西藏拉萨河谷区藏川杨和北京杨树干液流特征及其对环境因子的响应（英文）
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摘要
【目的】研究西藏拉萨半干旱河谷地带藏川杨和北京杨树干液流的干湿季变化特征及环境影响因素,以期为该地区造林树种选择和合理配置提供科学依据。【方法】运用Granier热扩散探针技术,于2015年旱季和雨季在西藏拉萨半干旱河谷对藏川杨和北京杨的树干液流进行连续观测,并同步测定太阳辐射(Q)、空气温度(T_a)、土壤含水量(SWC)、饱和蒸气压亏缺(VPD)等环境因子。【结果】1)拉萨河谷区主要气象因子在旱季和雨季存在较大差异,雨季的Q、T_a、SWC、VPD等均高于旱季,主要气象因子的平均值为雨季的60%左右。2)藏川杨和北京杨的树干液流日变化表现出昼高夜低的规律,二者在雨季的日变化为多峰曲线,旱季为单峰曲线。旱季和雨季藏川杨液流速率均显著大于北京杨,北京杨液流密度在旱季和雨季相比藏川杨的液流密度分别下降71%和58%;相比雨季的液流密度,2种杨树的液流密度在旱季分别下降65%和76%。3)在旱季和雨季,主要环境因子Q和VPD与2种杨树树干液流间具有显著相关性,且Q和VPD的日变化与2种杨树的液流速率日变化之间存在明显的时滞效应。Q和VPD对北京杨树干液流的影响小于对藏川杨树干液流的影响。【结论】在拉萨河谷区旱季和雨季较大气候差异的环境下,藏川杨和北京杨树干液流速率均具有较为明显的昼夜节律。但2树种树干液流在峰值、日平均值、启动时间以及受环境因子的影响方面均存在明显差异,特别是在干旱季节尤为显著,藏川杨作为乡土树种显示出更强的适应性。
【Objective】 In this study, the dry-wet seasonal variation characteristics of sap flow of the two afforestation poplar species in semi-arid Lhasa river valley, and the environmental impact factors were investigated in order to provide a theoretical base for species selection for vegetation reconstruction in the river valley. 【Method】 The Granier's thermal dissipation probe was employed to continuously measure the stem sap flow of Populus beijingensis and Populus szechuanica during the wet and dry seasons. At the same time, environmental factors, such as solar radiation(Q), air temperature(T_a), soil water content(SWC), and vapor pressure deficit(VPD), were recorded. 【Results】 The main meteorological factors in the Lhasa river valley were quite different in wet and dry seasons. The Q, T_a, SWC, and VPD values during the wet season were higher than that in the dry season, and the average of them in the dry season wrer around 60% of those in wet season. In both seasons, the sap flow velocity in P. beijingensis was lower than that in P. szechuanica. The sap flux density of P. beijingensis was 71% and 58% lower than those of P. szechuanica during the dry and wet seasons, respectively. During the dry season, the sap flux density of two poplars declined by 65% and 76% compared with that in wet season. The main environmental factors of Q and VPD had less influence on the stem sap flow of P. beijingensis than on that of P. szechuanica. 【Conclusion】 In the Lhasa river valley area between dry and rainy season, the sap flux density of two poplar species all had obvious circadian rhythm. However, there were significant differences in peak value, daily average value, start-up time and the impact environmental factors between the two species, especially in the dry season. P. szechuanica, as native tree species, showed a stronger adaptability.
【Objective】 In this study, the dry-wet seasonal variation characteristics of sap flow of the two afforestation poplar species in semi-arid Lhasa river valley, and the environmental impact factors were investigated in order to provide a theoretical base for species selection for vegetation reconstruction in the river valley. 【Method】 The Granier's thermal dissipation probe was employed to continuously measure the stem sap flow of Populus beijingensis and Populus szechuanica during the wet and dry seasons. At the same time, environmental factors, such as solar radiation(Q), air temperature(T_a), soil water content(SWC), and vapor pressure deficit(VPD), were recorded. 【Results】 The main meteorological factors in the Lhasa river valley were quite different in wet and dry seasons. The Q, T_a, SWC, and VPD values during the wet season were higher than that in the dry season, and the average of them in the dry season wrer around 60% of those in wet season. In both seasons, the sap flow velocity in P. beijingensis was lower than that in P. szechuanica. The sap flux density of P. beijingensis was 71% and 58% lower than those of P. szechuanica during the dry and wet seasons, respectively. During the dry season, the sap flux density of two poplars declined by 65% and 76% compared with that in wet season. The main environmental factors of Q and VPD had less influence on the stem sap flow of P. beijingensis than on that of P. szechuanica. 【Conclusion】 In the Lhasa river valley area between dry and rainy season, the sap flux density of two poplar species all had obvious circadian rhythm. However, there were significant differences in peak value, daily average value, start-up time and the impact environmental factors between the two species, especially in the dry season. P. szechuanica, as native tree species, showed a stronger adaptability.
