intercellular space (Pa); R, ideal gas constant (Pa·1·mol -1 ·K -1 ); T, temperature (K); V i.s., volume of intercellular space (1); V mt, O 2 mass-transfer rate (mol·kg -1 ·h -1 ); V res, respiration rate (mol·kg -1 ·h -1 ); w, weight of fruit (kg
G. Andrich, R. Fiorentini, A. Tuci, A. Zinnai and G. Sommovigo
D.R. Rudell, D.S. Mattinson, J.K. Fellman and J.P. Mattheis
`Fuji' apple (Malus ×domestica Borkh.) fruits were harvested periodically prior to and during fruit ripening. Ethylene evolution and respiration rates of skin, hypanthial, and carpellary tissue was determined in each fruit. Additionally, whole fruits were used for analyses of internal ethylene concentration, volatile evolution, starch content, flesh firmness, and soluble solids content. Ethylene production was greatest in the carpellary tissue at all sampling dates except the one occurring just before the rise in whole fruit internal ethylene concentration, when production in the skin and carpellary tissue was similar. Respiration was always highest in the skin, in which the climacteric rise was most drastic. Higher ethylene production in the carpellary tissue of pre- and postclimacteric fruit and higher respiration in the skin tissue, including a noticeable climacteric rise, is indicative of a ripening initiation signal originating and/or transduced through the carpels to the rest of the fruit.
B.B. Boynton, C.A. Sims, M.O. Balaban, M.R. Marshall, B.A. Welt and J.K. Brecht
Cantaloupes (Cucumis melo) in three separate trials were cut into 1-inch cubes and irradiated at 0, 0.25, 0.5, 0.75, 1.0, 1.25, or 1.5 kGy; 0, 0.1, 0.2, 0.3, 0.4, 0.5, or 0.7 kGy; and 0, 0.3, 0.6, or 0.9 kGy, respectively. They were then stored in air at 3 °C for up to 20 days, and respiration rate, measured as carbon dioxide (CO2) production, microbiological counts [total plate count (TPC) and yeast and molds], texture, and color were measured during storage. Respiration rates were initially higher in irradiated cantaloupe. After 8 days, respiration was similar between irradiated and control fruit. Irradiation moderated increases in respiration in a dose-dependent manner. Highest irradiation doses resulted in initial TPC reductions of 1.5 log compared to the non-irradiated controls, and also prevented the 2.5 to 3 log TPC increases seen in controls after 10 to 11 days of storage. Texture differed on day 1, when controls were most firm, but irradiation maintained greater firmness than controls after day 7. Irradiation of fresh-cut cantaloupe has potential for shelf life extension and for integration with modified atmosphere packaging systems.
Peter M.A. Toivonen, Frank Kappel, Sabina Stan, Darrell-Lee McKenzie and Rod Hocking
A convenient and reliable method that used a specially designed tool to apply a uniform bruising force in situ was developed to assess the relative susceptibility to fruit surface pitting in sweet cherry. Assessment of pitting with a visual scale after 2 weeks of 1 °C storage was found to be in close agreement with measurements of pit diameter. Using this method `Bing' showed the greatest susceptibility to pitting in both years of the study and `Bing', `Lapins', and `Sweetheart' cherries showed a decline in susceptibility as fruit matured. The predictive value of fruit firmness at harvest, fruit respiration at harvest, and weight loss in storage was assessed in relation to the severity of pitting. The model to best describe pitting was found to include all three physiological variables (firmness, respiration, and weight loss). While an acceptable model was obtained when combining all three cultivars, the best models were achieved when each cultivar was considered separately. It was concluded that there are likely unmeasured variables involved in determining susceptibility to pitting. Hence the best approach to predicting pitting susceptibility is the application of the pit-induction method described in this work.
