Law Rome Research Articles

APPLE SCALD DEVELOPMENT AND REGULATION

We have compared changes in α-farnesene and conjugated trienols, as well as gene expression, in scald-resistant cultivars, e.g., 'Gala' and 'Braeburn', and in scald-sensitive cultivars, e.g., 'Granny Smith', 'Delicious' and 'Law Rome'. We also carried out similar comparisons in 'Granny Smith' between controls and treatments that diminish scald symptoms, e.g., low O 2 and 1-methylcyclopropene (1-MCP). The data show that the initiation of the C 2 H 4 climacteric plays a crucial role in scald development, since treatments that retard the onset of the climacteric, e.g., low O 2 and 1-MCP, also inhibit symptoms of scald development. Furthermore, if either low O 2 or 1-MCP is applied after the initiation of the C 2 H 4 climacteric, their inhibitory effects on scald development decrease. The treatments that retard the C 2 H 4 climacteric onset also strongly inhibit the rise in α-farnesene and conjugated trienols. In 'Granny Smith' apples, we studied the effect of temperature on scald development, as well as changes in the content of α-farnesene and conjugated trienols. The data show that, at temperatures above 7°C, scald failed to develop but the rise in α-farnesene and conjugated trienols was not affected. It should be noted that in scald-resistant cultivars stored at 1°C there was an increase in both α-farnesene and conjugated trienols, though not as high as in sensitive cultivars. However, if the auto-oxidation of α-farnesene and trienols is the cause of scald disorder, their levels in the resistant cultivars ought to have been sufficient for the induction of the disorder. It is thus obvious that low temperature must induce enzymes that create the scald-causing compounds. We observed that the concentration of malondialdehyde (MDA) increased only in the areas showing scald symptoms, which in turn indicates that oxidative processes were involved in scald development. Alternatively, in the resistant cultivars the anti-oxidant capacity may be higher than in the sensitive ones. In short, the data show that in addition to cultivar type, low temperature and the induction of the C 2 H 4 climacteric play a crucial role in scald development.

The Man of Law's Tale and Rome

This essay examines Rome and materialism in Chaucer's Man of Law's Tale. Opening with a reflection on place/thing associations in American modernist poetry, especially Eliot's "Prufrock," this essay argues that the tale locates Rome in a world of both Mediterranean trade as well as devotional commerce to critique image-based devotion, offering Custance as a foil to "dead" images. From the outset the tale associates Rome with commerce—or place and things—as it draws on a reformist tradition that condemned Rome for the traffic in indulgences and relics. Writing at the time of the papal schism, Chaucer concludes the tale with a picture of Rome, as in the Second Nun's Tale, as a renewed papal home.

‘Law Rome’ and ‘Golden Delicious’ Apples Differ in Their Response to Preharvest and Postharvest 1-Methylcyclopropene Treatment Combinations

Experiments were conducted to compare the effects of different preharvest and postharvest 1-methylcyclopropene (1-MCP) treatment combinations on ‘Law Rome’ and ‘Golden Delicious’ apple fruit. Preharvest 1-MCP sprays had minimal effects on maturity as determined by flesh firmness, starch index, internal ethylene concentration, and soluble solids concentration. Fruit internal ethylene concentration and firmness loss after 30- to 40-days storage at 0 °C plus 7 days at 20 °C were reduced by preharvest and postharvest 1-MCP treatments. The positive effects of preharvest 1-MCP on postharvest quality of ‘Law Rome’ declined in fruit that were harvested 3 days or more after spraying, whereas preharvest 1-MCP continued to have a positive effect on postharvest fruit quality of ‘Golden Delicious’ that were harvested up to 9 days after spraying. The loss in postharvest effects of preharvest 1-MCP treatment on ‘Law Rome’ at delayed harvests was reinstated by exposing fruit to gaseous 1-MCP on the day of harvest. These findings suggest that attached apple fruit of some cultivars may be capable of rapidly generating new ethylene receptors.

