Leaves of tomato and barley were inoculated with conidia of Blumeria graminis f. sp. hordei race 1 (R1) or Oidium neolycopersici (KTP-01) to observe cytological responses in search of resistance to powdery mildew. Both conidia formed appressoria at similar rates on tomato or barley leaves, indicating that no resistance was expressed during the prepenetration stage of these fungi. On R1-inoculated tomato leaves, appressoria penetrated the papillae, but subsequent haustorium formation was inhibited by hypersensitive necrosis in the invaded epidermal cells. On the other hand, KTP-01 (pathogenic to tomato leaves) successfully developed functional haustoria in epidermal cells to elongate secondary hyphae, although the hyphal elongation from some conidia was later suppressed by delayed hypersensitive necrosis in some haustoriumharboring epidermal cells. Thus, the present study indicated that the resistance of tomato to powdery mildew fungi was associated with a hypersensitive response in invaded epidermal cells but not the prevention of fungal penetration through host papilla.
The deterioration mechanism of ferric ferrocyanide (Fe 4 [Fe(CN) 6 ] 3 ・xH 2 O) which is called Prussian blue, used as a blue pigment in Ukiyo e printed in late Edo period, has been investigated. The two Ukiyo e of the same design differ in their degree of deterioration; one print has good color, but the other is seriously discolored. The conditions of their blue areas are compared. The composition of the Ukiyo e color pigments are analyzed by EDS (Energy Dispersive X ray Spectroscopy). FT IR (Fourier Transform infrared Spectrometer) is used to identify the functional group in the chemical compound. Areas of good blue color in the Ukiyo e contain Fe, which is the main element in ferric ferrocyanide. In the FT IR spectra, the absorption peak of around 2090 cm -1 corresponding to the CN triplet combination of ferric ferrocyanide (Fe 4 [Fe(CN) 6 ] 3 ・xH 2 O) is recognized. The Fe concentration in the faded blue area in the discolored sample is reduced to one third that in the nondiscolored sample at the same position. The peak corresponding to the CN group has disappeared. A non discolored sample is subjected to accelerated ageing under the condition of high temperature and high humidity (353 K, 65rh). The peak intensity of reflectivity in the aged sample decreases gradually with ageing.
AbstractPaper is often damaged by ink or pigments containing transition metal ions. Damage of Kozo paper (a kind of Japanese paper) caused by iron ions from Prussian blue pigments (iron ferrocyanide) or by the acidity of dilute sulfuric acid during artificial ageing was studied. The degradation induced by iron ions is suggested to be a synergistic process consisting of hydrolytic and oxidative reactions. The degradation state of the cellulose polymer in Kozo paper was investigated using fluorescence labeling of carbonyl and carboxyl groups in combination with gel permeation chromatography-multiple-angle laser light scattering. In addition to cellulose, Kozo paper contains a relatively large amount of hemicellulose, which was characterized by determination of uronic acid and neutral carbohydrates. The amount of carboxyl groups in Kozo paper decreased during ageing. A decrease in the amount of uronic acid originating from the hemicellulose in Kozo paper is considered the dominant factor in the observed decrease of total carboxyl contents, even if the oxidative reaction would increase the number of carboxyl groups. The amount of uronic acid and xylose in hemicellulose was influenced by iron ions during ageing, indicating the decomposition of hemicellulose. This result suggested that the hemicellulose in Kozo paper were affected first and prevented the hydrolytic and oxidative degradation of cellulose, which might enable Kozo paper to last longer.
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