In teaching a course in landscape plant materials, the landscape plants which exist on campus are an important and accessible resource. Management of location, health. and cultivar information is critical to optimizing this resource. As a classroom assignment, campus plant materials were inventoried, entered into FileMaker Pro 2.1, a database manager, characterized and assigned locations. The campus map was scanned using a Microtek ScanMaker IIXE and the image imported into MacDraw II. A symbol library, which included symbols for trees, shrubs, and groundcovers, was developed by scanning hand drawn images and then importing them into MacPain. These bit-mapped images could then be duplicated as often as necessary and placed in appropriate locations on the campus map in MacDraw II. In this way, students are exposed not only to landscape plant materials but also to database managers and computer graphics capabilities. This approach also has the advantage that database information can be easily coordinated with physical location. plant materials can be sorted based on their characteristics, and information can be routinely and easily revised and updated.
The increased demand for organic and sustainably grown produce has resulted in a demand for information on organic and biorational fungicides. The efficacy of these fungicides is often not established, yet they are aggressively advertised. In 2005 the efficacy of six organic and biorational fungicides and two controls were evaluated on field-grown red raspberries (Rubus idaeus `Prelude' and `Nova') for gray mold (Botrytis cinerea) management. Phytotoxicity of the fungicide treatments was evaluated on a weekly basis following each fungicide application. Fruit was harvested by hand, sorted into marketable and unmarketable categories and weighed. Subsamples of fruit were evaluated for postharvest disease development. Data analysis showed `Nova' was more susceptible to phytotoxicity than `Prelude'. The application of Phostrol resulted in the highest phytotoxicity rating when compared to all other fungicide treatments. The water spray control, standard fungicide (Captan/Elevate rotation) control, Endorse, and Lime Sulfur treatments resulted in negligible phytotoxity ratings. Applying Milstop, Milstop + Oxidate, and Oxidate + Vigor Cal Phos resulted in similar intermediate phytotoxicity ratings. Differences in marketable yield were nonexistent for the two cultivars and eight fungicide treatments. The predominant diseases observed in the postharvest evaluations were gray mold, blue mold (Penicillium sp.), and rhizopus soft rot (Rhizopus sp.) and/or mucor mold (Mucor sp.). This evaluation will be repeated in 2006.
Changes in phenolic metabolism are induced by minimally processing, which ultimately leads to the browning of lettuce tissue. Phenylalanine ammonia-lyase (PAL, EC 18.104.22.168.) is greatly influenced by storage temperature. Evaluation of PAL activity at temperatures going from 0 to 25 °C showed that peaks occurred sooner at higher temperatures but at lower levels. Heat-shock treatments (50 °C, 90 s) have a protective effect against browning, help to retain greenness of tissue, and decrease the production of phenolics when applied either after or before wounding. To achieve a considerable, beneficial effect from hot water treatments applied after wounding these should not be delayed more than 36 h. The best results for heat-shock treatments before wounding occurred when applied at ≈12 h before cutting the tissue. Although cycloheximide did reduce PAL activity in a similar pattern as heat-shock treatments, it did not prevent browning itself. Cycloheximide seems to cause some sort of chemical damage that promotes the browning of lettuce tissue. When cycloheximide was applied in combination with heat-shock treatments browning did not occur.
Natural plant pigments (produced as secondary metabolites in cell culture) can replace controversial synthetic chemical colorants to enhance the appearance of processed foods. Intensive bioreactor-based production systems designed for betalain pigment-producing cultures of Beta vulgaris are still not economically competitive, in part due to the slow, prohibitively expensive, and incomplete conventional methods (HPLC analysis, biomass estimates, cell counts) which must be used to assess culture status. As an alternative, software was written using Semper 6 (a high level programming language for image analysis) for collection of exacting morphometric (spatial) and photometric (spectral) process information from an intense violet cell line. Uniform, crisp images of 1 ml culture samples in multiwell plates were captured macroscopically, and the pattern of pigment production was traced at 3 day intervals over the course of a 15 day growth cycle with monochromatic color filters and image grey level data. Rod-shaped cells and aggregates were automatically sorted and measured using parameters of particle size, density, and circularity. The machine vision method offers greater opportunity to fine-tune cell selection for enhanced pigment content.
Late dormant copper (Cu) sprays and mid-summer foliar Cu sprays are being promoted within the Washington apple industry as a means to enhance fruit typiness and red skin color, respectively. While there appears to be theoretical bases for these practices, they have not been tested for horticultural significance. Differential late dormant spray treatments of Cu hydroxide (the Cu source most commonly recommended by agricultural consultants) were imposed in two `Delicious' orchards. Flower cluster Cu was positively related to Cu rate, but the sprays had no effect on leaf Cu or on six fruit typiness variables. Differential mid-summer spray treatments of water, Cu sulfate, and Cu oxysulfate solutions were imposed in three `Delicious' orchards and one `Fuji' orchard. The Cu sprays increased leaf Cu, but had no effect on market color grade measured using a commercial color sorter. The results appear to reflect Cu physicochemistry and timing of application. These preliminary results call into question the utility of the Cu sprays for improving apple fruit quality characteristics when trees show no visual signs of Cu deficiency. They do suggest some alternative ways to manage Cu nutrition in deciduous tree fruit orchards.