Superficial scald control after delayed treatment of apple fruit with diphenylamine (DPA) and 1-methylcyclopropene (1-MCP)

The effects of delayed treatments of diphenylamine (DPA) and 1-methylcyclopropene (1-MCP) on superficial scald development of ‘Cortland’ and ‘Law Rome’ apples were examined. Fruit were stored in air at 0.5 °C for 24 weeks after being treated with DPA or 1-MCP at harvest or after delays of 1, 7, 14 or 21 d (‘Law Rome’, experiment 1) or at harvest or after delays of 3, 7, 14 or 21 d (‘Cortland’ and ‘Law Rome’, experiment 2). Inhibition of scald development was affected by cultivar, DPA concentration, and delays between harvest and either DPA or 1-MCP application. Loss of scald control was associated with increasing internal ethylene concentrations (IEC) in the fruit with greater time delays before treatment, but to a greater extent for 1-MCP than DPA. DPA effects on scald development were independent of α-farnesene accumulation in the fruit skin but were associated with inhibition of its oxidation as indicated by lower concentrations of conjugated trienols (CTols). In contrast, 1-MCP effects were dependent on inhibition of α-farnesene accumulation and thereby the availability of less substrate for oxidation. The results show that minimal delays between harvest and treatment of fruit with either DPA or 1-MCP are necessary to maximize control of scald, but may be more critical for 1-MCP than for DPA.

Preharvest 1-Methylcyclopropene Delays Fruit Maturity and Reduces Softening and Superficial Scald of Apples During Long-term Storage

Three experiments were undertaken to evaluate the effects of different preharvest 1-methylcyclopropene (1-MCP) spray treatments on apple (Malus × domestica Borkh.) fruit maturity at harvest and quality after long-term storage in a regular atmosphere or controlled atmosphere (CA). Trees were sprayed within 7 days of the anticipated harvest date (H) and fruit for long-term storage were sampled at either H in the case of ‘Law Rome’ or at harvest dates that were delayed by up to 21 days (H + 21) in the case of ‘Golden Delicious’ and ‘Law Rome’. Preharvest 1-MCP sprays within 7 days of H reduced fruit drop, internal ethylene concentration, and starch index and reduced firmness loss during long-term storage of fruit at delayed harvest dates but had only minor effects on fruit maturity at H. Preharvest 1-MCP sprays reduced the incidence of superficial scald on ‘Law Rome’ apples more effectively than either diphenylamine or CA storage. Application of 1-MCP within 7 days of H may be used to delay harvest date, thereby allowing continued fruit growth without a concomitant advance in fruit maturity and to reduce firmness loss and superficial scald during long-term storage both for normal and delayed harvests.

Ethylene and α-Farnesene Metabolism in Green and Red Skin of Three Apple Cultivars in Response to 1-Methylcyclopropene (1-MCP) Treatment

Relationships among alpha-farnesene synthesis and oxidation, ethylene production and perception, antioxidative enzyme activities, and superficial scald development in fruit of three commercial apple cultivars were investigated at the biochemical and gene transcriptional levels. Scald-susceptible Cortland and Law Rome and scald-resistant Idared apples were untreated or treated with the ethylene action inhibitor 1-methylcyclopropene (1-MCP) and stored for up to 25 weeks at 0.5 degrees C. Separate blushed (red) and unblushed (green) peel tissue samples were taken at harvest and after 2, 4, 6, 10, 15, 20, and 25 weeks of storage. Large increases in peel tissue concentrations of alpha-farnesene and its conjugated trienol (CTol) oxidation products occurred in untreated Cortland and Law Rome and were about 4-9-fold greater than those in Idared. In both Cortland and Law Rome, accumulation of CTols in green peel was nearly twice that in red peel. 1-MCP treatment delayed and attenuated alpha-farnesene and CTol accumulation in each cultivar. Activities of peroxidase (POX) and catalase (CAT) were lower in red peel than in green peel, with the exception of CAT in Law Rome, whereas no effects of 1-MCP on enzyme activities were detected except for Cortland. In control fruit, internal ethylene concentrations (IECs) increased during the first 4-6 weeks to reach highest levels in Cortland, intermediate levels in Law Rome, and low levels in Idared. In 1-MCP-treated fruit, IECs increased gradually to modest levels by 25 weeks in Cortland and Law Rome but were almost nil in Idared. Expression patterns of the alpha-farnesene synthase gene MdAFS1, the ethylene receptor gene MdERS1, and the ethylene biosynthetic genes MdACS1 and MdACO1 were generally in accord with the patterns of alpha-farnesene and ethylene production. In particular, MdAFS1 and MdACS1 showed similar patterns of expression in each cultivar. Among the controls, transcript levels increased more rapidly in Cortland and Law Rome than in Idared during the first few weeks of storage. In 1-MCP-treated fruit, transcript abundance in Cortland and Law Rome rose to untreated control levels after 10-15 weeks but remained low in Idared. Scald symptoms were restricted to unblushed skin, and the incidence in controls after 25 weeks was nearly 100% in Cortland and Law Rome compared with 1% in Idared. 1-MCP treatment reduced scald incidence to 14, 3, and 0% in Cortland, Law Rome, and Idared, respectively. Overall, the results support the proposed role of CTols in scald induction and indicate that alpha-farnesene synthesis is tightly regulated by ethylene. However, gene transcription alone does not account for the big differences in ethylene and alpha-farnesene production in Cortland, Law Rome, and Idared apples.

