Progress 10/01/06 to 09/30/12
Outputs
OUTPUTS: (1) Developed simple and efficient methods for regenerating Epipremnum aureum Marble Queen and Spathiphyllum Supreme, respectively through direct somatic embryogenesis. Leaf explants of Marble Queen were cultured on MS basal medium supplemented with 4.5 micromole TDZ with 1.1 micromole NAA, and petiole explants were cultured on basal medium containing either 8.1 micromole CPPU or 9.1 micromole TDZ with 1.1 micromole NAA. Somatic embryos appeared in 4-6 weeks and were able to mature after transferring onto the fresh medium containing the same concentrations of growth regulators as they were initially induced. Shoots and roots developed well on the MS basal medium devoid of growth regulators. In general, plantlets grew vigorously in a shaded greenhouse after transplanting to a commercial soilless substrate. Young petioles were the preferred explants since six times more plantlets were regenerated from petiole explants than those of leaf explants. In the regeneration of Spathiphyllum, the highest frequencies of leaf explants with somatic embryos and embryo conversion were both 84.4%, which were induced by 9.1 micromole TDZ with 2.3 micromole 2,4-D. The frequencies for somatic embryo induction and embryo conversion were both 100% when petiole explants were induced by 4.5 micromole TDZ with 2.3 micromole 2, 4-D. The number of plantlets produced per leaf explant and petiole explant were as high as 67.4 and 74.4, respectively. Plantlets after transplanting to a soilless substrate grew vigorously in a shaded greenhouse. Studied effects of different wavelengths from light-emitting diodes (LEDs) on rooting and growth of adventitious shoots of Anthurium. Shoot height was the greatest in monochromic blue light, followed by red light. Shoot fresh and dry weights of plantlets grown under red plus blue light, however, were significantly greater than those grown under the other light qualities. Plantlets grown under red plus blue light had 22.7% greater total dry weight and more balanced root to shoot ratio than those grown under fluorescent white light. These results suggested the use of complex of red plus blue LED could be an option for improving growth of Anthurium plantlets in vitro. Identified three cultivars of ornamental pepper as banker plants for supporting Amblyseius swirskii against silverleaf whitefly, western flower thrips, and chilli thrips. Each cultivar was able to support 500-1000 all stages of A. swirskii in greenhouse conditions. The population of A. swirskii through the banker plants was released or dispersed to green bean plants significantly suppressed the three pests, with only 2.75 of silverleaf whitefly and 13.4 of thrips complex (all stages) per plant, respectively, compared to 379.5 and 235.4 per plant in the control treatments. Furthermore, sweet pepper seedlings heavily infested by chilli thrips were serious burned or died, where protected sweet pepper seedlings by the banker plant were grown in healthy status. PARTICIPANTS: Arthurs, S.P., D. Cantliffe, J. Cui, M. Dogramaci, K. Houben, R.J. Henny, F. Irizarry, C. Mannion, C.L. Mckenzie, L.S. Osborne, Y. Xiao TARGET AUDIENCES: Foliage plant growers, interiorscaper, irrigation companies, landscaper plant growers, potting media companies, vegetable growers, water management districts PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Marble Queen is a variegated cultivar; the established regeneration system may represent a method for new cultivar development of E. aureum. Except for those complete green and whitish plants, a few additional variants that were different from Marble Queen were identified from the variegated group. These variants were stable during a three-month growth in the shaded greenhouse. Analysis of simple sequence repeats amplified from 14 universal chloroplast primer pairs showed no variation between stock plants and selected variants. RT-PCR analysis of EaZIP, a marker gene involved in leaf variegation of E. aureum Golden Pothos, suggested little expression difference between green and whitish plants or between green and whitish sectors of a variegated leaf. However, SDS-PAGE analysis of proteins showed differences in band intensity and patterns. These results suggest that mechanisms underlying leaf variegation of Marble Queen differ from the closely related Golden Pothos. The established regeneration system and identified variants could be important materials for further investigation of leaf variegation in E. aureum. Our report was the first to document the regeneration of Spathiphyllum through somatic embryogenesis. The availability of this regeneration technique, in combination with the other reported methods using anther filaments as well as the recent progress in gynogenesis and chemical induced polyploidization will provide important tools for genetic improvement of this important flowering plant. Light quality significantly affects plant growth, our study showed that red + blue LED light source improves plant growth by a 22.7% increase in total dry weight compared to the conventionally used fluorescent white light source. Because the use of fluorescent lamps consumes 65% of the total electricity in a tissue culture laboratory, it is the highest non-labor cost. Fluorescent lamps also produce unneeded heat in culture rooms; therefore, the use of LED light sources could not only improve plantlet growth but also save non-labor costs in micropropagation. Invasive pests significantly threaten the horticulture industry. Chilli thrips was estimated to cause between $3 and $6 billion crop yield loss annually in the US. Current methods of controlling the invasive pests have been heavily relying on chemical application, which not only results in pest resistance but also potential environmental contamination. Biological control has been considered a major component of integrated pest management programs. The banker plant systems established in our studies will provide more stable and long-lasting method of pest control in an environmentally-friendly manner.
