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Bulletin of Botanical Research ›› 2020, Vol. 40 ›› Issue (3): 476-480.doi: 10.7525/j.issn.1673-5102.2020.03.020

• Scientific Notes • Previous Articles    

Root CO2 Efflux Variations of Betula platyphylla Among Sites and Root Diameter Classes in 12 Different Provenances

SUN Shuo, WANG Xiu-Wei, DU Meng-Tian, LI Jing-Hang, WANG Bo-Yi, LIU Gui-Feng   

  1. Ministry of Education Key Laboratory of Sustainable Forest Ecosystem Management, School of Forestry, Northeast Forestry University, Harbin 150040
  • Received:2019-10-29 Online:2020-05-05 Published:2020-05-29
  • Supported by:
    This research was financially supported by the National Natural Science Foundation of China(31670476);National Key R&D Program(2018YFC05070030);Fundamental Research Funds for the Central Universities(2572019BA15,2572019CP09)

Abstract: The 13 years old Betula platyphylla from 12 provenances in Caohekou and Maoershan were used as experimental materials. In the growing season, three diameter classes roots <0.5 mm, 2.0-5.0 mm and >5.0 mm were taken, respectively. The CO2 efflux rate of root system was measured by infrared gas analysis in vitro, in order to study the effect of root diameter, experiment site and provenance on CO2 efflux of B.platyphylla root. The root diameter and environment had significant(P<0.01) effects on root CO2 efflux rate, while provenance had no significant(P>0.05) effects on root CO2 efflux rate. Root CO2 efflux rate decreased significantly(P<0.01) with the increase of diameter class. All diameter class root CO2 efflux rate in Caohekou was greater than that in Maoershan(P<0.01). The root CO2 efflux rates of B.platyphylla in Caohekou and Maoershan with diameters <0.5 mm were 104.21 and 81.07 mol·g-1·s-1, the root CO2 efflux rates with diameters 2.0-5.0 mm were 41.08 and 30.91 mol·g-1·s-1, and the root CO2 efflux rates with diameters >5.0 mm were 24.87 and 11.37 mol·g-1·s-1, respectively. There were significant(P<0.05) differences in tree height and DBH among 12 provenances of B.platyphylla, and both tree height and DBH were negatively correlated with root CO2 efflux. The results of relevant studies will provide an important basis for more accurate assessment of CO2 efflux fluxes from tree roots.

Key words: root respiration, CO2 efflux, provenances, Betula platyphylla

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