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In vegetatively propagated plants, branches of periclinal chimera give rise to bud mutants, or `sports', which have been used to breed new cultivars. Here, we have examined DNA methylation profiles in the cells of the L1 and L2+3 layers from single plants of vegetatively propagated carnations. The band patterns of methylation-sensitive amplified fragment polymorphism (M-AFLP) of the genomic DNAs in the L1 and L2+3 layers of the carnation cultivar, `White Sim', vegetatively propagated over the past 50 years, were completely different. The bud mutant, `White Mind', obtained from `White Sim' about 25 years ago, also had very different M-AFLP patterns to the parental `White Sim' line. The cultivar, `Red', which was separated from `Satisfaction' as a bud mutant two years ago, showed similar patterns to `Satisfaction' in each corresponding layer. However, we were able to detect minor, but significantly different M-AFLP patterns between the cultivars, `Red' and `Satisfaction'. The number of bands that differed between these cultivars was larger in the L2+3 layers than in the L1 layers. The results indicate that the DNA methylation profiles differ between each cell layer derived from distinct cell lineages of vegetatively propagated plants, and that changes in these profiles occur frequently and accumulate in the cells of the L2+3 layers, rather than in the L1 layer. [ABSTRACT FROM AUTHOR]

Abstract: We used conventional cross-breeding techniques to develop a carnation with low ethylene sensitivity. A time-lapse video recording system for evaluating ethylene sensitivity of flowers, developed in our earlier study, proved useful for this breeding. We selected 10 new ethylene-resistant lines, in addition to the previously selected line 64–54. Lines 902–48a, 234–43S, and 234–36S showed extremely low ethylene sensitivity. The response time to 10μLL−1 ethylene of these three lines exceeded 50h in two independent experiments (2004 and 2005), whereas that of three sensitive control cultivars (‘White Sim’, ‘Excerea’, and ‘Scania’) was 6.2–8.0h. The mean vase life of the ethylene-resistant lines ranged from 7.6 to 12.7 days (1.4–2.3 times that of ‘White Sim’). The application of ethylene to carnation flowers induced autocatalytic ethylene production in both petals and gynoecia of 9 of the 11 ethylene-resistant lines without petal wilting, indicating that the autocatalytic ethylene production was regulated independently of the petal wilting reaction. This result further suggests that these lines have normal ethylene receptors and produce ethylene autocatalytically, but their petal wilting reaction stops at a point beyond the receptor. Two lines (118–64S and 120–69S) showed extremely low ethylene production at flower senescence and very low autocatalytic ethylene production from petals and gynoecia. [Copyright &y& Elsevier]

Differences in ethylene sensitivity among carnation (Dianthus caryophyllus L.) cultivars were evaluated using a time-lapse video recording system. Measurement of time to petal inrolling of ‘White Sim’, ‘Nora’, ‘Chinera’, and line 64-54 flowers subjected to a range of 1–20 μl l−1 ethylene showed that 10 μl l−1 was the optimum concentration for sensitivity evaluation with our video system. With this system we found clear differences in ethylene sensitivity among 10 cultivars and one line. ‘Candy’, ‘Pallas’, ‘Chinera’, and line 64-54 had lower ethylene sensitivities than the other seven cultivars. Line 64-54 had the longest ethylene response time (20.6 h to start of petal inrolling). Video monitoring is a simple and accurate way of evaluating ethylene sensitivity. We have also used the system to study changes in the ethylene sensitivity of carnation flowers after anthesis. We were able to detect a shift in responsiveness to ethylene that was impossible to detect by previous methods. In the Sim-type carnation cultivars tested (‘White Sim’, ‘Scania’, ‘U Conn Sim’, and ‘Nora’), ethylene sensitivity after anthesis decreased significantly with age in both early-cut and late-cut flowers. These results clearly showed that decline of ethylene sensitivity is caused by the increasing physiological age of flowers. Ethylene sensitivity after anthesis decreased with age in normal Sim-type carnations in the same way as in long-vase-life variants such as ‘Sandrosa’. [Copyright &y& Elsevier]

Abstract: Ethylene production and the expression of ethylene biosynthetic pathway genes of some carnation cultivars with a long vase life (‘Miracle Rouge’, ‘Miracle Symphony’ and ‘Sandrosa’) and a cultivar with a normal vase life (‘White Sim’) were investigated. None of the long-life cultivars exhibited normal climacteric-like ethylene production, or petal in-rolling during senescence, but they did exhibit slow petal desiccation. Ethylene production rates from senescing flowers were very low in all long-life cultivars, although slightly higher in ‘Sandrosa’ than in the two other long-life cultivars. Aminoethoxyvinylglycine (AVG) treatment prolonged flower life in ‘Sandrosa’, but did not affect flower life in ‘Miracle Rouge’ and ‘Miracle Symphony’, which indicated a role of 1-aminocyclopropane-1-carboxylate synthase (ACS) only in ‘Sandrosa’. 1-Aminocyclopropane-1-carboxylate (ACC) treatment markedly accelerated senescence of ‘Sandrosa’ but had only a small effect on ‘Miracle Rouge’ and ‘Miracle Symphony’, suggesting that ACC oxidase (ACO) was inhibited or downregulated in the two ‘Miracle’ cultivars. The levels of DC-ACS1, DC-ACS2 and DC-ACO1 transcripts in the gynoecium and petals were high at 5 and 6 days after harvest in ‘White Sim’ but were below the detection levels in ‘Miracle Rouge’ and ‘Miracle Symphony’. In ‘Sandrosa’, DC-ACS1 was below the detection limit, whereas the expression of DC-ACS2 and DC-ACO1 was very low. The results show that long vase life in these carnation cultivars, ‘Miracle Rouge’, ‘Miracle Symphony’ and ‘Sandrosa’, is correlated with low DC-ACS1, DC-ACS2 and DC-ACO1 expression in the gynoecium and petals. [Copyright &y& Elsevier]