Salpiglossis sinuata R. et P., a floriferous member of the Solanaceae, was studied for potential as a flowering potted plant when modified by growth retardants. Seedlings of an inbred line P-5 were covered with black cloth for an 8-hour photoperiod to permit vegetative growth to ≈16 -cm-diameter rosettes. Plants were then exposed to an 18-hour photoperiod for the duration of study. Flowering occurred 40 days after the plants were transferred to long days. Neither spray applications of uniconazole at 10, 20, 40, or 100 ppm, nor chlormequat chloride at 750, 1500, or 3000 ppm significantly retarded plant height. Applications of daminozide, ranging in concentration from 1000 to 5000 ppm, alone and in combination with chlormequat chloride, were effective at retarding plant height; however, concomitant restriction of corolla diameter was frequently observed. Chemical names used: 2-chloro- N,N,N -trimethylethanaminium chloride (chlormequat chloride); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); and (E) -1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl) -1-penten-3-01 (uniconazole).
Douglas C Needham and P. Allen Hammer
Anuradha Tatineni, Nihal C. Rajapakse, R. Thomas Fernandez and James R. Rieck
Responses to selected chemical growth retardants (daminozide, paclobutrazol, and prohexadione-Ca) and GA1 and GA3 under photoselective greenhouse covers with various phytochrome photoequilibrium estimates (φe) were evaluated using `Bright Golden Anne' chrysanthemum [Dendranthema ×grandiflora Kitam. (syn. Chrysanthemum morifolium Ramat.)] as the model plant to better understand the height control mechanism by far red (FR) light depleted environments. Plant height linearly decreased as φe increased from 0.72 to 0.83. The rate of height decrease of daminozide treated plants was less than that of water (control) or GA3-treated plants. The rate of height reduction was not different between control and GA3-treated plants among chambers with various φe. Both paclobutrazol and prohexadione-Ca reduced plant height regardless of φe, but the height reduction by paclobutrazol was more than that by prohexadioneCa. The combination of paclobutrazol and prohexadione-Ca reduced plant height more than either alone. GA1 reversed the height reduction caused by paclobutrazol and prohexadione-Ca regardless of φe, but the height increase by GA1 was more when it was applied with prohexadione-Ca than when applied alone. Results show that photoselective covers with high φe were effective in controlling height of chrysanthemums without chemical growth retardants. The linear relationship between plant height and φe suggests that effectiveness of photoselective covers increased as φe increased. The photosynthetic photon flux (PPF) transmission of photoselective covers decreased as the φe increased because of the increasing dye concentration. Identifying photoselective covers that effectively filter out FR light from sunlight and reduce plant height while minimizing the PPF reduction is critical for commercial success of photoselective covers. Gibberellins are, at least partially, involved in height control by photoselective covers. Photoselective greenhouse covers did not reduce responsiveness to gibberellins, and it appears that the mechanism may be to suppress gibberellin biosynthesis. Results also suggest that increased metabolism of GA1 to GA8 was not the mechanism of height control by photoselective covers. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) [daminozide]; (±)-(R*,R*)-b-((4-chlorophenyl)methyl)-a-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol [paclobutrazol]; 3,5-dioxo-4-(1-oxopropyl)cyclohexanecarboxylic acid [prohexadione-Ca]; gibberellic acid [GA].
Derek D. Woolard*, Judy Fugiel, F. Paul Silverman and Peter D. Petracek
Tables, graphs, and photographs can effectively convey detailed results of a PGR experiment. However, we have observed that demonstrating PGR treatment effects by time-lapse video creates a strong impact on both scientists and non-technical audiences. Time-lapse video also provides a method for obtaining a continuous visual record that can be used to establish the precise chronology of a slow process. Recent advances in notebook computers, inexpensive digital cameras (e.g. 3Com HomeConnect™), and time-lapse software (e.g. Picture WorkLive™) allow scientists and teachers to inexpensively prepare time-lapse videos. Important considerations for the production of quality time-lapse videos include: 1. treatment effects should be substantial, consistent, and visible, 2. digital camera images should be clear, 3. lighting should be constant and provide adequate brightness and proper color, 4. camera movement such as those due to vibrations should be minimal, 5. camera placement should simplify composition. Time-lapse videos of PGR treatment effects will be shown, and methods of production will be discussed.
