Study on the Effects of Exogenous Abscisic Acid on Salt-alkali Tolerance of Scrophularia ningpoensis Seed-lings / 中国药房

ABSTRACT

OBJECTIVE:To study the effects of exogenous abscisic acid(ABA)on salt-alkali tolerance of Scrophularia ning-poensis seedlings,and to provide theoretic evidence for cultivating S. ningpoensis in salt-alkali soil. METHODS:50 S. ningpoensis seedlings were divided into control group,salt-alkali group(75 mmol/L),salt-alkali(75 mmol/L)+ABA low-concentration,medi-um-concentration and high-concentration groups(10,50,100 μmol/L),with 10 plants in each group. 20 days after transplanting, the plants were sprayed with drugs every 4 days. Growth indexes of the plants(length of stem,fresh weight,dry weight,survival rate),physiological indexes [the contents of chlorophyll,soluble sugar (SS),soluble protein (SP) and free proline (Pro)],the contents of MDA and H2O2,the activities of antioxidase [the activities of SOD,POD,CAT,GR] and the contents of Na+ and K+in stem and root were determined in each group 2 weeks later. RESULTS:Compared with control group,stem height and survival rate of S. ningpoensis seedlings,SP,the contents of Na+ and K+ in the stem,the contents of Na+,CAT and GR in the roots were all decreased significantly in salt-alkali group;while chlorophyll,Pro,MDA and H2O2 contents,the content of K+ in the roots and the activities of SOD and POD were all increased significantly(P<0.05 or P<0.01). Compared with salt-alkali group,stem height of S. ningpoensis seedlings,fresh weight and chlorophyll content were increased significantly in salt-alkali+ABA medium-concentra-tion group,while MDA and the content of Na+ in the stem were decreased significantly;dry weight,the contents of SS and SP, the activities of SOD and CAT were increased significantly in salt-alkali+ABA low-concentration and medium-concentration groups, while the SS content was increased in salt-alkali+ABA high-concentration group;stem height and dry weight were decreased signifi-cantly in salt-alkali+ABA high-concentration group;Pro content of salt-alkali+ABA low-concentration and high-concentration groups were decreased significantly;H2O2,Na+ content in the roots were decreased significantly in salt-alkali+ABA low-concentra-tion,medium-concentration and high-concentration groups;while GR activity,K+ content in the stem and roots were increased sig-nificantly;POD activity were decreased significantly in salt-alkali+ABA medium-concentration and high-concentration groups. CON-CLUSIONSThe addition of a certain concentration of exogenous ABA can effectively increase salt-alkali tolerance of S. ningpoen-sis seedlings and strengthen the ability of the plant adapting to salt-alkali environment.