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The flowering control of Oncidesa Gower Ramsey ‘Honey Angel’ is important and in-demand by the industry. Therefore, an understanding of the development of inflorescence and vegetative shoot from the leaf axils on the current shoot is required. The internode of a young Oncidesa current shoot between the 0th (at the base of the pseudobulb) and 1st (immediately above the pseudobulb) nodes can enlarge to form a pseudobulb, and the axillary bud on the 0th or -1st (immediately below the 0th node) node can differentiate into an inflorescence bud. The axillary buds on the lower nodes (-2nd to -4th nodes) can remain vegetative. In this study, we investigated the growth and anatomical features of axillary buds at various stages during the growth of the current shoot. We sampled the axillary buds on the 0th to -4th nodes from the current shoots when they were 10, 15, 20, 25, and 30 cm in length for sectioning and anatomical observations. Vegetative buds on the -2nd to -4th nodes grew faster and had more nodes than the inflorescence bud when the current shoot grew from 10 to 25 cm. However, when the current shoot elongated from 25 to 30 cm, the length and node number in the inflorescence bud on the 0th node increased and the inflorescence branch primordia were observable. The length and node number of the inflorescence bud became the same as that of the vegetative buds, which had no further growth, whereas the current shoot grew from 25 to 30 cm. The pseudobulb began to emerge from the leaf sheath (unsheathing) when the current shoot had reached 30 cm in length. Therefore, the time when the pseudobulb started to unsheathe from its subtending leaf was critical for the reproductive growth of Oncidesa Gower Ramsey ‘Honey Angel’ when growth acceleration of the inflorescence bud occurred. Evaluating the current shoot length can be a nondestructive method of estimating the developmental stage of the inflorescence bud.

Cyrtopodium paranaense is a tropical terrestrial orchid, which propagates mainly through sexual seed germination. In this study, we document the asexual morphogenesis of the root tip to protocorm-like body (PLB) conversion in Cyrtopodium paranaense. Protocorm-like bodies sporadically developed from root tips of flask-grown seedlings in the absence of any exogenous plant growth regulators (PGRs). The compact PLBs ultimately gave rise to normal plantlets. Histological observations revealed that the root cap became dissociated from the root apex at an early stage followed by dispersed extension of root vascular strands into nascent PLBs. Protocorm-like bodies also developed from the root central stele tissue. In root tip segment cultures, PLBs were not formed without providing PGRs but were efficiently formed from root tips in Murashige and Skoog (MS) medium supplemented with 10.2 μM indole-3-acetic acid (IAA) and 9.0 μM thidiazuron (TDZ). Both IAA and TDZ promoted the formation of PLBs; however, TDZ did not induce PLB formation in the absence of IAA, indicating a synergistic effect of the two PGRs. Protocorm-like bodies were proliferated and subsequently plants regenerated in PGR-free MS medium. Root tip culture may be used as an alternative method for the propagation of Cyrtopodium paranaense.

Photosynthetic rate is reduced during midday in some crops; this phenomenon has been termed as midday depression (MD). Oncidium also suffers greatly from MD in the summer, resulting in reduced growth and poor flowering quality. Since high radiation usually accompanies high temperature midday in the summer, it is difficult to figure out the key factor that promotes MD. We investigated the photosynthetic activities of Oncidium Gower Ramsey in the following conditions: environment-controlled and nonenvironment-controlled. In a growth chamber that simulated field growth conditions, photosynthesis declined dramatically when the temperature was higher than 32 °C. Photosynthesis was also reduced when photosynthetically active radiation (PAR) exceeded the saturating point of Oncidium. Gower Ramsey, which is about 250 μmol·m^-2·s^-1. However, the reduction was slight when PAR was under 500 μmol·m^-2·s^-1. Daily photosynthetic patterns were changed when Oncidium Gower Ramsey was grown under different environments. By regression, we found that MD was not directly associated with PAR within the range of 0–400 μmol·m^-2·s^-1. By contrast, photosynthesis was significantly reduced when temperature was higher than 32 °C. This explains the observation of greater photosynthetic reduction and earlier occurrence of MD when Oncidium Gower Ramsey was grown in rain-shelter rather than in phytotron and growth chamber, since temperature in the rain-shelter was not controlled, while the others were controlled at 25 °C. When Oncidium Gower Ramsey was moved from 35 °C to 25 °C, the photosynthetic depression was relieved.

