Effect of different gelling agents on in vitro germination and seedling development of Echinocactus platyacanthus Link et Otto (Cactaceae)

Abstract

The gelling agent can have an effect on growth and development in vitro cultures. The aim of this study was to evaluate of different gelling agents in germination and development of seedlings Echinocactus platyacanthus in vitro. Seeds were sterilized and germinated on half strength concentration Murashige and Skoog (MS50%) media solidified with different gelling agents: 6 g L-1 Agar-Agar (Sigma), 8 g L-1 Bacto-Agar (Difco), 8 g L-1 bacteriological agar (Bioxon) and 3 g L-1 Gelrite Gellan Gum (Sigma). The germination index and percentage, plant growth and chlorophylls were evaluated. The highest percentage of germination was recorded in the culture medium gelled with agar-agar, followed by Gelrite, Bioxon and Bacto-Agar, the highest germination index was in Gelrite and lowest in Agar-Agar. The results show differences in the height and width of the germinated seedlings, root length and chlorophyll content which are influenced by the gelling agent used. Although no differences were observed in the water potential of the media, it is clear that each gelling agent has physicochemical characteristics such as gel strength will enable varying water available from the culture medium.