植物生态学报 ›› 2015, Vol. 39 ›› Issue (12): 1176-1187.DOI: 10.17521/cjpe.2015.0114

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黄土丘陵区刺槐和侧柏人工林树干液流特征及其对降水的响应

吴旭1, 陈云明2,3,,A;*(), 唐亚坤2,3   

  1. 1西北农林科技大学水土保持研究所, 陕西杨凌 712100
    2西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室, 陕西杨凌712100
    3中国科学院水利部水土保持研究所, 陕西杨凌 712100
  • 出版日期:2015-12-01 发布日期:2015-12-31
  • 通讯作者: 陈云明
  • 作者简介:

    # 共同第一作者

  • 基金资助:
    国家自然科学基金(41371506)、公益性行业(国家气象局)科研专项(重大专项)(GYHY20- 15060013)和西北农林科技大学博士科研启动费 (Z109021508)

Sap flow characteristics and its responses to precipitation in Robinia pseudoacacia and Platycladus orientalis plantations

WU Xu1, CHEN Yun-Ming2,3,*(), TANG Ya-Kun2,3   

  1. 1Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
    2State Key Laboratory of Soil Erosion and Dry-land Farming on Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
    and 3Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China
  • Online:2015-12-01 Published:2015-12-31
  • Contact: Yun-Ming CHEN
  • About author:

    # Co-first authors

摘要:

水分供应不足及水热不同步常导致黄土丘陵地区在春末和夏初出现季节性干旱。为阐明该地区主要造林树种的蒸腾耗水特征及其对降水的响应, 使用热扩散式树干茎流计(TDP)于2009年4-10月对黄土丘陵区安塞国家生态试验站刺槐(Robinia pseudoacacia)和侧柏(Platycladus orientalis)的树干液流密度(Fd)进行连续观测, 并同步测定了气象、土壤水分等环境因子。结果表明: 刺槐和侧柏在生长季内不同生长时期的Fd均表现为单峰型日变化特征, 刺槐最高液流峰值为0.12068 m3·m-2·h-1, 是侧柏最高液流值(0.03737 m3·m-2·h-1)的3.23倍。除生长旺盛季(7-8月)外, 刺槐和侧柏降水后的Fd明显高于降水前。同时反映水汽压差(VPD)和太阳辐射(Rs)的蒸腾变量(VT)能够很好地模拟Fd, 且两者呈显著的指数正相关关系, 随VT的增加Fd逐渐增大, VT增加到50 kPa (W·m-2)1/2左右时, Fd的变化趋于稳定; 通过对降水前后两个树种水力导度(拟合参数b值)分析, 相对于侧柏, 刺槐更易受降水的影响(p < 0.001)。因此, 可认为刺槐是降水敏感型植物, 而侧柏是降水不敏感型植物。该研究通过分析黄土丘陵区人工林树种对降水的差异性响应, 从树木水分利用方面能够为当地生态恢复过程中人工林的管理提供科学依据。

关键词: 刺槐, 侧柏, 树干液流, 环境因素, 水分利用

Abstract:

Aim In the loess hilly region, drought stress frequently occurs during the late spring and early summer as a result of insufficient water supply and asynchronous changes between temperature and precipitation. Our objective was to quantify the characteristics of water-consumption through transpirations and their responses to precipitation in the dominant plantations in this region. Methods Thermal dissipation probe (TDP) was used to measure the sap flow density (Fd) of Robinia pseudoacacia and Platycladus orientalis from April through October in 2009 in Ansai National Ecological Experimental Station. Environmental variables, including meteorological factors and soil water content, were simultaneously measured. Important findings The diurnal variation of Fd exhibited a single-peak curve during the growing season of R. pseudoacacia and P. orientalis. The maximum Fd was three times greater in R. pseudoacacia (0.12068 m3·m-2·h-1) than that in P. orientalis (0.03737 m3·m-2·h-1). Except in the rapid-growth season (July to August), the Fd of these two species during the post-precipitation period were significantly higher than that during the pre-precipitation period. The Fd of P. orientalis and R. pseudoacacia was well fitted with transpiration (VT), an integrated index calculated from both vapor pressure deficit (VPD) and solar radiation (Rs), using an exponential saturation function. Generally, Fd increased in response to rising VT, while these values tended to be stable when VT reached about 50 kPa (W·m-2)1/2. Furthermore, R. pseudoacacia showed more sensitive to precipitation (p < 0.001) than P. orientalis, according to different hydraulic conductance model coefficients (fitting parameter b) between pre- and post-precipitation periods. Therefore, R. pseudoacacia could be considered as a precipitation-sensitive species, while P. orientalisasa precipitation-insensitive species. Through analyzing the different responses of plantation species to precipitation in the loess hilly region, this study provides a scientific basis for the local plantation management from the aspect of tree water use during ecological restoration.

Key words: Robinia pseudoacacia, Platycladus orientalis, sap flow, environmental parameters, water use