Tissue culture of ornamental pot plant: A critical review on present scenario and future prospects

Regeneration via shoot organogenesis and somatic embryogenesis was observed from thidiazuron (TDZ)-treated leaf and petiole explants of greenhouse- and in vitro-grown African violet plants The response of cultures to other growth regulators over a range of 05 µM to 10 µM was 50% less than that observed with TDZ A comparative study among several cultivars of African violet indicated that 'Benjamin' and 'William' had the highest regeneration potential In 'Benjamin', higher frequencies of shoot organogenesis (twofold) and somatic embryogenesis (a 50% increase) were observed from in vitro- and greenhouse-grown plants, respectively At concentrations lower than 25 µM, TDZ induced shoot organogenesis, whereas at higher doses (5–10 µM) somatic embryos were formed These findings provide the first report of simultaneous shoot organogenesis and somatic embryogenesis of African violet explants in response to TDZ

Thidiazuron induces shoot organogenesis at low concentrations and somatic embryogenesis at high concentrations on leaf and petiole explants of African violet (Saintpaulia ionantha Wendl.)

The variegated Saintpaulia cultivar Thamires (Saintpaulia sp.), which has pink petals with blue splotches, is generally maintained by leaf cuttings. In contrast, tissue culture-derived progeny of the cultivar showed not only a high percentage of mutants with solid-blue petals but also other solid-color variants, which have not been observed from leaf cuttings. Solid-color phenotypes were inherited stably by their progeny from tissue culture. Petals from each solid-color variant were analyzed by high-performance liquid chromatography and shown to contain different proportions of three main anthocyanin derivatives: malvidin, peonidin, and pelargonidin. Analysis of flavonoid 3′, 5′-hydroxylase (F3′5′H) sequences showed no differences in the coding region among the variants and variegated individuals. However, a transposon belonging to the hAT superfamily was found in the promoter region of variegated individuals, and the presence of transposon-related insertions or deletions correlated with the observed flower-color phenotypes. Solid-blue flower mutants contained 8-base pair (bp) insertions (transposon excision footprints), while solid-pink mutants had 58- to 70-bp insertions, and purple- and deep-purple mutants had 21- and 24-bp deletions, respectively. Real-time reverse transcription polymerase chain reaction (RT–PCR) analysis showed that F3′5′H expression levels correlated with insertions and deletions (indels) caused by hAT excision, resulting in flower-color differences. Our results showed that tissue culture of Saintpaulia ‘Thamires’ elicits transposon excision, which in turn alters F3′5′H expression levels and flower colors.

Tissue culture-induced flower-color changes in Saintpaulia caused by excision of the transposon inserted in the flavonoid 3′, 5′ hydroxylase (F3′5′H) promoter

The relationship between genotype, tissue age and endogenous cytokinin levels on adventitious bud formation on Lachenalia leaf tissue were investigated. The genotypes studied, showed a variation in bud formation. The hybrid explants responded differently to factorial combinations of BA and NAA. The growth regulators could not substitute for the regeneration potential of the genotype. Tissue age had a pronounced effect on regeneration potential. Young tissue formed the largest number of buds. An interaction between tissue age and genotype was detected. Cytokinin levels in young leaf tissue were higher than in older tissue. In young tissue no relationship was observed between the cytokinin level and the number of buds formed. However, in older tissue it appears as if a relatively low endogenous cytokinin level enhanced bud formation.

The relationship between genotype, tissue age and endogenous cytokinin levels on adventitious bud formation on leaves of Lachenalia

1. Thin Cell Layer Concept.- 2. Tobacco Thin Cell Layer morphogenesis.- 3. Cells: Functional units of Thin Cell Layers.- 4. Control of plant organogenesis: genetic and biochemical signals in plant organ form and development.- 5. Methyl jasmonate and ethylene interfere with polyamine metabolism and organogenesis in tobacco Thin Cell Layers.- 6. Biochemical and molecular markers in programmed plant differentiation and manipulation of the morphogenetic pathways in tobacco and lily by using Thin Cell Layer technique.- 7. Thin Cell Layer morphogenesis as a powerful tool in ornamental plant micropropagation and biotechnology.- 8. Thin Cell Layers and floral morphogenesis, floral genetics and in vitro flowering.- 9. Regeneration and transformation of Lilium longiflorum by using Thin Cell Layer procedures.- 10. Thin Cell Layer studies of vegetable, leguminous and medicinal plants.- 11. Organogenesis of cereals and grasses by using Thin Cell Layer technique.- 12. Thin Cell Layer technology in fruit crop regeneration.- 13. Woody plant micropropagation and morphogenesis by Thin Cell Layers.- 14. Genetic transformation using Thin Cell Layer.- Index of species.- Index of subjects.

Thin Cell Layer Culture System: Regeneration and Transformation Applications

Production and growth analysis of plants from leaf cuttings, and from tissue cultures of disks from mature leaves and young axenic leaves of African Violet (Saintpaulia ionantha Wendl.)

Screening of Saintpaulia ionantha Wendl. cultivars for caulogenetic potential based on the in vitro responses of young axenic leaves on auxin and cytokinin factorial media

A. Plunkett

Papers

Production and growth analysis of plants from leaf cuttings, and from tissue cultures of disks from mature leaves and young axenic leaves of African Violet (Saintpaulia ionantha Wendl.)

Screening of Saintpaulia ionantha Wendl. cultivars for caulogenetic potential based on the in vitro responses of young axenic leaves on auxin and cytokinin factorial media