bluuebunny/crossref_metadata_2025 huggingface dataset:
Pinching Impacts Cut Poinsettia Stem Quality and Profit Potential
Authors: Warnock Daniel F. , Lash Heather
Published: February 2019

The development of the Renaissance series of cut poinsettias, Euphorbia pulcherrima, presents unique opportunities and challenges to cut flower producers. This series has curled bracts, long stem length, excellent vase life, and is highly marketable. Literature indicates that this crop is suited for pot or bed production, but does not compare how cultural methods impact stem quality. This study assessed the impact of pinching on final stem quality and crop profitability. Uniform rooted cuttings of `Renaissance Red' obtained from a commercial supplier were transplanted into a 1.2 × 2.4 m bed containing a soilless media to obtain two plants per 0.09 m2. A total of 56 cuttings were used and grown using standard production techniques. Transplanting occurred on 29 July 2004 with half of the plants being pinched on 19 Aug. 2004. To minimize border effects, plants in the outside rows were discarded. Upon harvest, stem length, stem diameter, bract diameter, floral development, and number of axillary shoots were determined for 30 interior plants. Both pinched and unpinched plants produced marketable stems; however, unpinched plants produced longer thicker stems with larger bracts. The number of stems obtained per square foot was greater with the pinched plants. While overall quality was reduced, this increase in stem number offset potential lost profit. The production of quality cut stems of `Renaissance Red' poinsettias is possible with either pinched or unpinched plants.
Post harvest Handling of Cut Linaria, Trachelium, and Zinnia
Authors: Dole John M. , Fanelli Frankie L. , Fonteno William C. , Harden Beth , Blankenship Sylvia M.
Published: February 2019

Optimum postharvest handling procedures were determined for Linaria maroccana `Lace Violet', Trachelium`Jemmy Royal Purple', and Zinnia elegans `Benary's Giant Scarlet' and `Sungold.' A 24-hour 10% or 20% sucrose pulse increased the vase life of Linaria by 2–4 days, resulting in a vase life of 9 days as compared to 5 days for control flowers held in deionized (DI) water. Use of floral foam and cold storage at 1 °C for 1 week decreased vase life. Treatment with either 0.1 or 1.0 ppm ethylene had no effect. The use of a commercial holding solution (Floralife Professional or Chrysal Professional 2 Processing Solution) or 2% or 3% sucrose increased vase life 4–10 days. For cut Trachelium, ethylene caused florets to close entirely or stop opening; 1-MCP and STS prevented these ethylene effects. Stems tolerated 4 days of 1 °C storage, but 1 week or more of storage reduced the 14-day vase life of unstored flowers to 9 days. Stems in 2% or 4% sucrose had a longer vase life compared to DI water. While the use of floral foam was not detrimental when used with sucrose solutions, it reduced vase life when sucrose was not used. Zinnia stems could not be cold stored for 1 week at 1 °C due to loss of turgidity and cold damage. Stems stored dry at 5 °C regained turgidity and averaged a vase life of 14 days; however, petals remained slightly twisted and curled after being in the vase for several days. Treatment with ethylene had no effect. Floral foam reduced vase life to 9–10 days.
Post harvest Handling of Cut Dahlia, Lupinus, Papaver, and Rudbeckia
Authors: Dole John M. , Fanelli Frankie L. , Fonteno William C. , Harden Beth , Blankenship Sylvia M.
Published: February 2019

Optimum postharvest handling procedures were determined for Dahlia `Karma Thalia', Lupinusmutabilis ssp. cruickshankii`Sunrise', Papaver nudicaule `Temptress', and Rudbeckia`Indian Summer.' Dahlia harvested fully open had a vase life of 7–10 days in deionized (DI) water that was increased by 1.5–2 days using commercial holding solutions (Chrysal Professional 2 Processing Solution or Floralife Professional). Neither floral foam nor 0.1–1.0 ppm ethylene had any effect on vase life. One week of cold storage at 1 °C reduced vase life up to 2 days. The longest vase life, 12–13 days, was obtained when floral buds, showing a minimum of 50% color, were harvested at the breaking stage (one petal open) and placed in 2% or 4% sucrose or a commercial holding solution. Lupinus flowers held in DI water lasted 8–12 days; 1 week cold storage at 1 °C reduced vase life by 3 days. Florets and buds abscised or failed to open when exposed to ethylene; STS pretreatment prevented the effects of ethylene. Commercial holding solutions increased Papaver vase life to 7–8 days from 5.5 days for stems held in DI water. While stems could be cold stored for 1 week at 1 °C with no decrease in vase life, 2 weeks of cold storage reduced vase life. Flowers were not affected by foam or ethylene. Rudbeckia had a vase life of 27–37 days and no treatments extended vase life. Stems could be stored at 2 °C for up to 2 weeks and were not ethylene sensitive. Floral foam reduced the vase life over 50%, but still resulted in a 13-day vase life.
Cation Exchange Capacity and Base Saturation of 64 Peat Mosses
Authors: Rippy Janet F. M. , Nelson Paul V. , Bilderback Ted
Published: February 2019