Publications
- 3. Gu, A., W. Liu, C. Ma, J. Cui, R.J. Henny, and J. Chen. 2012. Regeneration of Anthurium andraeanum from leaf expalnts and evaluation of microcutting rooting and growth under different light qualities. HortScience 47:88-92.
- 1. Zhao, J., J. Cui, J. Liu, F. Liao, R.J. Henny, and J. Chen. 2012. Direct somatic embryogenesis from leaf and petiole explants of Spathiphyllum Supreme and analysis of regenerants with flow cytometry. Plant Cell, Tissue and Organ Culture 110:239-249.
- 2. Zhao, J., Q. Zhang, J. Xie, C. Hung, J. Cui, R.J. Henny, and J. Chen. 2012. Plant regeneration via direct somatic embryogenesis from leaf and petiole explants of Epipremnum aureum Marble Queen and characterization of selected variants. Acta Physiologiae Plantarum 34:1461-1469.
- 4. Xiao, Y., P. Avery, J. Chen, C. Mckenzie, and L.S. Osborne. 2012. Ornamental pepper as blanker plants for establishment of Amblyseius swirskii (Acari Phytoseiidae) for biological control of multiple pests in greenhouse vegetable production. Biological Control 63:279-286.
- 5. He, Y., J. Zhang, H. Ma, Y. Tu, J. Chen, F. Chen, H. Xu, Z. Song, D. Cai, and X. Xue. 2012. Aerenchyma formation and increased accumulation of free proline in roots of xerophytic Aloe vera L. cultured in nutrient solutions. Journal of Medicinal Plants Research 6:243-252.
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: (1) Developed a simple and efficient method of regenerating Chlorophytum amaniense Fire Flash through indirect shoot organogenesis. Calluses were induced from sprouted seeds cultured on a MS basal medium supplemented with either 9.8 micromole 2iP or 9.1 micromole TDZ with 1.1 micromole NAA. Adventitious shoots were produced from the calluses subcultured on the same medium (either 9.8 micromole 2iP or 9.1 micromole TDZ with 1.1 micromole NAA). The shoots rooted easily in the basal medium containing 4.4 micromole BA and 2.7 micromole NAA, and plantlets were acclimatized and grew vigorously in a shaded greenhouse. (2) Discovered that foliar spray with Ti solutions reduced the occurrence of leaf lesion on potted zonal geranium Patriot Bright Violet inoculated with Xanthomonas hortorum pv. pelargonii and poinsettia Snowcap inoculated with Xanthomonas axonopodis pv. Poinsettiicola. The numbers of lesions on geranium leaves sprayed with Ti at 75 mM were 67% less than those in control plants. The numbers of lesion were 93% lower in poinsettia treated with Ti at 75 mM of Ti compared to those in the control plants. (3) Established papaya as a banker plant to support Encarsia sophia against silverleaf whitefly, Bemisia tabaci and corn as a banker plant for hosting predatory gall midge Feltiella acarisuga to suppress Tetranychus urticae. We also identified that predatory mite, Amblyseius swirskii and insidious flower bug, Orius insidiosus were able to control chilli thrips, Scirtothrips dorsalis and Montandoniola confusa as biological control agents of weeping fig thrips, Gynaikothrips uzeli. PARTICIPANTS: Ali, A.D., S.P. Arthurs, M. Brennan, D. Cantliffe, J. Cui, M. Dogramaci, K. Houben, R.J. Henny, F. Irizarry, C. Mannion, C.L. Mckenzie, D.J. Norman, L.S. Osborne, Y. Xiao TARGET AUDIENCES: Foliage plant growers, Interiorscaper, irrigation companies, landscaper plant growers, potting media companies, water management districts PROJECT MODIFICATIONS: Nothing significant to report during this reporting period
Impacts
(1)Fire Flash was recently introduced commercially as an exotic ornamental foliage plant and enjoys considerable market success as it has a self-heading and upright growing style, broad lanceolate leaves, and bright coral-colored midribs and petioles. The unique coral-colored petioles and midribs contrasting with dark green leaves make it a sought after cultivated foliage plant specimen. Another important characteristic of Fire Flash is its ability to tolerate interior conditions under a low light level of 8 micromole m-2 s-1 for eight months or longer. Propagation through seed and division has not met the growing demand for starting materials. Commercial tissue culture laboratories have begun producing liners for the ornamental plant industry; however, single liner plugs frequently develop multiple shoots after transplanting, resulting in unsalable plants with small distorted leaves. Thus, a new and reliable protocol for regenerating high quality Fire Flash liners is needed. The established method is simple and efficient and the regenerated plants are morphologically stable without multiple shoots and distorted growth. The use of this established protocol could significantly increase the propagation of the starting materials of Fire Flash to meet the demand for commercial production. (2) Bacterial diseases cause significant economic loss in the ornamental and floricultural industries. In today competitive marketplace, plants are not saleable with spotted leaves, retarded growth, or wilted stems. Xanthomonas blight on geranium is considered to be the most serious problem limiting geranium production, and Xanthomonas leaf spot of poinsettia is another important floral crop disease. Bactericides have been used for controlling xanthomonas in geranium and poinsettia. Most commonly used bactericides contain copper, manganese and zinc, but very few bactericidal control products are effective against established infections. Our study suggests that TiO2 could offer an alternative chemical to the currently labeled products for controlling xanthomonas leaf spots in geranium and poinsettia. (3) Invasive pests significantly threaten the horticulture industry. For example, chilli thrips has been estimated to cause between $3 and $6 billion crop yield loss annually in the US. Current methods of controlling the invasive pests have been heavily relying on chemical application, which not only results in pest resistance but also potential environmental contamination. Biological control has been considered a major component of integrated pest management programs. The banker plant systems established in our studies will provide more stable and long-lasting method of pest control in an environmentally-friendly manner. Banker plant systems are uniquely combines the advantages of both augmentative and conservation biological controls for sustainable suppression of targeted pests.
