Abstract
‘Enchantment’, ‘Prosperity’, ‘Harmony’, and ‘Hornback's Gold’ were the hybrid garden-type lilies most adaptable for pot plant use. With 6 or 8 weeks of post-plant-storage, a growth retardant was not required to obtain a final plant height between 30 and 50 cm. With 10 or 13 weeks of post-plant-storage at 0°C, ancymidol [N,N,N-2 tetramethyl-5-(1-methyl-ethyl)-4-[(1-piperidinylcarbonyl)oxy]-benzenamonium chloride] as a 0.5 mg a.i. (.0264% active ingredient) drench applied at shoot emergence or as a 100-ppm spray applied when shoots were 7.5 cm long, effectively reduced height and improved appearance.
The final plant heights of ‘Rainbow Hybrid’, ‘Sutter's Gold’ and ‘Pastel Hybrid’ were maintained between 30 and 50 cm with a 0.5 mg ancymidol drench. However, these cultivars were not as promising for pot plants because of narrow and short leaves and necrosis of lower foliage which detracted from their general appearance. The concentration of ancymidol used did not reduce sufficiently the final plant height of ‘Challenger’. Cost of the bulbs may be a factor when considering the use of cultivars such as ‘Challenger’ and ‘Pepper’ for use as pot plants.
The effects of the duration of cold storage, as well as the concentration, timing, and means of application of a solution containing 25 mg·L-1 each of benzyladenine (BA) and gibberellins (GA4+7) on the postharvest quality of cut Asiatic and Oriental lilies (Lilium sp.) were evaluated. Depending on the cultivar, lower leaves began to turn yellow between 1 and 2 weeks after placing non-cold-stored stems in a 20 °C room illuminated 12 h·d-1 with 8 μmol·m-2·s-1 from cool-white fluorescent lamps. Leaf yellowing continued to progress upward until the end of the vase life. Cold storage (3.3 °C) worsened the leaf disorder, particularly, on the Oriental lily `Stargazer'. The longer the duration of cold storage, the earlier the development of leaf yellowing and the higher the percentage of leaves that were chlorotic. In addition, cold storage induced bud blasting, inhibited flowers from fully opening, and reduced the longevity and fresh weight of open flowers and the vase life of cut stems. Spraying leaves with a solution containing 25 mg·L-1 each of BA and GA4+7 significantly reduced cold-storage-induced leaf yellowing, bud blasting, and vase life of three of the four cultivars tested. The development of leaf yellowing declined with increasing concentration of BA+GA4+7. The susceptibility of `Stargazer' to cold-storage-induced leaf yellowing and bud blasting can be counteracted by a concentration of growth regulators higher than that which was effective for the other cultivars. Timing of the BA+GA4+7 application was not critical, as there were no differences in leaf yellowing or bud development when the solution was sprayed before or after the cold storage. Addition of BA+GA4+7 (0.5 or 2.5 mg·L-1 of each) to the preservative solution or a pulsed treatment in solutions containing 25 mg·L-1 each of BA and GA4+7 for 4 hours prevented leaf yellowing, but increased bud blasting. For practical applications, growth regulators can be sprayed prior to or after cold storage in order to improve the postharvest leaf and flower quality of cut lilies.
Uniconazole was applied as a drench or spray to six hybrid lily (Liliurn sp.) cultivars. Spray application was generally more effective than drench in reducing shoot elongation rate in the first few weeks, and then the efficacy decreased and was less effective than the drench at later stages of plant development. At flowering, a uniconazole drench at 0.1 mg/pot was ineffective for height reduction in `Bravo', `Juliana', and `Sunray' lilies. At higher rates, uniconazole drench was similar to spray in reducing shoot growth in `Bravo' and 306-1 but less effective than spray in `Juliana', `Star Gazer', and `Sunray' lilies. Uniconazole spray reduced plant height at flowering in all the lilies compared to control plants. Days to flower was not affected in `Bravo', `Juliana', and `Sunray' but was increased in `Star Gazer', 306-1, and 306-2 by uniconazole spray treatments. Flowering duration was decreased only in 306-1 by uniconazole spray at 0.2 mg/pot. Chemical name used: (E)-1-(4-chlorophenyl) -4,4 -dimethyl-2-(l,2,4 -triazol-1-yl)-1-penten-3 -ol (uniconazole).
Abstract
Oriental hybrid lilies (Lilium speciosum Thunb.) are grown as flowering potted plants or cut flowers (Ball, 1985). However, a major problem with oriental hybrid lilies grown as pot plants is plant height greater than desired for an appropriate aesthetic ratio (Sachs et al., 1976). Uniconazole is an effective chemical growth retardant on other lily species and has the advantage over ancymidol of high activity at very low dosages (Hol-comb and McDowell, 1987; Shumac et al., 1988). With the present work, we evaluated the effectiveness of uniconazole in controlling height of two L. speciosum hybrids and compared uniconazole with ancymidol.