Jennifer K. Boldt and James E. Barrett
A daminozide plus chlormequat chloride tank mix spray was applied to six Coleus cultivars or breeding lines at different times during propagation. For UF 03-8-10 and `Coco Loco', plants sprayed on day 7 or day 10 were shorter than control plants at transplant, but plants sprayed on day 13 were not. Other cultivars did not respond to single applications. Five of the six cultivars responded to application on days 7 and 13. Plants of UF 03-8-3 and `Coco Loco' were significantly shorter than control plants at transplant. Plants of UF 03-8-10, UF 03-6-1, and UF 03-17-8 were shorter than control plants at 3 weeks after transplant. `Hurricane Louise' did not respond to the tank mix. A second study found a cultivar specific response to three chemical treatments applied as a spray on day 10 of propagation. At transplant, UF 03-8-10, UF 03-8-3, UF 03-6-1, and `Coco Loco' plants sprayed with the tank mix at 2500 plus 1500 mg·L-1, respectively, were significantly shorter than the control plants. A uniconazole spray at 2 mg·L-1 reduced elongation in UF 03-8-10, UF 03-8-3, and UF 03-6-1, compared to control plants. Ethephon at 250 mg·L-1 reduced elongation in UF 03-8-10, UF 03-8-3, and `Coco Loco' plants. None of the chemical sprays reduced elongation in `Hurricane Louise' at the concentrations applied. Ethephon increased axillary branching in all cultivars, and induced lower leaf abscission in UF 03-17-8 and `Hurricane Louise'; leaf malformation in UF 03-6-1 and `Coco Loco'; and color alteration in UF 03-6-1, UF 03-8-3, and `Coco Loco'.
Mauricio J. Sarmiento and Jeff S. Kuehny
Curcuma alismatifolia `Chiang Mai Pink' is a tropical perennial from the Zingiberaceae family with attractive flowers that make it useful as potted plant. Curcuma alismatifolia produces a tall inflorescence resulting in an unmarketable plant due to excessive height. Rhizomes of C. alismatifolia were soaked for 10 minutes in GA at concentrations of 0, 100, 200 or 500 ppm. The same plants were drenched with paclobutrazol at 0, 2, 3 or 4 mg a.i./container when shoots were 10 cm. GA significantly delayed rhizome emergence and flowering and reduced flower height. Paclobutrazol significantly reduced height; however, greater concentrations must be applied to obtain a marketable plant height. Number of flowering stems, postproduction life, and postproduction stretching were not affected by GA or paclobutrazol. Curcuma alismatifolia had an excellent postproduction life (4.64 ± 0.28 weeks) with little postproduction stretching (2.27 ± 0.38 cm).
Chamchuree Sotthikul and Pimchai Apavatjrut
Curcuma roscoeana Wall. is a tuberous perennial plant with tuberous rhizomes. It is an endangered species. In nature, it has a very low rate of multiplication. Propagation of C. roscoeana in vitro was done by culturing 0.5 × 1.0-mm shoot tips from young buds onto modified Murashige and Skoog (MS)+ 0.25 mg/L kinetin. Stem explants 10.0 mm in size, measured from the base of the plantlets longitudinally cut in half, were used in the experiments. The first experiment was done by varying the concentration of both kinetin and NAA, in MS liquid medium, at 0–8.0 mg/L and 0–0.05 mg/L, respectively. There were no significant differences of kinetin and NAA concentrations on the number of plantlets obtained. The 0.5-mg/L kinetin treatment gave the highest yield in number of new plantlets (3.1 plantlets/cultured explant). In the second experiment, various concentrations of BAP from 0 to 8.0 mg/l were tested. 2.8–3.7 plantlets were formed in the media with 0.05–2.0 mg/L of BAP. The most-suitable concentration of BAP was at 1.0 mg/L, providing 3.7 plantlets/cultured explants. Kinetin or BAP alone could be used in MS medium for rapid clonal propagation of C. roscoeana. The rooted plantlets could be successfully transferred into growing pots. Acknowledgement: The studies were supported in part by The King's Initiative Centre for Fruit and Flower propagation and Development, Ban Rai, Chiang Mai.