引文
Baker J M, Bavel C H M V. 1987. Measurement of mass flow of water in the stems of herbaceous plants. Plant Cell and Environment, 10(10):777-782.
Bauerle W L, Whitlow T H, Pollock C R. 2002. A laser diode based system for measuring sap flow by the heat-pulse method. Agricultural and Forest Meteorology, 110(4):275-284.
Chang X X, Zhao W Z, Zhang Z H. 2007. Water consumption characteristic of Haloxylon ammodendron for sand bindingin desert area. Acta Ecologica Sinica, 27(5):1826-1837.
Chi B, Cai T J, Man X L. 2013. Effects of influencing factors on stem sap flow in Larix gmelinii in northern Da Hinggan Mountains, northeastern China. Journal of Beijing Forestry University, 35(4):21-26.
Chen J, Ou Y X, Huang D W. 2015. Sap flow characteristics of four dominant tree species in a mixed conifer broadleaf forest in Dinghushan. Acta Ecologica Sinica, 35(12): 4097-4104.
Daley M J, Phillips N G. 2006. Interspecific variation in nighttime transpiration and stomatal conductance in a mixed New England deciduous forest. Tree Physiology, 26(4):411-419.
Granier A, Bobay V, Cash J H C. 1990. Vapour flux density and transpiration rate comparisons in a stand of maritime pine (Pinus pinaster Ait.) in Les Landed forest. Agricultural and Forest Meteorology, 51(4):309-319.
Granier A. 1987. Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements. Tree Physiology, 3(4):309-320.
Guan D X, Zhang X J, Yuan F H. 2012. The relationship between sap flow of intercropped young poplar trees (Populus× euramericana cv.N3016) and environmental factors in a semiarid region of northeastern China. Hydrological Processes, 26(19):2925-2937.
He Y T, Shi P L, Zhang X Z. 2009. Fine root production and turnover of poplar plantation in the Lhasa river valley, Tibet Autonomous Region. Acta Ecologica Sinica, 29(6): 2877-2883.
Lapitan R L, Parton W J. 1996. Seasonal variabilities in the distribution of the microclimatic factors and evapotranspiration in a short grass steppe. Agricultural and Forest Meteorology, 79(1-2):113-130.
Li G D, Fu F Z, Xi B Y. 2016. Study of transpiration and water consumption of triploid Pulus tomentosa at individual tree and stand scales by using thermal dissipation technology. Acta Ecologica Sinica, 36(10): 2945-2953.
Lu Y P, Mu X T. 1986. Climatic Characteristics of Lhasa River Basin. Meteorological, 1(7):24-25.
Luo C, Zha T G, Zhu M X. 2016. Influences of shallow groundwater on sap flow of riparian poplar plantations in northern China. Chinese Journal of Applied Ecology, 27(5):1401-1407.
Ma J X, Chen Y N, Li W H. 2011. Sap flow characteristics of four typical species in desert shelter forest and their responses to environmental factors. Environmental Earth Sciences, 67(1):151-160.
Mo K L, Chen L X, Zhou J. 2014. Transpiration responses of a poplar plantation to the environmental conditions on a floodplain in Northern China. Acta Ecologica Sinica, 34(20):5812-5822.
Ni C Y, Zhao P, Zhu L W. 2015. Hydraulic responses of whole tree transpiration of Schima superha to soil moisture in dry and wet seasons. Acta Ecologica Sinica, 35(3):652-662.
Norman J M. 1998. Introduction to environmental biophysics. Springer, 21(2):104.
Prior L D, Brodribb T J, Dyp T. 2013. From desert to rainforest, sapwood width is similar in the widespread conifer Callitris columellaris. Trees, 27(27):123-129.
Schaeffer S M, Williams D G, Goodrich D C. 2000. Transpiration of cotton wood willow forest estimated from sap flux. Agricultural and Forest Meteorology, 105(1/3):257-270.
Sun P S, Ma LY, Wang X P. 2000. Temporal and special variation of sap flow of Chinese pine (Pinus tabulaeformis). Journal of Beijing Forestry University, 22(5):1-6.
Tang X, Cui J H, Zhao X Y. 2011. Characteristics of maize transpiration and soil evaporation in Horqin sandland. Pratacultural Science, 28(5):788-792.