R.E. Myers, D.E. Deyton and C.E Sams
Dormant `Georgia Belle' peach [Prunus persica (L.) Batsch.] trees were sprayed in early February 1992 with single applications of 0%, 2.5%, 5.0%, 10.0%, or 20.0% (v/v) crude soybean oil. `Redhaven' trees were sprayed in February 1993 with single applications of 0%, 2.5%, 5.0%, 10.0%, or15% degummed soybean oil. Additional treatments of two applications of 2.5% or 5.0% oil were included each year. Both crude and degummed soybean oil treatments interfered with escape of respiratory CO2 from shoots and increased internal CO2 concentrations in shoots for up to 8 days compared to untreated trees. Respiration rates, relative to controls, were decreased for 8 days following treatment, indicating a feedback inhibition of respiration by the elevated CO2. Thus, an internal controlled atmosphere condition was created. Ethylene evolution was elevated for 28 days after treatment. Flower bud development was delayed by treating trees with 5% crude or degummed soybean oil. Trees treated with 10% crude or degummed soybean oil bloomed 6 days later than untreated trees. Repeated sprays of one half concentration delayed bloom an additional four days in 1992, but < 1 day in 1993 compared to a single spray of the same total concentration. Application of soybean oil caused bud damage and reduced flower bud density (number of flower buds/cm branch length) at anthesis. In a trial comparing petroleum oil and degummed soybean oil, yields of trees treated with 6% or 9% soybean oil were 17% greater than the untreated trees and 29%more than petroleum treated trees. These results suggest that applying soybean oil delays date of peach bloom and may be used as a bloom thinner.
M.S. Tian, Talebul Islam, D.G. Stevenson and D.E. Irving
Color, ethylene production and respiration of broccoli (Brassica oleracea L. var. italica) dipped in hot water (45 °C, 10 minutes; 47 °C, 7.5 minutes; and 20 °C, 10 minutes as control) were measured. Hot-water treatment (HWT) delayed yellowing. Compared to the control, ethylene production and respiration in broccoli dipped at 45 °C decreased but recovered, and rates of both were enhanced after 24 and 48 hours, respectively, at 20 °C in darkness. There was no recovery of ethylene production or respiration in broccoli dipped at 47 °C. Following HWT of 47 °C for 7.5 minutes, respiration, starch, sucrose, and soluble protein content of florets and stems decreased dramatically during the first 10 to 24 hours after harvest. At the same time, fructose contents in florets and stems increased. Glucose increased in the florets but decreased within 24 hours in stems. Thereafter, glucose and fructose in florets and stems decreased. Sucrose content in florets and stems increased dramatically within a short period of treatment (<10 hours) and then declined. Protein in HWT florets and stems decreased during the first 24 hours and then increased until 72 hours. Ammonia content was lower in HWT broccoli during the first 24 hours and then increased above the level in the controls.
Zhen Shu, Yimin Shi, Hongmei Qian, Yiwei Tao and Dongqin Tang
Chen, 2007 ). Senescence of plant tissues is generally accompanied by respiration increases; breakdown of carbohydrates, proteins, lipids, and nucleic acids ( Singh et al., 2000 ); higher production of reactive oxygen species (ROS) ( Del Rio et al
Christopher B. Cerveny, William B. Miller and Alan G. Taylor
-term R. asiaticus storage. The purpose of this research was to develop a storage protocol for R. asiaticus dried TRs by testing a range of storage moistures and temperatures and observing the influence on respiration and subsequent growth. Materials
Greg McCollum and Pilar Maul
). Eaks (1970) reported that exposure of citrus fruits to ethylene resulted in a temporary and repeatable increase in respiration. Ethylene will also induce abscission of citrus fruits ( Goren, 1993 ). Most notable among the responses of citrus fruits to
Jinmin Fu and Peter H. Dernoeden
injury to plants would be expected to result in an increase in respiration and possibly a reduction in photosynthesis. A concomitant decrease in photosynthesis and increase in respiration could cause a harmful depletion of carbohydrates. Few studies have