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Bare-root Phalaenopsis Blume orchids are frequently shipped by air freight intercontinentally. It was not known how temperature and duration in shipping affect their subsequent performance during greenhouse production. On 15 Sept., container-grown plants of vegetatively propagated Phalaenopsis (Atien Kaala Group) ‘TSC 22’ were removed from pots and individually weighed immediately. These bare-root plants were packed in cartons with shredded newspaper and placed in growth chambers at 15, 20, 25, or 30 °C in darkness. After 4, 7, and 14 days, one-third of the plants were removed from each temperature treatment, weighed, planted in pots, and then placed in a greenhouse. Weight loss increased with increasing air temperature and duration in storage. Chilling injury (CI) was more severe at 15 °C than 20 °C storage temperature and was progressively more severe as storage duration increased from 4 to 14 days. Plants had no sign of CI at 25 °C or 30 °C regardless of storage duration. Leaf loss was most severe on plants stored at 15 °C for 7 days (three leaves) or 14 days (five leaves) or at 30 °C for 14 days (three leaves). Storing plants 14 days or less between 15 °C and 25 °C did not affect the time of spiking (emergence of the flowering shoot), but at 30 °C, spiking was delayed by 5 to 8 days regardless of the duration. Storage resulted in reduced flower count, but not flower size, regardless of temperature and duration. In a second experiment, potted Phalaenopsis plants of the same clone were thermal-acclimatized in growth chambers in mid-September for 10 days at 25 °C followed by another 10 days at 20 °C before being stored in pots or bare-root at 15 °C, 20 °C, 25 °C, or 30 °C for 10 days. Thermal acclimatizing at 25 °C and 20 °C reduced the severity of CI and leaf loss after being stored for 10 days at 15 °C either bare-root or in pots, but did not reduce leaf loss resulting from heat at 30 °C. Repotting or storing bare-root plants did not affect spiking or flowering date under otherwise similar conditions. Nondisturbed plants in pots stored at temperatures between 20 °C and 30 °C for 10 d had higher flower count as compared with bare-root plants that were similarly stored. Spiking of nonacclimatized, bare-root plants was delayed after 10 days at either storage temperature, whereas flowering was delayed by 15 °C and 30 °C only. Bare-root Phalaenopsis orchids should be shipped near 25 °C during the warm period of the year and between 25 °C and 15 °C in the late fall through early spring to avoid CI or heat stress.

Most Phalaenopsis (the moth orchid) species and hybrids start to produce flowering shoots in the fall, bloom in January or February, and become limited in supply by April when market demand is strong. Means to defer the onset of flowering were studied. Starting 15 Sept. 1994, seedlings of 2-year-old hybrid Phalaenopsis TAM Butterfly were exposed to repeated cycles of 1 d darkness/1 d light (natural photoperiod, 1D/1L); 4 d darkness/3 d light (4D/3L); 7 d darkness/7 d light (7D/7L); and the natural photoperiod control (0D/7L). The dark treatments were achieved by covering plants with black fabric or by placing them in a dark cage. Treatments were terminated on 16 Dec., and all plants were exposed to the natural photoperiod. The control plants bloomed on 20 Jan. 1995, whereas the 4D/3L plants did not reach anthesis until 14 Apr., nearly 3 months later. Flowering of the 1D/1L and 7D/7L plants was also deferred until early April. Regardless of treatments, flower count and size were unaffected. In another experiment, beginning 15 Sept. 1995, 3-year-old plants were exposed to repeated weekly cycles of 2D/5L, 3D/4L, 4D/3L, or 5D/2L until 22 Jan. 1996. The nontreated control plants bloomed on 8 Feb. 1996, whereas the 5D/2L did not reach anthesis until 6 May. The 4D/3L treatment was not as effective as it was in 1994 and resulted in anthesis only 4 weeks after the control. In the last experiment, starting on 22 Jan. 1996, plants were removed at 2-week intervals from a 5D/2L treatment that was initiated on 15 Sept. 1995 and exposed to the natural photoperiod. Staggered anthesis was achieved. However, plants that bloomed in May and June had reduced flower count but not flower size.

Results of a series of experiments showed that the ground, noncomposted woody stem core of kenaf (Hibiscus cannabinus L.) can be used successfully as a container medium amendment for producing potted tropical foliage and woody nursery crops. The growth of Brassaia actinophylla Endl., Hibiscus rosa-sinensis L. `Jane Cowl', and Pittosporum tobira (Thunb.) Ait. `Wheeler's Dwarf' in 70% or 80% kenaf (by volume, the balance being peatmoss or perlite or vermiculite and other nutrients) was similar to or greater than growth in two popular commercial mixes. Undesirable shrinkage of certain kenaf-amended media during plant production was reduced greatly by mixing it with at least 30% peatmoss or by using a coarser kenaf grind. As the portion of peatmoss increased from 0% to 30%, noncapillary porosity and water-holding capacity per container increased. A medium consisting of 50% kenaf, 40% peatmoss, and 10% vermiculite held as much water as a commercial medium. However, plants in most kenaf-amended media required more-frequent irrigation than those in the commercial media.

