and photosynthesis. Annual Review of Plant Physiology, 1982, 33, 317- 345. doi: 10.1146/annurev.pp.33.060182.001533
	Forster M A. 2014. How significant is nocturnal sap flow? Tree Physiology, 34(7): 757–765.
	Franks P J, Drake P L, Froend R H. 2007. Anisohydric but isohydrodynamic: seasonally constant plant water potential gradient explained by a stomatal control mechanism incorporating variable plant hydraulic conductance. Plant, Cell & Environment, 30(1): 19–30.
	Fricke W. 2019. Night-time transpiration–favouring growth? Trends in Plant Science, 24(4): 311–317.
	Fuentes S, Mahadevan M, Bonada M, et al. Night-time sap flow is parabolically linked to midday water potential for field-grown almond trees. Irrigation Science, 2013, 31 (6): 1265- 1276. doi: 10.1007/s00271-013-0403-3
	Goldstein G, Andrade J L, Meinzer F C, et al. 1998. Stem water storage and diurnal patterns of water use in tropical forest canopy trees. Plant, Cell & Environment, 21(4): 397–406.
	Gordon N D, McMahon T A, Finlayson B L, et al. 2004. Stream hydrology: an introduction for ecologists. New York: John Wiley and Sons.
	Gould P D, Locke J C W, Larue C. et al. The molecular basis of temperature compensation in the Arabidopsis circadian clock. The Plant Cell, 2006, 18 (5): 1177- 1187. doi: 10.1105/tpc.105.039990
	Granier A, Bobay V, Gash J H C, et al. Vapour flux density and transpiration rate comparisons in a stand of Maritime pine (Pinus pinaster Ait. ) in Les Landes forest. Agricultural and Forest Meteorology, 1990, 51 (3): 309- 319.
	Green S R, McNaughton K G, Clothier B E. Observations of night-time water use in kiwifruit vines and apple trees. Agricultural and Forest Meteorology, 1989, 48 (3): 251- 261.
	Grossiord C, Buckley T N, Cernusak L A, et al. Plant responses to rising vapor pressure deficit. New Phytologist, 2020, 226 (6): 1550- 1566. doi: 10.1111/nph.16485
	Hasanuzzaman M, Zhou M & Shabala S, 2023. How does stomatal density and residual transpiration contribute to osmotic stress tolerance? Plants, 12(3): 494.
	Haworth M, Marino G, Loreto F, et al. Integrating stomatal physiology and morphology: evolution of stomatal control and development of future crops. Oecologia, 2021, 197 (4): 867- 883. doi: 10.1007/s00442-021-04857-3
	Hogg E H, Hurdle P A. Sap flow in trembling aspen: implications for stomatal responses to vapor pressure deficit. Tree Physiology, 1997, 17 (8-9): 501- 509. doi: 10.1093/treephys/17.8-9.501
	Howard A R, Donovan L A. Helianthus nighttime conductance and transpiration respond to soil water but not nutrient availability. Plant Physiology, 2007, 143 (1): 145- 155. doi: 10.1104/pp.106.089383
	Huang C W, Domec J C, Ward E J, et al. The effect of plant water storage on water fluxes within the coupled soil–plant system. New Phytologist, 2017, 213 (3): 1093- 1106. doi: 10.1111/nph.14273
	Huang J T, Zhou Y X, Yin L H, et al. Climatic controls on sap flow dynamics and used water sources of Salix psammophila in a semi-arid environment in northwest China. Environmental Earth Sciences, 2015, 73 (1): 289- 301. doi: 10.1007/s12665-014-3505-1
	Jasechko S, Sharp Z D, Gibson J J, et al. Terrestrial water fluxes dominated by transpiration. Nature, 2013, 496 (7445): 347- 350. doi: 10.1038/nature11983
	Kim D, Oren R, Oishi A C, et al. Sensitivity of stand transpiration to wind velocity in a mixed broadleaved deciduous forest. Agricultural and Forest Meteorology, 2014, 187, 62- 71. doi: 10.1016/j.agrformet.2013.11.013
	Körner C. 1994. Scaling from species to vegetation: the usefulness of functional groups//Schulze E-D, Mooney H A, eds. Biodiversity and ecosystem function. Berlin, Heidelberg: Springer,117−140.
	Liu X M, Luo Y Z, Zhang D, et al. 2011. Recent changes in pan-evaporation dynamics in China. Geophysical Research Letters, 38(13): L13404-1–L13404-4.
	Lombardozzi D L, Zeppel M J B, Fisher R A, et al. Representing nighttime and minimum conductance in CLM4.5 global hydrology and carbon sensitivity analysis using observational constraints. Geoscientific Model Development, 2017, 10 (1): 321- 331. doi: 10.5194/gmd-10-321-2017
	Martínez-Vilalta J, Poyatos R., Aguadé D, et al. A new look at water transport regulation in plants. New Phytologis, 2014, 204 (1): 105- 115. doi: 10.1111/nph.12912
	McCarthy H R, Pataki D E. Drivers of variability in water use of native and non-native urban trees in the greater Los Angeles area. Urban Ecosystems, 2010, 13 (4): 393- 414. doi: 10.1007/s11252-010-0127-6
	Mcculloh K A, Johnson D M, Meinzer F C, et al. 2014. The dynamic pipeline: hydraulic capacitance and xylem hydraulic safety in four tall conifer species. Plant, Cell and Environment, 37(5): 1171–1183.
	McVicar T R, Roderick M L, Donohue R J, et al. Global review and synthesis of trends in observed terrestrial near-surface wind speeds: Implications for evaporation. Journal of Hydrology, 2012, 416/417, 182- 205. doi: 10.1016/j.jhydrol.2011.10.024
	Morison J I L, Baker N R, Mullineaux P M, et al. Improving water use in crop production. Philosophical Transactions of the Royal Society B: Biological Sciences, 2007, 363 (1491): 639- 658.
