bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate pH Impacts Efficacy of Ethephon Drenches on Growth of Herbaceous Perennials
Authors: Aiken Margaret G. , Scoggins Holly L. , Latimer Joyce G.
Published: February 2019

Ethephon [(2-chloroethyl) phosphonic acid] is widely used as a growth regulator in floricultural crop production, with foliar sprays as the typical application method. Ethephon efficacy is determined by rate of uptake and subsequent ethylene evolution, which can be influenced by a number of factors, including solution pH. This study examines whether an ethephon substrate drench (100 mg⋅L−1 at a volume of 296 mL per 2.8-L container) would allow for plant uptake in two herbaceous perennials, Verbena bonariensis (L.) ‘Lollipop’ and Veronica spicata (L.) ‘Goodness Grows’, as measured by subsequent effects on shoot growth and days to flower. We also investigated substrate pH effects on ethephon drench efficacy by analyzing the shoot responses to ethephon applied at a range of starting substrate pH (4.5 to 7.0) compared with untreated plants grown under the same substrate pH conditions (controls). One or more measurements of shoot growth (height, width, shoot dry weight) were reduced in both taxa treated with ethephon as compared with controls. Veronica plant growth was not influenced by substrate pH in either the control or ethephon-drenched plants. For Verbena plants receiving the ethephon drench, as substrate pH increased, height and width increased. For example, when ethephon was applied at substrate pH 4.5, finished plant height averaged 32.0 cm, compared with 43.5 cm for those plants that received the drench at a substrate pH of 7.0. Increasing substrate pH conditions also influenced the days to flower in Verbena plants. Ethephon-treated plants at a substrate pH of 4.5 required an average of 6.5 days longer to flower than those at a substrate pH of 7.0. In summary, ethephon drench applications can result in significant growth regulation effects, as seen in both Veronica and Verbena. Furthermore, increasing substrate pH can reduce the efficacy of ethephon drench applications.
Cost Analysis of Using Recycled Water in Container Production: A Case Study of Southern New Jersey
Authors: DeVincentis Alyssa J. , Brumfield Robin G. , Gottlieb Paul , Johnson James R.
Published: February 2019

Management of agricultural irrigation water is extremely important as fresh water resources are being depleted on a global scale. In anticipation of regulatory restrictions, several greenhouse and nursery operations in New Jersey have implemented systems that disinfect and recycle their irrigation water. This study compared the disinfection methods at two greenhouses and three container nurseries, focusing on the qualitative and quantitative benefits of using chlorine gas, ultraviolet light, ozone, and copper for water disinfection. The data were collected during on-site visits where the growers were interviewed on camera. A cost analysis was performed, but the most efficient disinfection technique could not be determined due to the variability between businesses and various unquantifiable benefits of proactive water management recycling, such as improved plant health, decreased fungicide and fertilizer use, a cleaner operation, reduced runoff, reduced pressure on aquifers, and increased customer satisfaction. The investment and maintenance costs per hectare and 1000 L were calculated, which can be useful reference tools for growers. The net present value (NPV) of each disinfection system was calculated to analyze the profitability of the investments. All three container nurseries had positive NPV values and profitable investments, which improved with cost sharing from the National Resource Conservation Service. This information will be useful in the future as growers throughout the state, and country, may be required to deal with the stricter regulation of their irrigation runoff.
Matching Subjective Assessments of Sod Strength to Quantitative Measurements of Peak Shear Force with Predominately Kentucky Bluegrass Sod
Authors: Guillard Karl , Fitzpatrick Richard J.M. , Burdett Holly
Published: February 2019

Adequate turfgrass sod strength for harvesting and handling is typically determined by the producer’s past experience and subjective appraisal. This study was conducted to determine the relationship between producer subjective sod-strength assessments and quantitative shear-strength measurements with predominantly kentucky bluegrass (Poa pratensis L.) turf. Across three consecutive growing seasons, 93 samples were collected from sod fields in Rhode Island and assessed for sod strength by subjective and quantitative methods. Producer subjective ratings of sod strength were significantly (P < 0.0001) associated with quantitative measurements of peak force required to shear a sod strip. Minimally acceptable strength occurred most frequently when peak shear force was between 55 and 85 kg·m−1 width of sod; whereas preferred sod strength occurred most frequently when peak shear force was between 70 and 140 kg·m−1 width of sod. Once peak force exceeded 58 and 86 kg·m−1, there was a > 50% probability that sod strength would be judged at least adequate and at preferred strength, respectively, up to a peak force of 140 kg·m−1. The results suggest that quantitative measurements of shear strength can be related to producer subjective assessments, and provide unbiased benchmark values to guide management decisions for kentucky bluegrass sod production.
The Potential of LEDs in Plant-based Bio-pharmaceutical Production
Authors: Norikane Joey H.
Published: February 2019

Fraunhofer USA, Inc. Center for Molecular Biotechnology (FhCMB) has pioneered a transient plant-based biopharmaceutical platform to produce vaccines and therapeutics quickly and cost-effectively. Using this platform, plants are grown hydroponically in a controlled environment. The plants are vacuum infiltrated with a recombinant Agrobacteria carrying a plant viral–based hybrid vector and returned to a controlled environment for the target protein to be produced in infiltrated plant tissue. When target protein levels peak in leaf tissue, the plants are harvested and homogenized, extract is clarified and the target protein is purified. There are multiple opportunities in this system for light-emitting diodes (LEDs) to be applied to optimize biomass accumulation and the production of target proteins. There is potential to develop specific photo-recipes to optimize plant growth and target protein production.
Commercial Transition to LEDs: A Pathway to High-value Products
Authors: Stutte Gary W.
Published: February 2019