Problems of inconsistent initial pH in peat moss-based substrates that are created using standard formulas for limestone additions, and pH drift from the target in those substrates may be due to variations in the CEC and BS of peat moss. This study was conducted to determine whether such variation exists. Sixty-four peat moss samples were obtained from several bogs across Alberta, Canada. Adsorbed cations on each peat moss sample were displaced with hydrochloric acid (HCl), and flushed out with three deionized water washes. The displacing/flushing solution was collected and later analyzed for concentration of bases (Ca, Mg, K, and Na) using atomic absorption spectrometry. After cations were removed, the peat moss exchange sites were saturated with barium acetate [Ba(OAc)2] to displace the H+, which were then collected by a second flushing with deionized water. This second displacing/flushing solution was titrated with measured amounts of NaOH to a phenolphthalein end point. Base saturation and CEC were calculated. There were significant variations in CEC (ranging from 108.12 to 162.25 cmol·kg-1) and BS (ranging from 13.52% to 63.97% of CEC) among the peat moss samples. Ca accounted for 78.08% of the BS. For a given peat moss, the higher the BS, the lower the neutralization requirement to achieve a target pH. Also, high CEC peat mosses may have greater buffering capacity than those with low CEC, which may result in less pH drift.
Tank Mixtures Differentially Impact Survival of Predatory Mites used to Manage Western Flower Thrips
Authors: Warnock Daniel F. , Lash Heather
Published: February 2019

Greenhouses contain a vast array of insect, mite, and disease pests primarily managed by applications of conventional and biorational pesticides including insecticides, miticides, and fungicides. However, biorational pesticides have a narrow range of pest activity. As a result, greenhouse producers tank mix to broaden application activity. Research has demonstrated that tank mixing can result in either synergistic or antagonistic interactions for targeted pests. However, the impact of tank mixing insecticides and fungicides on predatory mites, Neoseiulus cucumeris, used to manage western flower thrips, Franklinella occidentalis, is unknown. The objective of this research was to determine how mixtures of four different pesticides (Conserve, Avid, Cleary's, and Decree), alone and in all possible combinations affect predatory mite survival in a laboratory bioassay. Individual 2-day-old adult mites, isolated in a cell of a bioassay tray, were exposed to one of the 15 pesticide treatments, or a water control. Treatments were replicated 15 times. Trays were held in an environmental chamber and mite mortality was assessed after 24 hours. Mite mortality was differentially impacted by some pesticide treatments when compared with the water control. One pesticide mixture, Conserve + Cleary's, significantly reduced mite survival compared to other pesticide treatments or the water control. Up to 70% of the mites exposed to this treatment died. The combination of Conserve + Cleary's should be avoided as a tank mixture when the biological control agent, Neoseiulus cucumeris, is used to manage western flower thrips.
Operating a Process-based Simulation Model within a User-friendly Windows Environment to Predict the Transpiration and Photosynthesis of Red Maple Trees
Authors: Bauerle William L. , Timlin Dennis J. , Pachepsky Yakov A. , Anantharamu Shruthi
Published: February 2019

Application of process-based models beyond the research community has been limited, in part because they do not operate in a user-friendly Windows environment. We describe the procedure of adapting a spatially explicit biological-process model, MAESTRA, to run in a standard graphical user interface (GUI). The methods used to adapt the MAESTRA model are generally applicable to other process-based models and therefore simplify other coupling attempts. We discuss recommendations based on our experiences for model input structure and interface design, two components that will allow various models to work with a generic interface. MAESTRA uses modified versions of the Ball-Berry stomatal conductance (gs) and Farquhar photosynthesis(Anet) models to estimate transpiration and photosynthesis on a leaf area basis and scale the sunlit and shaded fractions to the whole tree. We present MAESTRA estimates within a standardized graphical user interface for crop simulators (GUICS) windows environment and furthermore, we provide dialog boxes and graphical displays of the MAESTRA model input and whole tree output for red maple trees. In so doing, we present a technology transfer via the GUICS that prevents any watering down of the science behind the MAESTRA model, yet allows an accurate decision support tool to reach a wide audience.
Nitrogen Fertility Affects Growth and Water Use of Cercis siliquastrum Tree Species Native to Lebanon
Authors: Zahreddine Hala G. , Struve Daniel K. , Talhouk Salma N.
Published: February 2019

The Mediterranean region is a center of great plant diversity, harboring around 25,000 plant species, more than 20% of them endemic. Since the last Lebanese flora record in 1966, the country has experienced habitat fragmentation and destruction, due to overgrazing, overexploitation of natural resources, and urban expansion. A large number of Lebanese tree species have unexplored economic potential as either ornamental or medicinal plants. This study aimed at exploring the effects of two nitrogen fertility treatments on the growth and water use of 2-year-old Cercis siliquastrum seedlings. C. siliquastrum seeds were collected from different locations and mother trees in Lebanon in mid-Aug. 2001. Two-year old plants were then transplanted into 3-gal. containers and were randomly assigned to one of two N fertility programs, 25 ppm or 100 ppm. Plants from all redbud sources were significantly taller in the low N treatment and had significantly higher RGR than plants growing at 100 ppm N. On the other hand, plants growing at 100 ppm N level had significantly higher LAR and lower NAR than plants growing at 25 ppm N. There were significant differences in LAR and plant heights among the different sources. Water use was conducted monthly. It ranged from 3.6 × 10-4 to 1.3 × 10-3 g·cm Ht-1 per hour at 25 ppm and from 2.6 × 10-4 to 1.3 × 10-3 g·cm Ht-1 per hour at 100 ppm N through the experiment.
Comparison between Peat and Fresh Rice Hulls: Hydraulic and Chemical Characteristics
Authors: Sambo Paolo , Evans Mike R. , Gianquinto Giorgio
Published: February 2019

