The developmental pattern of leaf color distribution during plant development in 10 cultivars of Caladium ×hortulanum Birdsey was investigated. We used the color occupying the largest area in the terminal leaf as the dominant color, and expressed the leaf color stability during plant development by the ratio of the percentage of the dominant color area in the terminal leaf to that of the dominant color area in the initial leaf (leaf color stability index). In some cultivars, leaf color stability index was clearly greater than 1 (leaf-color-unstable cultivar), but in some cultivars it was close to 1 (leaf-color-stable cultivar). In plants regenerated from leaf explants of leaf-color-unstable cultivars, many (21% to 43%) color variants were observed but only a few (0% to 6%) occurred from leaf explants of leaf-color-stable cultivars. Tissue culture appears to be a useful technique for rapid propagation based on leaf color stability in leaf-color-stable and leaf-color-unstable cultivars.
Eakhlas U. Ahmed, Takahiro Hayashi and Susumu Yazawa
Hisanao Suzue, Munetaka Hosokawa and Susumu Yazawa
Exposing the shoot apical meristem (SAM) is necessary in horticultural practices such as shoot tip culture, colchicine treatment, gene transfer, and so on. However, ordinary methods of exposing SAMs require extensive training and are labor-intensive. We developed equipment to expose SAMs quickly and easily by blowing compressed air on the shoot tips. Using this equipment allowed SAMs to be exposed more rapidly than the ordinary methods. Exposure time was shortened from 27.8 s to 7.4 s, 15.7 s to 7.9 s, and 59.7 s to 6.8 s in chrysanthemum (Chrysanthemum morifolium), dahlia (Dahlia spp.), and Lilium leichtlinii, respectively. To determine whether blowing compressed air caused injury to SAMs, we used shoots in which the SAMs had been already exposed and observed resin sections of SAMs that had been subjected to the additional compressed air treatment for several seconds. Results showed that blowing additional compressed air for as long as 9 s did not injure SAMs. Using this equipment, we can expose SAMs without using a stereomicroscope by blowing compressed air to the top of shoots for several seconds. Over 70% of SAMs could be exposed in a 7- to 13-s blowing treatment without injury. We could successfully use this equipment in shoot tip culture and leaf primordia-free SAM culture.
Hiroaki Ito, Takahiro Hayashi, Masaki Hashimoto, Katsuro Miyagawa, Saori Nakamura, Youichi Mizuta and Susumu Yazawa
A protocol for the preparation of preserved flowers retaining natural color and texture of ‘Moondust Velvet Blue’ carnations (Dianthus caryophyllus) was developed. This three-step process consists of soaking flowers in ethyl alcohol, then soaking them in polypropylene glycol, followed by a rinse with ethyl alcohol. Some kinds of flowers processed in this manner retained their natural color and texture for at least 6 months. The physicochemical properties of appropriate solvents used for retaining natural pigmentation and texture are discussed. This protocol is applicable to 13 kinds of flowers among 30 kinds of flowers tested and adds a new dimension to postharvest techniques for cut flowers.