Publications
- Xiao, Y., L.S. Osborne, J. Chen, C.L. Mckenzie, K. Houben, and F. Irizarry. 2011. Evaluation of corn plant as potential banker plant for supporting predatory gall midge, Feltiella acarisuga (Diptera Cecidomyiidae) against Tetranychus urticae (Acari Tetranychidae) in greenhouse vegetable production. Crop Protection 30:1635-1642.
- Dogramaci, M., S.P. Arthurs, J. Chen, C.L. Mckenzie, F. Irizarry, and L.S. Osborne. 2011. Management of chilli thrips Scirtothrips dorsalis (Thysanoptera: Thripidae) on peppers by Amblyseius swirskii (Acari Phytoseiidae) and Orius insidiosus (Hemiptera Anthocoridae). Biological Control 59:340-347.
- Xiao, F., J. Chen, D. Cantliffe, C. Mckenzie, K. Houben, and L.S. Osborne. 2011. Establishment of papaya banker plant system for parasitoid, Encarsia sophia (Hymenoptera Aphilidae) against Bemisia tabaci (Hemiptera Aleyrodidae) in greenhouse tomato production. Biological Control 58:239-247.
- Henny, R.J. and J. Chen. 2011. Leprechaun Aglaonema. HortScience 46:950-951.
- Arthurs, S., J. Chen, M. Dogramaci, A.D. Ali, and C. Mannion. 2011. Evaluation of Montandoniola confusa Streito and Matocq sp. nov. and Orius insidiosus Say (Heteroptera Anthocoridae), for control of Gynaikothrips uzeli Zimmerman (Thysanoptera Phlaeothripidae) on Ficus benjamina. Biological Control 57:202-207.
- Cui, J., J. Liu, J. Chen, and R.J. Henny. 2011. Regeneration of Chlorophytum amaniense Fire Flash via indirect shoot organogenesis. HortScience 46:466-469.
- Norman, D. and J. Chen. 2011. Effect of foliar application of titanium dioxide on bacterial blight of geranium and Xanthomonas leaf spot of poinsettia. HortScience 46:426-428.
- Dogramaci, M., J. Chen, S.P. Arthurs, C.L. Mckenzie, F. Irizarry, K. Houben, M. Brennan, and L.S. Osborne. 2011. Mini-aspirator, a new device for collection and infestation of small arthropods to plants. Florida Entomologist 94:22-27.
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: (1) Studied genetic relationships of 44 cultivars of Codiaeum variegatum, commonly known as crotons, using AFLP markers. The 44 cultivars were divided into seven clusters which concurred with the known history of croton geographical isolation, adaptation, introduction, and breeding activities. Additionally, genetic distance among the 44 cultivars was less than 0.322, indicating that they have a narrow genetic base. The narrow genetic base may indicate that the cultivars were derived from a common progenitor. On the other hand, 81% of the 549 fragments were polymorphic and the average polymorphic information content (PIC) was 0.22, which suggests that the cultivars are genetically highly polymorphic. The high polymorphisms may be attributed to significant gene loss or gain facilitated by mutation and/or chromosome variation, thus contributing to a wide range of leaf morphological differences among cultivars. (2) Established a method of regenerating Dracaena surculosa Florida Beauty through indirect shoot organogenesis. The highest callus induction frequency was 63.2% from stem explants and 69.6% from bud explants when they were cultured on MS basal medium supplemented with 49.2 micromole 2iP and 2.3 micromole IAA. The highest shoot formation frequency was 65.7% from stem-derived callus cultured on the basal medium containing 61.5 micromole 2iP and 1.1 micromole IAA and 88% from bud-derived callus cultured with 49.2 micromole 2iP and 1.1 micromole IAA. The highest number of shoots per piece of stem- and bud-derived calluses was 3.8 and 6.7, respectively. Adventitious shoots developed better root systems in the basal medium supplemented with 2.0 micromole IAA. Plantlets after transplantation into a soilless substrate grew vigorously in a shaded greenhouse. (3) Documented that low-pressure fog-based irrigation systems using deep well water protected foliage plants from chilling injury and also used 86% less water than mist irrigation systems. (4) Identified EaZIP (Epipremnum aureum leucine zipper), a nuclear gene homologue of tobacco NTZIP and Arabidopsis CHL27, was reduced more than 4000-fold in qRT-PCR analysis in the yellow sector of E. aureum Golden Pothos leaves. EaZIP encodes the Mg-protoporphyrin IX monomethyl ester cyclase, one of the key enzymes in the chlorophyll biosynthesis pathway. Examination of EaZIP expression in naturally variegated Golden Pothos confirmed that EaZIP transcript levels were correlated with leaf chlorophyll contents, suggesting that this gene plays a major role in the loss of chlorophyll in the yellow sector of Golden Pothos. PARTICIPANTS: Kent O. Burkey, Geoffrey C. Danny, Diane E. Darlington, Min Deng, Edward Hanlon, Brent K. Harbaugh, Richard, J. Henny, Chiu-Yueh Hung, Qiansheng Li, Yuncong Li, Juanxu Liu, Terri A. Mellich, Seenivasan Natarajan, George O'Connor, Lawrence R. Parsons, Amy L. Shober, Maria Silveira, Robert H. Stamps, Craig D. Stanley, Ying-Hsuan Sun, Christine Wiese, Alfred L. Williams, Jiahua Xie TARGET AUDIENCES: Foliage plant growers, Interiorscaper, irrigation companies, landscaper plant growers, potting media companies, water management districts PROJECT MODIFICATIONS: Nothing significant to report during this reporting period