One of the most widely used substrates in nursery production is peat, which is used as plain substrate or mixed with other media. Peat use is problematic, primarily because of the high price and the environmental implications connected with its extraction and disposal. For these reasons, the exploitation will be restricted in the future in both Europe and America. Thus, researchers are under pressure to find alternative substrates that can be used in an inexpensive and environmentally friendly way. Although aged, carbonized and composted rice hulls have been used to a limited extent, more studies are needed to characterize fresh rice hulls as a growing medium. This research was aimed at characterizing fresh hulls after being ground in different particle sizes, and comparing them with peat. Ground hulls were separated into four fractions (6-, 4-, 2-, and 1-mm diameter), which were characterized for pH, EC, CEC, organic matter, and total nitrogen content. The water retention curve was also estimated and the following hydraulic characteristics were measured and compared: TP, CC, AFP, EAW, and WBC. As expected, pH, N, and C content and CEC did not differ among rice hull fractions, while EC showed a slight but constant increase when particle dimensions decreased. Compared to peat, the TP of rice hulls was smaller independently from particle dimensions, but AFP was 19.5%, 44,1%, 114.2%, and 115.8% higher for 1-, 2-, 4-, and 6-mm particles, respectively, indicating a very good aeration capacity. EAW and WBC were higher only in 1- and 2-mm particles. A further experiment aimed at comparing the behavior of transplants in rice hulls (6 mm) and peat showed that tomato plantlets grew slower in the former, although transplants were of good, marketable quality.
Protected Culture Enhances Early Season Strawberry Fruit Yield and Quality in Southern California
Authors: Daugovish Oleg , Larson Kirk
Published: February 2019

Total and marketable yield, fruit size and fruit rot were evaluated for `Camarosa' and `Ventana' strawberries grown with or without protected culture in southern California in 2003 and 2004. In both years, bareroot transplants were established on 5 Oct. using standard “open field” production methods. Fifty-five days after transplanting, metal posts and arcs were positioned over portions of the field and covered with 0.0324-mm-thick clear polyethylene (Tufflite Thermal, Tyco Plastics, Inc., Minneapolis, Minn.) to create “tunnel” structures 5 m wide, 25 m long, and 2.5 m high. Each tunnel covered three contiguous strawberry beds, and experiment design was a randomized complete block with four replications, with individual plots consisting of 20 plants. In 2003, early season (Jan.–1 Apr.) marketable yields in tunnels were 90% and 84% greater than outdoor culture for `Ventana' and `Camarosa', respectively. In 2004, use of tunnels resulted in a 140% marketable yield increase for `Ventana' and 62% for `Camarosa' (Jan.–31 Mar.); however, unusually high temperatures (38 °C) in April resulted in reduced yields in tunnels thereafter. In both years, increased early production coincided with highest fresh market fruit prices, resulting in $5700–7700 greater returns per-acre compared to open field production. For both cultivars, tunnel production resulted in 37% to 63% fewer non-marketable fruit due to less rain damage, better fruit shape, and decreased incidence of gray mold. For all treatments, fruit size decreased as the season progressed and was more pronounced in tunnels after April. Overall, these studies indicate that tunnels have potential for enhancing early-season production and profitability of strawberries in southern California.
Iturup and Sakhalin Island Strawberries
Authors: Sabitov Andrey , Hummer Kim E. , Davis Tom
Published: February 2019

A plant-collecting expedition to Iturup and Sakhalin Islands, Russian Federation, occurred between 21 July and 12 Sept. 2003. Actinidia, Rubus, Ribes, and Vaccinium, as well as seven accessions of strawberries, Fragaria L., were collected. Among them, a wild strawberry, Fragaria iturupensis Staudt, was collected on the eastern slope of Atsonupuri Volcano, Iturup Island, at 630 and 650 m elevation. This species was similar in habit, leaf color and overall appearance to the American strawberry species F. virginiana Mill. Fruits were bright red, oblate spherical, about 1.4 cm in diameter, and had exerted achenes. The native distribution of this species was limited to the middle elevation of the slope of this volcano, and only on Iturup Island. Chromosome counts indicated that these plants were octoploid. Initial DNA fingerprinting aligned this sample with other octoploid species. In addition to this species, samples of F. yezoensis H. Hara (syn. F. nipponica Makino) were collected on Kuibyshewskii Bay of Cape Otlivnoy, Iturup, and near Ujno-Sakhalinsk City, Sakhalin Island. F. iinumae Makino was observed in Ogon'ki Village, Sakhalin Island. This report confirmed the existence of F. iturupensis, the only known native Asian octoploid strawberry, and documented its limited range. Seeds of these strawberry species are available for research by request from the U.S. Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository in Corvallis.
Economic Comparison of Five High-density Apple Planting Systems
Authors: Robinson Terence L. , DeMarree Alison M. , Hoying Stephen A.
Published: February 2019