The use of light-emitting diodes (LEDs) to support plant growth is a radical departure from use of gas-discharge lamps, which were developed in mid-19th and widely adopted by the industry during the 20th century. Initial investigation by the National Aeronautics and Space Administration (NASA) in the late 1980s on the use of LEDs to grow plant in space is resulting in an industry-wide transition from gas discharge to solid-state lighting systems. This global transformation is given urgency by national policies to reduce energy consumption and being facilitated by ready access to information on LEDs. The combination of research, government policy, and information technology has resulted in an exponential increase in research into the use and application of LED technology in horticulture. Commercial horticulture has identified the opportunities provided by LEDs to optimize light spectra to promote growth, regulate morphology, increase nutrient content, and reduce operating costs. LED-light technology is enabling the development of innovative lighting systems, and is being incorporated into large-scale plant factories for the production of edible, ornamental, and medicinal plants. An overview of prevalence of readily accessible information on LEDs and implications for future adoption in horticulture is discussed.
Dynamics and Distribution of Trunk-injected Phosphite in Coconut Palm
Authors: Yu Jiaming , Broschat Timothy K. , Latham William G. , Elliott Monica L.
Published: February 2019

Palms are an important component of landscapes in tropical, subtropical, and Mediterranean climates, but are anatomically very different from broadleaf trees. Very little is known about the movement and persistence of systemic fungicides into various parts of the palm canopy. This information is critical in selecting fungicides that may be effective against diseases that infect specific parts of the palm. In this study, potassium phosphite was injected into mature coconut palms (Cocos nucifera) at rates of 0, 30, 60, or 90 mL per tree. Various leaf tissue samples were collected periodically thereafter up through 60 weeks and were analyzed for phosphite concentrations. Phosphite moved quickly into leaflet tissue, but concentrations dropped off sharply between 1 and 5 weeks after injection. This drop in leaflet concentrations was balanced by a concomitant increase in spear leaf concentrations. Phosphite persisted at high concentrations in basal rachis tissue of both old and new leaves throughout the experiment. This suggests that this material may be useful for controlling diseases that infect spear leaves and petiole or rachis tissue, but not leaflets.
Effects of Hormone Treatments on Cut Flower Opening and Senescence in Wintersweet (Chimonanthus praecox)
Authors: Sui Shunzhao , Luo Jianghui , Liu Daofeng , Ma Jing , Men Weiting , Fan Lu , Bai Yu , Li Mingyang
Published: February 2019

Wintersweet (Chimonanthus praecox) is a woody garden plant with fragrant flowers, which blooms in deep winter. The vase life of fresh cut flowers is 8–9 days. We applied ethylene and 1-methylcyclopropene (1-MCP; an ethylene action inhibitor) to test the role of ethylene in flower opening and senescence. In addition, abscisic acid (ABA), gibberellic acid (GA3), two cytokinins, 6-benzylaminopurine (6-BA), and zeatin (ZT) were also applied. The expression pattern of CpSRG1, a senescence-related gene, was analyzed. Ethylene treatment accelerated flower opening and senescence, decreasing vase life by 2.1 days. It also decreased flower break strength, indicating the induction of abscission. 1-MCP slowed opening, delayed senescence, and prolonged vase life by 2.6 days. Ethylene dramatically induced the expression of the CpSRG1 gene, while 1-MCP suppressed it. ZT promoted flower opening and increased vase life by 1.6 days. It suppressed the expression of CpSRG1. 6-BA, GA3, or ABA had no significant effect on flower opening and senescence of wintersweet.
Genetic Diversity, Population Structure, and Formation of a Core Collection of 1197 Citrullus Accessions
Authors: Zhang Haiying , Fan Jianguang , Guo Shaogui , Ren Yi , Gong Guoyi , Zhang Jie , Weng Yiqun , Davis Angela , Xu Yong
Published: February 2019

Watermelon belongs to the genus Citrullus. There have been continuing interests in breeding of watermelon for economic benefits, but information on the scope and utilization of genetic variations in Citrullus is still limited. The present study was conducted in 2012–13, to evaluate the genetic diversity and population structure of the 1197 line watermelon collection maintained by the Beijing Vegetable Research Center (BVRC), which belongs to seven Citrullus species including Citrullus naudinianus, Citrullus colocynthis, Citrullus rehmii, Citrullus ecirrhosus, Citrullus amarus, Citrullus mucosospermus, and Cirullus lanatus subsp. vulgaris. Twenty-three highly informative microsatellite markers evenly distributed in the watermelon genome were used to assess genetic diversity in this collection. The markers detected on an average of 6.05 alleles per locus with the average value of polymorphism information content (PIC) at 0.49. A high level of gene diversity [Nei’s gene diversity index (Nei) = 0.56] and a low observed heterozygosity (Ho = 0.10) were revealed within the collection. Structure analysis grouped the 1197 accessions into two main populations (Pop I and Pop II) and an admixture group. Pop I contained 450 accessions from C. lanatus subsp. vulgaris (446) and C. mucosospermus (4). Pop II comprised 465 accessions, 379 of which belonged to C. lanatus subsp. vulgaris and 86 to C. naudinianus (3), C. ecirrhosus (2), C. rehmii (2), C. colocynthis (11), C. amarus (58), and C. mucosospermus (10). The remaining 282 accessions were classified as an admixture group. The two main populations were further subdivided into four subgroups. The groupings were consistent with the estimation of F statistics (Fst) and Nei’s genetic distances in collections. We confirmed the distinct genetic backgrounds between American and East Asian ecotypes. Subsequently, we defined a core set consisting of 130 accessions including 47 from Pop I, 68 from Pop II, and 15 from the Admixture group. This core set was able to capture all 133 alleles detected by 23 simple sequence repeats (SSRs) in 1197 accessions. These results will facilitate efficient use of genetic variations in Citrullus in watermelon breeding and help optimization of accessions in genomewide association studies.
Weed Management, Training, and Irrigation Practices for Organic Production of Trailing Blackberry: II. Soil and Aboveground Plant Nutrient Concentrations
Authors: Dixon Emily K. , Strik Bernadine C. , Bryla David R.
Published: February 2019