Individual 'Stargazer' flowers lasted about 4.5 to 5 days and weighed ≈14 g. Addition of 2% sugar into the vase solution neither affected the longevity nor the size of the flowers but significantly enhanced anthocyanin content and, thus, the intensity of petal color. Defoliation of Oriental lilies, the common practice of retail florists, did not affect the opening, longevity, and size of the open flowers, but did result in lighter-color petals when placed in a solution without sugar. Addition of sugar to the vase solution counteracted the adverse effects of defoliation on petal color. Sugar in the vase solution did not overcome the increased bud blasting and the reduced longevity and size of flowers induced by cold storage. However, it enabled more flowers to open fully, which, without sugar, remained only partially open. Excised bud experiments revealed that bud size of 6.1 cm and 7.0 cm were critical for opening of non-cold-stored and cold-stored buds, respectively. Unlike other cut flower species in which flowers for long-term storage or long-distance transport are harvested at a tighter-bud stage than those intended for the local market, in 'Stargazer', harvesting of stems where the smallest bud is >7.0 cm would be critical in reducing cold-storage-induced bud blasting.
( Lilium sp.) is a widely cultivated ornamental geophyte. Studies on Lilium nutrition have been reported ( Argo and Biernbaum, 1994 ) and tissue nutrient levels (mmol·kg −1 ) of high-quality lilium plants are 1700 to 2900 nitrogen (N), 32 to 226
Anthocyanins are major pigments responsible for the color of lily (Lilium sp.) flowers. Anthocyanin synthesis is part of the flavonoid metabolic pathway. Numerous transcription factors, including R2R3-MYBs, basic helix-loop-helix (bHLH), and tryptophan–aspartic acid repeat (also known as WD40 or WD repeat) proteins, known to regulate flavonoid biosynthesis have been identified in various plant species. However, there is limited information available on WD repeat proteins in lilies. In this study, we identified a WD repeat gene in the Oriental hybrid lily ‘Sorbonne’ (Lilium hybrid WD repeat, LhWDR). LhWDR contains no introns, and has a 1100–base pair open reading frame, encoding a putative protein of 370 amino acids. LhWDR was found to be localized in the cytoplasm of transgenic Arabidopsis thaliana root cells. Expression patterns of LhWDR in different organs and at different periods of lily tepal growth revealed that the expression levels of this gene are closely associated with anthocyanin accumulation. A yeast two-hybrid assay demonstrated that full-length LhWDR interacts with the 420 N-terminal amino acids of Lilium hybrid bHLH2. Interestingly, overexpression of LhWDR in A. thaliana led to an upregulation of the dihydroflavonol 4-reductase gene, which is an important structural gene downstream of the anthocyanin pathway. These results indicate that the WD repeat protein LhWDR might interact with a bHLH transcription factor to regulate anthocyanin biosynthesis.
One of the problems associated with preplant bulb dips into plant growth regulator (PGR) solutions is the lack of knowledge of solution efficacy as an increasing number of bulbs are treated. We evaluated the effectiveness (“longevity”) of paclobutrazol (Bonzi) and uniconazole (Sumagic) solutions repeatedly used to dip hybrid lily (Lilium sp.) bulbs. Experiments were conducted over a 2-year period, using sequential 1-minute dips into paclobutrazol (100 or 200 mg·L–1) or uniconazole (2.5 mg·L–1). No difference in plant height occurred as the number of bulbs dipped into PGR solutions increased to at least 55 bulbs per liter. This was true whether bulbs were washed (with tap water to remove soil particles attached to the bulbs) or unwashed prior to the PGR dip. These findings have an important impact on cost effectiveness of bulb dips, as the more times the solution can be used, the lower the cost. Washed bulbs were taller than unwashed bulbs due to lower PGR liquid uptake in washed bulbs (about 1 mL less per bulb) compared to the unwashed bulbs. These results indicate that the hydration condition of bulbs prior to dipping can affect the amount of PGR liquid uptake and therefore final plant height.
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.
Several pulse solutions were tested for their effectiveness in preventing leaf senescence on four cut oriental lily cultivars (Lilium sp. `Acapulco', `Kissproof', `Noblesse' and `Star Gazer'). Stems were pulsed 24 hours after harvest for 1 hour, stored in boxes in the dark for 5 days at 3 °C (37.4 °F) then evaluated in postharvest conditions. A new commercial product called Chrysal BVB, a proprietary mixture manufactured by Pokon & Chrysal (Miami) containing cytokinine and gibberellic acids, was the most effective product tested. Chrysal BVB [1 mL·L–1 (0.1%)] prevented leaf chlorosis and abscission on `Acapulco' and `Noblesse' and significantly reduced it by 82% on `Star Gazer' and by 69% on `Kissproof'. Stems pulsed in Fascination, a commercial mixture containing 1.8% gibberellins (GA4+7) and 1.8% benzyladenine [5.4 mg·L–1 (ppm) each], virtually prevented leaf chlorosis on `Noblesse', reduced it by 50% or more on `Acapulco' and `Star Gazer', and significantly delayed it 8 days on `Kissproof'. A 10 μm (2 ppm) pulse in thidiazuron, a substituted phenylurea with cytokinin-like properties, delayed leaf chlorosis on `Star Gazer' but to a lesser extent compared to BVB and Fascination. Chrysal SVB, a propri-etary mixture manufactured by Pokon & Chrysal containing gibberellic acid, had no effect on reducing leaf chlorosis on `Star Gazer'. None of the pulse solutions had adverse effects on bud opening, flower quality or vase life. Maintaining stems in a bulb flower preservative significantly reduced leaf chlorosis and abscission in all cultivars when stems were not pretreated with a pulse solution or when a pulse solution was ineffective.