Effects of nitrogen application on growth, stomatal conductance, transpiration, and chlorophyll content were studied in Spathiphyllum Schott 'Sensation' grown in sphagnum peat (SP)- and coir dust (CD)-based media with top-irrigation or subirrigation. Maximum shoot dry weight occurred at 8 mM N in plants grown in SP-based medium under top-irrigation and subirrigation, and in CD-based medium under subirrigation. For plants in CD-based medium under top-irrigation, maximum shoot dry weight was obtained at 16 mm N. In SP- or CD-based medium, shoot dry weight was greater at 4 and 8 mm N under subirrigation than under top-irrigation. Stomatal conductance and transpiration were reduced by nitrogen deficiency (0 N), greatly enhanced by 4 mm N, and decreased gradually at higher N levels. Chlorophyll content increased with increasing N concentration up to 8 mm. The percentage of maximum total dry weight increased quadratically as leaf N content increased from 1.5% to 3.5%. Nitrogen at 16 and 32 mm increased the number of leaves with marginal necrosis. Reduced growth and more leaves with marginal necrosis occurred in SP- or CD-based media with EC > 1.25 dS·m-1 in the middle and bottom layers.
Timothy K. Broschat and Kimberly A. Klock-Moore
Areca palms [Dypsis lutescens (H. Wendl.) Beentje & J. Dransf.], spathiphyllums (Spathiphyllum Schott. `Figaro'), ixoras (Ixora L. `Nora Grant'), tomatoes (Lycopersicon esculentum Mill. `Floramerica'), marigolds (Tagetes erecta L. `Inca Gold'), bell peppers (Capsicum annuum L. `Better Bell'), and pentas [Pentas lanceolata (Forssk.) Deflers. `Cranberry'] were grown in a pine bark-based potting substrate and were fertilized weekly with 0, 8, 16, 32, or 64 mg (1.0 oz = 28,350 mg) of P per pot. Shoot, and to a much lesser extent, root dry weight, increased for all species as weekly P fertilization rate was increased from 0 to 8 mg/pot. As P fertilization was increased from 8 to 64 mg/pot, neither roots nor shoots of most species showed any additional growth in response to increased P. Root to shoot ratio decreased sharply as P fertilization rate was increased from 0 to 8 mg/pot, but remained relatively constant in response to further increases in P fertilization rate.
Timothy K. Broschat
Chinese hibiscus (Hibiscus rosa-chinensis), shooting star (Pseuderanthemum laxiflorum), downy jasmine (Jasminum multiflorum), areca palm (Dypsis lutescens), and `Jetty' spathiphyllum (Spathiphyllum) were grown in containers using Osmocote Plus 15-9-12 (15N-3.9P-10K), which provided phosphorus (two experiments), or resin-coated urea plus sulfur-coated potassium sulfate, which provided no phosphorus (one experiment). Plants were treated with water drenches (controls), drenches with metalaxyl fungicide only, drenches with phosphoric acid (PO4-P), drenches with metalaxyl plus phosphorus from phosphoric acid, drenches with PhytoFos 4-28-10 [4N-12.2P-8.3K, a fertilizer containing phosphorous acid (PO3-P), a known fungicidal compound], or a foliar spray with PhytoFos 4-28-10. Plants receiving soil drenches with equivalent amounts of P from PhytoFos 4-28-10, PO4-P, or PO4-P+metalaxyl generally had the greatest shoot and root dry weights and foliar PO4-P concentrations. There were no differences between the control and metalaxyl-treated plants, indicating that root rot diseases were not a factor. Therefore, responses from PhytoFos 4-28-10 were believed to be due to its nutrient content, rather than its fungicidal properties. Foliar-applied PhytoFos 4-29-10 produced plants that were generally similar in size to control plants or those receiving metalaxyl only drenches. Fertilizers containing PO3-P appear to be about as effective as PO4-P sources when applied to the soil, but are relatively ineffective as a P source when applied as a foliar spray. A distinct positive synergistic response for shoot and root dry weights and foliar PO4-P concentrations was observed for the PO4-P+metalaxyl treatment when no P was applied except as a treatment.