Cultivar Effects on Quality of Fresh Cut Apple Slices from 1-Methylcyclopropene (1-MCP)-Treated Apple Fruit

ABSTRACT: The effects of 1 -methylcyclopropene (1 -MCP) treatment of whole fruit on the subsequent quality and shelf-life of fresh-cut apple slices have been investigated. ‘Delicious,’ Empire, ‘Idared’, Law Rome, and ‘Mutsu’ apples were treated at 0.5°C with 1 μL/L of 1 -MCP for 24 h and stored in air 1 and 4 mo before being used for preparation of slices. 1-MCP reduced internal ethylene concentrations and maintained firmness of the whole fruit in‘Delicious,’ Empire, and ‘Idared’, but not consistently for ‘Law Rome’ and ‘Mutsu.’ Slices prepared from fruit of cultivars that responded to 1 -MCP had lower ethylene production rates and were firmer than those from untreated fruits. However, 1-MCP treatment did not consistently affect the extent of browning or aroma volatile concentrations. In cultivars in which treatment of apples with 1-MCP at harvest maintained the original fresh quality of intact fruit by suppressing ethylene production, fruit were firmer, and thus a superior fresh- cut product with an extended shelf-life potential was obtained. However, in general, slices prepared from untreated and 1-MCP-treated fruit deteriorated at similar rates.

Expression of α-farnesene synthase gene AFS1 in relation to levels of α-farnesene and conjugated trienols in peel tissue of scald-susceptible ‘Law Rome’ and scald-resistant ‘Idared’ apple fruit

Abstract Nontreated control and 1-MCP-treated fruit of the scald-susceptible ‘Law Rome’ and scald-resistant ‘Idared’ cultivars were compared with respect to scald incidence, internal ethylene concentration (IEC), α-farnesene metabolism, and expression of the gene encoding α-farnesene synthase ( AFS1 ), the final, rate-limiting enzyme in the α-farnesene biosynthetic pathway. The incidence of scald in nontreated ‘Law Rome’ apples after 20 weeks at 0.5 °C plus 1 week at 20 °C averaged 86%; 1-MCP treatment reduced increases in IEC and reduced the incidence of scald to less than 1%. Fruit of ‘Idared’ showed no scald regardless of the treatment. 1-MCP also inhibited α-farnesene production, suggesting that ethylene induces transcription of key genes involved in α-farnesene biosynthesis. In both ‘Law Rome’ and ‘Idared’, a sharp increase in AFS1 mRNA during the first 4–8 weeks of storage preceded a proportional rise in α-farnesene and a subsequent increase in CTols. However, maximum levels of AFS1 transcript, α-farnesene, and CTols were, respectively, 2.5-, 4-, and 33-fold greater in ‘Law Rome’ than in ‘Idared’ apples. 1-MCP suppressed the increases in AFS1 transcript and α-farnesene early in storage, although AFS1 expression and α-farnesene synthesis had recovered in treated ‘Law Rome’ fruit after 20 weeks, consistent with increasing IEC in these fruit.