Organic production of blackberries is increasing, but there is relatively little known about how production practices affect plant and soil nutrient status. The impact of cultivar (Black Diamond and Marion), weed management (nonweeded, hand-weeded, and weed mat), primocane training time (August and February), and irrigation (throughout the summer and none postharvest) on plant nutrient status and soil pH, organic matter, and nutrients was evaluated from Oct. 2012 to Dec. 2014 in a mature trailing blackberry (Rubus L. subgenus Rubus Watson) production system. The study site was certified organic and machine harvested for the processed market. The planting was irrigated by drip and fertigated with fish hydrolysate and fish emulsion fertilizer. Soil pH, organic matter content, and concentrations of soil nutrients, including ammonium-nitrogen (NH4-N), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), manganese (Mn), and zinc (Zn), were greater under weed mat than in hand-weeded plots. Soil K and boron (B) were below recommended standards during the study, despite a high content of K in the fish fertilizer and supplemental B applications. Primocane leaf nutrient concentrations were below the N, K, Ca, and Mg sufficiency standards in ‘Black Diamond’ and were lower than in ‘Marion’ for N, phosphorus (P), Ca, Mg, S, B, and Zn in at least one year. In contrast, floricane leaves and fruit tended to have higher nutrient concentrations in ‘Black Diamond’ than in ‘Marion’. Weed management strategy affected many nutrients in the soil, leaves, and fruit. Often, use of weed mat led to the highest concentrations. Withholding irrigation postharvest had limited effects on plant nutrient concentrations. Primocane training time affected the nutrients in each plant part differently depending on year.
Susceptibility of Highbush Blueberry Cultivars to Phytophthora Root Rot
Authors: Yeo John R. , Weiland Jerry E. , Sullivan Dan M. , Bryla David R.
Published: February 2019

Phytophthora cinnamomi Rands is a ubiquitous soilborne pathogen associated with root rot in many woody perennial plant species, including highbush blueberry (Vaccinium corymbosum). To identify genotypes with resistance to the pathogen, cultivars and advanced selections of highbush blueberry were grown in a greenhouse and either inoculated or not with propagules of P. cinnamomi. Two experiments were conducted, including one with 10 commercially established cultivars and another with seven newly released cultivars, three commercially established cultivars, and three advanced selections of highbush blueberry. Pathogen resistance was based on the shoot and root dry biomass of the inoculated plants relative to the noninoculated plants within each genotype, as well as on the percentage of root infection among the genotypes. Resistant genotypes included four commercially established cultivars, Aurora, Legacy, Liberty, and Reka, and two new cultivars, Overtime and Clockwork. When these genotypes were inoculated, average relative shoot biomass was ≥60% of that of the noninoculated plants, whereas relative root biomass was ≥40%. ‘Star’, as well as two advanced selections (an early- and a late-season type) may also have some degree of resistance, but further investigation is needed. Relative shoot biomass of the susceptible genotypes, on the other hand, ranged from 19% to 53% and relative root biomass ranged from 11% to 26%. The susceptible genotypes included ‘Bluetta’, ‘Bluecrop’, ‘Bluegold’, ‘Blue Ribbon’, ‘Cargo’, ‘Draper’, ‘Duke’, ‘Elliott’, ‘Last Call’, ‘Top Shelf’, and ‘Ventura’. These cultivars are not recommended at sites with conditions conducive to root rot, such as those with clay soils and/or poor drainage.
Yield Stability of Heirloom Dry Bean (Phaseolus vulgaris L.) Cultivars in Midwest Organic Production
Authors: Swegarden Hannah R. , Sheaffer Craig C. , Michaels Thomas E.
Published: February 2019

Heirloom dry bean (Phaseolus vulgaris L.) cultivars are distinct in their seed characteristics, although little information regarding their performance at the field scale in the Midwest is currently available. Demand for organic heirloom dry beans from direct-to-consumer markets in Minnesota motivated our examination of the crop’s suitability for local production. Heirloom cultivars were evaluated on the basis of yield and yield stability at four small-scale organic vegetable productions in southeast Minnesota. Yield data from 2013 and 2014 were subject to static and dynamic stability biplot analyses. The mean yield of heirloom cultivars was ≈44% lower than commercial market class checks included in the trial; heirloom yields ranged from 825 to 2127 kg·ha−1, with a mean of 1362 kg·ha−1. Stability analyses and economic incentives suggest that the production of heirloom cultivars, especially ‘Jacob’s Cattle Gold’, ‘Lina Sisco’s Bird Egg’, ‘Peregion’, and ‘Tiger’s Eye’, could provide growers with the opportunity to diversify their production, differentiate themselves in local markets, and maintain economic return.
Storage Temperature and 1-Methylcyclopropene Treatment Affect Storage Disorders and Physiological Attributes of ‘Royal Gala’ Apples
Authors: Lee Jinwook , Mattheis James P. , Rudell David R.
Published: February 2019

