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  • Author or Editor: D. G. Richardson x
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`D'Anjou' pear (Pyrus communis L.) trees were sprayed with zero or 32.3 mm CaCl2 during fruit development at 55, 86, 125, and 137 d from full bloom and harvested at 85% (immature), 100% (mature), and 110% (overmature) maturity stages. The fruit were stored in air at –1 °C for several periods to determine the effect of CaCl2 treatments on chilling requirement to accomplish ripening during 11 d at 20 °C. Immature or mature unsprayed fruit required 55 d, while the overmature fruit required 40 d at –1 °C to gain the capacity to produce ethylene during ripening at 20 °C. Calcium sprays increased flesh firmness at harvest by 15 N, fruit Ca concentrations by an average of 0.01 mg·g-1, fresh mass basis, and the chilling requirements by at least 15 d. Unsprayed immature fruit contained more Ca than the sprayed mature or overmature fruit, but their chilling requirement was similar. These results suggest that high Ca concentrations may increase the chilling requirement of `d'Anjou' pears in a developmentally related manner.

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To determine the ability of `d' Anjou' pear fruit to produce climacteric ethylene postharvest, fruit were harvested at a mature green stage, chilled at -1 °C for various times, then transferred to 20 °C to ripen. In addition, fruit were first held at 20 °C for various times, then at –1 °C for various durations, followed by transfer to 20 °C for 11 days. As storage time at –1 °C increased from 0 to 70 days, the time required to induce climacteric ethylene when transferred to 20 °C progressively decreased from 90 to 0 days. The total storage time (sum of d at chilling and nonchilling temperature) needed to induce climacteric ethylene remained nearly constant (70 to 90 days). However, this was not the case with fruit held initially at 20 °C, then transferred to –1 °C. The total storage time needed before the pears produced climacteric ethylene ranged from 70 to 110 days and increased with time of storage at 20 °C. These fruit required more time at –1 °C than those first stored at –1 °C. The chilling requirement mechanism of `d' Anjou' pears remains intact even during storage at nonchilling temperature and diminishes with senescence.

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Pear trees (Pyrus communis L.), cv. d'Anjou, received foliar applications of X-77 surfactant and 32.3 mm CaCl2 at 55, 85, 125, and 137 days after full bloom (DAFB) and fruit were harvested at 147 DAFB. Samples of fruit were stored in air either at 20 °C continuously or at 5 or 10 °C for several periods, then transferred to 20 °C, to determine the effects of storage temperature and CaCl2 treatments on the development of the ethylene climacteric and flesh firmness loss. Control fruits held continuously at 20 °C required 70 days for the onset of climacteric ethylene production, which commenced when firmness had decreased to ≈20 N. Calcium-sprayed fruit required 80 days at 20 °C before the rise in ethylene and resisted softening for ≈50 days. Regardless of calcium treatment, pears stored at 5 or 10 °C required only 40 days to produce climacteric ethylene; fruit softening and internal ethylene concentration after storage at 10 °C were intermediate between those of fruits stored at 5 and 20 °C. Calcium application did not alter the sequence of ripening events.

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Abstract

Diurnal leaf and fruit water Potentials (Ψ) of sweet cherry (Prunus avium L.) showed that fruit pedicel Ψ was always lower at 6 AM then leaf Ψ but leaf Ψ as usually lower during the day. Varietal differences in Ψ occur but fruit maturity does not appear to have an effect. Minimum fruit pedicel Ψ was reached at about 2 PM and then recovered to the earlier higher Ψ as water uptake occured during the night.

Open Access

Abstract

Chlorogenic acid and arbutin reduced spore germination of Penicillium expansum Lk. ex Thom, and mycelial growth of Mucor piriformis Fischer. Arbutin decreased growth of Botrytis cinerea Per ex Fr. However, chlorogenic acid increased both germination and growth of B. cinerea.

Open Access

Kernel oil content increased while moisture content decreased during development. Oil concentration of varieties was between 59.6% and 67%, at harvest and the major lipid class was triglycerides. Oleic acid increased from 10% to become the most abundant fatty acid at harvest (74%). Linoleic increased from about 4% to around 30% early in the season but then decreased although it finally represented a high proportion of total fatty acids (19-22%). Total vitamin E increased as oil content increased. α-tocopherol was the major form of vitamin E and its concentration increased to around 400μg/g oil throughout the season and was almost 90% of total vitamin E. β-tocopherol was only a minor constituent and decreased from the beginning to around 10-20 μg/gm of oil at the end. Γ-tocopherol increased during the first stage of growth and then decreased during the second and third stages.

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Abstract

Alfalfa greening, (green stain, green mottle, or superficial cork) is a physiological disorder of ‘Anjou’ pear fruit, Pyrus communis L. This disorder is characterized by green streaks, blotches, and specks on the skin occurring most frequently at the stem end; it may also extend to the calyx end where superficial cork is also frequently present. Mineral analysis of the peel and whole fruit of alfalfa greening-affected fruit indicated that the disorder was associated with higher nitrogen, potassium, and phosphorus content but lower calcium levels than normal fruit.

Open Access

Oil content, fatty acid and vitamin E composition of seventeen varieties of hazelnuts, thirteen types of nuts, and seven different oil seeds were determined as part of a larger study on Hazelnut kernel quality. Alpha-tocopherol was the predominant (90%) tocopherol in all hazelnut varieties. In other nuts α- and Γ-tocopherols were predominant Delta-tocopherol was found in some kinds of nuts but it was not found in hazelnuts. All four kinds of tocopherols were found in oil seeds and tocotrienols were found in some. Hazelnuts are a rich source of α-tocopherol. Oil concentration varied among hazelnut cultivars and ranged from a low of 57.9% in Hall's Giant to 67% in Tombul. Macadamias were the highest in oil content (76.9%). Oleic acid and linoleic acid comprised more than 90% of the fatty acid composition in most nuts.

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