In vitro Propagation of Vanda testacea (Lindl.) Reichb.f. – A Rare Orchid of High Medicinal Value

Foliar explants of Vanda testacea (Lindl.) Reichb. f. were cultured on Mitra (M) medium with 1.0 mg/l BAP, Kn each and 1.0 mg/l NAA individually and in combination for initiation of regeneration response, proliferation of regenerants and subsequent development of plantlets. Juvenility of the tissues and chemical stimulus were important factors in initiating the regeneration response in the explants. The relatively older leaf explants (>1cm in length) remained recalcitrant to regeneration the representing younger ones (<1cm in length) responded to certain chemical regimes. BAP, Kn individually in the medium should direct PLB regeneration whereas when used with NAA, the explants showed callus proliferation and further differentiated into PLBs. An individual treatment with NAA (1.0 mg/l) impaired the response frequency and delayed further morphogenetic processes leading to plantlet development. The best response in the explants (in terms of high regeneration frequency, early initiation, PLB proliferations, and plantlet development) was observed in 1.0 mg/l BAP alone/with 1.0 mg/l NAA + activated charcoal. Plantlets were transferred to pots containing epiphytic compost (1 charcoal : 1 brick pices : 1 bats). Nearly 75% of plantlets survival was recorded. Key words: In vitro, Orchid, Vanda testacea, Micropropagation, Protocorm-like bodies, callus D.O.I. 10.3329/ptcb.v19i1.4077 Plant Tissue Cult. & Biotech. 19(1): 1-7, 2009 (June)

Effects of Nitrogen and Sucrose Level on the Regeneration of Cichorium intybus L. var. sativus

The regeneration medium supplemented with 2.0 mg/L BAP and 0.1 mg/L IAA allowed high efficient shoot regeneration from leaf discs and petioles of Cichorium intybus L. var. sativus. Multiple shoots ranged from 10 to 14 per explant were observed only 10 to 15 days after the initial culture. Reduced nitrogen and sucrose levels influenced on shoot regeneration frequency and growth rates. Especially, in C. Intybus L. var. sativus cv. Cesare explants cultured in the medium containing 50 mg/L MS macroelement and 1.5% sucrose displayed high regeneration frequency of 100%.

TOWARDS GENETIC TRANSFORMATION OF QUINCE AND PEAR

Quince (Cydonia oblonga) is widely used as a dwarfing rootstock for pear (Pyrus communis). We have devised procedures for Agrobacterium-mediated gene transfer using leaf discs of quince. The following factors were particularly important for recovery of shoots after incubation of leaf discs with Agrobacterium: an efficient regeneration system, the use of an effective antibiotic to eliminate Agrobacterium while maintaining a high regeneration frequency, and the choice of selectable markers. The regeneration frequency of control leaf discs on a medium containing 30 μM thidiazuron and 0.3 μM naphthaleneacetic acid was 100%. The frequency decreased linearly with increasing concentrations of antibiotics. Timentin. which consists of ticarcillin and a 6-lactamase inhibitor, was more effective in eliminating Agrobacterium than cefotaxime and carbenicillin. Vectors with the bar gene (bialaphos resistance) were better than those with the npt 11 gene (kanamycin resistance), since kanamycin bleached the leaf discs, resulting in poor regeneration. Bialaphos-resistant quince shoots which were positive in Southern hybridization have been obtained. The same procedures are being applied for transformation of pear.