Growth and Physiological Indexes of Cucumber Seedlings with Na_2CO_3 Stress

Using 'Jinyou 1' and 'Chun 4' cucumber species as materials,effects of Na2CO3 stress on the growth and physiological indexes of cucumber seedlings were studied by sand culture.The results showed that root/shoot ratios of the two species were decreased with the increase of Na2CO3 concentration,but soluble sugar content,proline content and SOD activity were increased,yet the content of chlorophyll were increased at first and declined later.The relative conductivity and MDA content were increased with the increase of Na2CO3 concentration for 'Jinyou 1',but ones were the lowest at the 20 mmol·L-1 Na2CO3 concentration,and then increased for 'Chun 4'.The result of principal component analysis displayed that MDA content,SOD activity,soluble sugar content,proline content and the content of chlorophyll b were important in Na2CO3 stress evaluation for cucumber seedlings.The analysis results using 5 physiological indexes showed that Na2CO3 tolerance of 'Jinyou 1' was higher than 'Chun 4'.