We performed an economic analysis of five orchard production systems [Slender Pyramid/M.26 (840 trees/ha), Vertical Axis/M.9 (1538 trees/ha), Slender Axis/M.9 (2244 trees/ha), Tall Spindle/M.9 (3312 trees/ha), and Super Spindle (5382 trees/ha)] using composite yield and labor usage data from several replicated research plots in New York state. Other costs and fruit returns were averages from a group of commercial fruit farms in New York state. The systems varied in costs of establishment from a low of $18,431/ha for the Slender Pyramid system to high of $47,524/ha for the Super Spindle system. The large differences in establishment costs were largely related to tree density. All of the systems had a positive internal rate of return (IRR) and net present value (NPV) after 20 years. They ranged from a low of 7.5% IRR for the Slender Pyramid system to a high of 11.1% IRR for the Slender Axis system. Profitability, as measured by NPV, was curvilinearly related to tree density with intermediate densities giving greater profitability than the highest densities. The optimum density was 2600 trees/ha when NPV was calculated per hectare, but only 2200 trees/ha when NPV was calculated per $10,000 invested. The earliest break-even year was 10 for the Slender Axis and Tall Spindle systems. The latest break-even year was 13 for the Slender Pyramid. An estimate of the number of hectares required to produce a $100,000 annual profit to the business was 222 for the slender pyramid system and 84–104 ha of the three best systems (Super Spindle, Tall Spindle, and Slender Axis). The analysis revealed that efforts to control establishment costs of land, trees and support system can substantially increase lifetime profits.
Rootstocks and Interstem/Rootstock Combinations for Lower Midwest Apple Orchards
Authors: Taylor Bradley H. , Geisler-Taylor Dagmar M.
Published: February 2019

Use of precocious, high-yielding, dwarfing rootstocks for apple trees in southern Illinois has been limited by the prevalence of fire blight and crown rot diseases, as well as soil and climate stresses. Apple orchards in the region are generally situated on heavy clay soils and often receive excess rainfall in spring and fall, followed by drought in summer. New dwarfing rootstocks adapted to these biotic stresses were used as interstems on robust, vigorous rootstocks, to determine if earlier and greater cumulative yields could be obtained compared to the current industry standard MM. 111. The treatments consisted of 20 various interstem/rootstock combinations with `Ruby Jon Jonathan' as the scion that were propagated and grown as feathered maidens in the nursery. The trees were planted at 4.5 × 6.0 m in a randomized complete-block design with eight replications in May 1996 at the Southern Illinois University Horticultural Research Center at Carbondale, Ill. The trees were trained in a vertical axis system with minimal initial pruning and complete deblossoming in the first 2 years. Trees were allowed to crop during the third- through ninth-leaf. Cumulative yields of the best performing interstem/rootstock combinations were two to three times greater compared with MM. 111. The trees on the most vigorous rootstocks consistently produced the largest fruit size, but four dwarfing clones, G. 30, V. 1, Bud. 9, and M. 7, used as interstems, generally produced higher yields with similar fruit size. These advantages were obtained without the negative side effects (excess root suckers, lack of scion uniformity, and increased mortality) traditionally associated with interstem performance in the lower Midwest.
Nitrogen Uptake in a Range of Alternative Orchard Floor Management Systems
Authors: McDonald Sarah F. , Azarenko Anita Nina , Chozinski Annie , Righetti Tim
Published: February 2019

The percentage of N from fertilizer removed from the field by fruit trees is low. Overapplication of N in orchards has been a common practice and is a concern due to environmental and tree growth problems caused by excess N. Orchard floor management practices (OFMP) can improve the physical and chemical properties of the soil and may alter the soil biological community. Biological activity can affect mineralization rate and thus nutrient availability. The purpose of this study was to determine the effect of alternative OFMP on fertilizer N uptake. Research plots were located in Corvallis, Ore. (COR) (7-year-old `Fuji'), and Hood River, Ore. (HR) (3-year-old `Red Delicious'). Treatments were begun in 2001 in a split-plot completely randomized design with three replications. Main plot treatments were herbicide or cultivation. Subplot treatments were no amendment, bark mulch, compost, and barley/vetch mown and blown into the tree row. Depleted NH3SO4 was applied to single-tree replicates at budbreak. Trees were destructively harvested at harvest of 2003. At HR, the percentage of N derived from fertilizer (NDFF) was significantly lower in the whole tree, leaves, new wood, old wood, spurs, and roots of trees from compost than from unamended plots (P < 0.05). At COR, the NDFF in the leaves, fruit, new wood, spurs and roots was significantly lower in trees from compost plots than unamended plots (P < 0.05). The NDFF also tended to be lower in trees from bark mulch-treated plots than control plots, although differences were not always significant. Vetch/barley amendment resulted in NDFF similar to no amendment. There were no significant differences between the total N of trees from unamended and compost plots. Trees from compost-treated plots appear to be acquiring N from sources other than fertilizer.
Polypropylene Row Covers Greatly Enhance Growth and Production of Fourth-leaf Sweet Cherry Trees
Authors: Nunez-Elisea Roberto , Cahn Helen , Caldeira Lilia , Seavert Clark F.
Published: February 2019