Impacts
(1) Codiaeum variegatum or crotons are small evergreen trees and shrubs with varied leaf shapes and vivid foliage colors displayed as shades, blends, combinations, or solid patches of red, pink, orange, yellow, lavender, black, and green. Leaf sizes range from small (6 cm long) to large (35 cm long), and margins can be entire or trifurcate. Leaf shapes vary from simple ovate to linear, some are slightly or deeply cut, others are connected with the blade only by the midrib. Thus, crotons are valued mainly for their attractive foliage. Currently, more than 300 cultivars are reported in the world, and they are cultivated as either landscape plants or containerized foliage plants. However, genetic relatedness of cultivars has been largely unknown. The genetic relationships established in our study based on AFLP markers will be important for future germplasm identification and conservation and new cultivar development. (2) Dracaenas as ornamental plants are propagated through cuttings, which are predominately imported from Central America. Imported cuttings may carry and spread pathogens and pests. For example, a sample of 24 plant shipments, including cuttings of D. surculosa, entering the United States from Costa Rica, Honduras, and Guatemala found half of the shipments infested with mites. The regeneration method we established in this study for D. surculosa will reduce the dependency on imported cuttings, which often bring new or invasive pests into the United States. (3) Foliage plants are generally sensitive to chilling temperature. Conventional methods of heating such as electric heaters and solid, liquid, or gas fuel burners are expensive to install and costly to run and maintain and, therefore, significantly increase the cost of plant production. Burning fuels can cause crop and environmental damage from air pollution. Our study documented that fog-based irrigation systems protected foliage plants from chilling injury. It has been estimated that cold protecting using fog may require only 20% and 0.3% of the fuel energy compared with using sprinkler irrigation or combustion heaters, respectively. (4) Variegated plants comprise almost one third of commercially produced ornamental plants. Because of magnificent multicolored leaves, variegated foliage plants are widely used in interior plantscapes. However, information regarding molecular bases of leaf variegation has been limited. In the study of Golden Pothos we found that EaZip was reduced more than 4,000-fold in the yellow sector compared to its expression in the green sector of leaves. The identified genes provide further insight into leaf variegation and possibility for developing new cultivars with novel variegation patterns.
Publications
- Stamps, R.H., S. Natarajan, L. Parsons, and J. Chen. 2010. Water-based cold protection of foliage plants in shadehouses. HortScience 45:1668-1672.
- Shober, A.L., C. Wiese, G.C. Denny, C.D. Stanley, and J. Chen. 2010. Plant performance and nutrient losses during containerized bedding plant production using composted dairy manure solids as a peat substitute in substrate. HortScience 45:1516-1521.
- Henny, R.J. and J. Chen. 2010. Scenic Bay Aglaonema. HortScience 45:1281-1282.
- Liu, J., M. Deng, R.J. Henny, J. Chen, and J. Xie. 2010. Regeneration of Dracaena surculosa through indirect shoot organogenesis. HortScience 45:1250-1254.
- Deng, M., J. Chen, R.J. Henny, and Q. Li. 2010. Genetic relationships of Codiaeum variegatum cultivars analyzed by amplified fragment length polymorphism markers. HortScience 45:868-874.
- Henny, R.J., J. Chen, and T.A. Mellich. 2010. Philodendron scandens subsp. oxycardium Frilly Philly. HortScience 45:830-831.
- Deng, M., J. Chen, R.J. Henny, and Q. Li. 2010. Chromosome number and karyotype variation in Codiaeum variegatum cultivars. HortScience 45:538-540.
