Response of In Vitro Strawberry to Silver Nitrate (AgNO3)

Abstract

Response of Toyonoka strawberry to AgNO3 was studied. Types and combinations of plant growth regulators had significant effects on shoot regeneration efficiency. Explants cultured for 10 days in shoot regeneration medium in the presence of AgNO3 not only enhanced shoot regeneration efficiency but also expedited the initiation of adventitious buds. Highest regeneration (87.38%) and number of shoots per explant (11.67) were achieved in shoot regeneration media containing 1.5 mg·L–1 TDZ, 0.4 mg·L–1 IBA and 1.0 mg·L–1 AgNO3. Half-strength MS containing 1.0 mg·L–1 AgNO3 was an optimum medium for rooting. AgNO3 advanced root emergence and increased percent rooting, root length, dry weight and activity. Lower concentrations of AgNO3 inhibited ethylene production and promoted shoot regeneration and growth. It had a significant stimulatory effect on chlorophyll, soluble protein contents and antioxidant enzyme activities. Chlorophyll and soluble protein contents, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were increased in the presence of AgNO3 and reached maximum at 1.0 mg·L–1 AgNO3. Root water content, superoxide free radicals (O2.-), malondialdehyde (MDA) content, proline accumulation and IAA-oxidase activity in leaves were increased while (IAA) content was decreased in the presence of AgNO3. Chemical names used: indole-3-butyric acid (IBA); silver nitrate (AgNO3); thidiazuron (TDZ); N6-benzyladenine (BA); 2,4-dichlorophenoxy acetic acid (2,4-D); indole-3-acetic acid (IAA); α-naphthalene acetic acid (NAA); gibberellic acid (GA3); bovine serum albumin (BSA); 2,3,5-triphenyl-2H-tetrazolium chloride (TTC).