Nhut’s research while affiliated with Kagawa University and other places

Callus formation at the cutting base is an interesting and common phenomenon in cuttings; however, little is known of histology and hormonal dynamics during the adventitious root formation (AR) and callusing stages of cuttings, also the relationship between them, were the aims of this study. The results showed that all SeNPs selenium nanoparticles (SeNPs) concentrations (1.0; 3.0; 5.0; 7.0 and 9.0 mg/L) and control (-) which is AR stimulants-free showed an impact AR formation without callusing in passion fruit cuttings. Meanwhile, regardless of the callus accumulation induced by cortex cell proliferation at cutting base that promoted by 2.5 mg/L IBA-control (+), no ARs differentiated from callus but rather from vascular cambium cells. It implies callus formation is not an obligatory trigger/signal for AR formation. Interestingly, SeNPs regulate IAA, Kin, zeatin, GA3 and ABA levels that peak during the S1 phase (S1-induction root/callus founder cells) consequent an increase in GA3/IAA, GA3/CKs, GA3/ABA ratios and a decrease in CKs/ABA ratio causing early vascular differentiation and of cambial derivatives behavioral modification, when crosstalk further regulates responses during AR-forming cellular reprogramming. On the other hand, callus induced by IBA impeded AR formation and growth traits due to increased endogenous 2ip, IAA/CKs and decreased GA3/IAA ratio during S1. Furthermore, the sustained high maintenance IAA/CKs and IAA/ABA ratios during S1-S3 (S3-massive rooting phase) favor callusing. SeNPs derived-plantlets without accumulate callus exhibited higher survival rate and superior growth during acclimatization stage compared with those controls, emphasizing that callusing was detrimental to passion fruit cuttings.

Panax vietnamensis Ha et Grushv., an endemic Panax genus of Vietnam, is a well known Vietnamese ginseng (Ngoc Linh ginseng) rich in pharmaceutical compounds, most importantly saponin. Its cultivation takes a long time, generally 5–7 years, and needs extensive efforts to quality control in the face of environmen-tal stresses including soil, shade, climate, pathogens and pests. In vitro techniques have been widely explored for rapid and efficient production of ginseng biomass and ginsenosides. The establishment of cell and adventitious root cultures of P. vietnamensis opens the way to commercial applications. Various physiological and biochemical parameters affecting the biomass production and ginsenoside accu-mulation have been investigated. These parameters are effect of various phytohor-mones, sucrose and activated charcoal (AC) on shoot regeneration and proliferation from callus, and adventitious and secondary root formation. The saponin analysis of calli and roots showed the presence of ginsenoside-Rg 1 , majonoside-R 2 , and ginsenoside-Rb 1 . These results indicated that P. vietnamensis biomass has a great potential to produce saponin as a new source for the pharmaceutical and cosmetic industry. Abbreviations AC Activated charcoal MS Murashige and Skoog NAA α-napthaleneacetic acid 2, 4-D 2, 4-dichlorophenoxyacetic acid TDZ Thidiazuron IBA Indole-3-butyric acid

The present work describes a procedure that allows for the easy and rapid induction of somatic embryos, calli, shoots and adventitious roots of Vietnamese ginseng (Panax vietnamensis Ha et Grushv.) from longitudinal thin cell layers (lTCLs). In order to investigate the morphogenesis of this medicinal plant, the effect of separately–supplemented plant growth regulators and combinatorial effect of co–supplemented auxins and cytokinins in dark or under 16-hour photoperiod was examined. After eight weeks of culture, the lTCL explants excised from petiole of three-month-old in vitro plants and cultured on a semi solid basal Murashige and Skoog (MS) media supplemented with 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.1 mg/l thidiazuron (TDZ) in dark, 2.0 mg/l α-napththaleneacetic acid (NAA) in dark and 1.0 mg/l 2,4-D under light gave the highest rate of callogenesis (100%), embryogenesis (53.3%) and adventitious root formation (100% with a mean of 16.7 roots), and shoot formation (26.7%), respectively. The metabolite of petiole lTCL-derived calli qualitative and quantitative analyses were performed by using high-performance liquid chromatography and thin layer chromatography. The simple procedure, together with similar saponin profiles between the resulted in vitro tissues and plants grown in nature, suggest its potential use in generating Vietnamese ginseng in large amount for medicinal purpose.