Black, woven polypropylene row covers were compared to chemical sprays as methods to manage ground vegetation in a `Regina'/Gisela 6 orchard planted in 2001. Row covers were installed within 1 month of planting. Exposed row cover width was 2.4 m, with edges (30 cm on each side) buried in the ground. Only a 30-cm band along the edge of row covers was sprayed with herbicide to facilitate mowing. Weed management of control trees consisted of chemical herbicide sprays. Trees were not fertilized since planting in 2001. Irrigation of all trees was applied with low volume (20 L·h-1) microsprinklers and scheduled according to soil water content. Row covers significantly increased trunk cross-sectional area (TCSA) by about 30% annually. By Summer 2004, trees with ground covers had filled their allotted space within rows, while control canopies were ≈50 cm apart. Trees in row covers produced a 130% higher average yield than controls (7.4 kg/tree vs. 3.2 kg/tree). Row covers produced larger and firmer fruit, which matured 2–3 days later than controls. Groundcovers slightly increased soil temperature from April to September by ≈2 °C at 5- and 10-cm depths. Roots under ground covers were denser and more spread out than in controls and water use efficiency was higher for trees growing in ground covers. Amount and labor for herbicide application was reduced to less than half with row covers. Although ground covers are expensive at ≈$2000 per acre, their cost could be offset by earlier and higher production and by long-term savings in labor, water use, and herbicides. Durability of row covers is expected to exceed 15 years.
Fine Root Dynamics in an Organic Apple Orchard under Two Ground Floor Management Systems
Authors: Stefanelli Dario , Zoppolo Roberto J. , Perry Ronald L.
Published: February 2019

Fine root dynamics, timing of the events, and their relationship with soil conditions are of major interest because the understanding of these phenomena will permit a better synchronicity between nutrients and plant uptake. The goal of this research is to study the effect of different soil conditions, generated from two ground floor management systems, on fine root dynamics of apple trees under organic protocol in Michigan. The research has been conducted at the Clarksville Horticultural Experimental Station (CHES) of Michigan State University (MSU), in the organically certified (by OCIA) orchard of “Pacific Gala” grafted on M9 NAKB 337, established in May 2000. The orchard floor management systems being studied are: 1) a mulch made of alfalfa hay on the tree rows, with a width of 1.8 m and 2) the “Swiss Sandwich System” (SSS) that consists in superficial tillage of two strips 80 cm wide at each side of the tree row, leaving a 40 cm strip in the middle (on the tree row, under the canopy) where volunteer vegetation is allowed to grow. Root dynamics are studied on four replicas of two trees per each of the two ground treatments (16 in total) in a block design. For each tree in the trial four clear butyrate minirhizotrons have been installed (64 in total) at a 45° angle facing the tree, in the summer of 2002. Root dynamics, measured through pictures taken with a Bartz Technology digital camera and analyzed with a new software under development at MSU. During the 2003 season differences between the two systems have been found depending on the parameter taken in consideration. Mulch had different root distribution compared to SSS. Mulch treatment showed shallower roots even if below 90 cm the two systems didn't show any difference.
Characterization of Sequences Up-regulated in Peach Bark in Response to Low Temperature
Authors: Bassett Carole L. , Farrell Robert E. , Artlip Timothy S.
Published: February 2019

Genes whose expression is regulated by exposure to low temperature (LT) in peach (Prunus persica L. Batsch.) bark were identified by PCR suppression subtractive hybridization. Among the genes identified by this technique were several that had previously been associated with LT responsiveness, as well as a few that have not been reported to be regulated by cold. Genes represented by the first group included Ppdhn1, previously characterized as a seasonally expressed gene predominantly seen in bark tissue collected in winter months. A novel dehydrin found in this study, Ppdhn3, was also observed to be up-regulated at LT and seasonally expressed. Two genes not previously associated with LT response were found to be up-regulated at 5 °C. These genes encode a polypeptide related to some unknown mitochondrial process (Pptar1p) or a transducin-like protein (Pptlp1) that may be associated with signal transduction. Expression of these genes with respect to seasonal variation and drought stress is compared to genes from peach bark (Ppdhn1 and Ppdhn2), whose patterns of expression in different seasons and under water deficit are well documented.
Cold Hardiness and Budbreak of Two Buckthorn Species
Authors: Stewart J. Ryan , Graves William R. , Landes Reid D.
Published: February 2019

Can Carolina buckthorn (Rhamnuscaroliniana) persist north of its native habitat without becoming invasive? Its distribution (USDA zones 5b to 9b) suggests that genotypes vary in cold hardiness, and invasiveness of other Rhamnus sp. has been linked to unusually early budbreak each spring. Therefore, we investigated depth of cold hardiness and vernal budbreak of Carolina buckthorns from multiple provenances and made comparisons to the invasive common buckthorn (Rhamnus cathartica). Budbreak was recorded in Ames, Iowa, from 9 Apr. to 10 May 2002. Buds of common buckthorn broke earlier than those of Carolina buckthorn, and mulching plants of Carolina buckthorn hastened budbreak. Stem samples were collected in October, January, and April from a plot in Ames, Iowa (USDA zone 5a), of Carolina buckthorns from three provenances (Missouri, Ohio, and Texas) and of naturalized common buckthorns. A similar schedule was followed during the next winter, when two plot locations [Ames, Iowa, and New Franklin, Mo. (USDA zone 5b)], were compared, but Carolina buckthorns from only Missouri and Texas were sampled. Carolina buckthorn and common buckthorn survived midwinter temperatures as low as –21 °C and –24 °C, respectively. Provenance differences were minimal; Carolina buckthorns from Missouri were more hardy than those from Ohio and Texas only in April of the first winter. We conclude that its cold hardiness will permit use of Carolina buckthorn beyond where it is distributed in the southeastern United States. Delayed budbreak of Carolina buckthorn relative to that of common buckthorn may underscore the potential for Carolina buckthorn in regions with harsh winters and may lessen its potential to be as invasive as common buckthorn.
Hydroperoxide Lyase Activity Necessary for Normal Aroma Volatile Biosynthesis of Tomato Fruit, Impacting Sensory Perception and Preference
Authors: Canoles Mauricio , Soto Marisol , Beaudry Randolph
Published: February 2019