- Hung, C., Y. Sun, J. Chen, D. Darlington, A.L. Williams, K.O. Burkey, and J. Xie. 2010. Identification of a Mg-protoporphyrin IX monomethyl ester cyclase homologue, EaZIP, differentially expressed in variegated Epipremnum aureum Golden Pothos is achieved through a unique method of comparative study using tissue regenerated plants. Journal of Experimental Botany 61:1483-1493.
- Li, Y., E. Hanlon, G. OConnor, J. Chen, and M. Silveira. 2010. Land application of compost and other wastes (by-products) in Florida: regulations, characteristics, benefits, and concerns. HortTechnology 20:41-51.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Research accomplishments 2009: (1) Developed a protocol for improving Pachira aquatica growth and subsequent interior performance. P. aquatica trunks were grown in a shadehouse under three photosynthetic photon flux densities (PPFD). Two months after planting, the plant canopy was sprayed once with paclobutrazol solutions. Results showed that lowering production light levels affected the photosynthetic-light response curve and reduced the light compensation point. Foliar application of paclobutrazol reduced internode length, thereby resulting in plants with reduced canopy height and width and a more compact growth form. Plants with the compact growth form did not grow substantially, dropped fewer leaflets, and maintained their aesthetic appearance after placement indoors for 6 months. Thus, the ornamental value and interior performance of P. aquatica plants can be significantly improved by producing them under a PPFD range between 285 and 350 micromol/m2/s1 and foliar spraying of paclobutrazol once at a concentration between 50 and 150 ppm. (2) Established methods of using composted dairy manure as a component of container substrates for foliage plant propagation. A total of 14 substrates were formulated using composted dairy manure in different proportions by volume. Testing of the substrates showed that composted dairy manure- and peat-based substrates had similar physical and chemical properties and the percentages of rooting and seed germination in composted dairy manure-based substrates were equal to or better than those of the peat-based controls. The success in using up to 60% composted dairy manure in rooting and seed germination substrates suggests that cowpeat can be an alternative to peat for foliage plant propagation. (3) Produced tetraploids from in vitro cultured Dieffenbachia Star Bright M-1 using colchicines. DNA flow cytometry analysis showed that there were 13 tetraploids and 29 mixoploids among 63 colchicine-treated selections. Tetraploids had significantly smaller and thicker leaves, greater specific leaf weights, and longer stomata than diploids. They also showed increased net photosynthetic rate, decreased stomatal conductance, intercellular CO2 concentration, transpiration rate, and increased water use efficiency. Tetraploids appeared robust and their smaller size could make them potentially more durable plants used as living specimens for interior use. (4) Regenerated Lonicera macranthoides through indirect shoot organogenesis. The protocol for callus induction from leaf explants cultured on Gamborg B5 medium was 1.0 ppm BA with 0.5 ppm 2,4-D, which resulted in 86.7% of leaf explants producing calluses in 4 weeks. The best formulation for shoot induction was B5 medium containing 0.2 ppm KT and 1.0 ppm NAA where 73.4% of cultured calluses produced shoots in 8 weeks, and shoot numbers ranged from 3 to 6 per callus piece. Adventitious shoots were cut and rooted in half-strength Murashige and Skoog (MS) medium supplemented with 3.0 ppm 3-indolebutyric acid (IBA). PARTICIPANTS: Arthurs, S., M. Brennan, R.D. Caldwell, J. Cui, M. Deng, M. Dogramaci, K. Houben, J. Holm, R.J. Henny, C. McKenzie, T.A. Mellich, Q. Li, L.S. Osborne, S.M. Scheiber, X. Wang. TARGET AUDIENCES: Dairy industry, foliage plant growers, landscaper plant growers, potting media companies PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
(1) Pachira aquatica has recently been introduced as a new ornamental foliage plant and is widely used for interiorscaping. Its growth and use under low light conditions, however, have two problems: leaf abscission and accelerated internode elongation. Thus far, there is no information available regarding cultural practices to control the two problems in P. aquatic. The established protocol can improve P. aquatica growth and subsequent interior performance, which will expand this new plant's production and interior use in the foliage plant industry. (2) Peat has been a major component of substrates used in container plant production since the 1960s. Highly porous with the capacity to hold water, peat makes an ideal rooting and growing medium for potted plants. But harvesting peat (and draining valuable peatlands in the process) releases the carbon stored in peat into the atmosphere as carbon dioxide. And because peat plays an important role in wetland ecosystems - peat bogs improve groundwater quality and are unique habitats for wild plants and animals. The use of peat has been challenged and peat mining is increasingly regulated. The use of composted dairy manure will provide the containerized plant industry with an alternative to peat, which in turn reduces peat mining and encourages composting of dairy manure, thus contributing to the well-being of our environment. (3) The introduction of new forms of plants is important to the foliage plant industry. The tetraploids developed in our program were miniatures of Dieffenbachia Star Bright M-1 with a higher net photosynthetic rate and higher water use efficiency. Interior evaluation showed that the tetraploids had increased adaptability to interior low light conditions and tolerance to drought, which may suggest that chromosome doubling could be a strategy for increasing plant tolerance to stressful environments such as interior low light and low humidity conditions. (4) Lonicera species are not only important ornamental plants but also popular medicinal plants. Cutting propagation has been difficult in some of the species. Our study established a simple and efficient protocol through which a large number of plantlets can be regenerated from leaf explants in 12 weeks. The established protocol will improve Lonicera propagation by providing a large number of disease-free and uniform plants for both the ornamental and medicinal plant industries.
