植物生态学报 ›› 2016, Vol. 40 ›› Issue (12): 1298-1309.DOI: 10.17521/cjpe.2016.0012

• 研究论文 • 上一篇    下一篇

不同地下水矿化度对柽柳光合特征及树干液流的影响

孔庆仙1,2, 夏江宝2,*, 赵自国2, 屈凡柱2   

  1. 1北京林业大学水土保持学院, 北京 100083
    2滨州学院山东省黄河三角洲生态环境重点实验室, 山东滨州 256603
  • 出版日期:2016-12-31 发布日期:2016-12-30
  • 通讯作者: 夏江宝
  • 基金资助:
    国家自然科学基金(31370702)、山东省自然科学基金省属高校优秀青年人才联合基金(ZR2015JL014)和山东省重点研发计划项目(2015GNC111022)

Effects of groundwater salinity on the characteristics of leaf photosynthesis and stem sap flow in Tamarix chinensis

Qing-Xian KONG1,2, Jiang-Bao XIA2,*, Zi-Guo ZHAO2, Fan-Zhu QU2   

  1. 1College of Water and Soil Conservation, Beijing Forestry University, Beijing 100083, China
    and
    2Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta, Binzhou University, Binzhou, Shandong 256603, China
  • Online:2016-12-31 Published:2016-12-30
  • Contact: Jiang-Bao XIA

摘要:

为揭示柽柳(Tamarix chinensis)光合能力及耗水特征对地下水矿化度的响应规律, 以黄河三角洲建群种——柽柳3年生植株为研究对象, 在1.2 m的潜水水位下, 模拟设置淡水、微咸水、咸水和盐水4种不同的地下水矿化度, 测定柽柳叶片光合-光响应、蒸腾速率和树干液流的日变化。结果表明: 地下水矿化度通过影响土壤盐分可显著影响柽柳光合特性及耗水性能。随地下水矿化度升高, 柽柳叶片净光合速率(Pn)、最大Pn、蒸腾速率、气孔导度、表观量子效率和暗呼吸速率均先升高后降低, 而水分利用效率(WUE)持续降低。淡水、微咸水和盐水处理下, 柽柳Pn光响应平均值分别比咸水处理降低44.1%、15.1%和62.6%; 微咸水、咸水和盐水处理下, 柽柳WUE光响应平均值分别比淡水处理降低25.0%、29.2%和41.7%。随地下水矿化度升高, 柽柳叶片光饱和点先升高后降低, 而光补偿点持续升高, 光照生态幅变窄, 光能利用率变低。淡水和盐水处理下, 柽柳Pn下降分别是非气孔限制和气孔限制引起的。柽柳树干液流速率随地下水矿化度升高而先升高后降低, 咸水处理下树干液流速率日变幅最大, 日液流量最高。淡水、微咸水和盐水处理下日液流速率平均值分别比咸水处理降低61.8%、13.1%和41.9%。咸水矿化度下柽柳有较高的光合特性, 在蒸腾耗水较严重的情况下可实现高效生理用水, 适宜柽柳较好地生长。

关键词: 光合作用, 液流, 耗水, 蒸腾速率, 水分利用效率, 盐胁迫, 地下水, 黄河三角洲

Abstract: AimsThe objective of this study was to investigate the change pattern of leaves photosynthesis and stem sap flow of Tamarix chinensisin under different groundwater salinity, which can be served as a theoretical basis and technical reference for cultivation and management of T. chinensis in shallow groundwater table around Yellow River Delta.MethodsThree-year-old T. chinensis, one of the dominated species in Yellow River Delta, was selected. Plants were treated by four different salinity concentrations of groundwater—fresh water (0 g∙L-1), brackish water (3.0 g∙L-1), saline water (8.0 g∙L-1), and salt water (20.0 g∙L-1) under 1.2 m groundwater level. Light response of photosynthesis and the diurnal courses of leaf transpiration rate, stem sap flux velocity and environment factors under different groundwater salinity were determined via LI-6400XT portable photosynthesis system and a Dynamax packaged stem sap flow gauge based on stem-heat balance method, respectively.Important findings The result showed that groundwater salinity had a significant impact on photosynthesis efficiency and water consumption capacity of T. chinensis by influencing the soil salt. The net photosynthetic rate (Pn), maximum Pn, transpiration rate, stomatal conductance, apparent quantum yield and dark respiration rate increased first and then decreased with increasing groundwater salinity, while the water use efficiency (WUE) continuously decreased. The mean Pn under fresh water, brackish water and salt water decreased by 44.1%, 15.1% and 62.6%, respectively, compared with that under saline water (25.90 µmol∙m-2∙s-1). The mean WUE under brackish water, saline water and salt water decreased by 25.0%, 29.2% and 41.7%, respectively, compared with that under fresh water (2.40 µmol∙mmol-1). With the increase of groundwater salinity from brackish water to salt water, light saturation point of T. chinensisdecreased while the light compensation point increased, which lead to the decrease of light ecological amplitude and light use efficiency. Fresh water and brackish water treatment helped T. chinensis to use low or high level light, which could significantly improve the utilization rate of light energy. The decrease in Pn of T. chinensis was mainly due to non-stomatal limitation under treatment from saline water to fresh water, while the decrease in Pn of T. chinensis was due to stomatal limitation from saline water to salt water. With increasing groundwater salinity, stem sap flux velocity of T. chinensis increased firstly and then decreased, reached the maximum value under saline water. The mean stem sap flux velocity under fresh water, brackish water and salt water decreased by 61.8%, 13.1% and 41.9%, respectively, compared with that under saline water (16.96 g·h-1). Tamarix chinensis had higher photosynthetic productivity under saline water treatment, and could attained high WUE under severe water deprivation by transpiration, which was suitable for the growth of T. chinensis.

Key words: photosynthetic efficiency, sap flow, water consumption, transpiration rate, water use efficiency, salt stress, groundwater, Yellow River Delta