Expression of Alpha-farnesene Synthase Gene AFS1 in Relation to Levels of Farnesene and Conjugated Trienols in Peel Tissue of Scald-susceptible `Law Rome' and Scald-resistant `Idared' Apple fruit

Fruit of different apple cultivars vary widely in susceptibility to superficial scald. The genetic and biochemical factors involved in this variation are unknown. Conjugated trienol (CTol) oxidation products of alpha-farnesene have been linked with scald induction, and a high rate of farnesene synthesis in peel tissue of scald-prone apples early in storage is often associated with development of the disorder. Pre-storage treatment of apple fruit with 1-methylcyclopropene (1-MCP) inhibits the early burst of farnesene production and prevents scald, suggesting that ethylene induces transcription of genes involved in farnesene synthesis. We recently cloned a gene from apple peel tissue, AFS1, which encodes alpha-farnesene synthase, the last enzyme in the farnesene biosynthetic pathway. In this study, expression of AFS1 was compared in scaldsusceptible Law Rome (LR) and scald-resistant Idared (IR) apples at harvest and over 20 weeks of storage at 0.5 C. AFS1 transcript levels were closely correlated with accumulation of farnesene and CTols. In fruit of both cultivars, a sharp increase in AFS1 mRNA during the first 4 to 8 weeks of storage preceded a proportional rise in farnesene and a subsequent increase in CTols. However, maximum levels of AFS1 transcript, farnesene, and CTols were, respectively, 2.5-, 4-, and 33-fold greater in LR than in IR apples. Treatment of fruit with 1-MCP at harvest suppressed the increases in AFS1 transcript and farnesene early in storage, but AFS1 expression and farnesene synthesis recovered in LR fruit after 20 weeks. Scald incidence in LR apples after 20 weeks at 0.5 °C plus 1 week at 20 °C averaged 86%, whereas IR fruit had no scald. 1-MCP treatment reduced scald incidence in LR to <1%.

Cloning and functional expression of an ( E, E)-alpha-farnesene synthase cDNA from peel tissue of apple fruit.

Increased production of terpenes and many other aroma-related volatiles occurs with the onset of ripening in apple ( Malus domestica Borkh.) fruit. The gaseous plant hormone ethylene plays a key role in the induction of volatile synthesis, but the mechanism is not yet understood. Using a degenerate primer based on a short conserved sequence shared by several sesquiterpene synthases, reverse transcription-polymerase chain reaction with RNA isolated from peel tissue of 'Law Rome' apples yielded an approx. 800-bp gene fragment. This was used to screen a cDNA library generated from the peel tissue mRNA. A full-length terpene synthase (TS) cDNA 1,931 nucleotides long was isolated. The 1,728-bp open reading frame encodes a protein 576 amino acids long with a molecular mass of 66 kDa. Sequence analysis of the apple TS showed it to be most similar to several monoterpene synthases. Oddly, the TS includes an RR(X(8))W motif near the N-terminus that is common among monoterpene synthases but it lacks the plastid transit peptide sequence typically associated with genes of that group. Expression of the apple TS gene in Escherichia coli gave myc-epitope-tagged and untagged proteins estimated at approx. 68 and approx. 66 kDa, respectively. In assays of sesquiterpene synthase activity, with farnesyl diphosphate as substrate, the untagged bacterially expressed TS gene product synthesized ( E, E)-alpha-farnesene almost exclusively. In monoterpene synthase assays, with geranyl diphosphate as substrate, the untagged apple TS produced only ( E)-beta-ocimene, albeit at much reduced levels. Addition of a C-terminal myc tag appeared to completely prevent production of soluble protein under all of the expression conditions tested. This is the first report of an ( E, E)-alpha-farnesene synthase gene ( AFS1; GenBank accession number AY182241) from a flowering plant. RNA gel blots showed that AFS1 transcript increased about 4-fold in peel tissue of apple fruit during the first 4 weeks of storage at 0.5 degrees C. In contrast, when fruit were treated at harvest with 1-methylcyclopropene, a blocker of ethylene action, AFS1 mRNA declined sharply over the initial 4 weeks of cold storage, and fell to nearly undetectable levels by 8 weeks.