Seedling Phalaenopsis (P. Taisuco Eagle × P. Taisuco Rose) plants with an 8- to 10-cm leaf span were grown in 10-cm pots filled with a medium consisting of 70% fine fir bark and 30% peatmoss (by volume). Plants were given (in N–P₂O₅–K₂O) 10–30–20, 15–10–30, 15–20–25, 20–5–19, 20–10–20, or 20–20–20 fertilizers at the 100 or 200 mg N/liter rate. Pots were leached with water following every two fertigations. After 7 months, leaf span, leaf size, total leaf area, and fresh weight were not affected by fertilizer type. The differences in leaf numbers were small. The higher rate of fertilizer resulted in plants with wider leaf span (32.8 vs. 28.5 cm), more (5.5 vs. 4.8), larger (103 vs. 89 cm²) leaves, and greater total leaf area (355 vs. 275 cm²) than did the lower rate. In another experiment, similar plants with a leaf span of 15 to 18 cm were grown in 10-cm pots with 100% fine fir bark or a mixture of 80% fine fir bark and 20% peatmoss. They were fertigated with water having an EC - 0.05, 0.40, 0.75, 1.10, or 1.40 dS·m^–1 containing 1 g·liter^–1 20–20–20 fertilizer three times and then drenched with their respective water containing 0.6 g·liter^–1 Ca NO₃)₂·4H₂O. After 11 months, water salinity did not affect the date of spiking. Plants receiving water with EC = 1.10 dS·m^–1 had more leaves and spikes than other treatments. Plants in the bark/peatmoss mix began spiking earlier, had more leaves (6.7 vs. 5.7), and more inflorescences (1.9 vs. 1.5) than those in 100% bark. There was no salinity x medium interaction in all the parameters recorded.

It not clear how a prolonged period of cool days and warm nights affect Phalaenopsis hybrids which take up CO₂ mainly at night. The `Lava Glow' clone of the hybrid Doritaenopsis (Phal. Buddha's Treasure × Doritis pulcherrima) 15 cm in leaf span were subjected to day/night (12 h each daily) temperatures of 30/25, 25/30, 25/20, or 20/25 °C at 170 umol.m^-2 .s-¹ PPF. After nine months, plants under the higher average daily temperature (ADT) produced more leaves. Those grown at 30/25 °C had the largest leaf span and total length of the new leaves. Plants under 30/25, 25/30, 25/20, or 20/25 °C had 5.0, 4.7, 3.6, and 2.8 new leaves and 72, 61, 42, and 28 cm in total new leaf length, respectively. Cool days and warm nights resulted in smaller leaf span and reduced leaf growth, particularly at 20/25 than at 25/30 °C. Within a given ADT, cooler days resulted in shorter leaves. Leaves produced by plants at the lower ADT had a smaller length to width ratio and the more desirable oval shape. The most striking effect of 20/25 °C was that 14 out of 15 plants bloomed, whereas only 5 plants under 25/20 °C and none in the 30/25 or 25/30 °C treatment flowered. In a second experiment, 18-22 cm plants were subjected to 30/20, 20/30, 25/15, or 15/25 °C. After 29 weeks, similar results were obtained. All plants under 15/25 °C bloomed, whereas none in the other treatments produced flowers. Long-term exposure to 15/25 °C resulted in slow leaf production and undesirable small leaves. These results suggest that, with day temperatures in the 20-15 °C range, nights 10-5 °C warmer are not desirable for rapid vegetative growth. However, cool days and warm nights may be used to effectively induce the flowering process.

Blooming Phalaenopsis orchids have become a popular pot plant in recent years. Plants start producing spikes after experiencing cool air in early fall, bloom in early spring, and become limited in supply after April when market demand is strong. Deferring spiking and flowering by maintaining the greenhouse air constantly above 28°C is cost prohibitive. Previous research has discovered that plants must be given light while being exposed to cool air to induce spiking. In Fall 1994, 2-year old Phalaenopsis TAM Butterfly plants were exposed to repeated cycles of 1 day in darkness and another day in light (1D/1L), 4D/3L, 7D/7L, or 0D/7L (continuous lighted control) between 15 Sept. and 16 Dec. Each plant was removed from the treatment once it had started spiking. The control plants bloomed on 20 Jan. 1995, whereas the 4D/3L plants did not reach anthesis until April 17, nearly three months later. Flowering of the 1D/1L and 7D/7L plants was also deferred until early April. The treatments had no adverse effect on flower count or size. In 1995, 3-year old plants were exposed to 0D/7L (control), 2D/5L, 3D/4L, 4D/3L, or 5D/2L from 15 Sept. to 22 Jan. 1996. The control plants spiked on 17 Oct. and bloomed on 8 Feb. 1996 when spikes had just emerged from plants in the 5D/2L treatment. The 5D/2L plants are expected to bloom in late May or early June. The other treatments were not as effective as that in 1994 and resulted in blooming only 2–3 weeks after the untreated control. The results of this research will help producers to stagger or precisely program the time of flowering to meet the market demand.