Lyn A. Gettys and William T. Haller
plants in landscapes that are irrigated with herbicide-treated water. Materials and methods Anthurium, caladium, spathiphyllum, and syngonium were purchased in Apr. and May 2009 from Agri-Starts IV, Inc. in Apopka, FL. All plants were purchased as liners
Dong Sik Yang, Ki-Cheol Son, and Stanley J. Kays
indoor concentration of benzene and toluene was reduced by Hedera helix L., Spathiphyllum wallisii Regal, Syngonium podophyllum Schott., and Cissus rhombifolia Vahl. ( Yoo et al., 2006 ). There are substantial differences in the rate of removal
Andrew J. Macnish, Ria T. Leonard, and Terril A. Nell
’, Dracaena marginata ‘Bicolor’ and ‘Magenta’, Euphorbia splendens ‘Short and Sweet’, Spathiphyllum ‘Ty's Pride’). Ethylene treatment also accelerated senescence (i.e., browning) of the spadix and the surrounding spathe on Anthurium scherzerianum ‘Red
Paul K. Murakami and Fred D. Rauch
Three formulations of an encapsulated urea product and one sulfur-coated urea were evaluated at 0 to 4 times the recommended rate on Chomaedorea elegans, Chomaedorea seifrizii, Chrysalidocarpus lutescens, Spathiphyllum `Tasson', and Rhapis excelsa against a standard controlled-release fertilizer at equal N rates. Each plant species responded differently to the fertilizer sources. Chomaedorea seifrizii and Spathiphyllum `Tasson' did not exhibit preferences for fertilizer source from top-growth measurements. Chomaedorea elegans, Chrysalidocarpus lutescens, and Rhapis excelsa growth measurements indicate that fertilizer source affected growth and quality of the plants. The general recommendation for foliage plant production is an equal ratio of ammoniacal to nitrate nitrogen sources. Economically, this ratio makes the fertilizer more expensive than other traditional fertilizers. The use of a controlled-release urea fertilizer has the benefit of being a cheaper source of N and would lower the cost of production, but results on the selected foliage plants indicate that the fertilizer composition is important in plant production.
Timothy K. Broschat
Spathiphyllum Schott. `Mauna Loa Supreme' and areca palm (Chrysalidocarpus lutescens H. Wendl.) were grown for 6 months in 3.5-liter containers using a pine bark–sedge peat–sand container medium or a native sand soil. Plants were fertilized with equivalent amounts of a 21N–3P–12K fertilizer applied weekly as a liquid, monthly as a soluble granular, bimonthly as a lightly coated controlled-release, or every 6 months as a heavily coated controlled-release fertilizer. All leachates were collected and analyzed weekly for NO3-N, PO4-P, and K. Amounts of all three nutrients leached per week varied considerably in response to fertilizer reapplications or high rainfall. Nitrate leaching generally decreased over time, PO4-P leaching increased, and K remained relatively constant. Shoot dry weights of spathiphyllum were equivalent for all fertilization methods, but areca palm shoot dry weights were highest with liquid fertilization and lowest with the soluble granular fertilizer. Nutrient leaching for all three ions was highest for the soluble granules and lowest for the two controlled-release formulations.
Timothy K. Broschat
Spathiphyllum Schott. 'Mauna Loa Supreme' grown for 6 months in a fine sand soil or a 5 pine bark: 4 sedge peat: 1 sand medium (by volume) were fertilized with 7.6g N, 1.4g P, and 4.5g K/3.5-liter container by 4 different methods. The same raw fertilizer prills (21N-3P-12K) were applied weekly as a liquid, monthly as soluble granules, bimonthly as a lightly resin-coated fertilizer (Osmocote), or every 6 months as a heavily resin-coated fertilizer. All leachates were collected and were measured and analyzed weekly for N O3, PO4, and K. Spathiphyllum grew best in the sand soil with either of the controlled release formula- tions, but fertilization method had no effect on growth in the potting medium. Nitrate and K leaching losses from the potting medium were lowest from the controlled release fertilizers and highest from the soluble granules. Liquid fertilization resulted in the highest amounts of PO4 lost to leaching and controlled release fertilizers the least. In the fine sand soil, NO3 leaching was equivalent from all methods. Soluble granules had the highest levels of leached K and PO4 and the lightly-coated fertilizer lost the least due to leaching.
M.Y.C. Goo and B.S. Sipes
Fourteen tropical ornamental plants were evaluated for their host status to a population of Radopholus citrophilus isolated from anthurium. No nematodes were recovered from the roots of Aglaonema commutatum, Caryota mitis, Cycas revoluta, Dracaena deremensis, Neodypsis decaryii, Ravenea spp., or Spathiphyllum wallisii 5 months after inoculation, making these plants nonhosts. Low numbers of R. citrophilus were recovered from the roots of Phoenix roebellinii, Rhapis excelsa, and Howea forsteriana, suggesting that they were poor hosts to this nematode population. Anthurium trifidum, Chamaedorea neathebella, Chamaedorea seifrizii, and Calathea variegata were hosts for the nematode, allowing population increases of 2.47 to 29.92 times the inoculation density. C. seifrizii and C. variegata represent new hosts of R. citrophilus.