Abstract: To study the salt tolerance of tobacco plants transformed with lotus vacuolar Na⁺/H⁺ antiporter gene NnNHX1，a plant expression vector pCAMBIA1301-220-NnNHX1 was constructed and then was transformed into wild Nicotiana tabacum by Agrobacterium-mediated leaf disc transformation. The expression of NnNHX1 in transgenic tobacco was detected by quantitative PCR analysis. Salt stress test on transgenic tobacco and then the chlorophyll，proline and MDA content，relative conductivity，SOD，POD and other physiological indexes and the generation rate of transgenic tobacco seed were measured in salt stress condition. The results showed that among the seven transgenic tobacco strains，the expression of NnNHX 1 in T-N1，T-N2 and T-N10 strains was higher. Under salt stress，the growth conditions of both tissue culture seedlings and potted seedlings of transgenic tobacco were better than control tobacco. The chlorophyll and proline content and cell membrane integrity（relative conductivity and MDA）and antioxidant enzyme（SOD and POD）activity in transgenic tobacco were better than that of control tobacco，and the transgenic tobacco seed germination was significantly higher than control. Indicated that lotus NnNHX1 gene could normaly translated and expressed in tobacco，and over expression of NnNHX1 enhanced salt tolerance of transgenic tobacco.

Key words: lotus, NnNHX1 gene, transgenic, tobacco, salt tolerance