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- Author or Editor: A. Altman x
Chemical analysis of chloride in seeds of 11 species and varieties of citrus (on their own roots) showed marked differences in chloride content. The concentration of chloride in the seeds was directly related to known concentrations of chloride in leaves of the same varieties, and to the order of their appearance in a list of “salt tolerance”. No significant differences were found in the chloride content of seeds from one variety upon 5 rootstock varieties. Similarly, no effect of salinized irrigation water on the chloride content of the seeds could be detected. Fractionation analysis of the seeds of 2 varieties (low and high in chloride content) revealed that in both varieties about 15–20% of the total chloride was present in the aqueous supernatant (“cell sap”). In the low-Cl seeds, 42% of the total CI was found in the aqueous residue and 43% in the benzenic fraction (fats). The corresponding fractions in the high-Cl seeds were 74% and 6%, respectively.
Continuous postharvest treatment of carnation flowers (Dianthus caryophyllus L. cv. Elliot's White) with 50 or 100 mM aminotriazole significantly extended useful vase life relative to flowers held in distilled H2O. No morphological changes symptomatic of floral senescence appeared in treated flowers until 12 to 15 days after harvest. The longevity of aminotriazole-treated flowers was extended to ≈18 days. The respiratory rate of aminotriazole-treated carnations was suppressed, and they exhibited no respiratory climacteric throughout the period of observation. The responsiveness of aminotriazole-treated flowers to exogenous ethylene appeared temporally regulated. Flowers treated with 50 mM aminotriazole for 2 days senesced in response to application of 10 μl exogenous ethylene/liter, whereas flowers treated for 24 days exhibited no morphological response to ethylene treatment. Chemical name used: 3-1H-amino-1,2,4-triazole-1-yl (aminotriazole).
Sim-type carnation flowers (Dianthus caryophyllus L., cv. Elliot's White) continuously treated with 50 mM or 100 mM 3-amino-1,2,4-triazole (amitrole) and held in the dark at 18°C did not exhibit a respiratory climacteric relative to dH2O-treated controls. No morphological changes symptomatic of floral senescence appeared in treated flowers until 12-15 days post-harvest. Other triazoles were not effective in prolonging senescence. Amitrole appears to inhibit ethylene biosynthesis by blocking the enzyme-mediated conversion of S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylate. Ethylene action appears to be progressively inhibited in that flowers held in treatment solution for 2 d or less responded to application of 10 uL/L exogenous ethylene whereas flowers held 10 d or longer exhibited no response. Electrophoretic resolution of total crude extracts evidenced protein synthesis as well as degradation. Western analysis and total activity assays showed an amitrole concentration-specific inhibition of catalase activity.
Treating `Elliott's White' cut carnations with 50 or 100 mm aminotriazole for 4 days inhibits the respiratory climacteric and significantly extends vase life. Aminotriazole induced time- and concentration-dependent inhibition of ethylene evolution and onset of the ethylene climacteric by inhibiting ACC synthase activity. Flowers treated with 50 or 100 mm aminotriazole for 2 days exhibited concentration-dependent increases in ethylene evolution, respiratory activity, ACC synthase activity, and petal ACC content in response to the application of exogenous ethylene at 10 μl·liter-1. Senescence-associated morphological changes, increased ACC synthase activity, ACC content, and ethylene evolution were completely inhibited in flowers treated for 4 days with 100 mm aminotriazole. Although treatment with 50 mm aminotriazole for 4 days did not completely inhibit components of the ethylene biosynthetic pathway, no morphological or respiratory responses to the application of exogenous ethylene at 10 μl·liter-1 were observed, a result indicating that prolonged aminotriazole treatment inhibited ethylene action. Chemical names used: 3-1H-amino-1,2,4-triazole-1-yl (aminotriazole), 1-aminocyclopropane-1-carboxylic acid (ACC).
Morphological changes during development of cultured citrus explants (Citrus sinensis (L.) Osbeck cv. Shamouti) were observed with a scanning electron microscope (SEM). Prophylls of resting buds, covered with epidermal hairs, were closely appressed until the growth of a new shoot; they then expanded. The addition of 10-5 m 6-benzylaminopurine to the medium resulted in the formation of several adventitious buds, surrounded by multiple prophylls, in the axil of the petiole. Abscission of the petiole from the explant involved formation of a separation zone with no evidence of new dividing cells, or active cell division and formation of callus tissue in the abscission zone.
Differences in aperture area and frequency of stomata on fruits of two muskmelon (Cucumis melo L.) genotypes were determined by computerized image analysis of photomicrographs obtained by microrelief techniques. Acetate impressions of surface cellular features on polar and equatorial regions of the fruit were viewed by phase contrast microscopy, and photomicrographs of random fields of stomata were made. A minicomputer-based image processor scanned each photomicrograph and digitized the image of individual stomata. The image was displayed on a monitor and a digitizing tablet was used to mark end points on the axes of an ellipse circumscribing the effective aperture. A FORTRAN image processing system calculated the area of each ellipse. Resulting data showed a significantly lower stomatal aperture area and stomatal frequency on the surface of fruits of the netted genotype.