The methods for leaf-derived callus induction, callus proliferation, adventitious shoot induction and plant regeneration of Vietnamese ginseng (Panax vietnamensis Ha et Grushv.) were examined. In this study, callus induction was formed on both medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) alone or in combination with thidiazuron (TDZ). The highest callus induction frequency was obtained on Murashige and Skoog (MS) medium supplemented with 1.0 mg/l 2,4-D and 0.2 mg/l TDZ. The best callus proliferation medium was Schenk and Hildebrandt (SH) supplemented with 0.2 mg/l TDZ and 1.0 mg/l 2,4-D. The maximum callus-derived shoot number (8.2) was obtained on SH medium supplemented with 50 g/l sucrose in combination with 2.0 mg/l 6-benzylaminopurine (BA). The most successful rooting of regenerated adventitious shoots was obtained on SH medium with 1.0 mg/l α-naphthalene acetic acid (NAA). Plantlets were successfully acclimatized without growth chamber facility on Ngoc Linh mountain with a survival rate of 85% after two months. On the other hand, substantial increase of root length was observed. This study describes an efficient method for in vitro regeneration of P. vietnamensis, which could be considered for large-scale multiplication and propagation of this important medicinal plant.

In this paper, somatic embryogenesis induction of Eustoma grandiflorum is presented. Each in vitro-derived leaf was horizontally cut into two segments and cultured on MS (Murashige and Skoog, 1962) medium supplemented with BA, NAA or 2,4-D, individually or in combination. Embryogenic calli formation was observed on the leaf segments cultured on MS medium supplemented with various concentrations of 2,4-D (0.5, 1.0, 2.0, 3.0 or 4.0 mg l-1) in the dark. Embryonic callus formation rate was 85.5% in all leaf segments on MS medium supplemented with 0.5 mg l-1 2,4-D after 30 days of culture. Embryogenic calli were subcultured on MS medium supplemented with 1.0 mg l -1 NAA and BA (0.5, 1.0, 2.0, 3.0, 5.0 mg l-1) to induce embryo-like structures (ELSs or globular embryos). ELSs were obtained at a high frequency from embryogenic calli cultured on MS medium supplemented with 0.5 mg l-1 BA and 1.0 mg l-1 NAA after 15 days of culture. Somatic embryo formation occurred on MS medium supplemented with BA at various concentrations (0.5, 1.0, 2.0, 3.0, 4.0 or 5.0 mg l-1) and 100% somatic embryo-derived plantlets were recovered after the conversion of mature embryos on MS medium containing 1.0 mg l-1 BA. Normal development was observed after 21 days of culture.

Cryopreservation of nodal explants of an endangered plant species (Cen-taurium rigualii Esteve) using encapsulation-dehydration method. Biodiversity Conservation, 6: 583-590. Halmagyi A., Fischer-kluver G., Mix-wagner G., Schumacher H. M. (2004). Cryopreservation of Chrysanthemum morifolium (Dendranthema grandiflora Ramat.) using different approaches. Plant Cell Reports, 22: 371-375.

Histological changes in epidermal and sub -epidermal cell layers of Begonia rex induced to form de novo unicellular hairs, buds and roots.. Direct somatic embryogenesis and regeneration of plants from seedling explants of peanut (Arachis hypogae L.): Promotive role of thidiazuron.

Panax vietnamensis Ha et Grush. has been interested and researched from 1973. Application of biotechnology to increase root biomass of P. vietnamensis is studying in Vietnam, whereas, industrial-scale culture of multiple adventitious roots of P. ginseng has succeeded by bioreactor system in South Korea. In previous study, we had determined optimal medium for callus-regenerated adventitious roots of P. vietnamensis on MS medium (Murashige and Skoog,1962) supplemented with 3 mg/l NAA, 30 g/l sucrose and 8 g/l agar. In this study, we investigated optimal medium for multiplication of adventitious roots and primary application of bioreactor system to multiplication of adventitious roots of P. vietnamensis provide material for saponin isolation. Results had shown optimal medium for multiplication of adventitious roots is SH medium (Schenk and Hildebrandt, 1972) supplemented with 3 mg/l NAA, 30 g/l sucrose, 8 g/l agar. Increase of adventitious roots biomass after 8 weeks culture were achieved 6.05 times on SH medium supplemented with 3 mg/l NAA, 30 g/l sucrose by 3-litre balloon-type bubble bioreactor (Korea).