Drought and Darkness during Long-Term Simulated Shipping Delay Post-Shipping Flowering of Phalaenopsis Sogo Yukidian ‘V3’

Abstract

We investigated the relationship between simulated shipping (SS) without watering or light and post-shipping growth and flowering of Phalaenopsis Sogo Yukidian ‘V3’. Two experimental environments were created: a low-temperature chamber for simulated shipping and a growth chamber for simulated finishing at the destination. Plants from both the control and treatment groups were moved from the low-temperature chamber to the growth chamber after the end of the simulated shipping. Control plants received continuous light and regular irrigation; plants in the treatment group were placed in the low-temperature chamber under light (LSS) or dark (DSS) conditions for 10, 20, 30, 40, or 50 days, without irrigation. Once DSS duration exceeded 40 days, the leaf-yellowing rate increased rapidly. Chlorophyll content decreased from day 10 to 30 of DSS and slightly increased in LSS and DSS over 40 days. The photochemical reflectance index decreased with the SS duration. The maximum quantum yield PSII photochemistry (Fv/Fm) values sharply decreased after the end of SS; after 40 days, neither LSS nor DSS plants recovered to the normal range. In the same SS duration, the number of days to spiking was delayed in the DSS. In addition, the number of days to spiking was delayed, owing to the longer SS duration. LSS for 50 days induced early flowering, as in the control group, but lowered flower quality. The results demonstrate that drought stress from long-term shipping (>40 days) delayed flowering. In particular, DSS delayed flowering more than LSS due to the decrease in chlorophyll content and the reduction in carbohydrates through respiration.