Stimulation of Rooting from Cuttings of Strawberry Runner Plants by Abscisic Acid under High Temperature Condition

Abstract

Constant rooting by cuttings to raise seedlings at high temperatures during summer in a forced elevated bench culture system of strawberry is important. Abscisic acid (ABA) applied to crown tissue of cuttings of strawberry runner plants at higher temperature (30°C) without low temperature treatment (storage for 2 days at 5°C) stimulated rooting to the same level as at low temperature; however, naphtaleneacetic acid, gibberellic acid, and benzyl adenine did not stimulate rooting well. Sucrose synthase (SuSy) activity increased 1 day after starting ABA treatment at 30°C and 2 days after 5°C exposure. SuSy activity treated with ABA at 30°C was always higher than that without ABA at 30°C. Soluble acid invertase activity at 5°C increased at 1 day compared with that at 30°C, and the activity when treated with ABA at 30°C did not change compared with that without ABA at 30°C. Bound acid invertase activity showed no marked differences among crown tissues treated at 5°C, 30°C, and with ABA at 30°C. The content of ABA in crown tissue of cuttings at 5°C was compared with that at 30°C, but they showed only a slight difference. At high temperature, cuttings of strawberry runner plants produced roots by ABA without low temperature treatment.