Church Law and Church Order in Rome and Byzantium: A Comparative Study by Clarence Gallagher (Birmingham Byzantine and Ottoman Monographs 8) Ashgate, Aldershot 2002. Pp. xi + 279, £45.00 hbk

Book reviewed in this article:CHURCH LAW AND CHURCH ORDER IN ROME AND BYZANTIUM: A Comparative Study by Clarence GallagherTHE ETHICS OF COMMUNITY by Frank G. Kirkpatrick (New Dimensions to Religious Ethics Series)TRANSCENDENT EXPERIENCE: Phenomenology and Critique by Louis Roy OPTHE PLACE OF GOD IN PIERS PLOWMAN AND MEDIEVAL ART by Mary Clemente Davlin OPHISTORY OF THE WORLD CHRISTIAN MOVEMENT, vol.1 EARLIEST CHRISTIANITY TO 1453 by Dale T. Irvin and Scott W. Sunquist

Chemicals, Timing, and Environmental Factors Involved in Thinner Efficacy on Apple

HORTSCIENCE, VOL. 37(3), JUNE 2002 Fallahi, E., M. Kilby, and J.W. Moon. 1990. Effects of various chemicals on dormancy, maturity and thinning of peaches. Deciduous Fruit and Nut. University of Arizona, College of Agr. Rpt., Ser. P-83, p. 121–128. Fallahi, E., R.R. Lee, and G.A. Lee. 1998. Commercial-scale use of hydrogen cyanamide for blossom thinning of apple and peach. HortTechnology 8:556–560. Fallahi, E., B.R. Simons, J.K. Fellman, W.M. Colt. 1992. Use of hydrogen cyanamide for apple and plum thinning. Plant Growth Regulat. 11:435–439. Fallahi, E., M.W. Williams, and W.M. Colt. 1997. Blossom thinning of ‘Law Rome Beauty’ apple with hydrogen cyanamide and monocarbamide dihydrogensulfate. J. Tree Fruit Prod. 2:33–44. Ferree, D.C. 1996. Performance of benzyladenine as a chemical thinner on eight apple cultivars. J. Tree Fruit Prod. 1:33–50. Greene, D.W. 1984. Microdroplet application of GA4+7 + BA: Sites of absorption and effects on fruit set, size, and shape of ‘Delicious’ apples. J. Amer. Soc. Hort. Sci. 109: 28–30. Greene, D.W., K.I. Hauschild, and J. Krupa. 2001. Effect of blossom thinners on fruit set and fruit size of peaches. HortTechnology 11:179–183. Greene, D.W. and W.J. Lord. 1985. Effects of chemical thinners on ‘Delicious’ apple trees previously sprayed with GA4+7 +BA. HortScience 20:84–86. Hildebrand, E.M. 1944. The mode of action of the pollenicide, Elgetol. Proc. Amer. Soc. Hort. Sci. 45:53–58. Johnson, S. 1998 Consistent tonnage needed for profitability. Good Fruit Grower 49(7):9–10. Looney, N. 1998. Chemical thinning of ‘Fuji’ apple. Compact Fruit Tree. Proc. Annu. Conf. Intl. Dwarf Tree Assn. 30:55–57. Sanderson, P. 1998. Consistent tonnage needed for profitability. Good Fruit Grower 49(7):9-10. Southwick, S.M., K.G. Weis, J.T. Yeager, and M.E. Rupert. 1998. Blossom thinning of ‘Loadel’ cling peach with a surfactant: Effects of concentration, carrier volume, and differential applications within the canopy. HortTechnology 8:55–58. Taylor, J. 1998. Consistent tonnage needed for profitability. Good Fruit Grower 49(7):9-10. Williams, K.M. 1998. Blossom thin for consistent crops. Good Fruit Grower 49(7):8. Williams, M.W. 1993. Comparison of NAA and carbaryl petal–fall sprays of apples. HortTechnology 3:428–429. Williams, M.W. 1994. Factors influencing chemical thinning and update on new chemical thinning agents. Compact Fruit Tree 27:115–122. Williams, M.W. and Edgerton. 1981. Fruit thinning of apples and pears with chemicals. U.S. Dept. Agr., Agr. Bul. 289.

