Search

The effect of ionic composition in medium on proliferation of shoot tip-derived PLBs of two Calanthe species, C. aristulifera and C. striata, was investigated by using the media with 12 different ionic compositions, which were systematically modified according to the method of Ichihashi (1992) based on the composition of modified Gamborg’s B5 medium. These two species showed almost the same growth response to the ionic compositions and the growth of PLBs was inhibited on media with higher ratios of NH4+ and Ca2+, but promoted with higher ratios of both K+ and H2PO4−. Based on the results of PLB growth, optimum cationic compositions calculated for C. aristulifera and C. striata were NH4+ : K+ : Ca2+ : Mg2+=10.4 : 70.0 : 9.6 : 10.0 and 10.9 : 68.1 : 11.0 : 10.0, respectively, whereas optimum anionic compositions were NO3− : H2PO4− : SO42−=42.1 : 43.7 : 14.2 and 43.0 : 42.9 : 14.1, respectively. The percentages of NO3− and H2PO4− in the optimum medium thus obtained were about half and 12-hold of the control B5 medium, respectively. Among the 100 micropropagated C. striata plants examined, no obvious variation in flower shape and color were observed except two plants which had larger and thicker flowers than original plants. Those two variants were confirmed to be chromosome doubled tetraploids by flow cytometric analysis.

ミズゴケで栽培したドリテノプシスの乾物重と成分含有率に及ぼす培養液のイオン組成の影響について検討した．茎葉，根，花序などの乾物重と乾物割合は，処理区間での差は比較的少なかった．しかし，K+濃度の増加は茎葉の乾物重の増加に，Ca2+濃度の増加は減少につながった．乾物率は器官間での違いが大きく，茎葉部では6.4～7.4％であったのに対し，根部は8.5～10.4％，花序部では7.0～8.4％となった．各成分の含有率は培養液中の特定のイオン比率が上昇すれば同種元素含有率は増加したが，陽イオンあるいは陰イオン群内の他種のイオンの吸収は抑制された．本実験の陽イオン処理区では茎葉のCa含有率，花序のP含有率に違いが見られた．また，陰イオン処理区では根のP，Ca含有率，花序のN，Ca含有率に違いが見られた．これは，各イオンの吸収と移動が，培養液組成によって影響を受けたことによるものと考えられた．K+はH2PO4−の吸収・転流を阻害し，NO3−はCa2+の吸収を促進したが，その機作については不明であった．

The effects of different nutrient solutions on growth and ionic absorption of Doritaenopsis plants grown in sphagnum moss were investigated by using systematically arranged ionic treatments. Chlorophyll content was the highest in the nutrient treatment containing the highest NO-3 concentration. Fresh weight of the plant was affected by the ionic composition of each nutrient solution; in high cationic treatments, shoot growth was promoted by K+ but inhibited by Ca2+. In anionic treatments, no significant effect on shoot growth occurred. Growth of root and inflorescence changed with ionic composition of a nutrient solution, such that an increase of NH+4 advanced the date of full blooming, whereas an increase in SO2-4 decreased the weight of the inflorescence. The optimal ranges of ions are NH+4, 16.6%-21.8%; K+, 38.3%-45.6%; Ca2+, 19.2%-24.9%; Mg2+, 17.0%; NO-3, 64.8%-70.9%; H2PO4, 10.7-13.7%; SO2-4, 17.8%-22.3% when Σ Mn±=8.5 meq·liter-1.

Potato extract (PE), corn extract (CE) and papaya extract (PAE) significantly enhanced plantlet regeneration from PLBs (protocorm-like bodies) when 50 mL L - 1 of an extract was supplemented to the New Phalaenopsis (NP) medium containing sucrose. Among the treatments, CE 50 mL L - 1 induced the highest rate (66.63%) of plantlet regeneration from PLBs. Organic extracts of potato, corn and papaya at 50-100 mL L - 1 in NP medium also enhanced the subsequent growth of mini-plantlets. However, a higher level (200 mL L - 1 ) of extract in the medium inhibited the growth of the plantlets. Among these extracts, PE at 100 mL L - 1 showed the optimum effect on the acceleration of shoot growth while CE at the same concentration was optimum for root growth.

Growth rates of Phalaenopsis callus differed depending on the volume of media. Whereas callus growth on 5-ml of medium slowed after 8 weeks of culture, that on 10- and 20-ml of media grew slower after 10 and 12 weeks, respectively. Taro extract (TE), potato extract (PE), coconut water (CW), and apple extract (APE) enhanced callus growth but the effects depended on the quantity of each supplement. TE was the best additive tested on callus growth when 50 to 200 ml·1-1 were added. Banana homogenate (BH) and peptone had little effect on callus growth, whereas sweet potato extract (SPE) proved inhibitory at all levels tested. The effects of TE, PE, and CW depended on each callus. No synergistic effects of CW, TE, PE, and APE were observed.