Wang X F, Sun Y Y, Li K. 2013. Seasonal dynamics of Albizia kalkora stem sap flow in Yunmou dry-hot valley of Southwest China. Chinese Journal of Ecology, 32(3):597-603.
Wu X, Chen Y M, Tang Y K. 2015. Sap flow characteristics and its responses to precipitation in Robinia pseudoacacia and Platycladus orientalis plantations. Chinese Journal of Plant Ecology, 39(12):1176-1187.
Xu S Q, Ji X B, Jin B W. 2015. Dynamics and responses of sap flow of typical sand binding plants Haloxylon ammodendron to environmental variables. Chinese Journal of Plant Ecology, 39(9): 890-900.
Xu X Y, Sun B P, Ding G D. 2008. Sap flow patterns of three main sand-fixing shrub sand the responses to environmental factors in desert areas. Acta Ecologica Sinica, 28(3):895-905.
Yan X L, Xi B Y, Jia L M, et al. 2015. Response of sap flow to flooding in plantations of irrigated and non-irrigated triploid poplar. Journal of Forest Research, 20(4):1-11.
Yang X L, Zhao K T, Ma H P. 2010. Ecological studies on vegetation quantity in the semiarid valley region of Lasa. Scientia Silvea Sinicae, 46(10):15-22.
Yang Z G, Shi Y, Yu X X. 2012. Characteristic of stem sap flux velocity of individual trees and its response to environmental factors in the Beijing Mountain area. Research of soil and Water Conservatlon, 19(2):195-200.
Yunusa I A M, Walker R R, Loveys B R. 2000. Determination of transpiration in irrigated grapevines: comparison of the heat-pulse technique with gravimetric and micrometeorological methods. Irrigation Science, 20(1):1-8.
Zang C X, Yang J, Yuan J. 2010. Relationships between whole plant sap flux characteristics of Caragana intermedia and environmental factors in loess hill gully region. Chinese Journal of Ecology, 29(3):420-426.
Zhang X Y, Gong J D, Zhou M X. 2003. A Study on the stem sap flow of Populus euphrtaicr and Tamaris spp. by heat pulse technique. Journal of Glaciology and Geocryology, 25(5):585-590.
Zhao CY, Si J H, Feng Q. 2014. Xylem sap flow of Populus euphratica in relation to environmental factors in the lower reaches of Heihe. Journal of Desert Research, 34(3): 718-724.
Zhao K T, Yang X L, Ma H P. 2013. Analyses on community characteristics and soil microorganism dynamics during ecological restoration of Sophora moorcroftiana in the semiarid valley of Lhasa. Scientia Silvea Sinicae, 49(2): 15-20.
Bauerle W L, Whitlow T H, Pollock C R. 2002. A laser diode based system for measuring sap flow by the heat-pulse method. Agricultural and Forest Meteorology, 110(4):275-284.
Chang X X, Zhao W Z, Zhang Z H. 2007. Water consumption characteristic of Haloxylon ammodendron for sand bindingin desert area. Acta Ecologica Sinica, 27(5):1826-1837.
Chi B, Cai T J, Man X L. 2013. Effects of influencing factors on stem sap flow in Larix gmelinii in northern Da Hinggan Mountains, northeastern China. Journal of Beijing Forestry University, 35(4):21-26.
Chen J, Ou Y X, Huang D W. 2015. Sap flow characteristics of four dominant tree species in a mixed conifer broadleaf forest in Dinghushan. Acta Ecologica Sinica, 35(12): 4097-4104.
Daley M J, Phillips N G. 2006. Interspecific variation in nighttime transpiration and stomatal conductance in a mixed New England deciduous forest. Tree Physiology, 26(4):411-419.
Granier A, Bobay V, Cash J H C. 1990. Vapour flux density and transpiration rate comparisons in a stand of maritime pine (Pinus pinaster Ait.) in Les Landed forest. Agricultural and Forest Meteorology, 51(4):309-319.
Granier A. 1987. Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements. Tree Physiology, 3(4):309-320.
Guan D X, Zhang X J, Yuan F H. 2012. The relationship between sap flow of intercropped young poplar trees (Populus× euramericana cv.N3016) and environmental factors in a semiarid region of northeastern China. Hydrological Processes, 26(19):2925-2937.
He Y T, Shi P L, Zhang X Z. 2009. Fine root production and turnover of poplar plantation in the Lhasa river valley, Tibet Autonomous Region. Acta Ecologica Sinica, 29(6): 2877-2883.
Lapitan R L, Parton W J. 1996. Seasonal variabilities in the distribution of the microclimatic factors and evapotranspiration in a short grass steppe. Agricultural and Forest Meteorology, 79(1-2):113-130.