Sphagnum moss has been used as the major substrate for cultivating Phalaenopsis spp. in China, Japan, and Taiwan. With a lengthened duration of cultivation, the pH of the moss gradually declines. It is not understood what causes this decline in substrate pH. Using the vegetatively propagated Phal. Sogo Yukidian ‘V3’, this study investigated if substrate, fertilization, light, and plant roots could be the cause of pH decline in the substrate. The results showed that, although increasing fertilizer concentration resulted in a low initial pH (pH measured by the pour-through technique at first fertilization), fertilization itself was not the primary cause of the long-term pH decline. Regardless of whether the sphagnum moss was fertilized, the pH of the substrate without plants increased as time progressed, whereas the pH of the substrate in which living Phalaenopsis plants were growing declined with time. Although the magnitude and course of pH decline were different in various substrates, the pH of sphagnum moss, artificial textile fiber, and pine bark substrates in which living plants were growing declined with time. Whether the substrate was exposed to light (clear pots) or not (opaque pots) had no effect on substrate pH, indicating that algae were not a factor in pH decline. Therefore, the roots of Phalaenopsis may be the major contributor to substrate pH decline during production.

The popularity of the nobile-type dendrobium (Dendrobium nobile hybrids) has been increasing globally. More information regarding the effects of long-distance shipping, from producing countries to destination market countries, on the post-shipping plant performance is needed. In this study, two nobile-type dendrobium cultivars were subjected to simulated dark shipping (SDS) at various temperatures and durations. Changes in net CO₂ uptake rate (Pn), chlorophyll fluorescence, and leaf relative water content after plants had been treated with SDS were investigated. Furthermore, shipped plants were vernalized to investigate the effect of dark shipping on the subsequent flowering quality. Dark shipping for 7 days at 15 °C did not affect the post-shipping photosynthetic performance of D. Lan Tarn Beauty. Increasing the shipping duration from 7 to 21 days increased the time required for Pn recovery from 1 to 12 days. Dendrobium Lan Tarn Beauty recovered its Pn within 4 days when shipped for 21 days at 10 °C, and this was prolonged to 11 days when the plants were shipped at 20 °C. Changes in Fv/Fm indicated that there was no marked damage to either cultivars, and the leaf relative water content was little affected by SDS. Dendrobium Lan Tarn Beauty and D. Lucky Girl shipped at 10 °C flowered 5 and 8 days earlier, respectively, compared with unshipped plants. Regardless of the shipping conditions, shipped D. Lucky Girl had a lower flower diameter and higher total flower count than unshipped plants. No differences were found in the number of nodes with flowers or the total flower count between shipped and unshipped D. Lan Tarn Beauty. Our study suggested that dark shipping for up to 21 days is possible for nobile-type dendrobiums. We recommend shipping temperatures of 10 to 15 °C to reduce the detrimental effects caused by long-term dark shipping.

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.

Phalaenopsis is one of the most important ornamental crops and is frequently transported between continents. In this study, the effects of the duration and temperature of simulated dark shipping (SDS) and the temperature difference between cultivation greenhouses and shipping containers on the carbohydrate status and post-shipping performance were investigated. With a prolonged SDS from 0 to 40 days at 20 °C, the percentage of the vegetative Phalaenopsis Sogo Yukidian ‘V3’ plants with yellowed leaves increased from 0% to 50%, and the total carbohydrate contents in the shoot and roots gradually decreased over time. Furthermore, roots had greater reductions in glucose and fructose concentrations than the shoot after 40 days of SDS. After 7 days of SDS, the youngest bud and the nearly open bud on blooming plants of Phalaenopsis amabilis were found to be the most negatively affected among flowers and buds of all stages. These buds had lower soluble sugar concentrations and flower longevities compared with those of unshipped plants. The results of a temperature experiment showed that yellowing of the leaves and chilling injury (CI) occurred in Phalaenopsis Sogo Yukidian ‘V3’ after 21 days of SDS at 25 and 15 °C, respectively, regardless of pre-shipping temperature acclimation. However, 10 days of acclimation at 25/20 °C (day/night) before SDS reduced CI and reduced the time to inflorescence emergence. Higher accumulations of sucrose in the shoot and glucose and fructose in roots were found after 21 days of SDS at 15 °C compared with those at 25 and 20 °C. In conclusion, the carbohydrate status of Phalaenopsis was positively related to the post-performance quality. A reduction in the commercial quality after SDS may be attributed to a decline in carbohydrates. The optimal temperature for long-term dark shipping is 20 °C, and we recommend providing 10 days of lower-temperature acclimation (25/20 °C) before shipping to enhance the chilling tolerance and to promote early spiking of Phalaenopsis plants.

