Effects of salt stress on physiological characteristics of fennel.

Content of chlorophyll,relative permeability of plasma membrane,MDA,proline content and soluble sugar content under different conditions of salt stress were measured using the fennel variety Denong Number 1 as material.The results showed that the content of chlorophyll in leaf increased first and then decreased.Proline content had no significant difference with the treatment of lower salt concentration,but it increased rapidly and was higher than CK by 27.9% at salt concentration of 6mg/g.Meanwhile,the damage degree of plasma membrane aggravated as well.Low salt concentration reduced accumulation of MDA,while high salt concentration promoted synthesis of MDA.The highest content of MDA was 32.0μmol/g at the treatment of 10mg/g salt concentration.However,soluble sugar content showed the opposite tendency.Therefore,it was possible that osmostic adjustment of fennel was regulated by soluble sugar content under mild salt stress,and it was regulated by proline content under severe salt stress.