The aldehydes cis-3-hexenal, hexanal, and trans-2-hexenal; the alcohols 1-hexanol, and cis-3-hexenol; and the ketone 1-penten-3-one are produced as a consequence of lipid degradation following tissue disruption and are among the most important volatile compounds in tomato (Lycopersicon esculentum Mill.) aroma. The biosynthesis of cis-3-hexenal and other volatiles noted involves the action of a sequence of enzymes including lipase, lipoxygenase (LOX), hydroperoxide lyase (HPL), isomerase, and alcohol dehydrogenase (ADH) on glycerolipids containing the fatty acids, linoleic acid (18:2) and linolenic acid (18:3), via the LOX pathway. In the current work, the formation and sensory perception of volatile compounds was studied in tomato plant lines where HPL activity was genetically altered. LeHPL co-suppression dramatically reduced the production of lipid-derived C6-volatiles in leaves, but in fruits, only unsaturated C6-volatile production was affected, suggesting LeHPL-independent formation of hexanal occurs in fruits, but not in leaves. Increased production of 5-carbon volatiles is proposed as an alternative way to metabolize 13-hydroperoxy linolenic acid in plants with reduced LeHPL activity. Changes in the volatile profile of leaves and fruits of tomato lines in which LeHPL activity is reduced markedly are readily detected by nontrained sensory panels. The studies demonstrate that a marked reduction in the activity of one of the most critical steps in the LOX pathway can markedly impact sensory perception. Efforts to improve total volatile formation may require the modification of LOX pathway at several steps simultaneously, including precursor formation, and LOX and HPL activities.
Wound-induced Phenolic Accumulation and Browning in Lettuce (Lactucasativa L.) Leaf Tissue is Reduced by Exposure to n-alcohols
Authors: Saltveit Mikal , Choi Youngjun , Tomás-Barberán Francisco
Published: February 2019

A wound signal originates at the site of injury in lettuce [Lactucasativa (L.)] leaf tissue and propagates into adjacent tissue where it induces a number of physiological responses that include increased phenolic metabolism with the de novo synthesis of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), the synthesis and accumulation of soluble phenolic compounds (e.g., chlorogenic acid), and subsequent tissue browning. Exposing excised mid-rib leaf tissue to vapors (20 μmol·g-1 FW) or aqueous solutions (100 mm) of n-alcohols inhibited this wound-induced tissue browning by 40% and 60%, respectively. Effectiveness of the alcohol increased linearly from ethanol to the seven-carbon heptanol, and then was lost for the longer n-alcohols 1-octanol and 1-nonanol. The 2- and 3-isomers of the effective alcohols did not significantly reduce wound-induced phenolic accumulation at optimal 1-alcohol concentrations, but significant reductions did occur at much higher concentrations (100 μmol·g-1 FW) of the 2-, and 3-isomers. The active n-alcohols were maximally effective when applied during the first 2 h after excision, and were ineffective if applied 12 h after excision. Phospholipase D (PLD) and its product phosphatidic acid (PA) are thought to initiate the oxylipin pathway that culminates in the production of jasmonic acid, and PLD is specifically inhibited by 1-butanol, but not by 2- or 3-butanol. These results suggest that PLD, PA, and the oxylipin pathway may be involved in producing the wound signal responsible for increased wound-induced PAL activity, phenolic accumulation, and browning in fresh-cut lettuce leaf tissue.
Carbon Dioxide Is a Promoter of Ethylene Action in Potato Tubers
Authors: Daniels-Lake Barbara J. , Prange Robert K. , Walsh John R.
Published: February 2019

In three consecutive years of storage trials, the effects of reduced O2 levels, elevated CO2 levels, and ethylene on the fry color and sugar content [sucrose and reducing sugars (glucose and fructose)] of `Russet Burbank' potato (Solanumtuberosum L.) tubers were evaluated. The potatoes were stored in modified atmosphere chambers and the atmosphere mixtures were supplied from compressed gas cylinders. Fry color and sugar content were assessed at the start of each trial and after several weeks of exposure to the treatment atmospheres. Four 4-week trials were conducted in 2002 and two 9-week trials were conducted in each of 2003 and 2004. No differences in fry color or sugar content attributable to either increased CO2 or decreased O2 were observed, compared with untreated controls, in any year. In the second and third years, only selected treatments were repeated, with or without 0.5 μL·L-1 ethylene. Ethylene alone caused a moderate darkening of fry color and an increase in reducing sugars. However, the fry color and reducing sugar content of tubers exposed to a combination of elevated CO2 and ethylene were considerably darker and higher, respectively, than observed with ethylene alone. No similar interaction between ethylene and O2 level was observed. These results suggest that CO2 promoted ethylene-induced fry color darkening, which may explain the contradictory effects of CO2 on fry color frequently observed by the potato industry. This is contrary to published research on other fruits and vegetables, which has generally shown that CO2 inhibits ethylene action.
Environmental Losses of Soil-applied Nitrogen Sources in Lowbush Blueberry Production
Authors: Percival David , Thyssen Gloria , Sanderson Kevin , Burton David
Published: February 2019