	Muchow R C, Fisher M J, Ludlow M M, et al. Stomatal behaviour of kenaf and sorghum in a semiarid tropical environment. II. during the day. Functional Plant Biology, 1980, 7 (5): 621- 628. doi: 10.1071/PP9800621
	Neumann R B, Cardon Z G, Teshera-Levye J, et al. 2014. Modelled hydraulic redistribution by sunflower (Helianthus annuus L. ) matches observed data only after including night-time transpiration. Plant, Cell & Environment, 37(4): 899–910.
	Nobel P S. 1999. Physicochemical & environmental plant physiology. Pittsburgh: Academic Press.
	Oren R, Sperry J S, Katul G G, et al. 1999. Survey and synthesis of intra- and interspecific variation in stomatal sensitivity to vapour pressure deficit. Plant, Cell & Environment, 22(12): 1515–1526.
	Phillips N G, Ryan M G, Bond B J, et al. Reliance on stored water increases with tree size in three species in the Pacific Northwest. Tree Physiology, 2003, 23 (4): 237- 245. doi: 10.1093/treephys/23.4.237
	Pivovaroff A L, Sack L & Santiago L S. Coordination of stem and leaf hydraulic conductance in southern California shrubs: a test of the hydraulic segmentation hypothesis. New Phytologist, 2014, 203 (3): 842- 850. doi: 10.1111/nph.12850
	Resco de Dios V. Circadian regulation and diurnal variation in gas exchange. Plant Physiology, 2017, 175 (1): 3- 4. doi: 10.1104/pp.17.00984
	Resco de Dios V, Chowdhury F I, Granda E, et al. Assessing the potential functions of nocturnal stomatal conductance in C₃ and C₄ plants. New Phytologist, 2019, 223 (4): 1696- 1706. doi: 10.1111/nph.15881
	Resco de Dios V, Díaz-Sierra R, Goulden M L, et al. Woody clockworks: circadian regulation of night-time water use in Eucalyptus globulus. New Phytologist, 2013, 200 (3): 743- 752. doi: 10.1111/nph.12382
	Resco de Dios V, Gessler A. Circadian regulation of photosynthesis and transpiration from genes to ecosystems. Environmental and Experimental Botany, 2018, 152, 37- 48. doi: 10.1016/j.envexpbot.2017.09.010
	Resco de Dios V, Gessler A, Ferrio J P, et al. Circadian rhythms have significant effects on leaf-to-canopy gas exchange under field conditions. GigaScience, 2016b, 5, 43. doi: 10.1186/s13742-016-0149-y
	Resco de Dios V, Gessler A, Ferrio J P, et al. Circadian rhythms regulate the environmental responses of net CO₂ exchange in bean and cotton canopies. Agricultural and Forest Meteorology, 2017, 239, 185- 191. doi: 10.1016/j.agrformet.2017.03.014
	Resco de Dios V, Goulden M L, Ogle K, et al. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems. Global Change Biology, 2012, 18 (6): 1956- 1970. doi: 10.1111/j.1365-2486.2012.02664.x
	Resco de Dios V, Loik M. E, Smith R, et al. 2016a. Genetic variation in circadian regulation of nocturnal stomatal conductance enhances carbon assimilation and growth. Plant, Cell & Environment, 39(1): 3–11.
	Scholz F G, Phillips N G, Bucci S J, et al. 2011. Hydraulic capacitance: biophysics and functional significance of internal water sources in relation to tree size//Meinzer F C, Lachenbruch B, Dawson T E, eds. Size- and age-related changes in tree structure and function. Dordrecht: Springer, 341–361.
	Tyree M T. Plant hydraulics: the ascent of water. Nature, 2003, 423 (6943): 923- 923. doi: 10.1038/423923a
	Venturas M D, Sperry J S, Hacke U G. Plant xylem hydraulics: what we understand, current research, and future challenges. Journal of Integrative Plant Biology, 2017, 59 (6): 356- 389. doi: 10.1111/jipb.12534
	Wu S P, Gu X X, Zheng Y H, et al. Nocturnal sap flow as compensation for water deficits: an implicit water-saving strategy used by mangroves in stressful environments. Frontiers in Plant Science, 2023, 14, 1118970. doi: 10.3389/fpls.2023.1118970
	Wu Y Z, Zhang Y K, An J, et al. Sap flow of black locust in response to environmental factors in two soils developed from different parent materials in the lithoid mountainous area of North China. Trees, 2018, 32 (3): 675- 688. doi: 10.1007/s00468-018-1663-6
	Xu H, Zhang Z Q, Chen J Q, et al. Regulations of cloudiness on energy partitioning and water use strategy in a riparian poplar plantation. Agricultural and Forest Meteorology, 2018, 262, 135- 146. doi: 10.1016/j.agrformet.2018.07.008
	Yu K L, Goldsmith G R, Wang Y J, et al. Phylogenetic and biogeographic controls of plant nighttime stomatal conductance. New Phytologist, 2019, 222 (4): 1778- 1788. doi: 10.1111/nph.15755
	Zeppel M J B, Lewis J D, Phillips N G, et al. Consequences of nocturnal water loss: a synthesis of regulating factors and implications for capacitance, embolism and use in models. Tree Physiology, 2014, 34 (10): 1047- 1055. doi: 10.1093/treephys/tpu089
	Zeppel M, Tissue D, Taylor D, et al. Rates of nocturnal transpiration in two evergreen temperate woodland species with differing water-use strategies. Tree Physiology, 2010, 30 (8): 988- 1000. doi: 10.1093/treephys/tpq053
	Zhu M X, Xue W L, Xu H, et al. Diurnal and seasonal variations in soil respiration of four plantation forests in an urban park. Forests, 2019, 10 (6): 513. doi: 10.3390/f10060513

