Experiments were conducted to evaluate storage temperature, storage irradiance and prestorage foliar sprays of gibberellin, cytokinin or both on postharvest quality of Oriental hybrid lilies (Lilium sp. `Stargazer'). Cold storage of puffy bud stage plants at 4, 7, or 10 °C in dark for 2 weeks induced leaf chlorosis within 4 days in a simulated consumer environment, and resulted in 60% leaf chlorosis and 40% leaf abscission by 20 days. Cold storage also reduced the duration to flower bud opening (days from the end of cold storage till the last flower bud opened), inflorescence and flower longevity, and increased flower bud abortion. Storage at 1 °C resulted in severe leaf injury and 100% bud abortion. Providing light up to 40 μmol·m-2·s-1 during cold storage at 4 °C significantly delayed leaf chlorosis and abscission and increased the duration of flower bud opening, inflorescence and flower longevity, and reduced bud abortion. Application of hormone sprays before cold storage affected leaf and flower quality. ProVide (100 mg·L-1 GA4+7) and Promalin (100 mg·L-1 each GA4+7 and benzyladenine (BA)) effectively prevented leaf chlorosis and abscission at 4 °C while ProGibb (100 mg·L-1 GA3) and ABG-3062 (100 mg·L-1 BA) did not. Accel (10 mg·L-1 GA4+7 and 100 mg·L-1 BA) showed intermediate effects on leaf chlorosis. Flower longevity was increased and bud abortion was prevented by all hormone formulations except ProGibb. The combination of light (40 μmol·m-2·s-1) and Promalin (100 mg·L-1 each GA4+7 and BA) completely prevented cold storage induced leaf chlorosis and abscission.
The interactions of ancymidol drenches, postgreenhouse cold storage, and hormone sprays on postharvest leaf chlorosis and flower longevity of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) were investigated. Ancymidol drenches (0.5 mg/plant twice) during early growth resulted in leaf chlorosis in the greenhouse which intensified further during postharvest. Cold storage (4 °C) of puffy bud stage plants for 2 weeks also accelerated leaf chlorosis. The combination of ancymidol treatment with cold storage resulted in the most severe leaf chlorosis. Promalin (GA4+7 and BA each at 100 mg·L-1) sprays completely prevented postharvest leaf chlorosis, whereas ProGibb (GA3 at 1000 mg·L-1) was ineffective. Cold storage reduced flower longevity and increased bud abortion, however, the degree of bud abortion varied among experiments in different years. Both ProGibb and Promalin sprays increased flower longevity. Compared to positive DIF (difference between day and night temperature) grown plants, forcing under negative DIF (-8 °C) increased the severity of postharvest leaf chlorosis. Leaves were sampled from basal, middle, and upper sections of the stem after 4 and 12 days in a postharvest evaluation room, and analyzed for soluble carbohydrates and N. Total leaf soluble carbohydrates and N concentrations were less in basal and middle sections of negative DIF-grown plants than in positive DIF-grown plants. Leaf chlorosis was associated with depletion of soluble carbohydrates and N in the leaves. Chemical names used: α-cyclopropyl-α-(p-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); gibberellic acid (GA3); gibberellins A4A7 (GA4+7); N-(phenylmethyl)-1H-purine 6-amine (benzyladenine).