Publications
- (1) Henny, R.J., J. Chen, and T.A. Mellich. 2009. Epipremnum aureum Green Genie. HortScience 44:1783-1784.
- (2) Henny, R.J. and J. Chen. 2009. Key Lime Aglaonema. HortScience 44:1767-1768.
- (3) Li, Q., M. Deng, J. Chen, and R.J. Henny. 2009. Effects of light intensity and paclobutrazol on production and interior performance of Pachira aquatica Aubl. HortScience 44:1291-1295.
- (4) Henny, R.J., J. Chen, and T.A. Mellich. 2009. Epipremnum aureum Pearls and Jade. HortScience 44:824-825.
- (5) Henny, R.J., J. Holm, J. Chen, and M. Scheiber. 2009. In vitro induction of tetraploids in Dieffenbachia Star Bright M-1 by colchicine. HortScience 44:646-650.
- (6) Arthurs, S., C. McKenzie, J. Chen, M. Dogramaci, M. Brennan, K. Houben, and L.S. Osborne. 2009. Evaluation of Neoseiulus cucumeris and Amblyseius swirskii (Acari: Phytoseiidae) as biological control agents of chilli thrips, Scirtothrips dorsalis (Thysanoptera: Thripidae) on pepper. Biological Control 49:91-96.
- (8) Wang, X., J. Chen, Y. Li , Q. Nie, and J. Li. 2009. An efficient procedure for regeneration from leaf-derived calluses of Lonicera macranthoides Jincuilei, an important medicinal plant. HortScience 44:746-750.
- (7) Li. Q., J. Chen, R.D. Caldwell, and M. Deng. 2009. Cowpeat as a peat substitute of container substrates for foliage plant propagation. HortTechnology 19:340-345.
- (9) Cui, J., J. Chen, and R.J. Henny. 2009. Regeneration of Aeschynanthus radicans via direct somatic embryogenesis and analysis of regenerants with flow cytometry. In Vitro Cellular and Developmental Biology-Plant 45:34-43.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Research accomplishments 2008: (1) Established a method for regenerating Aeschynanthus radicans Mona Lisa through direct somatic embryogenesis. Globular somatic embryos were formed directly from cut edges of leaf explants and cut ends or on the surface of stem explants 4 weeks after culture on MS medium supplemented TDZ with NAA, TDZ with 2,4-D, or BA and kintin with 2,4-D. Somatic embryos matured, and some germinated into small plants on the initial induction medium. Approximately 30-50 plantlets were regenerated from each stem or leaf explant. The regenerated plants grew vigorously after transplanting to a soil-less substrate in a shaded greenhouse with more than a 98% survival rate. (2) Established a method of regeneration of Syngonium podophyllum White Butterfly through the formation of protocorm-like bodies. Culture of nodal explants on the MS medium supplemented with 2iP, BA, CPPU, or TDZ with 2,4-D resulted in the formation of protocorm-like bodies, adventitious shoots, and subsequently well rooted plantlets. Regenerated plantlets were stable and grew vigorously with 100% survival rates after ex vitro transplanting to a container substrate in a shaded greenhouse. (3) Identified Dieffenbachia cultivar tolerance of chilling temperatures. Eight popular cultivars were chilled in walk-in coolers at 2, 7, or 12 C for 6, 12, or 24 h. Chilled plants were placed back in the shaded greenhouse for chilling injury and growth evaluation. Leaf injury occurred in all cultivars chilled at 2 C, except for Panther; and the longer the exposure at this temperature, the greater the injury. No visual injury was observed among plants chilled at 7 and 12 C except Tropic Honey that had 26% of leaves injured at 7 C. Based on the percentage of injured leaves 12 days after chilling at 2 C for 24 h, the sensitivity of the eight cultivars ranked as follows: Tropic Honey > Sterling > Carina ≥ Octopus > Camille > Camouflage > Star Bright > Panther. (4) Quantified heavy metal leaching from coal fly ash amended substrate. Three fly ashes collected from Florida, Michigan, and North Carolina and a commercial dolomite were amended in a basal substrate. The formulated substrates were used to produce Syngonium podophyllum Berry Allusion in 15-cm diameter containers in a shaded greenhouse. Leachates from the containers were collected during the entire six months of plant production and analyzed for heavy metal concentrations. There were no detectable As, Cr, Hg, Pb, and Se in the leachates; Cd and Mo were only detected in a few leachate samples. The metals constantly detected were Cu, Mn, Ni, and Zn, and the total amounts leached during the six-month production period were 95, 210, 44, and 337 microgram per container, indicating that such amounts in leachates may contribute little to contamination of surface and ground water. PARTICIPANTS: Cui, J., J. Liu, M. Deng, R.J. Henny, T.A. Mellich, M.S. Brennan, X. Shen, M.E. Kane, S.M. Scheiber, R.C. Beeson, Jr., Q. Wang, B. Pearson, R.H. Stamps, and L.R. Parsons TARGET AUDIENCES: Foliage plant growers, landscaper plant growers, potting media companies PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