Keith A. Funnell and Royal D. Heins
We gratefully acknowledge the supply of plant material by Neal Mast Greenhouses, Byron Center, Mich. Use of trade names does not imply endorsement of the products named or criticism of similar ones not named. The cost of publishing this
R.E. Byers, D.H. Carbaugh and C.N. Presley
Submerging `Stayman' apples in nonionic and anionic surfactant-water solutions caused increased water uptake and fruit cracking. The primary sites of water uptake were lenticels and injured areas of the fruit cuticle. Fruit cracking caused by submerging fruit in 1.25 ml X-77/liter surfactant was used to predict the natural cracking potential of `Stayman' strains and apple cultivars in the field. Submerging apples in aqueous pesticide mixtures did not Increase fruit cracking or water uptake. Fruit cracking and uptake of surfactant-water were not correlated between apple cultivars. In a surfactant-water bath, `Starkrimson Delicious' absorbed more water than `Stayman', `York', `Jonathan', and `Golden Delicious'; no `Starkrimson Delicious' fruits cracked, but 32% to 80% of the other cultivars did. In field tests, four airblast spray applications of GA4+7 in July and Aug. 1987 reduced fruit cracking from 56% to 21%, and five applications In July, Aug., and Sept. 1988 reduced fruit cracking from 93% to 75%. In 1987, daminozide reduced cracking, but, in 1988, neither daminozide, NAA, nor Vapor Gard alone reduced cracking. However, in 1988, a combination treatment of GA4+7, daminozide, NAA, and Vapor Gard reduced fruit cracking from 93% to 22%. Also, two scorings of the trunk with a carpet knife reduced fruit cracking 22%. Chemical names used: alkylaryl polyoxyethylene alcohol glycol (X-77); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); naphthaleneacetic acid (NAA); di-1-p-methene (Vapor Gard); gibberellic acid (GA4+7).
Moritz Knoche, Norman K. Lownds and Martin J. Bukovac
Effect of carrier volume (range 119 to 668 L·ha-1) on dose response relationships of daminozide and GA3 was investigated using bean (Phaseolus vulgaris L.) seedlings as a model system. Carrier volume was varied by altering nozzle travel speed thereby maintaining constant flow rate and droplet size. Response was indexed by inhibition (daminozide) or stimulation (GA3) of elongation of first plus second internodes above primary leaves 14 days after spray application. Increasing dose by increasing concentration and/or increasing carrier volume at constant concentration increased response. For a given dose retained, response to daminozide was related positively to carrier volume, while GA3 response was not affected. Chemical names used: butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); gibberellic acid (GA3).
Keith A. Funnell and Royal D. Heins
The postharvest quality of potted Asiflorum lily `Donau' (Lilium hybrid) was evaluated after plants were sprayed with 0, 50, 250, or 500 mg·L-1 (BA equivalent) of Promalin (GA4+7 to BA ratio was 1:1) or Accel (GA4+7 to BA ratio 1:10) and stored at 2 to 3 °C for 0, 10, or 20 days. As storage was prolonged, more leaves senesced once plants were removed for evaluation. Leaf senescence declined with increasing concentrations of either Promalin or Accel, but Promalin was more effective. Application of 250 mg·L-1 Promalin completely eliminated leaf senescence over the 20-day shelf-life evaluation period, irrespective of duration of cold storage. The treatments did not affect flower bud opening or plant height. Chemical names used: gibberellin (GA4+7); benzyladenine (BA).