Environmental losses of soil-applied nitrogen fertilizers were examined during 2004 in commercial wild blueberry fields in the vegetative phase of production in Nova Scotia (NS) and Prince Edward Island (PE). A randomized complete-block experimental design with five treatments, five replications, a plot size of 8 × 6 m, and 2-m buffers between plots was used. Treatments consisted of a control (no fertilizer application) and nitrogen applications (N at 35 kg·ha-1) of ammonium sulphate (AS), urea (U), diammonium phosphate (DAP), and sulfur-coated urea (SCU). Nitrogen applications occurred on 19 May and 9 June at the Kemptown (NS) and Mount Vernon (PE) sites, respectively. Cumulative ammonia volatilization was determined through the use of open top chambers with volatilization samples collected on 1, 2, 5, 8, and 12 days after treatment application. In addition, leaf tissue and yield component data were collected. A significant volatilization treatment effect was present at the Kemptown site with the U and SCU treatments having volatilization rates that were 321% and 207% greater than the control, respectively. Therefore, results from this study indicate that volatilization losses are significant and site specific and can negatively influence blueberry growth.
Mobilization of Iron from Ferric Citrate In Vitro
Authors: Smith Brandon R. , Cheng Lailiang
Published: February 2019

Plants grown on calcareous soils often exhibit symptoms of Fe-deficiency induced chlorosis despite a high content of total Fe in the leaf tissue. Iron is transported in the xylem primarily as the ferric citrate (Fe-Citr) chelate, and changes in pH, HCO -3, and Citr can lead to the formation of different Fe-Citr species. Understanding how Fe dissociates from these chelates may help explain why Fe is immobilized in the leaves. The goal was to quantify Fe mobilization (Fe-Mob) from Fe-Citr in an assay system buffered at pH 5, 6, or 7 when: 1) the molar ratio of HCO -3 to Fe increased in a 1 Fe: 1 Citr system; 2) the molar ratio of Citr increased in a 1 Fe: 3 HCO -3 system; and 3) solutions were photoreduced (PR) or left in the dark. For non-PR solutions, Fe-Mob from Fe-Citr using 500 μmol NADH was the greatest at the 1 Fe: 0 HCO -3-level, and decreased as HCO -3 increased. Fe-Mob also decreased as buffer pH increased from 5 to 7. Increasing the Citr ratio was effective in increasing Fe-Mob, but the effect decreased as buffer pH increased from 5 to 7. PR solutions behaved quite differently. In the 1 Fe: 1 Citr system, little to no Fe-Mob was detected at any buffer pH. However, there were already large pools of Fe2+ in solution, which decreased as HCO -3 increased, irrespective of buffer pH. Increasing the Citr ratio greatly increased Fe-Mob in the 1 Fe: 3 HCO -3 system, and mobilization decreased as buffer pH increased. Increasing Citr did not increase the amount of Fe2+ in solution. This work illustrates that increasing the HCO -3: Fe ratio can lead to an immobilization of Fe, and that increasing the Citr ratio can aid in Fe-Mob from Fe-Citr when the HCO -3: Fe ratio is high. Increasing the Citr ratio, however, does not increase the amount of PR Fe2+.
Do Circadian Rhythms Accentuate K Deficiency in Geranium?
Authors: Pitchay Dharmalingam S. , Gray John , Frantz Jonathan M. , Horst Leona , Krause Charles
Published: February 2019

Geranium (Pelargonium ×hortorum) typically follows the C3 metabolic pathway. However, it switches to CAM metabolism under certain abiotic stress environments. This switch may affect the nutritional requirement and appearance of visible deficiency symptoms of these plants. Because potassium (K) plays a key role in stomatal function, K-deficiency was studied in geranium. Plants were grown hydroponically in a glass greenhouse. The treatments consisted of a complete, modified Hoagland's solution with millimolar concentrations of macronutrients, 15 NO3-N, 1.0 PO4-P, 6.0 K, 5.0 Ca, 2.0 Mg, and 2.0 SO4-S and micromolar concentrations of micronutrients, 72 Fe, 9.0 Mn, 1.5 Cu, 1.5 Zn, 45.0 B, and 0.1 Mo, and an additional solution devoid of K. It took longer to develop the classic K deficiency symptoms than other bedding plant species commonly require. The K-stress plants' dry weight was 10% and 37% of control at incipient and advanced stage, respectively. When portions of geranium leaves were covered, symptomology on leaves with K stress developed rapidly (within 2 days) compared to the uncovered portion of the leaf blade. Control plants contained an abundance of marble-shaped K crystals in the adaxial surface of leaf mesophyll, but were lacking in the K-deficient plants. Geranium is more prone to K stress during short days than long days and an additional supply of K would be needed for normal growth in short days.
America's Funniest Home Videos and the Lottery Come to Plant Propagation: Using Technology to Promote Learning
Authors: Markhart Albert (Bud) H.
Published: February 2019

Large lectures continue to challenge teaching and learning. Our plant propagation course attracts a large number of non-majors seeking to fulfill their science requirement. Although the laboratory is quite successful in maintaining interest, the lecture is plagued by poor attendance and lack of commitment. To deal with these issues, I have incorporated an audience response system (as used in America's Funniest Home Videos) and a multiple-choice exam that uses a scratch-off answer system similar to the instant-win lottery tickets. The audience response system facilitates attendance, and both systems provide immediate feedback to questions. Student and faculty assessment will be presented. Technological and pedagogical challenges will be discussed.
Interactive Web-based Plant Identification and Use
Authors: Danielson Helen E. , Wilson Sandra B.
Published: February 2019

