Plant Diversity ›› 2014, Vol. 36 ›› Issue (05): 611-621.doi: 10.7677/ynzwyj201413243

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Influence of Elevated CO2 Concentration and Nitrogen Source on Photosynthetic Traits in the Invasive Species Eupatorium adenophorum (Asteraceae)

OUYANG-Fen-1、2, ZHENG Guo-Wei-1, LI Wei-Qi-1、3   

  1. 1 Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 Biology Department, Honghe University, Mengzi 661100, China
  • Received:2013-12-24 Online:2014-09-25 Published:2014-03-25
  • Supported by:

    NSFC (31070262), West Light Foundation of the Chinese Academy of Sciences (CAS), Germplasm Bank of Wild Species

Abstract:

Increases in the concentration of atmospheric CO2 and plant invasion are two important problems that face humans worldwide. In some plants, exposure to a shortterm elevated concentration of CO2 (SE[CO2]) promotes photosynthesis, but the promotion of elevated [CO2] (E [CO2]) to photosynthesis might disappear after longterm treatment (socalled “CO2 acclimation”); this might result from the associated inhibition of nitrate assimilation. The present study investigated the physiological effects of shortterm (8 days) and longterm (40 days) exposure to E[CO2] when these were combined with different forms of inorganic N (full N; nitrate (NO3-)N) in the invasive species Eupatorium adenophorum. Exposure to E[CO2] increased the biomass of Eadenophorum, regardless of the duration of exposure to E[CO2] and the type of inorganic N that was supplied. E[CO2] could promote the photosynthesis of Eadenophorum seedlings fertilised with nondepleted Hoagland solutions (full N). For plants fertilised with NH4+depleted Hoagland solution (NO3-N), LE[CO2] treatment promoted the photosynthesis of Eadenop horum, but the promotion of photosynthesis by E[CO2] disappeared under SE[CO2] conditions. Photosynthetic pigments contents were determined to estimate potential changes in the photosynthetic capacity of Eadenophorum. For plants fertilised with nondepleted Hoagland solution, there were no significant differences in chlorophyll among the three [CO2] treatments, but the treatment of SE[CO2] increased the levels of chlorophyll in leaves. The apparent promotion of biomass accumulation and photosynthesis at LE[CO2] without a decrease in chlorophyll indicates that Eadenophorum might not acclimate to longterm exposure to E[CO2]. NH4+ depletion did not affect the capacity of LE[CO2] to promote the photosynthesis of Eadenophorum. Thus, considering some plants fertilised with NO3- acclimating to LE[CO2], Eadenophorum might be more competitive in areas where the soils are relatively poor in NH4+ as levels of atmospheric CO2 continue to rise.

Key words: Elevated CO2, Eadenophorum, Invasive plants, Photosynthesis acclimation, NO3- assimilation

CLC Number: 

  • Q 945