Sprouting temperature and growth regulators influence cut flower quality of Sandersonia aurantiaca

Abstract

Tubers of Sandersonia aurantiaca Hook. were soaked in 1000 mg · L-1 GA3, 20 mg · L-1 uniconazole, 200 mg · L-1 benzyladenine, or water for 2 hours and then sprouted at 12, 18, or 24°C. The effects of these treatments on flower stem quality were then determined at forcing temperatures of 18, 24, or 30°C. Stem length increased with sprouting temperature only at a forcing temperature of 18°C. Floret numbers increased with sprouting temperature at all forcing temperatures, but the effect was greatest at the 18°C forcing temperature. The 12°C sprouting treatment reduced floret numbers at all forcing temperatures. Soaking tubers in GA3 increased stem length but drastically reduced floret numbers, while soaking in uniconazole reduced stem length but had no significant effect on floret numbers. Soaking in BA strongly promoted branching, which resulted in large increases (>30%) in floret numbers per stem with little change in stem length. Of the three growth regulators, only BA was effective in improving cut flower stem quality. Chemical names used: gibberellic acid (GA3); (E)-(+)-(S)-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3 -ol (uniconazole); N6-benzylamino purine (benzyladenine; BA).