Encapsulation of embryonic axes of Camellia sinensis (L.) O. Kuntze (tea) and subsequent in vitro germination.

摘要

Zygotic embryonic axes of Camellia sinensis were coated with 3% and 4% sodium alginate matrices to select the best alginate concentration for the production of synthetic seeds. Germinability and plantlet development of encapsulated and non-encapsulated embryonic axes were evaluated under in vitro conditions. The results revealed that 3% (w/v) sodium alginate with 100 mM calcium chloride dihydrate provided the most suitable matrix of those tested, for encapsulation of embryonic axes. Naked and coated axes, cultured on Murashige and Skoog basal medium alone (MS1) or with 3 mg l-1 benzyl amino purine (BAP) and 0.5 mg l-1 indole butyric acid (IBA), (MS2), gave high rates of survival (100%) and germination (93-100%). However, they responded differently during germination and plant conversion. Somatic embryogenesis was observed in the hypocotyl region of coated and uncoated axes cultured on MS1 medium. Efficient plant recovery from non-encapsulated (73.3%) and encapsulated (42.2%) axes was achieved on MS2 medium. Further, shoot length and the number of leaves were significantly higher for non-encapsulated than for encapsulated embryonic axes after 8 weeks incubation. In this experiment, coating materials were prepared in distilled water alone. Therefore, plant recovery rate and shoot growth were statistically similar to those of non-embryonic axes cultured on MS1 medium. This study showed that incorporation of plant growth regulators into the culture medium is required for efficient conversion of normal plantlets from embryonic axes. This protocol is important for storing tea embryonic axes as synthetic seeds, to extend seed viability, and for germplasm exchange.