Application of Thin Cell Layer Technique in Studying Morphogenesis of Panax vietnamensis Ha et Grushv

Abstract

     In the present study, the morphogenesis of leaf tTCLs, petiole lTCLs and petiole tTCLs, and main root tTCLs of Panax vietnamensis Ha et Grushv. was investigated. Explants were cultured on MS media containing 30 g/l sucrose, 8 g/l agar and different concentrations of plant growth regulators including NAA, 2,4-D, BA and TDZ (alone or in combination). After 10 weeks of culture, results indicated that leaf tTCLs, petiole lTCLs and main root tTCLs gave the embryogenesis, callogenesis and root formation whilst petiole tTCLs resulted in callogenesis and root formation but not embryogenesis. The highest embryogenesis rate (89.6%), callogenesis rate (91 - 98.8%) and root formation rate (98.8%) were recorded when leaf tTCLs were cultured on media supplemented with 2.0 mg/l NAA and maintained under a long photoperiod with 16:8-h light-dark cycle (LD 16:8); leaf tTCLs, petiole lTCLsand petiole tTCLs, main root tTCLs were cultured on media with 2,4-D plus BA under a long photoperiod and darkness; and media with 1.0 mg/l NAA under darkness, respectively. Light conditions significantly affected the morphogenesis of all explant types. LD 16:8 was found to be suitable for embryogenesis, and formation of globular, heart- and torpedo-shaped, and cotyledonary embryos were observed. The darkness, on the other hand, showed to be effective for root formation and callogenesis, milk-white roots with few branches and yellowish friable calli were obtained.