Red, yellow, and blue light significantly enhanced the germination of Cattleya walkeriana var. coerulea 'Hi' x Cattleya walkeriana var. semialba in vitro. Both fresh and dry weights of germinating seedling grown under red, yellow, and blue light were heavier, but those grown under green light were lighter in comparison to those germinating under white light. In subsequent culture, shoot and root growth of seedlings was also enhanced under red and yellow light. Blue light enhanced fresh weight and shoot length, but it did not enhance the dry weight of seedlings. Under green light shoot length and the number of leaves per plant increased, but fresh weight, dry weight, leaf length and width, and root growth of seedlings were smaller. Green light also accelerated shoot and root development from the leaf axis. Dehydrogenase activity in roots, as evaluated by the TTC method, was the highest in blue light and the lowest in red light treatment.

The effects of sucrose, maltose, and sorbitol on callus growth of Phalaenopsis, Doritaenopsis, and Neofinetia were investigated. Calli derived from these three genera, grown on sucrose medium enriched with coconut endosperm, grew rapidly but remained friable and yellowish even after 3 subcultures at 8-week intervals. Calli of most cultivars, grown on maltose or sorbitol medium, initiated protocorm-like bodies (PLBs) which subsequently developed into plantlets. Regenerated plantlets were normal and healthy in appearance. Calli of a few Phalaenopsis and Neofinetia proliferated into green masses and continued to grow but did not develop either PLBs or plantlets.

Protocorm like bodies (PLBs) derived from callus of Phalaenopsis utilized sucrose, maltose and sorbitol for their growth in vitro. These carbon sources affected differently and could control PLB growth. On sucrose supplemented medium a few PLBs produced plantlets and most others regenerated yellowish or greenish callus like body (CLB). Almost 80% of unrooted and 58% of rooted plantlets developed yellowish green CLB at the base of plantlets. On maltose supplemented medium, PLBs regenerated PLBs and a few plantlets. In subsequent culture, about 44% of unrooted and 24% of rooted plantlets initiated green PLBs at the base of cultured plantlets. On sorbitol supplemented medium, most of the PLBs developed plantlets and a few additional PLBs. Among the carbon sources tested, sorbitol supported plantlet development the best in vitro and proved to be the most suitable carbon source for plantlet initiation and development from PLB.

The isolation, culture, and plant regeneration of protoplasts derived from callus of Phalaenopsis was established. Callus was obtained by the culture of a lateral bud on a young flower stalk. Protoplasts were isolated enzymatically from callus which was precultured on P basal medium (without coconut water (CW) and sucrose) for 30 days. The first cell division was observed after 7-10 days of culture in the basal medium supplemented with 2, 4-dichlorophenoxyacetic acid (2, 4-D) or CW. After 60 days of culture, the protoplasts cultured in the medium supplemented with 0.05-0.1 mg/l 2, 4-D and 10% (v/v) CW formed numerous colonies by the addition of fresh medium. The colonies developed into small calli and turned green under continuous light condition, and small calli produced PLBs in the same liquid medium. The PLBs derived from protoplasts regenerated shoots readily on P basal regeneration medium (10% (v/v) CW, 0.3% (w/v) Gelrite). The shoots developed into whole plants after transfer onto Hyponex medium (3g/l Hyponex (N:P:K, 6.5:6:19), 2.0% (w/v) sucrose, 0.05% (w/v) activated charcoal, 0.3% (w/v) Gelrite).

Our purpose was to develop a more rapid method for plantlet regeneration from bud explants and callus of C. esculenta var. esculenta and to study the effects of several culture medium components.

Old statistics are available regarding orchid production in Aichi prefecture in Japan. The value of orchids produced in 1965 was 15 730 000 yen ($43 694, $1 = 360 yen). In 1991 production reached 6 887 181 000 yen ($49 194 150, $1 = 140 yen), which is a 438-fold increase in 26 years. Production of all potted ornamental plants increased 1.93-fold in pot number and 4.45-fold in volume between 1975 and 1991. The increase in potted orchid production was considerably greater, being 2.45-fold in number and 7.95-fold in volume (Fig. 5-1). The total production of pot plants in Japan during 1991 was 204 762 000 pots valued at 100 564 797 000 yen ($718 319 979). Orchid pot-production was 8.4% (17 211 000) of the number of pots and 29.7% ($213 341 457) of the volume. Production of orchid-pots in Aichi prefecture alone was 27.9% of the number and 23.1% of the volume (Figs. 5-2, 5-3 ).

Utilization of clones is an important component in the economic production of orchids. Controlled cultivation is possible and effective only when plants are uniform. Among the three major orchids produced in Japan, only Cymbidium production starts with plantlets multiplied from shoot tips cultured in vitro. These shoot tips produce protocorm-like bodies (PLBs). Shoot development follows PLB formation in many standard-type Cymbidium hybrids. Several miniature-type Cymbidium cultivars and/or temperate species are an exception. Mass rapid clonal propagation (MRCP) of standard-type Cymbidium is fairly easy and was the first to be utilized for commercial production. In nobile-type Dendrobium production, multiplication by traditional cuttings is common. Difficulties in the formation of PLB and a higher risk of somaclonal mutations hinder practical utilization of MRCP in these orchids. Seedlings are used for Phalaenopsis production. Phalaenopsis is a monopodial orchid, which means that research that utilizes shoot tips damages the mother plants. This has created difficulties, and development of MRCP procedures has been delayed. Several MRCP methods using plant parts other than shoot tips have been developed recently, and production of clones has started.