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Bulletin of Botanical Research ›› 2022, Vol. 42 ›› Issue (2): 299-308.doi: 10.7525/j.issn.1673-5102.2022.02.015

• Physiology and Ecology • Previous Articles     Next Articles

Yaqi Dai1, Yanping Liu1,3, Lu Han2,3, Haizhen Wang2,3,*   

  1. 1.College of Life Science,Tarim University,Alar 843300
    2.College of Plant Science,Tarim University,Alar 843300
    3.Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin,Xinjiang Production & Construction Corps,Alar 843300
  • Received:2021-03-04 Online:2022-03-20 Published:2022-02-22
  • Contact: Haizhen Wang
  • About author:Dai Yaqi(1996—),femal,master candidate,mainly engaged in physiological research of plant stress.
  • Supported by:
    National Natural Science Foundation of China(31660117);Regional Innovation Guidance Plan of Xinjiang Production and Construction Corps(2018BB047)


In order to explore the eco-physiological mechanism of Populus euphratica Oliv adapting to the arid desert environment,P. euphratica Oliv. that the key species in the Tarim desert ecosystem was used as material. It was conducted to research the change of photosynthetic gas exchange, antioxidative enzyme activity and osmoregulation substances of P. euphratica grown at different groundwater depths(GWD). The results showed that:(1) the diurnal courses of net photosynthetic rate(Pn), transpiration rate(Tr) and stomatal conductance(Gs) of P. euphratica under different GWD conditions showed the single peak curves respectively, while the diurnal variation of intercellular CO2 mole fraction(Ci) were the “V” curve, the valley value was significantly reduced at GWD=5.5 m(P<0.01) respectively. Pn and Gs changed synchronously, and the peak value appeared at 12:00, while the Tr peak value lagged 2 hours. The peak values of Pn in different GWD were significantly different(P<0.05), while the peak values of TrGs and Ci valley were significantly reduced in GWD=5.5 m(P<0.01) respectively. PnTrGs Ci, water-use efficiency(WUE) and light utilization efficiency(LUE) decreased with GWD increasing, and the daily mean value of Gs and LUE significantly decreased at GWD=5.5 m(P<0.05) respectively. However, there was no significant difference in the daily mean values of PnTrCi and WUE under different GWD conditions(P>0.05) respectively; (2)The decline of Pn in P. euphratica from 12:00-16:00 was mainly restricted by stomatal factors, while the decline of Pn from 16:00-20:00 was mainly limited by non-stomatal factors; (3)The relationship between eco-physiological factors and PnTr under different GWD conditions were analyzed with correlation, partial correlation and stepwise regression methods, it was found that Gs was the main factor affecting Pn and Tr of P. euphratica respectively. The correlation degree between Pn and photosynthetically active radiation(PAR), Tr and Gs were enhanced respectively with GWD increasing, indicating that GWD directly regulated the air-water exchange; (4)The malondialdehyde content(MDA), superoxide dismutase activity(SOD), peroxidase activity(POD) and free proline content(Pro) were increased respectively with GWD increasing, but the content of soluble protein(SP), soluble sugar(SS) were both decreased, which indicated that the cell membrane permeability and photosynthetic carbon assimilation were inhibited respectively with GWD increasing. P. euphratica enhanced the protective enzyme activity(POD, SOD) and osmoregulation content(Pro) to cooperate against drought stress caused by GWD increasing, and ensured to maintain the basic normal physiological activities. This was the eco-physiological strategy for P. euphratica to adapt arid desert environment.

Key words: Populus euphratica Oliv., groundwater depth, gas exchange, osmoregulation substances, protective enzyme activity

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