Greenhouse cultural methods must minimize runoff to keep pace with environmental regulation aimed at protecting water resources. Two experiments were designed to investigate the effect of N fertilization rate on New Guinea impatiens (Impatiens ×hawkeri) and peace lily (Spathiphyllum Schott) in an ebb-and-flow subirrigation system. Maximum growth response for impatiens was centered around 8 mm N levels as measured by root and shoot fresh and dry weight, height, leaf number, leaf area, and chlorophyll concentration. For peace lily, growth peaked at about 10 mm N. Growing medium was divided into three equal layers: top, middle, and bottom. Root distribution favored the middle and bottom layers, and the relative distribution of roots was consistent as N level increased. EC remained low in middle and bottom layers at N concentrations below 10 mm, but increased significantly for all layers at levels above 10 mm. The EC for the top layer was 2 to 5 times higher than in the middle or bottom layers at all N levels. Increased nitrate concentration paralleled increased EC, while pH decreased as N concentration increased for impatiens and peace lily.
Matthew W. Kent and David Wm. Reed
Albert T.Y. Mak and D.M. Yeh
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.
Matthew W. Kent and David Wm. Reed
Greenhouse cultural methods must change rapidly to minimize runoff and to keep pace with environmental regulation aimed at protecting water resources. Two experiments were designed to investigate the effect of N fertilization rate on New Guinea impatiens (Impatiens ×hawkeri) and peace lily (Spathiphyllum Schott) in an ebb-and-flow subirrigation system. Maximum growth response for impatiens was centered around 8-mM N levels as measured by root and shoot fresh and dry weight, height, leaf number, leaf area, and chlorophyll concentration. For peace lily, growth peaked around 10 mM N. Growing medium was divided into three equal layers: top, middle, and bottom. Root distribution favored the middle and bottom layers, and the relative distribution of roots was consistent as N level increased. Soluble salts remained low in middle and bottom layers at N concentrations below 10 mM, but increased significantly for all soil layers at levels above 10 mM. The top layer contained two to five times higher soluble salt levels than in the middle or bottom layers at all N levels. Increased nitrate concentration mimicked increases in soluble salts, while pH decreased as N concentration increased for both impatiens and peace lily.
Jianjun Chen, Richard J. Henny, Pachanoor S. Devanand, and Chih-Cheng T. Chao
Peace lily (Spathiphyllum Schott) is one of the most popular tropical ornamental foliage plants and is used worldwide for interiorscaping. However, little information is available on the genetic relationships of cultivars. Using amplified fragment length polymorphism (AFLP) markers with near-infrared fluorescence-labeled primers, this study analyzed genetic relatedness of 63 commercial cultivars and breeding lines. Forty-eight EcoRI + 2/MseI + 3 primer set combinations were initially screened, from which six primer sets were selected and used in this investigation. All cultivars were clearly differentiated by their AFLP fingerprints, and the relationships were analyzed using the unweighted pair-group method of arithmetic average cluster analysis (UPGMA). The 63 cultivars were divided into four clusters. All commercial cultivars or breeding lines resulted from crosses of some of the cultivars, a total of 45, were positioned in cluster I with Jaccard's similarity coefficients between 0.61 and 0.88. There was only one cultivar in cluster II. Cluster III contained 16 cultivars; they are either species or breeding lines generated from interspecific hybridization. Cluster IV had one unknown species. This study provides genetic evidence as to why cultivars from cluster I and III are not readily crossable because the Jaccard's similarity coefficient between the two clusters was only 0.35. Results also indicate that commercial cultivars are genetically close. Strategies for increasing genetic diversity of cultivated peace lily should be sought for future breeding efforts.
Mung Hwa Yoo, Youn Jung Kwon, Ki-Cheol Son, and Stanley J. Kays
Foliage plants of Hedera helix L. (english ivy), Spathiphyllum wallisii Regal (peace lily), Syngonium podophyllum Schott. (nephthytis), and Cissus rhombifolia Vahl. (grape ivy) were evaluated for their ability to remove two indoor volatile organic air pollutants, benzene and toluene. Removal was monitored when the aerial portion of plants was exposed singly to 1 μL·L-1 or to 0.5 μL·L-1 of each gas in a closed environment over 6-hour periods during the day and the night. Selected physiological processes were assessed before and immediately after treatment to determine the effect of the gases on the plants. The effectiveness of plants in the removal of air pollutant(s) varied with species, time of day, and whether the gases were present singly or as a mixture. When exposed to a single gas, S. wallisii, S. podophyllum, and H. helix displayed higher removal efficiencies (ng·m-3·h-1·cm-2 leaf area) of either gas than C. rhombifolia during the day. The efficiency of removal changed when both gases were present; H. helix was substantially more effective in the removal of either benzene or toluene than the other species, with the removal of toluene more than double that of benzene. When exposed singly, the removal of both compounds was generally higher during the day than during the night for all species; however, when present simultaneously, H. helix removal efficiency during the night was similar to the day indicating that stomatal diffusion for english ivy was not a major factor. The results indicated an interaction between gases in uptake by the plant, the presence of different avenues for uptake, and the response of a single gas was not necessarily indicative of the response when other gases are present. Changes in the rates of photosynthesis, stomatal conductance, and transpiration before and after exposure indicated that the volatiles adversely affected the plants and the effects were not consistent across species and gases. Deleterious effects of volatile pollutants on indoor plants may be critical in their efficacy in improving indoor air quality and warrant further study.
David A. Francko, Kenneth G. Wilson, Qingshun Q. Li, and Maria A. Equiza
, ranging from tropical plants with little or no resistance to freezing to more cold-tolerant species. Foliage plants included the common tropical house plant peace lily ( Spathiphyllum spp.), the tropical banana species dwarf cavendish banana ( Musa
Seong-Hyun Park and Richard H. Mattson
in each room were identical. Room B contained single plants of arrowhead vine, cretan brake fern, variegated vinca, and yellow star jasmine arranged with two plants each of dendrobium, peace lily, golden pothos, and kentia palm. Measurements. Data
Seong-Hyun Park and Richard H. Mattson
contained single plants of arrowhead vine, cretan brake fern, variegated vinca, and yellow star jasmine, arranged with two plants each of dendrobium, peace lily, golden pothos, and kentia palm. Measurements. Medical and psychological data were collected from
Alicia Rihn, Hayk Khachatryan, Benjamin Campbell, Charles Hall, and Bridget Behe
using organic production methods but not certified”), and conventional. Origin included Fresh from Florida (in-state), grown in the United States (domestic), and grown outside the United States (imported). Dragon tree ( D. marginata Lam.), peace lily
Thomas A. Obreza and Jerry B. Sartain
at P < 0.05. Table 8. Container-grown foliage (peace lily) plant size and relative amount of nitrate-nitrogen (NO 3 -N) and orthophosphate-phosphorus (PO 4 -P) leached 6 months after enhanced efficiency fertilizer (EEF) or water-soluble fertilizer