样树编号 Tree No.	胸径 DBH/cm	树高 Tree height/m	冠幅 Canopy diameter/m		树冠投影面积 Crown projected area/m²	边材面积 Sapwood area/cm²
样树编号 Tree No.	胸径 DBH/cm	树高 Tree height/m	东西 East-west	南北 North-south	树冠投影面积 Crown projected area/m²	边材面积 Sapwood area/cm²
1	14	16	4.12	3.26	10.55	72.86
2	14.2	19.2	4.04	2.93	9.30	74.76
3	19.98	21.6	3.3	4.39	11.38	139.23
4	26.23	22.4	5.26	3.83	15.82	228.54
5	30.99	25.12	7.14	6.15	34.49	309.62
6	25.7	22.56	5.47	5.42	23.29	220.20
7*	36.53	21.9	7.46	6.8	39.84	417.72
8	40.28	19.2	9.16	8.14	58.56	499.07
9*	30.59	22.5	4.66	8.98	32.87	302.38
10*	33.97	20.7	5.90	9.8	45.41	365.96

类别 Category	全称 Full name	简写 Abbreviation	单位 Unit
树木水分生理指标 Tree water physiological indicators	气孔导度 Stomatal conductance	g_s	mol·m^?2 s^?1
	蒸腾速率 Transpiration rate	Tr	mmol·m^?2 s^?1
	叶片水势 Leaf water potential	Ψ	MPa
	树干液流密度 Sap flux density	J_s	g·cm^?2 s^?1
环境因子 Environmental factors	太阳辐射 Solar radiation	R_s	W·m^?2
	风速 Wind speed	v	m·s^?1
	大气温度 Air temperature	T_a	?C
	空气相对湿度 Relative humidity	RH	%
	饱和水汽压差 Vapor pressure deficit	VPD	kPa
	土壤含水量 Soil water content	SWC	m³·m^?3
	土壤水势 Soil water potential	SWP	kPa
	土壤温度 Soil temperature	ST	?C
昼夜节律因子 Circadian rhythm factors	日落后历时 Hours after dusk	t_night	h

水分生理指标 Water physiology indicators	饱和水汽压差 Vapor pressure deficit
水分生理指标 Water physiology indicators	R²	P
g_s	0.015	0.174
Tr	<0.001	0.937
Ψ	0.053	0.043
J_s	0.034	0.086

环境分组 Environmental grouping	分组依据 Basis for grouping	树木水分生理指标 Tree water physiological indicators	环境因子 Environmental factors
NU	R_s<5 W·m^?2 & $ \Delta $VPD≥0.1 kPa	g_s, Tr, Ψ, J_s	v, T_a, RH, VPD, SWC, SWP, ST, (t_night)
NS	R_s<5 W·m^?2 & ΔVPD<0.1 kPa	g_s, Tr, Ψ, J_s	T_a, RH, VPD, SWC, SWP, ST, (t_night)
DT	R_s≥5 W·m^?2	g_s, Tr, Ψ, J_s	R_s, v, T_a, RH, VPD, VWC, SWP, ST

生理指标 Physiology indicators	环境分组 Environmental grouping
生理指标 Physiology indicators	NU	NS	DT
g_s	54.9	28.4	40.4
Tr	67.1	26.1	51.9
Ψ	18.6	38.8	35.0
J_s	63.0	57.1	109.2