Abstract

Glandular trichomes on leaf epidermis of Artemisia annua was a major site for artemisinin production. The influence of culture vessel fitted with or replaced with perforated cap was investigated on growth and microstructures of in vitro A. annua leaves. Increment in height and fresh biomass of plantlets regardless of clones (TC1, TC2 and Highland) in culture vessel fitted with normal cap were significantly higher than those cultures with perforated cap after eight weeks of culture. Desiccation of the culture medium was observed in culture vessels fitted with or replaced with perforated caps. Three clones showed different growth profile and sensitivity toward ventilation. T-shaped trichome (non-glandular) and capitates trichome (glandular trichome) were found on adaxial and abaxial epidermis of A. annua leaves. Using perforated cap induced more trichomes on the adaxial surface of leaf for all three tested clones. Stomata of plantlets cultured in culture vessels with normal caps were always opened and opposite trend observed in culture vessels replaced with perforated caps. Results indicated that ventilation due to cap type influenced the growth of in vitro plantlets and microstructures of A. annua leaves.

Key words: Artemisia annua, in vitro plantlets, perforated cap, leaf trichome.