Superficial Scald, Carbon Dioxide Injury, and Changes of Fermentation Products and Organic Acids in `Cortland' and `Law Rome' Apples after High Carbon Dioxide Stress Treatment

`Cortland' and `Law Rome' apples [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] were either nontreated or treated with the inhibitor of superficial scald development, DPA, and exposed to air or CO2 (40 or 45 kPa) in air at 2 °C for up to 12 days. Fruit exposed to air or 45 kPa CO2 were sampled during treatment, and peel and flesh samples taken for fermentation product and organic acid analyses. After treatment, fruit were air stored for up to 6 months at 0.5 °C for evaluation of disorder incidence. `Cortland' apples were most susceptible to external CO2 injury and `Law Rome' to internal CO2 injury. DPA treatment markedly reduced incidence of both external and internal injury. Fermentation products increased in peel and flesh of both cultivars with increasing exposure to CO2, but the extent of the increase was cultivar dependant. Acetaldehyde concentrations were about 10 times higher in peel and flesh of `Law Rome' than that of `Cortland' apples. Ethanol concentrations in the flesh were similar in both cultivars, but were about twice as high in `Cortland' than in `Law Rome' peels. Neither acetaldehyde nor ethanol concentrations were affected consistently by DPA treatment. Succinate concentrations, often regarded as the compound responsible for CO2 injury, increased with CO2 treatment, but were not affected by DPA application. Citramalate concentrations were reduced by CO2 treatment in `Law Rome' peel, but other acids were not consistently affected by CO2. Results indicate that acetaldehyde, ethanol or succinic acid accumulation are not directly responsible for CO2 injury in apples. Chemical name used: diphenylamine (DPA).

Carbon Dioxide Effects on Metabolism of Two Apple Fruit Cultivars

Susceptibility of apple fruit to CO2 can be affected by cultivar and postharvest treatment with diphenylamine (DPA). To study possible metabolic reasons for CO2 injury development, `Cortland' and `Law Rome' apple fruit were either untreated or treated with DPA at harvest, and then exposed to air or 45 kPa CO2 for up to 12 days. Fruit were sampled at 3-day intervals during treatment, and peel and flesh samples were taken for organic acid and fermentation product analysis. Additional fruit were removed to air and stored for 25 weeks for evaluation of injury. `Cortland' apple fruit had more external CO2 injury, but less internal CO2 injury than `Law Rome'. DPA treatment markedly reduced incidence of both external and internal injury. Fermentation products increased in peel and flesh of both cultivars with increasing exposure to CO2. However, acetaldehyde concentrations were ≈10 times higher in peel and flesh of `Law Rome' than `Cortland' apples. Ethanol concentrations in the flesh were similar in both cultivars, but were about twice as high in `Cortland' than `Law Rome' peel. Neither acetaldehyde nor ethanol concentrations were affected consistently by DPA treatment. Cultivar or DPA treatment did not affect accumulation of succinate, often regarded as the compound responsible for CO2 injury. These results do not indicate that acetaldehyde, ethanol, or succinate accumulation is responsible for CO2 injury in apple fruit.

439 Cultivar Variation in Response to 1-Methylcyclopropene Application to Apple Fruit in Air and Controlled-atmosphere Storage

The inhibitor of ethylene binding, 1-methylcyclopropene (1-MCP) has been applied to `Gala', `Cortland', `McIntosh', `Empire', `Delicious', `Jonagold', and `Law Rome' apples under air and/or controlled atmosphere (CA) storage conditions. 1-MCP gas concentrations ranged from 0 to 2 mL·L–1. Effects of 1-MCP were greater in CA than air storage. A dose response of internal ethylene concentrations and flesh firmness to 1-MCP was found in cultivars such as `McIntosh' and `Law Rome', whereas in others, such as `Delicious' and `Empire', ripening was generally prevented by all 1-MCP concentrations. We have further investigated the effects of 1-MCP on `McIntosh' by increasing rates of the chemical to 50 mL·L–1, and confirming that fruit of this cultivar respond poorly if fruit have entered the climacteric prior to 1-MCP application. Efficacy of 1-MCP is affected by cultivar and storage conditions, and that successful commercial utilization of the chemical will require understanding of these relationships.

