Silver nanoparticles enhanced efficiency of explant surface disinfection and somatic embryogenesis in Begonia tuberous via thin cell layer culture

In vitro culture establishment is one of the most important stages in micropropagation. The disinfectant effectiveness depends on the type of surface disinfectant, concentration and the time treatment. In this initial study, silver nanoparticles (AgNPs) were used as a disinfectant for petioles, flower stalks and stems of Begonia tuberous. In addition, thin cell layer culture (TCL) technique has been applied for the purpose of somatic embryogenesis. The results showed that AgNPs were effective in eliminating infectious microorganisms on B. tuberous explants; which were identified included 4 species of fungi (Fusarium sp., Aspergillus aculeatus, Trichoderma sp. and Penicillium sp.) and 1 species of bacteria (Pseudomonas sp.). At concentrations of 200 ppm and 300 ppm, AgNPs were not only effective in disinfection but also increased the induction rate of somatic embryogenesis in flower stalk TCL explants (approximately 40.00%); a similar effect was observed in stem TCL explants at the same concentration. Meanwhile, for petiole TCL explants, the induction rate of somatic embryogenesis was optimal when using AgNPs at a concentration of 100 - 300 ppm to disinfected the explant. In contrast, at high (400 ppm) or low (50 ppm) concentrations of AgNPs did not play a disinfecting role and stimulated somatic embryogenesis. In addition, explants derived from AgNPs sterilization did not show any abnormalities in somatic embryogenesis with shapes such as globular, heart, torpedo, and cotyledon. AgNPs showed double efficacy in sterilization of explants and improved efficiency of somatic embryogenesis from TCL petioles, flower stalks and stems explants; thus increasing the efficiency micropropagation of B. tuberous.

Efficiency of shoot regeneration and micropropagation of purple passion fruit (Passiflora edulis Sims.) via internodal longitudinal thin cell layer culture

The thin cell layer culture technique (TCL) has been used for the effective tissue culture of several dozen plants with commercial importance such as field crops (rice, cereals), horticultural commodities (fruits, vegetables, ornamental plants), medicinal plants and herbs (Panax vietnamensis Ha et Grushv.), and even forestry trees (Pinus sp.), and woody fruit plants (Citrus spp., apple). In the present, TCL was used to evaluate the efficiency of shoot regeneration and propagation for purple passion fruit (Passiflora edulis Sims.). The internodes were cut longitudinally (lTCL) and was used as an initial material. The results showed that the shoot regeneration rate and number of shoots from internode-lTCL depended on position of internodes (1, 2, 3, 4 and 5) and the plant growth regulator (BA and NAA). After 8 weeks of culture, internode-lTCL derived from 3rd internode of P. edulis cultured on MS medium supplemented with 1.5 mg/L BA in combination with 1.0 mg/LNAA gave the highest shoot regeneration rate (83.33%), and number of shoots (3.00 shoots/explant). These shoots were cultured on modified MS (MSM) medium supplemented with 1.0 mg/L BA showed higher efficiency of shoot multiplication (3.56 shoots/explant and 6.67 cm height) than the other BA treatments. In addition, the highest rooting rate was 76.67% when cultured on MSM medium containing 2.0 mg/L IBA. The survival rate of plantlets was 83.33% when transferred into greenhouse condition after 10 weeks. The results of this study were the initial success in establishing an effective in vitro regeneration and propagation of Passiflora edulis Sims. through internode-lTCL.

Comparative Efficiency Analysis of Different Explants and Contribution of Polyamines on in vitro Propagation of Dendrobium Hybrid Sonia

An efficient method of plant regeneration and subsequent growth and development of Dendrobium hybrid Sonia was developed using intact seedling, shoot tip and thin cell layer. Maximum number of PLBs was obtained in MS liquid medium supplemented with 0.5 mg/l NAA and 1mg/l BAP through shoot tip and thin cell layer culture (TCL). Highest number of adventitious shoot formation was recorded in 0.5 mg/l of NAA and 2 mg/l of BAP through shoot tip culture. In shoot tip and TCL cultures, the necrosis was checked in presence of NAA (0.5 mg/l) and BAP (1 mg/l). Maximum callus frequency was recorded in NAA and BAP (0.5 mg/l) through thin cell layer culture. Direct PLB formation was better at 1.0 μM concentration in all the three polyamines tested. Three polyamines tested were effective in direct PLB formation as well as adventitious shoots. Plant Tissue Cult. & Biotech. 30(1): 77-86, 2020 (June)