干旱区研究

Arid Zone Research ›› 2016, Vol. 33 ›› Issue (1): 172-178.doi: 10.13866/j.azr.2016.01.22

• Plant Ecology • Previous Articles     Next Articles

Response of Populus euphratica at Different Ages to Rainfall Pulses in the Desert Riparian Forest of the Lower Reaches of the Heihe River

LIU Shu-bao1,2, CHEN Ya-ning2, CHEN Ya-peng2, LI Yang3, REN Zhi-guo4   

  1. 1. Xinjiang Key Laboratory for Environmental pollution monitoring and risk warning,Xinjiang Academy of Environmental Protection Science,Urumqi 830011,Xinjiang,China;
    2. State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,Xinjiang,China;
    3. Nuclear and Radiation Safety Center,Ministry of Environmental Protection,Beijing 100082,China;
    4. Heihe Remote Sensing Experimental Research Station,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,Gansu,China
  • Received:2014-03-05 Revised:2014-06-20 Online:2016-01-15 Published:2016-01-29

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Abstract: Stable isotopes of oxygen and hydrogen were considered to be a good tool and have been used to identify the source of water,because different source of water possess different oxygen or hydrogen isotope signatures.Until now,several approaches have been developed to quantify the contribution of different water source to plants based on the isotopic mass-balance principal.We researched the response of Populus euphratica for different ages to rainfall pulsation,playing a key role in formulating the conservation strategy of Populus euphratica under the climate change.In this study,we analyzed the soil water of different depth,groundwater and precipitation on the contribution ratio of plants,combined with the change of soil water content,discussed the response of Populus euphratica to rainfall pulsation before and after rain,based on the composition of the stable oxygen and hydrogen isotope (δ18O,δD) of the xylem of Populus euphratica in different ages and different potential water sources in the lower reaches of the Heihe River.The results showed that:① There were significant differences of δ18O value in the xylem of young Populus euphratica before and after rain,-3.498‰ and -7.928‰,but there were no significant differences of mature Populus euphratica,-7.202‰ and -7.225‰;② Water source absorption ratio changes greatly of young Populus euphratica before and after rain.Before rain,the main absorption of 0-30 cm of soil water,the using proportion is as high as 88%-90%,the mean value of 89.9%,only using 2.9% underground water.After the rain,the use of precipitation is up to 60%,the mean value of 19%;The main water sources of mature Populus euphratica were underground water and deep subsoil water.The depth range of the mature Populus euphratica is wider than young Populus euphratica.

Key words: rainfall, Populus euphratica, isotopes, Heihe River