A video-imaging technique, using commercial software to process images obtained at 550 nm, was established to estimate chlorophyll content of cucumber fruit disks. The chlorophyll content of excised disks was extracted, determined, and regressed on the video-image grey level. They were linearly related. The change in grey level of the whole visible image accurately indicated the change of green color during fruit development on the vine and the loss of green color after 1 week of storage at 13C. The relationship of the chlorophyll content on grey level was quadratic for three imaging methods: 1) average grey level of the five disks; 2) average grey level of the whole cucumber image; and 3) average grey level of central one-third of the whole cucumber image. Chlorophyll content was most highly correlated to the grey level of the disks themselves (residual SD = 6.74 μg·cm-2), but this sampling technique was destructive. Both one-third of the fruit image (SD = 9.25 μg·cm-2) and the whole image (SD = 9.36 μg·cm-2) provided satisfactory precision. For simplicity, whole-fruit imaging is suitable for estimating fruit chlorophyll content and for quantifying fruit green color intensity. Potential use of this technique in product sorting and shelf life prediction of long English cucumbers is discussed.
To examine the feasibility of using a laser Doppler vibrometer (LDV) for fruit quality evaluation, measurements of firmness derived by this method were compared with those acquired using a contact accelerometer. Apples (Malus pumila Miller var. Domestica Schneider `Fuji'), kiwifruit [Actinidia deliciosa (A. Chev.) Liang et Ferguson, `Hayward'], Japanese pear [Pyrus pyrifolia (Burm. f.) Nakai var. Rehd. `Nijusseiki'], and Hassaku (Citrus hassaku Hort. ex Tanaka) were used. Fruit were subjected to sine waves at frequencies from 5 to 2000 Hz at the basal surface, and the vibrations resulting from these transmissions were precisely montitored at the upper surface with a LDV monitor. Measurements on all of the tested single fruit exhibited a distinct phase shift in the applied sine wave and in the responance frequency, dependent on frequency used. These shifts were also detected by an accelerometer, but in this case the range of frequency was restricted to an upper limit of 400 Hz for kiwifruit and 800 Hz for Japanese pear and Hassaku. Efforts to extend the range using a greater vibrational mass with the accelerometer resulted in anomalous tissue behavior, most likely due to excesive compression when the weight exceeded 1 g. Hence firmness measurements of fruit depended on the phase shift and resonance frequency, which were achieved with more precision by LDV than accelerometer. Since LDV measurements of fruit firmness were made without directly contacting the fruit surface, it could be potentially used for on-line quality evaluation and fruit sorting.
Composting of municipal solid waste (MSW) has received renewed attention as a result of increasing waste disposal costs and the environmental concerns associated with using landfills. Sixteen MSW composting facilities are currently operating in the United States, with many more in the advanced stages of planning. A targeted end use of the compost is for horticultural crop production. At the present time, quality standards for MSW composts are lacking and need to be established. Elevated heavy metal concentrations in MSW compost have been reported; however, through proper sorting and recycling prior to composting, contamination by heavy metals can be reduced. Guidelines for safe metal concentrations and fecal pathogens in compost, based on sewage sludge research, are presented. The compost has been shown to be useful in horticultural crop production by improving soil physical properties, such as lowering bulk density and increasing water-holding capacity. The compost can supply essential nutrients to a limited extent; however, supplemental fertilizer, particularly N, is usually required. The compost has been used successfully as a sphagnum peat substitute for container media and as a seedbed for turf production. High soluble salts and B, often leading to phytotoxicity, are problems associated with the use of MSW compost. The primary limiting factor for the general use of MSW compost in horticultural crop production at present is the lack of consistent, high-quality compost.
The landscape plants that exist on the Alabama A&M University, Normal, campus are readily accessible for a plant identification and use course. Managing location, health, and cultivar information is critical to optimizing this resource. As a classroom assignment, campus plants were inventoried; entered into FileMaker Pro 2.1, a relational database manager; characterized; and assigned locations on campus. The campus map was scanned using a Microtek Scanmaker IIxe and the image was imported into MacDraw II. A symbol library, which included symbols for trees, shrubs, and groundcovers, was developed by scanning hand-drawn images and then importing them into MacPaint. These bit-mapped images were duplicated as often as necessary and placed in appropriate locations on the campus map in MacDraw II. Students were exposed to landscape plant materials, database managers, and computer graphics capabilities. This approach has other advantages: database information can be easily coordinated with physical location, plants can be sorted based on their characteristics, and information can be routinely and easily revised and updated. The database is used in the landscape plant materials class as a teaching tool and for self-guided tours.
The possibility of using chlorophyll fluorescence for detecting internal quality of strawberry has been investigated. The mature fruit were marked and stored at 0 and 5 °C for 5, 10, and 15 days. After storage they were placed in the dark for 20 min and fluorescence measurement then was taken at the marked place with a fluorescence probe with a light intensity of 20 μmol·m–2·s–1. Samples were also taken from the marked place for laboratory analysis to determine chlorophyll and total soluble solute content. Firmenss was detected by an Instron Universal Testing Machine taking measurement at the marked section of the fruit. Rot was detected visually. Multiple regression and simple correlation were detected between fluorescence and laboratory-analyzed data. Multiple correlation coefficient (R) ranged from 0.80 to 0.97. Simple correlation (r) ranged from 0.44 to 0.89. The results of this study indicated that chlorophyll fluorescence is capable of detecting internal quality of strawberry and may potentially extend to other fruits. Feasible applications of the method include packinghouse, sorting of fruits, and parent and progeny quality assessment in a strawberry breeding program.