Search Results

You are looking at 1 - 10 of 15 items for

  • Author or Editor: M.E Patterson x
Clear All Modify Search

Abstract

‘Bartlett’ pears (Pyrus communis L.) were kept in cold storage in air, and at CO2 concentrations of 5, 10, 15, and 20%. The mitochondrial fraction from the fruit pulp was extracted periodically, made into acetone powder and assayed for activity of succinic dehydrogenase. Progressive decreases in activity of the enzyme were observed with increases in CO2 concentration in the storage atmosphere.

Open Access

Abstract

‘Barttett’ pears (Pyrus communis L.) were stored in air or 10% CO2 at 0°C for 90 days. Electronmicroscopy study of the core, representing the ovary tissue confined by the inner concentric vascular bundles, revealed extensive ultrastructural alterations of various membranous systems in CO2-treated fruit, including the mitochondria, the plastids, the tonoplast and the cytoplasm. These alterations in protoplasmic membranes accompanying CO2 treatment suggest loss in cellular organization and may explain the injurious effect of CO2 in fruit.

Open Access

Table grapes cvs. Flame Seedless, Black Monukka and Canadice and blueberries cvs. Bluecrop and Northland were exposed to chlorine dioxide (C102) gas under laboratory conditions. Chlorine dioxide was generated chemically. Grapes were fumigated in a plexiglass chamber with C102 for 30 minutes, packed in TKV lugs with Botrytis inoculum planted among the clusters and stored at 0° C for 8 weeks. Blueberries were consumer packed with 5, 10, and 15 gr. Absorb (C102 generator) in Tyvex sachets, enclosed in pillow-pak bags and stored at 0° C for 75 days and at 20 or 30° C for 16 days.

At periodical intervals, moisture loss, decay and quality parameters were evaluated. Chlorine dioxide caused bleaching and skin injury around the capstem on blueberries but not on grapes. Decay was reduced with C102 treatment but moisture loss increased in blueberries. We could store grapes for two weeks without fungal growth. Storage for longer periods necessitated treatment with higher concentrations of C102 which were not generated under our laboratory conditions.

Free access

Abstract

When the water content of cherries (Prunus avium L.) was increased by more than 5% of the initial weight following immersion in distilled water, the force to bioyield (FBY) and the maximum slope of a compression curve (slope 2) decreased, and impact-induced surface pitting increased. When water content of cherries was decreased by more than 2% of the initial weight following dehydration, FBY increased and the minimum slope of a compression curve (slope 1) and impact-induced surface pitting decreased. Force to bioyield and slope 1 and 2 increased with an increase in fruit turgor potential (ψp) and a decrease in fruit osmotic potential (ψπ). There was a slight positive correlation between fruit water potential (ψ) and FBY and slope 1. Fruit texture changed diurnally, corresponding to changes in fruit ψ. This diurnal texture change, however, was largely a response to diurnal differences in fruit temperature.

Open Access

Abstract

The resistance of sweet cherries to compression damage as measured by the fruit firmness variables, [force to bioyield (FBY), slope of a compression curve, and maximum and residual forces of a compression-relaxation curve] decreased linearly with increasing fruit temperture. The incidence of impact-induced surface pitting decreased linearly as fruit temperature increased. The rate of decrease in impact damage per degree increase in fruit temperature was a function of the cultivar, contact surface, and drop height.

Open Access

Table grapes cvs. Flame Seedless, Black Monukka and Canadice were fumigated with 2 levels of Deccodione smoke tablets for 30 minutes. Grapes were packed in TKV lugs with Botrytis inoculum planted among the clusters and stored at 0° C for up to 9 weeks. Size of smoke particles was determined. Fruit was evaluated at weekly intervals for decay and quality parameters. Deccodione residues on fruit were determined and found to be within acceptable limits set for this chemical. It was possible to store the grapes for up to 4 weeks at 0° C in good condition. Beyond this period effect of fumigation was lost. There was no bleaching of pigments around the capstem as is seen with sulfur dioxide fumigation. Storage for prolonged periods will necessitate increasing the dose of Deccodione tables and/or repeating the fumigation.

Free access

Abstract

Sweet cherry (Prunus avium L.) flower and pistil weight at anthesis decreased at late bloom times. Fruit from early-opening flowers remained larger through harvest and developed higher soluble solids and color than fruit from flowers than opened later. Time of anthesis was delayed and fruit color and soluble solids decreased linearly as flower or fruit location progressed basipetally on one- and 2-year-old wood.

Open Access

Abstract

Ethylene production of 470 ‘Hi-Early Red Delicious’ apples harvested from primary, secondary, tertiary, etc., branches of 4 uniform trees of Malus domestica Borkh. was measured to determine pattern of ripening in relation to fruit position on the tree. Considerable variation was noted between and within branches. Some fruits showed surprisingly high ethylene (about 200 ppm at 155 days and up to 500 ppm at 160 days after full bloom) while others measured less than 5 ppm. Regression analysis revealed a linear trend between primary branches from base to apex of the tree. Delayed ethylene production of fruits below terminal shoots suggests ripening regulators in shoot tissue are interacting to delay ethylene synthesis.

Open Access

Abstract

Changes in firmness, protein, color, respiration, cellulase, and polygalacturonase were followed during maturation and ripening of tomatoes, Lycopersicon esculentum L., on the plant and in detached fruit allowed to ripen at 20°C. Cellulase activity in the young fruit increased steadily during the maturation period. Cellulase activity in detached fruit ripened at 20°C increased rapidly during the onset of ripening and reached a higher level than in fruit ripened on the plant. Polygalacturonase activity was not detectable in developing fruit until after the fruit had initiated ripening. Polygalacturonase activity in detached fruit ripened at 20°C did not appear until the onset of the climacteric and then increased rapidly. This corresponded to the polygalacturonase activity in fruit allowed to ripen on the plant.

The changes during ripening appeared to follow a pre-determined pattern. Grow-regulating substances only moderately affected the onset of the climacteric rise, but markedly influenced the time interval to reach the climacteric peak. They also markedly affected the rate of the normal sequence of changes during ripening. Such changes as softening, color formation, and enzyme activities of cellulase and polygalacturonase were accelerated by ethephon and SADH and delayed by gibberellic acid and indoleacetic acid. Gibberellic acid suppressed polygalacturonase activity. After 14 days polygalacturonase activity in the control fruit was 25 times greater than in fruit treated with gibberellic acid. Cellulase activity in gibberellic acid treated fruit increased steadily during this period. The loss of firmness in treated fruit suggests that softening is initiated by action of cellulolytic enzymes and that pectinolytic enzymes are involved in subsequent changes in texture.

Open Access

Abscission, an active process resulting in the removal of an organ from the main body of a plant, occurs naturally in response to pathogens, disease, or when the plant part is no longer needed. Several delayed abscission mutants have been identified from the Univ. of Wisconsin T-DNA tagged mutant populations in Arabidopsis thaliana. One of the identified mutants, dab 5-1, is characterized by a delay in abscission causing the floral organs to remain attached past position ten; however, all other plant functions are normal. dab 5-1 has been thought to be involved in the secretory pathway. The present study was conducted to further characterize dab 5-1 expression at the cellular, tissue, and organelle levels using reporter gene constructs, light microscopy, scanning electron microscopy, and RT PCR. dab 5-1 expression was found in the roots, root tips, cotyledons, meristem, abscission zone, and anthers. Early abscission can lead to loss in yield and quality and we believe that understanding genes such as DAB5 will ultimately lead to crop improvement.

Free access