Abstract:

In order to study effects of salt stress on changes of soil microbial quantities and the diversity of soil microbial community by the technology of PCR-DGGE, two kinds of cucumbers with different saline tolerance were selected，Jinchun 5（salt-tolerant）and Jinyou 1（salt-sensitive），and four concentrations of NaCl were designed（0，100，200 and 300 mmol · L-1）. The results showed that salt stress could reduce the richness of soil bacterial community significantly（P<0.05）. The richness of salt-sensitive cultivar was high under low salt treatment, while the richness of salt-tolerant cultivar was high under high salt treatment. High salt stress had more effects on the rhizosphere bacterial community structure of salt-tolerant cultivar. Sequences of different bands of four stages belonged to four bacterial groups，Firmicutes，Proteobacteria，Gemmatimonadetes and Bacteroidetes. Most of them belonged to Alphaproteobacteria and Gammaproteobacteria. With the increasing of salt concentration，the plant heights of cucumber and yield per plant reduced.

Key words: cucumber, salt stress, rhizospheric soil, bacterial community structure, diversity