Effects of Simulated Dark Shipping on Photosynthetic Status and Post-shipping Performance in Phalaenopsis Sogo Yukidian ‘V3’

Abstract

Phalaenopsis plants are routinely shipped long distances in total darkness. To determine how these long dark periods affect photosynthetic status in Phalaenopsis Sogo Yukidian ‘V3’, changes of net CO2 uptake, photosystem II (PS II) efficiency, and abscisic acid (ABA) concentration after a long-term simulated dark shipping were investigated. Net CO2 uptake rate, malate concentration, and titratable acidity in potted Phalaenopsis Sogo Yukidian ‘V3’ decreased after a 21-day simulated dark shipping at 20 °C, but recovered gradually with time after shipping. It took 6 to 9 days to recover to a normal photosynthetic status after shipping. The value of Fv/Fm was little affected by shipping. Therefore, net CO2 uptake rate would be a better indicator for estimating the recovery time after shipping. After shipping, fresh weight loss, leaf ABA concentration, and number of yellowed leaves of bare-root plants were higher than those of potted plants, and increased with longer durations (7, 14, and 21 days) of the simulated dark period. The spiking (the emergence of flowering stems) date was delayed when plants were stored in a bare-root condition. The concentration of ABA in leaves rose in the first 3 days after simulated shipping and then decreased within the next 3 to 8 days. Plants that received photosynthetic photon flux (PPF) at 399 μmol·m−2·s−1 after shipping had lower PS II efficiency and reduced net CO2 uptake rate than those given less PPF levels. We recommend a post-shipping acclimation for 6 to 9 days with gradual light increase (34–72–140–200 μmol·m−2·s−1 PPF) or maintaining a light level of 140 μmol·m−2·s−1 PPF for Phalaenopsis to achieve a better photosynthetic status after prolonged dark storage.