In vitro root zone environments and their effects on growth and development of plants

In photoautotrophic micropropagation, plantlets must be grown under appropriate environmental conditions that promote photosynthesis. These conditions should include considerations of not only the aerial (headspace) environment, such as CO₂ concentration and photosynthetic photon flux, but also the root zone environment. While controlling the root zone environment is not easy, selection of supporting materials (i.e., replacing agar gel with porous supporting materials) that may create a better root zone environment (i.e., oxygen or nutrient availability) is relatively easy. Without sugar in the medium and with porous supporting materials and liquid medium, the system is more like a small hydroponic system, referred to as "microponics" (Hahn and Lee, 1996). Improvement of root zone environmental control in photoautotrophic micropropagation may well benefit from the expertise and techniques available from hydroponics.