‘Royal Gala’ apples [Malus domestica (Borkh.) Mansf.]can develop postharvest disorders such as flesh browning, senescent breakdown, peeling, cracking, or shriveling during and after cold storage. The objective of this study was to examine the effects of storage temperature and a range (0, 0.25, 0.5, or 1 µL·L−1) of 1-methylcyclopropene (1-MCP) concentrations on fruit quality attributes and incidence and severity of physiological disorders during and after cold storage. Storage temperature differentially affected internal ethylene concentration (IEC), fruit circumference, and cortex color. 1-MCP treatment resulted in significant effects on fruit quality attributes and severity of physiological disorders, regardless of storage temperature. Incidence and severity of diffuse flesh breakdown (DFB), shriveling, cracking, and peeling were highest in control fruit stored but radial stem-end flesh breakdown (RSFB) only primarily in 1-MCP-treated fruit. Incidence of RSFB was highest following storage at 0.5 °C compared with 3 °C. 1-MCP treatment had the most influence on disorder incidence/severity or quality attributes, while treatment concentration of 1-MCP was not significant. Overall, the results indicate that 1-MCP treatment can reduce the incidence of ‘Royal Gala’ DFB but may enhance sensitivity to RSFB, when fruit are stored at 0.5 or 3 °C. Incidence of DFB and RSFB are influenced differentially by storage temperature or by 1-MCP treatment, respectively, indicating they may be different disorders.
Effect of Irradiance and Temperature on Composition of Spinach
Authors: Gent Martin P.N.
Published: February 2019

The composition of spinach (Spinacea oleracea L.) was studied in response to daily light integral (DLI) and diurnal variation in a greenhouse. Values for plantings with different irradiance were compared using normalized daily light integral (NDLI), which was DLI divided by leaf area index. The dry mass as a ratio of fresh mass increased with NDLI as it increased from 3 to 27 mol·m−2·d−1. Reduced nitrogen (N) changed with time of day under high but not under low NDLI. Nitrate and amino acids were affected by temperature more than NDLI. Starch increased with NDLI to 27 mol·m−2·d−1 in morning or afternoon. However, sugars decreased with temperature more than with NDLI, due to a decrease in petioles up to 20 °C. Oxalic acid increased with NDLI or temperature. Over a diurnal cycle, starch had minimum value at 0800 hr and maximum at 1800 hr in all parts. The sugars, sucrose, glucose, and fructose, had a binary response with high values in the day and low values in the night. Oxalic acid increased at the end of the day. Other metabolites had no response to time of day. The growth of spinach may be slow in fall compared with summer due to the effect of low temperature on metabolism of sugars and nitrate.
KODA and its Analog Treatment Effects on Flowering and Spring Shoot Occurrence in Satsuma Mandarin
Authors: Nakajima Naoko , Ikoma Yoshinori , Matsumoto Hikaru , Sato Keiko , Nakamura Yuri , Yokoyama Mineyuki , Ifuku Ohji , Yoshida Shigeo
Published: February 2019

KODA [9-hydroxy-10-oxo-12(Z), 15(Z)-octadecadienoic acid] has previously been isolated from Lemna paucicostata, and is a compound known to promote flowering in plants. In this study, the effect of KODA on flower production and spring shoot occurrence in mature satsuma mandarin (Citrus unshiu Marc.) trees was examined in the field. The application of KODA in the summer or autumn had no discernible effect on flower production in the following year. However, when applied in summer, it promoted spring shoot occurrence in the following year, regardless of the number of flowers produced. In addition, C-KODA, a KODA analog, was more effective at producing this effect than KODA. The results suggest that the application of KODA or C-KODA may regulate spring shoot occurrence to improve the imbalance between the number of flower-bearing and vegetative shoots that leads to alternate bearing in satsuma mandarin trees.
Hydrogen Sulfide Alleviates Senescence of Fresh-cut Apple by Regulating Antioxidant Defense System and Senescence-related Gene Expression
Authors: Zheng Ji-Lian , Hu Lan-Ying , Hu Kang-Di , Wu Jun , Yang Feng , Zhang Hua
Published: February 2019

Hydrogen sulfide (H2S) has been identified as a multifunctional signaling molecule in plants. Here, we show that H2S delayed postharvest senescence of fresh-cut apples (Malus ×pumila) in a dose-dependent manner. Exogenous H2S application maintained significantly higher levels of ascorbic acid, flavonoids, total phenolics, reducing sugars and soluble proteins, and lower levels of free amino acids in apple slices compared with controls. Further investigations showed that H2S significantly reduced the accumulation of superoxide radicals, hydrogen peroxide (H2O2) and malondialdehyde (MDA). Apple fruits fumigated with H2S contained significantly higher activities of ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), guaiacol peroxidase (POD) and superoxide dismutase (SOD), and lower activities of lipoxygenase (LOX), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and protease relative to controls. H2S also upregulated MdDHAR expression and downregulated the expression of MdLOX2, MdPG1, MdPPO, MdACO1, MdERS1, and MdETR1 in postharvest apple tissue. The present study indicates that H2S was involved in delaying postharvest senescence of apples by acting as an antioxidant and by regulating senescence-related gene expression.
Vegetative Growth and Leaf Nutrient Status of ‘Carpino’ Chrysanthemum on a Pecan Wood-amended Commercial Substrate
Authors: Picchioni Geno A. , Martinez Sharon A. , Mexal John G. , VanLeeuwen Dawn M.
Published: February 2019

Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant woody biomass from hedge prunings with little economic value. Value-added uses could aid pecan growers, and one possible use is wood chips for potting substrates to lessen dependence on peatmoss, thereby aiding greenhouse growers. We evaluated vegetative growth and leaf nutrient responses of ‘Carpino’ garden chrysanthemum (Dendranthema ×grandiflorum) over a 60-day period. Plants were grown in five pecan wood chip substrate levels that substituted 0%, 25%, 50%, 75%, and 100% of peatmoss by volume. Three water soluble fertilizer (WSF) rates—N at 0, 200, or 400 mg·L−1 (0–N, 200–N, and 400–N, respectively)—were applied with each irrigation and to each of the wood substitution treatments. The WSF and wood substitution treatments interacted strongly. In the presence of wood, (25−100% substitution levels), increasing WSF to 400–N increased cumulative evapotranspiration (ET), crop height, total leaf number and area, total leaf and stem dry weight, and leaf N and P concentrations. However, with 0% wood substitution, 400−N provided little or no such enhancements. With 25% to 50% wood substitution, root dry weight increased by 61% to 91% from 0–N to 200–N, which may be an adaptive response to nutrient-limiting conditions at 200–N. Appearance of a white rot fungal species in and atop pecan wood-supplemented substrate supports the likelihood that microbial activity was, at least in part, responsible for the nutrient limitations. High WSF at 400–N in combination with 25% pecan wood substitution maintained adequate fertility and shoot growth that was comparable to the conventional peat-only substrate at 200–N. With low to moderate amounts of pecan wood, further adjustments to WSF rate and irrigation volume would support sustainable fertigation practices, reduce dependence on peatmoss by greenhouse industry, and provide a value-added recycling option for pecan growers.
Effect of the Spectral Quality and Intensity of Light-emitting Diodes on Several Horticultural Crops
Authors: Urrestarazu Miguel , Nájera Cinthia , Gea María del Mar
Published: February 2019

Light-emitting diode (LED) lamps signify one of the most important advances in artificial lighting for horticulture over the last few decades. The objective of this study was to compare the cultivation of four horticultural plants using a conventional white LED tube (T0) light against one with a good spectral fit to the maximum photosynthetic response (T1) at two intensities. The experiment was carried out with two types of young lettuce, tomato, and bell pepper plants. In a controlled environment chamber, six and four lamps per square meter were used to achieve high (H) and low (L) intensity, respectively. We measured the lighting parameters illuminance (lux) and photosynthetic photon flux (PPF) intensity (µmol·m−2·s−1). The dry and fresh weight, leaf area (LA), and specific index were measured to gauge plant growth. The photosynthetic activity and energy efficiency (EE) were recorded for each species over 60 days of cultivation. The results clearly demonstrate that, compared with conventional LED lamps, the specific horticultural LED lamps with an improved light spectrum increased the EE of the evaluated vegetables by 26%. At both the studied light intensities, plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance (lux). We therefore suggest that a specific, detailed spectral distribution study be conducted to predict the effect of the specific quantity and quality of light used in this study on a single parameter of plant growth.
Morphological and Physiological Responses of Nine Ornamental Species to Saline Irrigation Water
Authors: Wu Shasha , Sun Youping , Niu Genhua
Published: February 2019

To provide more species for landscapes where poor-quality irrigation water is used, salt tolerance of commonly used landscape plants should be characterized. Nine ornamental species, including six herbaceous and three woody, were irrigated with nutrient solution at electrical conductivity (EC) of 1.2 dS·m−1 (control) or saline solution at EC of 5.0 or 10.0 dS·m−1 (EC 5 or EC 10) for 8 weeks and their growth and physiological responses were determined. Although growth was reduced in orange peel jessamine (Cestrum ‘Orange Peel’) and mexican hummingbird bush (Dicliptera suberecta) as salinity increased, no obvious signs of stress or injury were observed, indicating that orange peel jessamine and mexican hummingbird bush were the most salt tolerant. Flame acanthus (Anisacanthus quadrifidus var. wrightii), rock rose (Pavonia lasiopetala), and ‘Dark knight’ bluebeard (Caryopteris ×clandonensis ‘Dark Knight’) had more growth reduction than that of orange peel jessamine and mexican hummingbird bush with minimal or no foliar damage in EC 5 and slight foliar damage in EC 10. Cardinal flower (Lobelia cardinalis) and mexican false heather (Cuphea hyssopifolia) exhibited mortality rates of 30% and 20%, severe foliar damage, and greater than 70% reduction in leaf area and dry weight in EC 10 compared with their respective controls. Although the growth reductions in butterfly blue (Scabiosa columbaria) were not as great as cardinal flower and mexican false heather, 40% of butterfly blue plants were dead with moderate foliar damage in EC 10. Therefore, cardinal flower, mexican false heather, and butterfly blue plants were considered as moderately salt sensitive. Eastern red columbine (Aquilegia canadensis) was the most salt sensitive among the species investigated with moderate foliar damage in EC 5 and all plants died in EC 10. Four out of the nine species tested had significant differences in net photosynthetic rate (Pn), stomatal conductance (gs), and/or relative chlorophyll content between the control and EC 10, and the difference varied with species. Shoot ion concentrations of the nine ornamentals were also affected by salinity levels and varied among species.
Development of Transgenic Escherichia coli with Improved Viability by Heterologous Expression of a Heat Shock Protein Gene from Carrot (Daucus carota L.)
Authors: Park Hanseul , Ahn Yeh-Jin
Published: February 2019

