Effect of brassinolide on callus growth and regeneration in Spartina patens (Poaceae)

Abstract

The effect of brassinolide (BL) on cultured calluses of Spartina patens (Ait.) Muhl. (Poaceae), a halophyte monocot was studied. BL at 0.03–0.04 mg l⁻¹ at fixed concentrations of IAA (0.2 mg l⁻¹) and BA (3.0 mg l⁻¹) added in MS medium increased the ratio for fresh weight (CIRFW) to dry weight (CIRDW) by 96–111% and 235–326%. Similarly, in callus regeneration capacity, BL at 0.03 mg l⁻¹ was most effective, increasing the shoot regeneration ratio (SRR) by 425%. BL at 0.04 mg l⁻¹ had not such an increasing effect as BL at 0.03 mg l⁻¹, which increased SRR by 79%. However, BL at 0.005 mg l⁻¹ promoted regenerated shoot growth most significantly, increasing the shoot height increasing ratio (SHIR) by 395% after a 40-day culture. BL at 0.05 mg l⁻¹ was least effective in the callus regeneration and regenerated shoot growth, decreasing SRR by 27% and SHIR by 52%. Present results suggest that BL at 0.03 mg l⁻¹ is suitable for the callus growth and shoot regeneration, while BL at 0.005 mg l⁻¹ effectively enhanced the regenerated shoot growth.