(1) Aeschynanthus are now among the most popular hanging baskets and potted flowering plants in the floriculture industry. Regeneration methods have not been established for this important genus. As the first time direct somatic embryogenesis has been established, our research provides the industry with a convenient tool for propagating disease free liners year round. (2) Syngonium has been micropropagated using shoot tips. Recently, however, Myrothecium leaf spot has become the most common disease of Syngonium. This opportunistic airborne fungal pathogen particularly occurs during the ex vitro rooting of microcuttings following shoot culture because the cutting base is especially susceptible to this pathogen. Sometimes more than 80% of microcuttings are infected. No commercial cultivars are resistant to this pathogen. Our established in vitro propagation through protocorm-like bodies produces well rooted plantlets for transplanting, which eliminates rooting of microcuttings. It thus will greatly reduce the Myrothecium leaf spot problem. (3) Chilling has been a significant cause of foliage plant injury not only in production but also in transportation, retail display, and interiorscaping. The identified chilling-tolerant Dieffenbachia cultivars could be used in commercial production, which may help reduce chilling injury incidences and also conserve energy normally used for greenhouse heating. Additionally, chilling-tolerant cultivars can be used in breeding programs for developing new cultivars with chilling tolerance. (4) Coal fly ash has been proposed to be an alternative to lime amendment and a nutrient source of container substrates for ornamental plant production. A great concern over this proposed beneficial use, however, is the potential contamination of surface and ground water by heavy metals. Our study showed that heavy metal leaching may contribute little to contamination of surface and ground water. In addition, plant growth indices and fresh and dry weights of S. podophyllum Berry Allusion produced from fly ash and dolomite amended substrates were comparable. Thus, selected fly ashes can be alternatives to commercial dolomites as amendments to container substrates for ornamental plant production. The use of fly ashes as container substrate amendments should represent a new market for the beneficial use of this coal combustion byproduct.
Publications
- Shen, X., M.E. Kane, and J. Chen. 2008. Effect of genotypes, explant sources and plant growth regulators on indirect shoot organogenesis of Dieffenbachia. In Vitro Cellular and Developmental Biology-Plant 44:282-288.
- Cui, J., J. Liu, M. Deng, J. Chen, and R.J. Henny. 2008. Plant regeneration through protocorm-like bodies induced from node explants of Syngonium podophyllum White Butterfly. HortScience (in press).
- Cui, J., J. Chen, and R.J. Henny. 2008. Regeneration of Aeschynanthus radicans via direct somatic embryogenesis and analysis of regenerants with flow cytometry. In Vitro Cellular and Developmental Biology-Plant (in press).
- Henny, R.J., J. Chen, T.A. Mellich, and M.S. Brennan. 2008. Mondo Bay Aglaonema. HortScience 43:1900-1901.
- Li, Q., J. Chen, R.H. Stamps, and L. R. Parsons. 2007. Variation in chilling sensitivity among eight Dieffenbachia cultivars. HortScience 43:1742-1745.
- Henny, R.J., J. Chen, T.A. Mellich, and M.S. Brennan. 2008. Moonlight Bay Aglaonema. HortScience 43:1598-1599.
- Scheiber, S.M., R.C. Beeson, Jr., J. Chen, Q. Wang, and B. Pearson. 2008. Evaluation of irrigation frequency and quantity on leaf gas exchange, growth, and nitrogen leaching of Coleus in a simulated landscape. HortScience 43:881-884.
- Li, Q., J. Chen, and Y. Li. 2008. Heavy metal leaching from coal fly ash-amended container substrates during Syngonium production. Journal of Environmental Science and Health Part B43:179-186.