A small heat shock protein gene from carrot (Daucus carota L.), Hsp17.7, was inserted into the Escherichia coli chromosome by RecE/RecT-based homologous recombination to increase cell viability during industrial fermentation, which frequently encounters adverse growth conditions. DNA construct “lipoprotein (Lpp) gene promoter—Hsp17.7 gene—flippase recombination target (Frt) cassette” flanked by the sequences of the insertion site of the E. coli chromosome (yddE pseudogene) was generated by polymerase chain reaction (PCR). The transformed E. coli cell lines that heterologously expressed Hsp17.7 exhibited shorter lag phase, compared with control cell line under normal (37 °C), heat (45 °C), and antifoam conditions. Cell viability was higher in the transformed cell lines in the heat (50 °C, up to 2-fold) and cold (2 °C, up to 1.7-fold) conditions. The soluble protein levels were also higher in the transformed E. coli cell lines by up to 20%, compared with control cell line in both stress conditions. The stress-tolerant transgenic cell lines developed in this study can contribute to more efficient and cost saving industrial cultivation of E. coli, which is most frequently used for recombinant protein production.
Genome Size and Ploidy Levels of Cercis (Redbud) Species, Cultivars, and Botanical Varieties
Authors: Roberts David J. , Werner Dennis J.
Published: February 2019

Cercis is an ancient member of Fabaceae, often cultivated as an ornamental tree, and can be found in numerous regions around the world. Previous studies have reported Cercis canadensis as being diploid with 2n = 2x = 14. However, there have been no further investigations into ploidy and genome size variation among Cercis taxa. A study was conducted to evaluate the relative genome size and ploidy levels of numerous species, cultivars, and botanical varieties of Cercis, representing taxa found in North America, Asia, and the Middle East. In addition, the genome size of Bauhinia forficata, a close relative of Cercis, was also determined. Genome size estimates (2C values) were determined by calculating the mean fluorescence of stained nuclei via flow cytometry. Propidium iodide was used as the staining agent and Glycine max was used as an internal standard for each taxon analyzed. Genome size estimates for all Cercis sampled ranged from 0.70 to 0.81 pg with an average size of 0.75 pg. The genome size of B. forficata was found to be smaller than any other Bauhinia sp. currently on record, with an average size of 0.87 pg. This study confirmed an initial estimation of the genome size of Cercis chinensis and found that floral buds of Cercis proved to be an excellent source of plant tissue for obtaining intact nuclei. All species, botanical varieties, and cultivars of Cercis surveyed for this study had remarkably similar genome sizes despite their wide range of distribution. This information can facilitate a better understanding of phylogenetic relationships within Cercideae and Cercis specifically.
Clarifying Affiliations of Salix gracilistyla Miq. Cultivars and Hybrids
Authors: Kuzovkina Yulia A. , Dodge Michael , Belyaeva Irina V.
Published: February 2019

Salix gracilistyla Miq., japanese pussy willow or rosegold willow, is an ornamental shrub commonly cultivated for its prominent display of catkins in early spring. Verification of stocks of willows in the North American landscape nursery trade revealed that another name—Salix chaenomeloides Kimura—is associated frequently with plants similar to S. gracilistyla. Morphological analyses conducted during this study have shown that the S. chaenomeloides binomial is misapplied often to S. gracilistyla, its cultivars and hybrids. A comparison of the diagnostic characters of S. gracilistyla and S. chaenomeloides is presented to explain the differences between these taxa and to promote the adoption of the correct names. Five cultivars of S. gracilistyla valued for their early spring catkin displays, variegated foliage, and pendulous habits, and two cultivars of a hybrid origin are summarized. Also, two new ornamental cultivars called Salix ‘Winter Glory’ and Salix ‘Rabbit’s Foot’ are described.
Ursolic and Oleanolic Acid in ‘Aroma’ Apple Peel as Affected by Rootstock, Harvest Maturity, and Storage Method
Authors: Lv Yanrong , Tahir Ibrahim I. , Olsson Marie E.
Published: February 2019

Apples contain substances with health-promoting properties, among them, triterpenes, including oleanolic acid (OA) and ursolic acid (UA), which are thought to have anti-inflammatory activity as well as inhibiting initiation, promotion, and metastasis of cancer. This study evaluated effects of harvest time, rootstock, and storage method on two major triterpenes in apple peel, to enhance the understanding of the relative importance of cultivation and environmental factors influencing triterpene concentration. OA and UA concentrations in the semi-dwarfing ‘MM.106’ rootstock apples were significantly higher than in the dwarfing ‘M.9’ rootstock apples at the majority of harvest times over the 2 years of investigations. In 2012 at harvest time, highest concentrations of OA and UA in ‘MM.106’ rootstock apples were 63.4 and 416.3 μg·cm−2, respectively, while they were 59.7 and 380.9 μg·cm−2, respectively, in ‘M.9’ rootstock apples. UA remained fairly stable in most cases during storage, and no difference was found between regular atmosphere storage and controlled atmospheric (CA) storage. OA concentration decreased after harvest time. Furthermore, OA showed different responses to regular atmosphere storage and CA storage, and year-to-year difference was also observed. The two rootstocks showed only slight differences in the effect on total soluble solids (TSS) and fruit color, while the titratable acidity (TA) in apples from trees on ‘M.9’ rootstock had lower levels in most cases at the third harvest time as compared with apples from trees on ‘MM.106’ rootstock. OA concentration was positively correlated with UA concentration both directly at harvest and after storage. OA and UA concentrations were positively correlated with TA and TSS, while they were negatively correlated with red color.
Impacts of Huanglongbing Symptom Severity on Fruit Detachment Force and Mechanical Properties of Sweet Oranges (Citrus sinensis)
Authors: Chen Hong , McCollum Greg , Baldwin Elizabeth , Bai Jinhe
Published: February 2019

