Masanori Goi

Cryopreservation of shoot tips of Chrysanthemum morifolium and related species native to Japan

SummaryThe shoot tips of Chrysanthemum morifolium (syn. Dendranthema grandiflorum) and related species native to Japan were cryopreserved using preculture for 2 days, slow cooling (0.2°C/min) until −40°C with 10% dimethyl sulphoxide and 3% glucose prior to immersion into LN2 and rapid thawing. High survival rates were observed in 3 cultivars of chrysanthemum, 12 species and 2 interspecific hybrids, and slightly low survival rates in 3 species. The shoot regeneration rates of the frozen shoot tips varied from 9.4 to 100% depending on species. Shoot tips of chrysanthemum showed high viability even after a storage of 8 months in LN2. The thawed chrysanthemum shoot tips grew and flowered normally in a greenhouse under natural conditions.

Cryopreservation of shoot tips of Caryophyllaceae ornamentals

SummaryShoot tips of 5 genera 38 species and cultivars of the Caryophyllaceae ornamentals were cryopreserved. Excised shoot tips were cooled at a rate of 0.5°C/min down to -40°C in the presence of 10% dimethyl sulphoxide and 3% glucose prior to immersion into liquid nitrogen. The shoot tips of all species and cultivars were viable after thawing. Little variation among species was observed in shoot regeneration. High viability of the cryopreserved shoot tips was maintained for up to 4 years. The plants derived from the cryopreserved shoot tips grew and flowered normally.

Optimal conditions for shoot production from Phalaenopsis flower-stalk cuttings cultured in vitro

Abstract This paper deals with the factors affecting the production of vegetative shoots from Phalaenopsis flower-stalk cuttings. Such vegetative shoots are required in order to obtain leaf segments for culture, which can later be induced to form protocorm-like bodies. Different daylengths (8, 16 or 24 h) had no effect on the production of shoots from the cuttings. About 50% of the buds developed into shoots at each daylength. However, shoot production was promoted when light intensity was decreased from 2.34 to 0.25 W m−2. At 0.25 W m−2, 79% of the cultures produced shoots. Aeration was important when culturing flower-stalk cuttings. Cuttings cultured in vessels plugged with rubber stoppers tended to produce flower stalks rather than shoots, as compared to those cultured in vessels covered with aluminium foil or plugged with a silicon stopper. The addition of charcoal or polyvinylpyrrolidone to the medium inhibited shoot production. Shoot production was improved when short cuttings were used. The greatest percentage (87) of shoot formation was achieved when 1-cm cuttings were used.

Morphological observation on vegetative growth and flower bud formation in Oncidium Boissiense

Abstract The growth habit, axillary bud differentiation, pseudobulb development and flower bud formation in Oncidium Boissiense, a sympodial orchid hybrid, were observed from 24 January to 2 October 1980. The axillary bud on the basal part of the latest back-bulb (last years growth) started to develop new growth (the “lead”) in early spring. The upper portion of the lead swelled to form a pseudobulb. The pseudobulb development started on 20 March and terminated between early July and early August. At the early stage of the lead development, four axillary buds had already differentiated at the axils of the basal sixth or seventh node and upwards. The uppermost bud started to elongate after mid-May, and developed into a flower-stalk. Branch formation in the axil of the bract on the flower stalk was observed in mid-May. Floret bracts were formed on the branches in mid-June. Floret primordia were differentiated at the axils of these bracts in early-July. Florets developed to the pollen-formation stage by 25 September and bloomed in mid-October 1980. Possible factors affecting flower-stalk development and floret initiation of this hybrid are discussed.