Li G D, Fu F Z, Xi B Y. 2016. Study of transpiration and water consumption of triploid Pulus tomentosa at individual tree and stand scales by using thermal dissipation technology. Acta Ecologica Sinica, 36(10): 2945-2953.
Lu Y P, Mu X T. 1986. Climatic Characteristics of Lhasa River Basin. Meteorological, 1(7):24-25.
Luo C, Zha T G, Zhu M X. 2016. Influences of shallow groundwater on sap flow of riparian poplar plantations in northern China. Chinese Journal of Applied Ecology, 27(5):1401-1407.
Ma J X, Chen Y N, Li W H. 2011. Sap flow characteristics of four typical species in desert shelter forest and their responses to environmental factors. Environmental Earth Sciences, 67(1):151-160.
Mo K L, Chen L X, Zhou J. 2014. Transpiration responses of a poplar plantation to the environmental conditions on a floodplain in Northern China. Acta Ecologica Sinica, 34(20):5812-5822.
Ni C Y, Zhao P, Zhu L W. 2015. Hydraulic responses of whole tree transpiration of Schima superha to soil moisture in dry and wet seasons. Acta Ecologica Sinica, 35(3):652-662.
Norman J M. 1998. Introduction to environmental biophysics. Springer, 21(2):104.
Prior L D, Brodribb T J, Dyp T. 2013. From desert to rainforest, sapwood width is similar in the widespread conifer Callitris columellaris. Trees, 27(27):123-129.
Schaeffer S M, Williams D G, Goodrich D C. 2000. Transpiration of cotton wood willow forest estimated from sap flux. Agricultural and Forest Meteorology, 105(1/3):257-270.
Sun P S, Ma LY, Wang X P. 2000. Temporal and special variation of sap flow of Chinese pine (Pinus tabulaeformis). Journal of Beijing Forestry University, 22(5):1-6.
Tang X, Cui J H, Zhao X Y. 2011. Characteristics of maize transpiration and soil evaporation in Horqin sandland. Pratacultural Science, 28(5):788-792.
Wang X F, Sun Y Y, Li K. 2013. Seasonal dynamics of Albizia kalkora stem sap flow in Yunmou dry-hot valley of Southwest China. Chinese Journal of Ecology, 32(3):597-603.
Wu X, Chen Y M, Tang Y K. 2015. Sap flow characteristics and its responses to precipitation in Robinia pseudoacacia and Platycladus orientalis plantations. Chinese Journal of Plant Ecology, 39(12):1176-1187.
Xu S Q, Ji X B, Jin B W. 2015. Dynamics and responses of sap flow of typical sand binding plants Haloxylon ammodendron to environmental variables. Chinese Journal of Plant Ecology, 39(9): 890-900.
Xu X Y, Sun B P, Ding G D. 2008. Sap flow patterns of three main sand-fixing shrub sand the responses to environmental factors in desert areas. Acta Ecologica Sinica, 28(3):895-905.
Yan X L, Xi B Y, Jia L M, et al. 2015. Response of sap flow to flooding in plantations of irrigated and non-irrigated triploid poplar. Journal of Forest Research, 20(4):1-11.
Yang X L, Zhao K T, Ma H P. 2010. Ecological studies on vegetation quantity in the semiarid valley region of Lasa. Scientia Silvea Sinicae, 46(10):15-22.
Yang Z G, Shi Y, Yu X X. 2012. Characteristic of stem sap flux velocity of individual trees and its response to environmental factors in the Beijing Mountain area. Research of soil and Water Conservatlon, 19(2):195-200.
Yunusa I A M, Walker R R, Loveys B R. 2000. Determination of transpiration in irrigated grapevines: comparison of the heat-pulse technique with gravimetric and micrometeorological methods. Irrigation Science, 20(1):1-8.
Zang C X, Yang J, Yuan J. 2010. Relationships between whole plant sap flux characteristics of Caragana intermedia and environmental factors in loess hill gully region. Chinese Journal of Ecology, 29(3):420-426.
Zhang X Y, Gong J D, Zhou M X. 2003. A Study on the stem sap flow of Populus euphrtaicr and Tamaris spp. by heat pulse technique. Journal of Glaciology and Geocryology, 25(5):585-590.
Zhao CY, Si J H, Feng Q. 2014. Xylem sap flow of Populus euphratica in relation to environmental factors in the lower reaches of Heihe. Journal of Desert Research, 34(3): 718-724.
Zhao K T, Yang X L, Ma H P. 2013. Analyses on community characteristics and soil microorganism dynamics during ecological restoration of Sophora moorcroftiana in the semiarid valley of Lhasa. Scientia Silvea Sinicae, 49(2): 15-20.