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include symptomology descriptions, images of the disorders, and reference tissue concentrations. Mealy-cup sage (Lamiaceae family) is a bedding annual planted by gardeners to provide color during the summer ( Armitage, 2001 ). Few nutrient disorders have

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Mealy blue sage ( Salvia farinacea var. farinacea Benth) is an attractive wildflower native to a wide range in the southern United States, including Texas, New Mexico, and Oklahoma ( Correll and Johnston, 1970 ; Diggs et al., 1999 ). Mealy blue

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) of the fruit, whereas in stored and soft fruit, cells were separated at the middle lamella without any damage (cell-to-cell debonding) ( Harker et al., 2002 ). Mealiness, which is characterized by texture deterioration, resulting in soft and dry fruit

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firmness long after harvest and have good storage capability ( Tong et al., 1999 ; Yoshida et al., 1998 ), the fruit of ‘Red Delicious’ and ‘Golden Delicious’ become mealy ( Hampson and Kemp, 2003 ) and soften rapidly when harvested late. Softening has not

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of fruit flesh, researchers found that mealy-textured apple fruits had dry granular structures with decreased intercellular adhesion ( Brummell et al. 2004b ; Li et al. 2020 ). Using transmission electron microscopy, it was also found that the middle

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Changes in flesh firmness and mealiness during storage were investigated in 24 apple [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] cultivars and selections (genotypes) up to 40 days after harvest under 20 ± 2 °C and 85% ± 5% relative humidity storage conditions. Flesh firmness was measured using a penetrometer, while mealiness was quantified by measuring the degree of cell separation in tissue induced by shaking discs of tissue in a sucrose solution. According to the relationship between the change in firmness and mealiness, the genotypes can be divided into four groups: those that did not soften and remained hard and nonmealy during storage; those that softened without mealiness; those that softened with slight mealiness; and those that softened with mealiness. Firmness decreased below 30 N in fruit that softened with mealiness, and the minimum firmness during storage was correlated with the degree of mealiness at 30 days of storage. The rate of softening was the highest in fruit that softened with mealiness. Therefore, it was concluded that, by measuring the firmness and changes in firmness that take place during storage, the genotypes resulting in softening with mealiness and those that result in softening without mealiness could be identified.

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`Huangjin' peaches were harvested at immature, mature, and over-mature stages according to ground color and firmness evaluations, and were stored at 0, 5, and 10 °C, respectively. After 4 weeks of cold storage, immature fruit developed a higher percentage of leatheriness but a lower level of mealiness than mature fruit. Over-mature fruit did not develop leatheriness, but developed a higher percentage of mealiness than mature fruit. Fruit stored at 5 °C developed more mealiness than fruit stored at 0 °C for the same period of storage, while fruit stored at 0 °C developed more leatheriness than fruit stored at 5 °C. When stored at 10 °C, fruit did not develop any leatheriness or mealiness regardless of maturity. Compared with juicy and mealy fruit after the same period of cold storage, fruit with leathery symptoms were significantly firmer following 4 days at 20 °C. 1-Aminocyclopropane-1-carboxylate oxidase (ACO) activity, 1-amino-cyclopropane-1-carboxylic acid (ACC) content, and polygalacturonase (PG) and β-galactosidase (GAL) activity were lower, and insoluble pectin content was higher, in leathery fruit than that in juicy and mealy fruit. Mealy fruit were as soft as juicy fruit after ripening at 20 °C for 4 days. Their ACO, PG, and GAL activity; ACC; and insoluble pectin content were similar. Results indicated that leatheriness is a typical chilling injury but mealiness is not.

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The peach mutation `Stony Hard' confers a slow softening attribute to the fruit and also confers a highly reproducible predisposal of fruit to soften abnormally to a mealy texture. Induction of mealiness required continuous 48-hour 100-ppm ethylene exposure. `Stony Hard' fruit exposed to low ethylene concentrations (l ppm) or discontinuous 100 ppm ethylene softened more rapidly than fruit exposed to ethylene-free air but to a normal texture. Ethylene treatment failed to induce mealiness in selections without the `Stony Hard' gene. As quantitative methods for assessment of mealiness, mesocarp-extractable juice decreased, and buffer soluble solids and soluble polysaccharide galacturonic acid content increased for mealy fruit. `Stony Hard' peach fruit represent the only known system in which the concentration and duration of exposure to ethylene can be used to manipulate softening and textural properties of the fruit. Supported by U.S. Dept. of Agriculture grant 93-34150-8409 and the Oklahoma Agricultural Experiment Station.

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Previous work by our group has demonstrated the potential feasibility of using high-temperature forced-air (HTFA) treatment for insect disinfestation of nectarines. Fruit quality of nine cultivars tested was unaffected following the application of a HTFA treatment targeted against Mediterranean fruit fly. In an extention of this work, we examined the effect of this treatment on peach and nectarine cultivars that have differing reported susceptibilities to the development of mealiness to determine if HTFA treatment has any effect on the occurrence of this disorder. Fruit were exposed to HTFA over 4 h until the fruit center registered a temperature of 47.2 °C, then stored at 5 °C for 1 to 3 weeks and 2 d at 23 °C, at which time the fruit were visually evaluated for symptoms of mealiness. `Summer Bright', `Ryan Sun', and `Elegant Lady', cultivars susceptible to the development of mealiness, showed a 66%, 24%, and 66% increase in the incidence of mealiness, respectively, due to HTFA treatment. `Summer Grand', a cultivar classified as nonsusceptible, did not develop mealiness in the absence of HTFA treatment, while 81% of the HTFA-treated fruit of this cultivar were classified as mealy following 2 weeks of storage. Enhancement of mealiness in stonefruit by heat is a very detrimental effect that must be carefully considered in the development of HTFA treatments for these commodities.

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`Elegant Lady', `O'Henry' and `September Sun' peaches [(Prunus persica (L.) Batsch (Peach Group)] and `Summer Bright' and `Summer Grand' nectarines [(Prunus persica (L.) Batsch f. nucipersica (Nectarine Group)] heated to a seed surface temperature of 47.2 °C over a period of 4 hours developed mealy flesh sooner and to a much greater extent than nonheated fruit following cold storage at 5 °C for 1 to 3 weeks. Exo- and endopolygalacturonase activities were reduced following 3 to 4 hours of heating and may have been responsible for the increased mealiness. Mealiness often developed in defined regions rather than throughout the entire fruit. Comparison of juicy and mealy regions within individual fruit revealed that mealy regions contained 65% and 86% less exo- and endopolygalacturonase activity, respectively, than juicy regions, whereas pectinmethylesterase activity was unchanged. Extractable protein was reduced by >50% in the mealy regions of the fruit. Intermittent warming periods of 24 hours at 20 °C at weekly intervals during storage at 5 °C were less effective in reducing mealiness in heat-treated than in control fruit. It is important that future work with heat treatments and stone fruit closely monitor potential effects on this disorder to avoid loss of market quality following treatment.

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