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  • Author or Editor: L. Gillespie x
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Radius of gyration (size), intrinsic viscosity, molecular weight, percentage of galacturonate, and percentage of neutral sugars were measured for chelate-soluble (CSP) and alkaline-soluble (ASP) pectins extracted from the cell walls of melting flesh (MF) and nonmelting flesh (NMF) peach [Prunus persica (L.) Batsch]. Weight percentage of cell walls, pectin content, and firmness were measured also. Peaches were extracted at 20, 21, and 22 weeks after flowering (WAF) and after various lengths of shelf storage at 25 ± 2C for the peaches picked at 21 WAF. Weight percentage of cell walls and firmness decreased markedly between the 21st and 22nd WAF; and between the 3rd and 6th day of storage for MF peaches as compared to NMF peaches. During these same periods, there were marked drops in the pectin content and the uronide content for MF as compared to NMF peaches. Size and intrinsic viscosity dropped markedly for CSP of MF peaches in comparison with NMF peaches during these same periods, whereas the molecular weight of CSP and ASP increased in MF peaches over that measured for NMF peaches. These results suggested that α -D-galacturonase (E.C. 3.2.1.15) was involved in softening only in the latter stages of ripening MF peaches. Further, cell wall polymers containing long thin pectin aggregates were destroyed, whereas cell wall polymers containing short thick pectin aggregates remained.

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The objectives of this research were to mimic the gradient irradiances to which wheat (Triticum aestivum L. cv. SuperDwarf) plants were exposed aboard the Russian space station Mir, and to determine whether these irradiances inhibit growth and floral development. SuperDwarf wheat plants were exposed to irradiances of 20–40, 60–80, 100–120, and 140–180 (PPF = μmol·cm–2·s–1) and grown to maturity. Twenty plants were randomly selected from each irradiance level and chlorophyll, total leaf area, shoot biomass, and total soluble leaf and plasma membrane (PM) proteins were recorded. Irradiance at increasing levels of intensity increased the fresh biomass, leaf area, chlorophyll content, and the total soluble PM and leaf proteins of wheat tissue. There were significant differences between the abaxial and adaxial sides of the wheat leaves in stomatal density, stomatal index, stomatal length and width, and number of stomata along 1-mm length of leaf. These data may be uniquely valuable for further studies of relationships between chlorophyll content, photosynthetic rate, and productivity of wheat grown aboard the Russian space station Mir, space missions of long duration, or future manned space stations to generate oxygen, purify water, remove carbon dioxide, produce food and recycle waste materials. (Supported by NASA Grant NCC 2-831 and the Utah Agr. Expt. Station.)

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Our objectives were to ascertain whether wheat (Triticum aestivum L. cv. SuperDwarf) plants, grown aboard the Russian space station Mir in the microgravity of space, exhibited any plant structure and histochemical changes compared with those ground-based plants grown in Moscow, Russia, and Logan, Utah. Plants were harvested at stages of ontogeny corresponding to day 6, 14, 25, 35, and 55 post-emergence and placed in 4% formaldehyde: 1% glutaraldehyde (4F: 1G) fixative, adjusted to pH 7.2, and stored in Aclam plastic bags. Upon return to earth, samples were dehydrated and embedded in Spurr's resin. Use of differential chromophores on semi-thin sections (1 μm) suggests no major artifacts in cellular structure. Enzyme localizations for lignin, carbohydrate, starch, alkaline and acid phosphatase indicate that plants grown aboard Mir appeared to have less lignin than ground control plants. (Supported by NASA Grant NCC 2-831 and the Utah Agr. Expt. Station.)

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Wheat (Triticum aestivum L. cv. SuperDwarf) plants grown in the microgravity of space aboard the Russian space station Mir and sampled for morphological and anatomical comparison to those ex-posed to gravity on earth will be stored in chemical fixative for relatively long periods of time. Our objective was to examine, evaluate, and verify that the integrity of the vascular system and cellular components of wheat plants is maintained following storage in a chemical fixative. In ground-based studies, wheat seedlings were harvested on days 9, 28, and 68 and preserved in 4% formaldehyde: 1% glutaraldehyde (4F: 1G) fixative, adjusted to pH 7.2. Samples of leaves and/or stems were taken from these stocks after various times in storage (24 h, 1, 6, 12, and 24 months), dehydrated, and embedded in Spurr's resin. Semi-thin (1 μm) and thin (50–70 nm) sections were examined by light and transmission electron microscopy. Overall, there seems to be no major artifacts in the cellular structure. The plasmalemma and other organelles appeared normal in this fixative. Use of differential chromophores suggests that enzyme localizations at both the light and electron microscopical levels are not adversely affected by long-term storage. (Supported by NASA Grant NCC 2-831 and the Utah Agr. Expt. Station.)

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Wheat (Triticum aestivum L. cv. SuperDwarf) plants grown in the microgravity of space aboard the Russian space station Mir and sampled for morphological and anatomical comparison to those ex-posed to gravity on earth will be stored in chemical fixative for relatively long periods of time. Our objective was to examine, evaluate, and verify that the integrity of the vascular system and cellular components of wheat plants is maintained following storage in a chemical fixative. In ground-based studies, wheat seedlings were harvested on days 9, 28, and 68 and preserved in 4% formaldehyde: 1% glutaraldehyde (4F: 1G) fixative, adjusted to pH 7.2. Samples of leaves and/or stems were taken from these stocks after various times in storage (24 h, 1, 6, 12, and 24 months), dehydrated, and embedded in Spurr's resin. Semi-thin (1 μm) and thin (50–70 nm) sections were examined by light and transmission electron microscopy. Overall, there seems to be no major artifacts in the cellular structure. The plasmalemma and other organelles appeared normal in this fixative. Use of differential chromophores suggests that enzyme localizations at both the light and electron microscopical levels are not adversely affected by long-term storage. (Supported by NASA Grant NCC 2-831 and the Utah Agr. Expt. Station.)

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