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Scientia Silvae Sinicae ›› 2018, Vol. 54 ›› Issue (9): 27-37.doi: 10.11707/j.1001-7488.20180904

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Influences of Elevated CO2 and Precipitation Regimes on Photosynthesis and Growth of Desert Shrub Reaumuria soongarica

Chong Peifang, Zhan Jin, Jia Xiangyang, Li Yi   

  1. College of Forestry, Gansu Agricultural University Lanzhou 730070
  • Received:2017-07-20 Revised:2017-08-29 Online:2018-09-25 Published:2018-09-10

Abstract: [Objective] At mospheric CO2 concentrations would increase from approximately 350 μmol·mol-1 today to over 700 μmo·mol-1 by the end of this century. The elevated CO2 islikely to have profound effects on the precipitation pattern in the future.This change would seriously affect the desert ecosystem,photosynthesis,above-and belowground biomass of desert plants,which could lead to the changes of ecosystem structure and function. Although many studies have examined the effects of precipitation and CO2,the interaction of changing precipitation pattern and elevated CO2 concentration on desert plantsis still not clear.[Methods] A pot experiment was conducted to study the interaction of elevated CO2 concentration and changing precipitation pattern on photosynthesis parameters such as photosynthesis rate and transpiration rate and so on, andon growth characteristics such as plant height,biomass and root/shoot ratio(R/S) of Reaumuria soongarica thatis a dominant plant species of desert steppe in the arid region of China, in order to assess the possible effect of global climate change on desert ecosystem. The two-year-old seedlings were subjected to two CO2 concentrations (350 and 700 μmol·mol-1) and three precipitation levels[natural precipitationas control(0), precipitation minus 30% (-30%), precipitation plus 30%(+30%)].[Result] Doubled CO2 concentration increased the photosynthesis rate and decreased the transpiration rate and stomatal conductance (P<0.05).The increase of precipitation by 30% had a significant promoting influence on the photosynthesis rateunder the elevated CO2,and a certain compensation effect on the transpiration rate and stomatal conductance inhibited by the elevated CO2.Long-term treatment with increased CO2 led to the photosynthetic acclimation by reducing the photosynthetic capacity.Elevated CO2 concentration and increasing precipitation were able to significantly stimulate the increase of plant height,aboveground biomass and total biomass of R.soongarica, and the elevated CO2 concentration reduced the decrease of the R.soongarica growth caused by the decrease of rainfall.Root biomass were increased under precipitation reduction by elvated CO2 concentration.

Key words: elevated CO2 concentration, precipitation, photosynthesis, biomass, Reaumuria soongarica

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