Growth and net photosynthetic rate of potato (Solanum tuberosum L.) `Benimaru' plantlet in vitro were studied under a conventional photomixotrophic condition [with 20 g sucrose/liter in the medium and under 70 μmol·m-2·s-1 photosynthetic photon flux (PPF)] with minimal ventilation (MV) and under photoautotrophic conditions (without sugar in the medium and under 190 μmol·m-2·s-l PPF) with enhanced natural ventilation using an air diffusive filter (DV) or with forced ventilation (FV). Fresh weight of the plantlets cultured in the FV and DV treatments was 2.4 times that of the plantlets cultured in the MV treatment. Net photosynthetic rate and dry weight per plantlet were the highest in FV followed by DV. For photoautotrophic micropropagation, FV was superior to DV.
Chieri Kubota and Toyoki Kozai
Jennifer Crane and Harrison Hughes
Plantlets of Solarium tuberosum L. `Russet Burbank', `Sangre', and `Centennial Russet' were grown in vitro from nodal cuttings. A medium overlay was used to reduce the humidity of the in vitro environment. This treatment was tested for its effect on plant growth and on the rate of water loss from detached leaves. The latter was assayed as indicative of hardening and consequent survival of plantlets once removed from in vitro culture. The paraffin medium overlay reduced the rate of water loss from detached leaves of cultured plantlets, but also reduced root growth.
D.J. Gray, K.A. Labeau and C.M. Benton
The development of grape somatic embryos (Vitis vinifera cv. Thompson Seedless) was studied using high-resolution light microscopy and scanning electron microscopy. Somatic embryos develop either from discrete embryogenic cell clusters (indirect somatic embryogenesis) or from previously formed somatic embryos (direct somatic embryogenesis). In both instances, embryo development begins when a small, isodiametric, densely cytoplasmic cell undergoes a series of organized divisions, which are identical to those observed during zygotic embryogenesis. Developing embryos pass through recognizable embryonic stages, remaining white and opaque through maturity. Upon germination, embryos begin to enlarge, become yellow, then green, and develop into morphologically correct plants. The cells of somatic embryos contain little starch, but abundant storage proteins. However, lipids comprise the primary storage compound. Some developmental abnormalities occur during embryogenesis, including overly enlarged hypocotyls and fewer or more than two cotyledons. In addition, relatively few somatic embryos grow into plants primarily due to inadequate shoot apical meristem development. These abnormalities are best attributed to inadequacies of the in vitro environment of medium in a culture vessel when compared to the in vivo environment of a seed.
Almudena Montoliu, Aurelio Gómez-Cadenas and Rosa M. Pérez-Clemente
concentrations ( Al-Bahrany, 2002 ; Bordón et al., 2000 ; Chakravarty and Goswami, 1999 ; Hassanein and Azooz, 2003 ). Because of the variable response of citrus species and cultivars to the in vitro environment, the objective of this study was to improve
Carmen Valero Aracama, Michael E. Kane, Sandra B. Wilson and Nancy L. Philman
capacity ( Grout and Aston, 1978 ), and dry matter accumulation ( Ziv, 1991 ). Often, these characteristics negatively impact the capacity for ex vitro acclimatization, but the degree to which plants are affected by the in vitro environment depends on the
How-Chiun Wu, Mei-Ling Kuo and Chia-Min Chen
the culture vessel so that the in vitro environment, including the growth medium, is not altered in such a way that it is detrimental to plantlet growth. In light of the challenges described earlier, during in vitro propagation of P. cynaroides
Bo-Ling Liu, Zhi-Bin Fan, Ze-Qun Liu, Xun-Hong Qiu and Yan-Hong Jiang
micropropagated plants. The slight increase in tanshinone in micropropagated plants might be due to the plant tissue culture environment or to the effect of endogenous hormones. Previous studies reported that the in vitro environment might increase the production
Meijun Zhang, Duanduan Zhao, Zengqiang Ma, Xuedong Li and Yulan Xiao
several advantages over photomixotrophic micropropagation (PM). The advantages include minimal microbial contamination, increased photosynthesis, growth and rooting in vitro, and survival percentages ex vitro when the in vitro environment is controlled to