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W.G. van Doorn

1 Senior scientist; e-mail: . The concentrations of reducing sugars and polysaccharides in the mucilage fractions were determined by Yuan Zhong, and the sucrose concentrations by Erik Schaap. The cost of publishing this

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Candelario Mondragon-Jacobo, Natalia Doudareva, and Bruce P. Bordelon

A method for extraction of high quality DNA from four Opuntia sp. and other cacti using a hexadecyltrimethylammonium bromide (CTAB) method is described. These plants typically contain high levels of mucilages, complex polysaccharide compounds that bind water, thus preventing DNA extraction by common miniprep methods. The method involves adjusting the amount of tissue used according to species and age, followed by processing in an extraction buffer to separate coarse material. Extended centrifugation and digestion time in a separation buffer with CTAB (2%) was used. Exposing tissue to both buffers maintained polysaccharides in solution and allowed easier recovery of the aqueous phase that contains the DNA. We found that 5-8 g were needed to obtain up to 153 μg·g-1 of DNA from tender tissue. Old tissue yielded 26% less. Extraction of DNA from 5-g samples of tender tissue of the ornamental cacti Stenocereus sp., Cleistocactus sp., and Echinocereus sp. was successful. For these species, average yields ranged from 25 to 53 μg per sample. The DNA obtained was suitable for polymerase chain reaction (PCR) amplification, producing clear, distinctive, and reproducible banding patterns useful for a variety of applications.

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Jack B. Fisher, Anders Lindström, and Thomas E. Marler

– I ; = 200 μm in D and J – N ; = 100 μm in E ; ruler divisions in millimeters in C . ( A ) C. edentata surface of trunk 24 h after cutting with drops of mucilage; three to four rings of vascular tissue present at this level of stem. ( B ) Cut

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Harry C. Bittenbender, Loren D. Gautz, Ed Seguine, and Jason L. Myers

Fermentation is a necessary step in the processing of cacao for chocolate ( Sukha and Seguine, 2015 ). Fermentation of the mucilage-covered beans is initiated by naturally present microorganisms such as yeasts, acetic and lactic acid forming

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Lawford Baxter and Luther Waters Jr.

Pods of okra (Abelmoschus esculentus L. Moench) stored in an atmosphere of 5% O2 and 10% CO2 at 10 ± 1C were compared with pods stored in air at the same temperature to determine the effects of storage environment on physical characteristics and ethylene evolution of the pods. Controlled-atmosphere-(CA) stored pods lost less weight, retained total solids and chlorophyll better, and had a higher mucilage viscosity than air-stored pods. Toughness, fibrousness, and incidence of microbial decay were lower in CA-stored pods than in air-stored pods. No differences were seen in the levels of alcohol-insoluble solids or discoloration of the cut surface between pods from the two storage environments. Ethylene evolution was lower in CA- than air-stored pods.

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William J. Carpenter and Joseph F. Boucher

The optimum conditions for priming pansy (Viola × wittrockiana) seeds were in aerated osmotic solutions of polyethylene glycol 8000 (PEG 8000) at – 1.0 MPa for 7 days at 15C. Priming at – 0.8 MPa and 15C caused 8% to 26% of seeds to germinate during 4 to 13 days of priming. Increasing numbers of abnormal seedlings developed when priming was extended beyond 7 days. Final germination percentages were better in laboratory studies at 35C for primed (51%) than nonprimed (10%) seeds. Removal of the mucilage released by the seed with 240 g KOH or 170 g NaOH/liter for 15 or 30 seconds during priming did not affect total germination percentages, but did improve seed handling. Primed seed had higher, faster, and more uniform germination than nonprimed seeds after sowing in growing medium in plant growth chambers or greenhouses.

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Avinoam Nerd, Fania Gutman, and Yosef Mizrahi

Fruit growth and ripening and the effect of various storage temperatureson fruit quality were studied in Hylocereus undatus and H. polyrhizus growing in Beer-Sheva (Israeli Negev desert) under greenhouse conditions. Dimensional growth of the fruit had a sigmoid pattern with a negligible growth after the onset of peel color change. The first change in peel color was recorded 24-25 d after anthesis in H. undatus and 26-27 d after anthesis in H. polyrhizus. In both species, peel color turned fully red 4-5 days after first color change (mean temperature for the study period was 26.6 ± 2.1 °C). Parallel to color changes the content of pulp, SSC and soluble sugars increased while firmness and the content of starch and mucilage decreased. The surge in acidity before color change indicated the beginning of ripening processes. In H. polyrhizus fruit, which have a red-violet pulp, the pigment increased in parallel to the development of peel color. The fruit were proved nonclimacteric, and when harvested at close to full color, they kept their marketing quality at least 2 weeks at 14 °C or 1 week at 20 °C. Storage at 6 °C is not recommended because fruit transferred from 6 °C to room conditions lose their firmness and flavor rapidly. In H. undatus chilling injury symptoms appeared.

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Shigenori Yaguchi, Tetsuya Nakajima, Toshihisa Sumi, Naoki Yamauchi, and Masayoshi Shigyo

, 1999 ). Therefore, several genes related to pectin biosynthesis may be concentrated on chromosomes 7A and 8A. In A. fistulosum , mucilage, which are well-hydrated gels of cellulose, hemicellulose, and pectin, accumulated in the winter leaf blade

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Santiago García-Martínez, Adrián Grau, Aranzazu Alonso, Fernando Rubio, Manuel Valero, and Juan J. Ruiz

and firm texture, a high proportion of seeds and mucilage, and are strongly flavored. Fruits weigh between 75 and 125 g, varying from elongated-oval to bell shape with dark green shoulders and without ribs. However, like most tomato landraces, De la

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Santiago García-Martínez, Adrián Grau, Aranzazu Alonso, Fernando Rubio, Pedro Carbonell, and Juan J. Ruiz

‘De la pera’ is a tomato landrace that is very popular in a limited area in southeastern Spain. The fruits from this landrace are juicy and have a firm texture, a strong flavor, and a high proportion of seeds and mucilage. The fruit weight ranges