This study evaluated the effects of huanglongbing (HLB) symptom severity on fruit detachment force (FDF) and fruit mechanical properties in sweet oranges (Citrus sinensis) as indicators of potential HLB-influenced preharvest fruit drop and postharvest damage and breakdown. FDF for fruit from HLB-asymptomatic trees (AS) was substantially greater than for fruits from HLB-symptomatic trees or branches. Fruit hardness, resilience, springiness, and cohesiveness values, measured by texture profile analysis (TPA), represent various aspects of fruit firmness and recovery capacity once compressed, and were lower in HLB-symptomatic fruits in comparison with AS fruits. On the other hand, puncture force, toughness, and deformation values, measured by a puncture test and representing peel toughness, were higher in HLB-symptomatic fruits than in the AS fruits. The results indicate that fruits from severely HLB-symptomatic sweet orange trees are more likely to have problems with preharvest fruit drop, and postharvest pressure damage and breakdown, but may have less puncture damage in harvesting, transportation, packing, and juice processing.
Abscisic Acid Impacts Tomato Carotenoids, Soluble Sugars, and Organic Acids
Authors: Barickman T. Casey , Kopsell Dean A. , Sams Carl E.
Published: February 2019

Plant growth regulators (PGRs) are chemicals used on a wide range of horticultural crops. These exogenous chemicals, similar to endogenous plant hormones, regulate plant development and stimulate a desired growth response, such as control of plant height. One such PGR is abscisic acid (ABA), which has been used effectively to improve fruit quality, specifically sugars and phytonutrients. The purpose of this study was to examine the effects of exogenous applications of ABA on tomato (Solanum lycopersicum) fruit quality, such as carotenoids, soluble sugars and organic acids, and ABA on tomato leaf chlorophylls and carotenoids. Furthermore, this study compared how ABA and calcium (Ca) treatments together affect fruit quality and whether there are added benefits to treating plants with both simultaneously. ABA treatments proved effective in increasing tomato fruit soluble sugars and decreasing organic acid concentrations. This study demonstrated that ABA is a viable PGR to significantly improve tomato fruit quality, specifically pertaining to carotenoids, soluble sugar, and organic acid concentrations.
Comparison of Carbon Footprint and Variable Costs of Selected Nursery Production Systems for a 5-cm-caliper Red Maple
Authors: Ingram Dewayne L. , Hall Charles R.
Published: February 2019

The objective of this study was to examine the differences in global warming potential (GWP) and variable cost structure of a 5-cm-caliper red maple tree grown using two alternative production methods including a traditional field [balled and burlapped (BNB)] production system and a containerized, pot-in-pot (PIP) production system. Feedback from nursery growers was obtained to model each production system including the labor required for each cultural practice, materials used, and the hourly usage of tractors and other equipment. Findings from the study indicate that the total system GWP and variable cost for the PIP tree system is −671.42 kg of carbon dioxide equivalent (CO2e) and $250.76, respectively, meaning that the tree sequesters much more carbon during its life than is emitted during its entire life cycle. The same holds true for the BNB tree; however, in this system, the GWP of the tree −666.15 kg CO2e during its life cycle at a total variable cost of $236.13. Thus, the BNB tree costs slightly less to produce than its PIP counterpart but the life cycle GWP is slightly less positive as well.
Does Consumer Awareness of Neonicotinoid Insecticides Influence Their Preferences for Plants?
Authors: Rihn Alicia , Khachatryan Hayk
Published: February 2019

Consumer awareness of neonicotinoid (neonic) insecticides is growing (in part) due to increased publicity and media attention. Environmental groups want neonic insecticides to be banned because of their perceived potential negative consequences on nontarget species (especially bees and other pollinator insects). Several retail outlets and governmental agencies are now requiring the ornamental horticulture industry (hereafter, green industry) to label plants grown using neonic insecticides. Although the scientific value of the mandatory labeling policies are debatable, neonic labeling may negatively influence consumers’ demand for plants. Research on consumers’ awareness of neonic insecticides is limited, and the extent to which awareness influences preferences and shopping behavior is less understood. This manuscript addresses these research gaps by investigating correlations between awareness of neonic insecticides, knowledge about related topics (e.g., gardening and pollinator insect health), and purchase likelihood, using an online survey of 921 U.S. consumers. Results indicate that only 24% of surveyed plant purchasers are aware of neonic insecticides. Consumers who are aware of neonic insecticides are more knowledgeable about plants that improve pollinator health and entomology than those who are not aware. Labels with “neonic-free” wording were the least preferred and influential pollinator-related in-store promotion. However, awareness of neonic insecticides was positively correlated with consumers’ purchase likelihood for “neonic-free” plants. Overall, awareness influences consumers’ shopping behavior, which could necessitate altering green industry pest management strategies as consumers’ awareness of neonic insecticides increases due to the negative publicity surrounding it.
Turf Manager Response to Changing Pesticide Regulations
Authors: Wallace Victoria H. , Bartholomew Candace , Campbell Julie H.
Published: February 2019