116 Preharvest Fruit Drop Studies, Harvest Quality, and Cold Storage of `Golden Delicious' and `Rome' Apples

Combinations of aminoethoxyvinylglycine (AVG, ReTain) and NAA gave better control of fruit drop of `Golden Delicious' than either alone. When the full rate of ReTain (50 g/A) was compared to a reduced rate of ReTain (86 g/ha) plus NAA, equivalent control of fruit drop of `Golden Delicious' resulted. ReTain delayed softening and starch depletion of `Golden Delicious' fruit. NAA in some cases promoted earlier fruit maturity; but when used in combination with ReTain, maturity was similar to ReTain-treated fruit. Fruit with the highest firmness and starch came out of cold storage in the best condition. Neither 1-methylcyclopropene (MCP, EthylBloc) or NAA inhibited fruit drop of `Golden Delicious' fruit when applied at harvest; but previous ReTain and NAA data indicate that late applications are frequently much less effective than if applied 4 weeks before harvest. Ethephon spray treatments caused more rapid and extensive fruit drop than the control. Trees gassed or sprayed with EthylBloc before ethephon sprays also dropped rapidly. `Golden Delicious' fruit on the tree were dramatically maintained firmer by the EthylBloc gas, and to a lesser extent by EthylBloc sprays by 19.1 N and 10.2 N firmness, respectively, tested on 28 Oct. Starch was maintained by the EthylBloc gas, but not by the sprays. These data indicated that EthylBloc applied as a gas or spray did have a physiological affect but did not control fruit drop. Fruit diameter, soluble solids and color did not appear to be affected. Further study of earlier applications of EthylBloc or combinations with fruit drop control agents may be needed to get fruit drop control. NAA plus Silwet L-77 inhibited fruit drop of `Law Rome', but none of the EthylBloc sprays inhibited fruit drop when applied at harvest. Previous data with ReTain and NAA indicated that late applications are frequently much less effective than if applied 4 weeks before harvest. EthylBloc sprays applied 21 Oct. dramatically maintained fruit firmness tested on 3 Nov. Starch was not maintained by the EthylBloc gas, but starch had almost disappeared by the application time on 21 Oct. Fruit diameter, soluble solids, and color did not appear to be affected. Further study of earlier applications of EthylBloc may be needed to demonstrate fruit drop control. Shading trees with 92% polypropylene shade material for 3 or 7 days caused more rapid fruit abscission at 7 days than 3 days and both were greater than the control.

Responses of early, mid and late season apple cultivars to postharvest application of 1-methylcyclopropene (1-MCP) under air and controlled atmosphere storage conditions

The potential for commercial application of 1-methylcyclopropene (1-MCP) to maintain quality of ‘McIntosh’, ‘Empire’, ‘Delicious’ and ‘Law Rome’ apples under air and controlled atmosphere (CA) storage conditions was investigated. These cultivars represent early, mid and late season apples with ripening rates ranging from fast to slow. 1-MCP gas concentrations used were 0.5, 1 and 2 m ll 1 , generated from measured amounts of Ethylbloc™ powder. Fruit of each cultivar were removed from storage at 6 week intervals during 30 weeks in air, or at 8 week intervals during 32 weeks in CA, and evaluated after 1 and 7 days at 20°C. Effects of 1-MCP were greater in CA than air storage. A dose response of internal ethylene concentrations and flesh firmness to 1-MCP was found in ‘McIntosh’ and ‘Law Rome’, but ‘Delicious’ and ‘Empire’ ripening was generally prevented by all 1-MCP concentrations. 1-MCP reduced superficial scald incidence, and accumulations of a-farnesene and conjugated trienols during air storage. The results indicate that the efficacy of 1-MCP is affected by cultivar and storage conditions, and that successful commercial utilization of the chemical will require understanding of these relationships. © 2000 Elsevier Science B.V. All rights reserved.