Phalaenopsis orchid is a slow-growing crop that responds slowly to fertilization. In this study, we used ¹⁵N-labeled Johnson’s solution to investigate the accumulation and use of fertilizer nitrogen (N) during the vegetative and reproductive growth stages of Phalaenopsis Sogo Yukidian ‘V3’ with a focus on the nitrogen source for inflorescence development. Labeling of fertilizer applied to mature plants 6 weeks before forcing or at 6 weeks into forcing showed that in the inflorescence, the ratio of N derived from fertilizer applied 6 weeks before forcing to the N derived from fertilizer applied 6 weeks into forcing was 31% to 69%, which shows the importance of newly absorbed fertilizer for supplying the N needed for inflorescence development. The fate of fertilizer N applied during the small, medium, or large plant stage of vegetative Phalaenopsis Sogo Yukidian ‘V3’ was traced separately with ¹⁵N-labeling. The capacity of the plant to accumulate N after fertilizer application was different during the various stages of vegetative growth, with large plants having more N storage capacity as a result of their greater biomass. However, the percentage of the accumulated N that was later allocated to the inflorescence was similar regardless of the stage of fertilizer application: of the fertilizer N absorbed during various stages of the vegetative period, 6% to 8% was allocated to the inflorescence at the visible bud stage. This result highlights the mobility of N stored early on within the plant. By calculation, of the total N in the inflorescence at the visible bud stage, the N absorbed during the small, medium, and large plant stages contributed 7%, 11%, and 25%, respectively, whereas N applied after spiking made up the other 57%. This result indicates that both N stored during the vegetative stage and N applied during the reproductive stage contribute significantly to inflorescence development.

Upper leaf necrosis (ULN) on Lilium `Star Gazer' is a calcium deficiency disorder. In this study, we evaluated the efficacy of foliar Ca sprays and bulb Ca dipping on reducing ULN. Necrosis severity of a single leaf was determined by an index from 0 (healthy) to 5, based on symptom progression and necrosed leaf area. Single leaf severity was then summed for all leaves to yield a whole-plant severity rating. Single daily applications of 25 mm calcium chloride or calcium nitrate sprays for 14 days significantly suppressed the degree of symptom expression; whole-plant severity was reduced from 18 (severely necrosed) to below 3 (essentially unnoticeable). Five single applications at 3.5-day intervals were not effective, even at concentrations up to 150 mm. At concentrations of 100 and 150 mm, 14 daily sprays of calcium chloride or calcium nitrate were toxic and caused leaf tip yellowing; calcium chloride caused more severe phytotoxicity than did calcium nitrate. For effectiveness of foliar Ca sprays, it was necessary to have the Ca solution reach the enclosed, young, expanding leaves. Preplant bulb immersion in calcium chloride was not effective even at concentrations as high as 400 mm for up to 16 hours.

Sphagnum moss, which has very different chemical and physical characteristics compared with other soilless media, is commonly used as a substrate to grow Phalaenopsis in countries such as Japan and Taiwan. Pour-through (PT) is a nondestructive, effective, and convenient medium extraction method developed for peat-based media. To know if PT can be applied to sphagnum moss and to set up a standard procedure, experiments were conducted to test the effects of volume and electrical conductivity (EC) of the displacing solution and the timing of leachate collection on leachate properties. Results demonstrated that applying distilled water with a volume less than 70 mL to 10.5-cm pots 1 h after fertigation did not influence leachate EC and pH. Applying displacing solution with EC between 0.001 and 0.93 dS·m⁻¹ 1 h after fertigation did not affect leachate EC or pH. Thus, in theory, a variety of solutions may be used for displacement. Leachate properties were found to remain consistent when collected between 20 and 160 min after fertigation. These results demonstrated that PT can be successfully used in Phalaenopsis cultivation with sphagnum moss. Furthermore, substrate EC obtained by PT extraction was highly correlated with that by the press method, confirming that PT is a feasible medium extraction method for sphagnum moss in Phalaenopsis cultivation.