Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (1): 204-211.DOI: 10.3773/j.issn.1005-264x.2008.01.024

• Research Articles • Previous Articles     Next Articles

INFLUENCE OF INCREASED ATMOSPHERIC NH3 ON PHYSIOLOGY INDEX AND BIOMASS OF MAIZE WITH DIFFERENT N EFFICIENCY

CHEN Xiao-Li1, LI Shi-Qing1,2,*(), REN Xiao-Long2, QIANG Hong2, JI Chun-Rong2, YAN Deng-Ming2   

  1. 1State Key Laboratory of Soil Erosion and Dryland Farming, Institute of Soil Erosion and Water Conservation, Chinese Academy of Sciences, Yangling, Shaanxi 712100, China
    2College of Resources and Environment Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China
  • Received:2006-10-30 Accepted:2007-02-03 Online:2008-10-30 Published:2008-01-30
  • Contact: LI Shi-Qing

Abstract:

Aims The main aim of this study was to investigate the response of various physiology indexes, e.g., chlorophyll index value (stand for the relative content of chlorophyll, SPAD value), net photosynthetic rate (Pn), stomatal conductance (Gs), and root shoot ratio (R/S) in two genetypes of maize (Zea mays) to NH3 concentration enrichment.
Methods We grew maize on Hoagland solution in PVC pots in open top chambers (OTCs). The experiment was a split-split plot design, which main treatments were two NH3 concentrations (10 and 1 000 nl·L-1). The sub-plot treatments of the experiment were two levels of nitrogen (high and low), and sub-sub-plot treatments were two N efficiency genotypes (high N efficiency, ‘NE5’, and low N efficiency, ‘SD19’). Air flow in OTCs was controlled by small fans and atmospheric NH3 concentration was measured accurately by two methods (NH3 determination tubes and GTL-C atmosphere detecting apparatus).
Important findings Under elevated atmospheric NH3, there were significant differences (p<0. 05) for physiology indexes between the two varieties, ‘NE5’ and ‘SD19’. Under high N medium, compared with 10 nl·L-1 atmospheric NH3 concentration, the SPAD value, Pn and Gs of ‘NE5’ treated with 1 000 nl·L-1 decreased 7.0%, 14.0% and 6.5%, respectively, and the corresponding targets of ‘SD19’ decreased 9.0%, 11.0% and 6.9%, respectively. Under low N medium, various physiology indexes of the two varieties significantly increased, i.e., the SPAD value, Pn and Gs of ‘NE5’ increased 5.7%, 7.1% and 17%, respectively, and the relative value of ‘SD19’ increased 7.0%, 11.0% and 22.0%, respectively. The results also demonstrated that under high N medium, the inhibition effect of increased atmospheric NH3 on ‘SD19’ shoot biomass was obviously lower than that of ‘NE5’, while under low N medium, NH3 concentration enrichment had more positive influence on ‘NE5’ (p<0. 05) than ‘SD19’. Moreover, the ratio of roots to shoots of ‘NE5’ and ‘SD19’ in the two atmospheric NH3 concentrations was related to maize growth periods, i.e., there were different changes for their root and shoot biomass in three sampling time, but still obeying certain laws. All these results indicated that the absorbed atmospheric NH3 by plants can improve crop nitrogen nutrition growing in low N medium, and there may be more significantly positive effect on low nitrogen efficiency genotypes.

Key words: Zea mays, NH3 concentration enrichment, N efficiency, genotypes, physiology indexes