Abstract:
Sacha inchi (Plukenetia volubilis) is a commercial tropical crop,which is sensitive to chilling.The exogenous ABA was applied on the seedlings by foliage spray and the chilling tolerance was studied.The chilling treatment was done at 4 ℃ for 2 days after the seedlings were sprayed by water or ABA solutions at 2,5,10 mol/L and 50 mol/L.Chilling increased the injury grades of the seedlings spayed by water,meanwhile the seedlings sprayed with ABA solution had a lower injury grade.Chilling led to a higher level of lipid peroxidation,production rate of super anion,and content of H2O2,and ABA application was helpful in reducing the injury grades.Chilling decreases the activities of antioxidant enzymes in sacha inchi leaves,and ABA can enhance the activity of superoxide dismutase,catalase,guaiacol peroxidase,glutathione reductase,and dehydroascorbate reductase;the activity of ascorbate peroxidase has no significant difference after ABA treatment.These results indicate that exogenous ABA can increase the chilling tolerance of sacha inchi seedlings by enhancing activities of antioxidant enzymes.ABA solution at 10 mol/L (and 10 mol/L) can increase the chilling tolerance.