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Abstract
Primordial leaves of Japanese persimmon (Diospyros kaki L. cv. Jiro) were excised from dormant buds and cultured on Murashige and Skoog medium with the nitrates reduced to half strength (MS½N) and supplemented with 0.1 to 10.0 µm zeatin + 0.1 to 10.0 µm IAA. After 40 days of culture in the dark, yellowish-white calli were formed at 10.0 µm zeatin + 1.0 µm IAA. When these calli were transferred to MS½N medium supplmented with zeatin (1.0 to 10.0 µm) + IAA (0 to 10.0 µm), 24% of them produced adventitious buds at 10.0 µm zeatin + 0.1 µm IAA under a 12-hr photoperiod. Further shoot growth occurred on the same medium without IAA. Basal ends of the shoots were quick-dipped in 1.25 mm IBA and placed on half-strength MS½ N medium. Nearly two-thirds of the dipped shoots rooted within 30 days. Plantlets regenerated in vitro were then transferred to a mixture of 1 peat: 1 perlite: 1 vermiculite and acclimatized for potting. Chemical names used: 1H-indole-3-acetic acid (IAA); 1H-indole-3-butyric acid (IBA); (E)-2-methyl-4-(1-H-purin-6-ylamino)-2-buten-1-o1 (zeatin).
Abstract
Dormant bud explants taken from mature trees of Japanese persimmon cv. Hiratanenashi were established successfully on modified Murashige and Skoog's medium with nitrate reduced to half-strength [MS (½NO3)] or woody plant medium, both supplemented with 22.2 μM (5 mg°liter−1) BA. Shoot proliferation in subcultures also was best at 22.2 μM (5 mg°liter−1) BA in MS (½NO3) medium, but growth was of the rosette type. Shoot elongation, however, was stimulated the most in the same medium supplemented with 24.6 μM (5 mg°liter−1) 2iP instead of BA. Rooting of the proliferated shoots was enhanced by the treatment with IBA at 1.23 mM (250 mg°liter−1). Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA), N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP), 1H-indole-3-butanoic acid (IBA).
Black spot disease is one of the most serious diseases in Asian pear cultivation, with the commercial cultivar Nijisseiki being susceptible. Ethylene is known to play major roles in regulating plant defense responses against various pathogens. We investigated the relationship between ethylene synthesis and black spot disease in ‘Nijisseiki’ pear leaves by treatment with an analog of ethylene and 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action. Interestingly, both treatments enhanced black spot disease symptoms. Both treatments also increased ethylene production in accordance with disease symptoms through altered gene expression of ethylene biosynthetic enzymes, especially 1-aminocyclopropane-1-carboxylate (ACC) synthase genes (PpACS3 and 4). Chemical names used: 1-methylcyclopropene (1-MCP), 1-aminocyclopropane-1-carboxylate (ACC).
This report identifies S-RNases of sweet cherry (Prunus avium L.) and presents information about cDNA sequences encoding the S-RNases, which leads to the development of a molecular typing system for S-alleles in this fruit tree species. Stylar proteins of sweet cherry were surveyed by two dimensional polyaclylamide gel electrophoresis (2D-PAGE) to identify S-proteins associated with gametophytic self-incompatibility. Glycoprotein spots linked to S-alleles were found in a group of proteins which had Mr and pI similar to those of other rosaceous S-RNases. These glycoproteins were present at highest concentration in the upper segment of the mature style and shared immunological characteristics and N-terminal sequences with those of S-RNases of other plant species. cDNAs encoding these glycoproteins were cloned based on the N-terminal sequences. Genomic DNA and RNA blot analyses and deduced amino acid sequences indicated that the cDNAs encode S-RNases; thus the S-proteins identified by 2D-PAGE are S-RNases. Although S1 to S6 -alleles of sweet cherry cultivars could be distinguished from each other with the genomic DNA blot analysis, a much simpler method of PCR-based typing system was developed for the six S-alleles based on the DNA sequence data obtained from the cDNAs encoding S-RNases.