Bougainvillea cuttings propagated in fall and winter often bloom profusely before putting out adequate shoot growth. These large flowers shade the small leaves, resulting in slow growth. In an attempt to solve this problem, rooted `Juanita Hatten' cuttings were planted in 11.5-cm pots, clipped to 5 cm, and placed under natural short day or a 4-hour night interruption on 7 Dec. Plants were sprayed on 8 Dec. and again on 2 Jan. with 0, 50, 100, or 200 mg GA₃/L or a combination of GA₃ and PBA at 200 mg·L^–1. Data were taken on the uppermost new shoot of each plant. Under long-day conditions, the first inflorescence was produced on the first node of all control plants, whereas plants treated with GA₃ at 100 or 200 mg·L^–1 produced the first inflorescences on higher nodes. The number of inflorescences on this shoot was unaffected by any treatment. GA₃ treatment resulted in longer shoots (6.7–10.2 cm vs. 2.4 cm) and more leaves (13.4–l6.2 vs. 7.5), with greater effects at higher concentrations. These shoots had several inflorescences at the base, followed by many nonflowering nodes and additional flowers near the tip. The GA₃ + PBA treatment had no effect on the position of the first inflorescence. However, shoots had twice as many nodes and fewer inflorescences than the controls and were shorter than those treated with GA₃ alone. Plants under short day responded similarly to respective treatments under the long-day conditions. Tests will be conducted to determine if stock plants need to be treated in early fall and cuttings collected from the new growth to prevent early flowering.

Lilium longiflorum Thunb. `Nellie White' plants were selected when their first flower buds reached 2 or 5 cm in length, sprayed with 2 mL of PBA at 0 or 500 mg·L^–1, and then placed under 1440 or 60 μmol·m^–2·s^–1 photosynthetic photon flux (PPF) during flowering. PBA resulted in delayed anthesis and increased dry matter accumulation in flowers under the high PPF but had no effect under the low PPF. PBA did not decrease the severity of flower bud abortion under the low PPF. Application of PBA induced the formation of numerous bulbils in the leaf axils. Regardless of PPF, PBA-treated plants had less dry weight in the main bulbs than the control plants. Chemical name used: N-(phenylmethyl)-9-(tetra-hydro-2H-pyran-2-yl)-9H-purin-6-amine (PBA).

Potted mature Phalaenopsis `Joseph Hampton' orchid (clone Diane) plants were placed in each of four growth chambers with 0, 8, 60, or 160 μmol·m^–2·s^–1 photosynthetic photon flux (PPF) for 12 hours daily and at 20C day/15C night air. Plants under 160 or 60 μmol·m^–2·s^–1 PPF began spiking (an elongating reproductive bud protruding through the base of its subtending leaf) in an average of 28 or 34 days, respectively. None of the plants placed under 0 or 8 μmol·m^–2·s^–1 PPF started spiking within 6 weeks. These plants, following return to a greenhouse, spiked and flowered 8 weeks later than those receiving 160 μmol·m^–2·s^–1. In a second experiment, plants were placed in each of three growth chambers and kept in complete darkness at 20C day/15C night for 2, 4, or 6 weeks before exposure to 160 μmol·m^–2·s^–1 PPF. Air was maintained at 20C day/15C night for an additional 6 weeks and then raised to 25C day/20C night to accelerate flowering. Plants exposed to 2, 4, or 6 weeks of darkness required 45, 60, or 77 days, respectively, to reach spiking. However, all plants spiked at similar times (31 to 35 days) after lighting began. Anthesis occurred at progressively later dates for plants placed in darkness for increasing durations, but plants in all treatments required 123 days to reach anthesis following their exposure to light. Flower count and size were not affected in both experiments.

An experiment was initiated to determine the effect of a low N, high P and K fertilizer applied during the flowering season on a hybrid moth orchid (Phalaenopsis TAM Butterfly Blume.). On 1 Sept., plants of flowering size receiving N, P, and K at 100, 44, and 83 mg·L^–1, respectively, from a 20N–8.8P–16.6K soluble fertilizer were given N, P, and K, at 30, 398, and 506 mg·L^–1 (high P), respectively, at each or every fourth irrigation. Control plants continued to receive the 20N–8.8P–16.6K fertilizer. The high P treatments, regardless of the frequency of application, had no effect on the date of emergence of the flowering stem (spiking), anthesis, or flower size. All plants treated with the high P fertilizer had fewer flowers (15 to 19) than the controls (24 flowers). Continuous application of adequate N appears to be more important than low N and increased P for optimal flowering. In a separate experiment using the same hybrid orchid, terminating fertilization completely on 1 Sept., 29 Sept., or 27 Oct. or when the flowering stems were emerging (1 Oct.) reduced flower count (≤19 vs. 24). Flower longevity was reduced by 12 d when fertilization was terminated on 1 Sept. Flower size was unaffected by any treatment in either experiment. Discontinuing fertilization prior to late November reduced flower count. Withholding fertilization for extended periods resulted in red leaves, loss of the lower leaves, and limited production of new leaves.