Chin J Plan Ecolo ›› 2010, Vol. 34 ›› Issue (5): 563-570.DOI: 10.3773/j.issn.1005-264x.2010.05.010

• Research Articles • Previous Articles     Next Articles

Salt tolerance of transgenic poplar by the introduction of AtNHX1 gene

JIANG Chao-Qiang1; ZHENG Qing-Song1; LIU Zhao-Pu1; XU Wen-Jun2; LI Hong-Yan1; and LI Qing1   

  1. 1College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China;
    2Jiangsu Quality and Technical Supervision Bureau, Nanjing 210008, China
  • Received:2009-07-01 Online:2010-05-01 Published:2010-05-01
  • Contact: LIU Zhao-Pu

Abstract: Aim Our objective was to test whether the overexpression of the Arabidopsis thaliana tonoplast Na+/H+ antiporter gene, AtNHX1, can improve salt tolerance in poplar.
Methods Transgenic and wild-type poplar (Populus × euramericana ‘Neva’) were subjected to low salt and high salt treatments. We investigated the effects of NaCl on the transgenic and wild-type poplar by measuring growth parameters, chlorophyll (Chl) and carotenoid (Car) content, net photosynthetic rate (Pn), maximal photochemical efficiency of PSII (Fv/Fm), ion content, leaf malondialdehyde (MDA) and electrolytic leakage after 30 days.
Important findings Compared with the control, the growth of wild-type plants was restrained significantly in the presence of both low salt and high salt. The dry weight of wild-type plants was significantly lower under salt stress than that of control, the dry weight decreased gradually with increasing NaCl concentration and their dry weight under high salt was just 50% of the control. However, the dry weight of transgenic plants in low salt was similar to the control up to the high salt treatment, where their dry weight was 74% of the control. Moreover, the dry weight of transgenic plants was significant higher than that of wild-type in both NaCl treatments, and the discrepancy of dry weight was increased with increasing NaCl concentration. In the presence of NaCl, Chl and Car content of transgenic plants were significantly higher than that of wild-type, and the transgenic plants maintained a remarkably high Pn and Fv/Fm. Although these transgenic plants accumulated more Na+ in their roots and leaf tissues under salinity conditions compared with the wild-type plants, they absorbed more K+ and maintained a higher K+/Na+ ratio. Moreover, these transgenic plants kept a lower MDA and electrolytic leakage level than that of wild-type. These findings indicate that transformation of AtNHX1 gene into poplar can confer plants more tolerance to salinity than wild-type poplar by maintaining better growth, higher Chl and Car content and improved Pn and Fv/Fm. These transgenic plants have potential for further applications in saline soil.