University of Florida's Department of Environmental Horticulture offers undergraduate and graduate courses at seven locations throughout the state. To ensure students have access to a sufficient variety of classes, many courses are delivered by distance education. Distance education has significantly expanded student enrollment while unifying lecture content and minimizing duplication of faculty resources. However, delivering hands-on laboratory portions of courses continues to be a challenge, thus necessitating the need for web-based supplemental learning tools. An interactive, web-based tour of the 1-acre Indian River Research and Education Center (IRREC) Teaching Garden was created, allowing students at all distance education sites to learn similar plant material and landscape design principles. The virtual tour was developed by converting digital panoramic images of the landscape to movie files. The movies are navigated using a computer mouse, and plants within the tour are hyperlinked to information sheets highlighting plant characteristics. Although the website was initially developed for a Florida native landscaping course, it can be utilized in other plant identification and landscape courses, as well as by those who wish to virtually explore the garden.
Antioxidant Profile and Contribution to Quality and Nutritional Attributes of Different Pecan Cultivars
Authors: Villarreal J. Emilio , Lombardini Leonardo , Cisneros-Zevallos Luis
Published: February 2019

The objective of this study was to evaluate kernels of different pecan (Carya illinoinensis) cultivars for their antioxidant profile and their contribution to nutritional and quality attributes. Kernels were analyzed for their antioxidant capacity (AC), phenolic, tannin, and vitamin C content. Fatty acid (FA) composition and phenolic profile were determined using, respectively, gas and liquid chromatographic techniques. AC was measured using one spectrophotometrical [2,2-diphenyl-1-picrylhydrazyl (DPPH)] and one fluorescence method [oxygen radical absorbance capacity (ORAC)]. Phenolic and tannin content were determined using spectrophotometrical assays. Ascorbic and dehydroascorbic acid were determined using a HPLC. Both AC methodologies gave similar results with marked differences between cultivars. `Desirable' had an antioxidant capacity of 47,747 μg·g-1 TEq/DW with DPPH method followed closely by `Cheyenne' (36,192 μg·g-1 TEq/DW) and, with smaller amounts, by `Cape Fear' and `Pawnee' (16,540 and 13,705 μg·g-1 TEq/DW, respectively). Total phenolic content showed a similar trend, but `Pawnee' showed a higher phenolic content than `Cape Fear'. The FA composition varied between cultivars. This phenolic profile jointly with FA composition and other compositional characteristics will provide the quality and nutritional attributes of each specific cultivar. Furthermore, the high antioxidant profile of pecans suggests that bioactive and anticancer properties should also be evaluated. Results from the present research can be used as an additional tool to evaluate pecan cultivars and help create new guidelines for breeding programs to select “healthier” pecans.
Citrus Limonoids Induce Apoptosis in Human SH-SY5Y Neuroblastoma Cancer Cells
Authors: Poulose Shibu M. , Harris Edward D. , Patil Bhimanagouda S.
Published: February 2019

Limonoids are triterpinoids unique to citrus and neem trees with potential cancer-preventing properties in animals and human cell lines. Antioxidant activity and apoptotic induction are thought to be the principal effects of citrus limonoids in the antiproliferative properties, but this postulate lacks firm experimental evidence. In this study four highly purified 17 β-D glucopyranosides of citrus, limonin glucoside (LG), obacunone glucoside (OG), nomilinic acid glucoside (NAG), and deacetylnomilinic acid glucoside (DNAG), were tested for their effects against human SH-SY5Y neuroblastoma cells. Neuroblastomas account for 10% of childhood cancers, and in our study the cultured cells were treated with different concentrations and different time intervals. Micromolar levels of LG and OG significantly (P ≤ 0.001) stopped cell growth and induced cell death in 24 hours, but had no adverse effect over Chinese hamster ovary (CHO) cells at the highest toxic level tested. The viability studies were based on trypanblue exclusion and dimethylthiazol diphenyltetrazolium (MTT) reduction assays. The limonoids significantly increased the downstream caspases 3/7 activity (P ≤ 0.005) within 12 hours of treatment, suggesting an explicit role of apoptotic induction, which was confirmed by flow cytometry and DNA fragmentation assays. Highest S phase cell number was reduced by LG, followed by OG, NAG, and DNAG as compared to the known inhibitor camptothecin. Structural variations of limonoids could be ascribed to antioxidant activity. This study strongly supports apoptosis induction as an anticancer mechanism of citrus limonoids. Funded by USDA 2001-52102-11257 and 2004-34402-14768.
The Effect of Community Gardens on Property Crime Rates in Inner City Houston
Authors: Gorham Michelle , Waliczek Tina M.
Published: February 2019

Today, in many of America's major cities, communal gardening projects have not only yielded produce to their participants, but also a plethora of neighborhood success stories, including feelings of wellbeing, safety, and the beautification of acres of vacant land. According to anecdotal evidence, the presence of a community garden can connect people to the earth, nature, and each other, as well as reduce crime. The purpose of this study was to determine if a relationship existed between reported property crimes and the presence of inner city community gardens in Houston, Texas. According to the Houston Police Department, property crimes include vandalism, breaking and entering, and burglary. Crime data for reported property crimes from 1995 through 2004 were obtained from the Houston Police Department. The Houston Police Department divides the city into “beats” and property crime rates were determined for each beat. At least one active community garden was targeted for each police beat. Results for the study compared crime rates within a 1/8-mile radius surrounding the community garden and the property crime rate for the entire police beat. In addition to the evaluation of crime data, community garden members were surveyed for thoughts and opinions pertinent to the presence of their particular community garden.