A mail survey was distributed to school turfgrass managers throughout Connecticut focusing on the differences between turfgrass management practices for kindergarten through eighth-grade (K-8) school grounds before, during, and after a 2010 ban on pesticide use at these facilities. The results indicate that as turf care protocol transitioned from an integrated pest management (IPM) program to new pesticide-free regulatory requirements, school grounds/athletic field managers did not significantly adjust their management programs. The percentage of managers applying pesticides on K-8 grounds decreased, as expected, with the implementation of the new pesticide ban; however, pesticide applications on high school grounds/athletic fields also decreased. Furthermore, it was observed that there had been minimal adoption of minimum risk 25(b) products, the suggested alternative to traditional synthetic pesticides. With respect to other cultural practices, we found that few changes have been made to other cultural practices that would improve turf quality. Budgetary issues facing school grounds/athletic field managers may have limited their ability to implement potentially costly management practices necessary to offset the loss of pesticides. Educational efforts to promote new management practices have the potential to inform school grounds/athletic field managers about new methods, thereby, potentially increasing adoption.
In Vitro Propagation of Camellia oleifera Abel. Using Hypocotyl, Cotyledonary Node, and Radicle Explants
Authors: Li Ze , Tan Xiaofeng , Liu Zhiming , Lin Qing , Zhang Lin , Yuan Jun , Zeng Yanling , Wu Lingli
Published: February 2019

Camellia oleifera Abel. is one of four major woody oil plants in the world. The objective of the current study was to evaluate the effect of different plant growth regulators (PGRs) and concentrations on direct organogenesis using cotyledonary nodes, hypocotyls, and radicle explants. High induction frequency of adventitious shoots were obtained from cotyledonary nodes, hypocotyls, and radicle explants (85.2%, 73.6%, and 41.0%, respectively) when cultured on half-strength Murashige and Skoog (1/2 MS) medium containing 2.0 mg·L−1 6-benzylaminopurine (BA) and 0.1 mg·L−1 indole-3-acetic acid (IAA). Microshoots from cotyledonary nodes, hypocotyls, and radicle explants were then transferred to 1/2 MS medium containing 2.0 mg·L−1 BA and 0.05 mg·L−1 indole-3-butyric acid (IBA) for shoot multiplication, resulting in 6.9 shoots per explant. The shoots were transferred to Woody Plant Medium (WPM) supplemented with various α-naphthalene acetic acid (NAA) and gibberellic acid (GA3) for shoot elongation. The mean length of shoots and the number of leaves per shoot were 3.7 and 6.6 cm, respectively, in WPM supplemented with 0.5 mg·L−1 NAA and 3.0 mg·L−1 GA3. The highest rooting of shoots (90.2%) or the number of roots per shoot (7.2) was obtained when elongated microshoots were transferred to 1/2 MS medium supplemented with 3.5% perlite, 1.0 mg·L−1 IBA and 2.0 mg·L−1 NAA. The rooted plantlets were successfully acclimatized in the greenhouse with a survival rate of 90.0%. The in vitro plant regeneration procedure described in this study is beneficial for mass propagation and improvement of C. oleifera through genetic engineering.
Effects of Foliar Application of Various Zinc Fertilizers with Organosilicone on Correcting Citrus Zinc Deficiency
Authors: Fu Xing-Zheng , Xing Fei , Cao Li , Chun Chang-Pin , Ling Li-Li , Jiang Cai-Lun , Peng Liang-Zhi
Published: February 2019

To compare the effects of various zinc (Zn) foliar fertilizers on correcting citrus Zn deficiency and to explore an effective correcting method, three common Zn fertilizers, Zn sulfate heptahydrate (ZnSO4.7H2O), Zn chloride (ZnCl2), and Zn nitrate hexahydrate [Zn(NO3)2.6H2O], were selected to spray the Zn-deficient citrus leaves, tested at different concentrations, with or without organosilicone surfactant. Zn content, chlorophyll levels, and photosynthesis characteristics of leaves were analyzed. Leaf Zn content was significantly increased with increase of the sprayed Zn concentration of the three Zn fertilizers. However, when the sprayed Zn concentration of ZnSO4.7H2O exceeded 200 mg·L−1, and Zn concentration of ZnCl2 or Zn(NO3)2.6H2O exceeded 100 mg·L−1, obvious necrotic spots formed on leaves. This necrosis disappeared when 0.025% organosilicone was added to the three Zn fertilizer solutions, even at a Zn concentration of 250 mg·L−1. Meanwhile, the Zn contents of leaves increased one to four times for these treatments. Furthermore, foliar application of the three Zn fertilizers significantly improved chlorophyll levels and photosynthetic capacity of Zn-deficient leaves. The data of chlorophyll and photosynthesis characteristics indicate that the correcting effect of ZnCl2 and Zn(NO3)2.6H2O is better than that of ZnSO4.7H2O, and could be further improved via supplement of organosilicone. In conclusion, ZnCl2 or Zn(NO3)2.6H2O containing 250 mg·L−1 of Zn and supplemented with 0.025% organosilicone is a safe and effective formulation of Zn foliar fertilizer for correcting citrus Zn deficiency.