Hypobaric storage removes scald-related volatiles during the low temperature induction of superficial scald of apples

Abstract ‘Law Rome’ and ‘Granny Smith’ apples were stored hypobarically in air at 5 kPa total pressure and also in air or controlled atmosphere (CA) at 1.5 or 3% O2 with 0 or 3% CO2, for 8 months at 1°C. Fruit were placed under hypobaric storage immediately after harvest or after 0.5, 1, 2, 3, 4, 5 or 6 months storage in air at 1°C to determine the effects of delaying imposition of hypobaric storage on ripening and scald development and on the production of α-farnesene and its oxidation product 6-methyl-5-hepten-2-one (MHO). If fruit were placed under hypobaric conditions within 1 month after harvest, scald did not develop. After a 3-month delay, scald development was similar to that for fruit stored continuously in air. Both cvs. produced MHO which accumulated in their epicuticular wax when fruit were placed under hypobaric storage after a 1-month or more delay in air. MHO which had partitioned in the epicuticular wax of fruit stored hypobarically after 2 or more months delay was released upon transfer of fruit to atmospheric pressure of 20°C; MHO accumulated and/or was produced in direct proportion to the delay prior to hypobaric storage. In another experiment with five apple cvs., the production rates of α-farnesene and MHO were low during hypobaric storage, but upon removal of fruit from storage after 7 months, the rates increased over a 7 day period in air at 20°C and then sharply decreased afterward. After storage, α-farnesene and MHO production rates were similar and high for ‘Law Rome’, ‘Mutsu’, ‘Red Delicious’ and ‘Golden Delicious’ apples and were the lowest for ‘Granny Smith’. Scald did not develop on any hypobarically stored fruit whereas it did on all cvs. except ‘Golden Delicious’ stored in air. It was proposed that hypobaric ventilation removes a scald-related volatile substance that otherwise accumulates and partitions into the epicuticular wax of fruit stored in air at atmospheric pressure.

Initial low oxygen stress controls superficial scald of apples

The effectiveness of initial low oxygen stress (ILOS) to control apple scald without postharvest application of scald inhibitors and fungicides was investigated. Scald susceptible (‘Granny Smith’, ‘Law Rome’, ‘Red Delicious’) and not susceptible (‘Idared’) fruits were harvested preclimacterically and treated at 1°C with (1) ILOS pretreatment or (2) no pretreatment as control. Fruit were then stored at 0.5–1°C in 3% O 2 with 0% CO 2 , 1.5% O 2 with 3% CO 2 , or 0.7–0.8% O 2 with 3% CO 2 in flow-through controlled atmosphere (CA) or in air. ILOS of 0.5 and 0.25% O 2 for 2 weeks resulted in excellent control of scald when fruits were subsequently held in CA (3% O 2 , 0% CO 2 ). Initial treatment with 0.25% O 2 for 2 weeks, and when this treatment was supplemented with an additional 2 weeks of low O 2 stress after 2 months of storage, were more effective treatment regimens for scald control than all other treatments. ILOS followed by CA storage at 1.5% O 2 gave complete control of scald. A commercial test of initial low O 2 stress confirmed its efficacy for controlling scald in several cultivars of apples. The production of α-farnesene and its volatile oxidation product 6-methyl-5-hepten-2-one (MHO) was inhibited by initial low O 2 stress treatments and 1.5% O 2 CA. The 0.25% O 2 initial stress treatment caused stronger inhibition of α-farnesene and MHO production than 0.5% O 2 initial stress treatment. The accumulation of MHO was related to scald development of apples.

Effects of irradiation on respiration and ethylene production of apple slices

Respiration and ethylene production rates of irradiated apple slices from four apple cultivars were measured for 72 h. Doses less than 1.2 kGy had no effect on rates of CO2 production and O2 consumption, and irradiation at doses between 1.2 and 2.4 kGy had minimal effect for all cultivars. Respiratory response of ‘Idared’, ‘Law Rome’ and ‘Empire’ slices to irradiation was curvilinear, with maximum respiration occurring in the 3–6 kGy dose range. Response of ‘Delicious’ slices was linear over the irradiation dose range (0–11 kGy) studied. Respiratory quotient increased with irradiation dose. The degree of maturity of the slices affected respiratory responses. Irradiation reduced ethylene production of all slices. These results suggest that irradiation doses of up to 2.4 kGy can be used with minimum effect on the respiratory physiology of tissues. © 2000 Society of Chemical Industry