Search

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.

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.