- Chen, J. and R.J. Henny. 2008. Role of micropropagation in the development of ornamental foliage plant industry. p. 206-218. In J.A. Teixeira da Silva (ed.) Floriculture, Ornamental and Plant Biotechnology vol V, Global Science Books, London, UK
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: (1) Developed a simple and effective method for quantification of leaf variegation. Using a digital camera or a scanner, the image of a variegated leaf was acquired into a computer. Total pixels of the entire leaf area and total pixels of each color within the leaf were determined through Adobe Photoshop. The percentage of each color total pixel count in relation to the total pixel count of the entire leaf was then obtained. Total leaf area was measured through a leaf area meter; the exact area of this color was calculated in reference to the pixel percentage obtained from the Photoshop program. The results were highly reproducible no matter who performed the quantification. (2) Analyzed genetic relationships of 56 Ficus cultivars across 12 species using AFLP markers. Most cultivars were differentiated by their AFLP fingerprints, and the cultivars were divided into 12 clusters that correspond to 12 species, indicating that no interspecific hybrids of ornamental Ficus are in
commercial production. The 12 species are genetically diverse with Jaccard similarity coefficients ranging from 0.21 to 0.43. However, cultivars within three genera, F. benjamina, F. elastica, and F. pumlia are genetically close. Twenty-seven of the 29 cultivars of F. benjamina and five cultivars of F. pumila had Jaccard similarity coefficients of 0.98 or higher, respectively. Nine cultivars of F. elastica shared Jaccard coefficients higher than 0.96. These results indicate potential genetic vulnerability of these cultivars within the three species. (3) Established a novel protocol for indirect shoot organogenesis of Dieffenbachia Camouflage, Camille, and Star Bright using leaf explants excised from in vitro shoot culture. The frequency of callus formation for Camouflage reached 96% for explants cultured on modified MS basal medium supplemented 5 µM TDZ with 1 µM 2,4-D. The number of shoots regenerated was high, up to 7.9 per pieces of calli (approximately 5 mm3) cultured
on basal medium supplemented 40 µM 2iP with 2 µM IAA. Regenerated shoots rooted well in a soilless substrate with an ex vitro survival rate of 100% and grew vigorously in a shaded greenhouse. (4) Isolated four Dieffenbachia somaclonal variants, three from Camouflage and one from Camille. The three from Camouflage had distinct foliar variegation, and the one from Camille differed in leaf shape. This study indicated the feasibility of selection of somaclonal variation for new cultivar development in Dieffenbachia.
PARTICIPANTS: Russell D. Caldwell, Biological Scientist, University of Florida; Qiansheng Li, Research Associate, University of Florida; Xiuli Shen, Graduate student of University of Florida; Mike E. Kane, Professor of University of Florida; Richard J. Henny, Professor of University of Florida; David J. Norman, Associate Professor of Univeristy of Florida; Dennis B. McConnell, Professor of University of Florida; Chih-Cheng T. Chao, Associate Professor of University of California-Riverside; and Jigui Fang, Postdoctoral Associate of University of California-Riverside
TARGET AUDIENCES: Ornamental foliage plant industry, foliage plant growers and nurserymen, plant breeders, interior plantscape firms
Impacts
Leaf variegation is an important trait to ornamental plants. More than one third of commercially produced ornamental foliage plants are valued for their foliar variegation, and consumer preferences for plant characteristics placed foliar variegation as the second most important consideration in the purchase decision. However, there is no method that can simply quantify the amount of variegated color on leaves. The method we developed was simple and highly reproducible and can be used for monitoring changes in colors and variegation patterns caused by abiotic and biotic stresses as well as quantifying differences in variegation patterns of plants developed in breeding programs. We were able to identify 56 Ficus cultivars based on their DNA fingerprints. This is the first molecular investigation of the genetic relationships of ornamental Ficus cultivars. The genetic similarity among cultivars established can help future Ficus germplasm identification, conservation, and
new cultivar development. Dieffenbachia consistently ranks among the top five most popular foliage plant genera based on annual wholesale value. However, plant regeneration via indirect shoot organogenesis has not been achieved in Dieffenbachia. The established method will provide more effective way to regenerate this important foliage plant and also to produce somaclonal variation. The identified four variants were morphologically distinct and could potentially be new cultivars after selection.
Publications
- Li, Q., J. Chen, D.B. McConnell, and R.J. Henny. 2007. A simple and effective method of quantifying leaf variegation. HortTechnology 17:285-288.
- Fang, J., J. Chen, R.J. Henny, and C.T. Cao. 2007. Ornamental Ficus species and cultivars analyzed by AFLP markers. Journal of American Society for Horticultural Science 132:807-815.
- Shen, X., J. Chen, M.E. Kane, and R.J. Henny. 2007. Assessment of somaclonal variation of Dieffenbachia plants regenerated via indirect shoot organogenesis from leaf explants. Plant Cell, Organ and Tissue Culture 91:21-27.
- Shen, X., J. Chen, M.E. Kane. 2007. Indirect shoot organogenesis from leaves of Dieffenbachia Camouflage. Plant Cell, Organ and Tissue Culture 89:83-90.
- Henny, R.J., J. Chen, and D.J. Norman. 2007. Tropic Honey Dieffenbachia. HortScience 42:398.
- Chen, J. and J.W. Huang. 2007. Increased accumulation of lead in the bronze mutant (E107) of pea (Pisum Sativum L.). Bulletin of Environmental Contamination and Toxicology 79:25-28.
- Chen, J., R.J. Henny, and F. Liao. 2007. Aroids are important medicinal plants. Acta Horticultuae 756:347-353.
- Wang, X., J. Chen, R. J. Henny, Y. Li, Q. Nie, and J. Li. 2007. In vitro culture of Epipremnum Aureum, Syngonium podophyllum, and Lonicera macranthodes, three important medicinal plant. Acta Horticultuae 756:155-161.
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