Cut lotus flowers (Nelumbo nucifera Gaertn. cv. Saddabutra), which are sold as closed buds, fail to open
and show rapid petal blackening when placed in vase water. We investigated the effect on bud opening
and petal blackening of treatments with an auxin, a gibberellic acid, and two cytokinins. Continuous
treatment of cut flowers placed in an aqueous solution containing
≥0.1 mM naphthylacetic acid (NAA)
hastened petal blackening and resulted in stem curvature, but lower concentrations (0.01–10 M) had
no effect. Depending on the experiment, continuous treatment with 0.03–0.45 mM of the gibberellin GA3
delayed petal blackening by 0.5–1.5 d (controls lasted 4 d), but in experiments during the hot/rainy season
(May–September) GA3 had no effect. At 25–100 M the cytokinin benzyladenine (6-benzylaminopurine;
BA) delayed petal blackening by about 1.0 d. Similarly, the cytokinin thidiazuron (TDZ) delayed petal
blackening by about 1.0 d, at 1.25–2.5 M. Pulse treatments had similar or better effects. A 3–12 h pulse
treatment with 0.45 mM GA3 or with 10 M TDZ delayed the time to petal blackening by 1.1–2.3 d.
However, none of these treatments promoted bud opening. It is concluded, nonetheless, that a pulse
treatment with GA3 or TDZ seems promising for practice.