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The present study evaluated the vegetative propagation of Saintpaulia (African violets). Five genotypes of Saintpaulia were used: Saintpaulia ionantha Shades of Autumn (G1), Saintpaulia ionantha Zoja (G2), Saintpaulia ionantha Delft (G3), Saintpaulia ionantha Milky Way Trail (G4) and Saintpaulia ionantha Tongwenis (G5). Three growth substrates consisting of sand (San, Gs1), sand and peat (San/Pea, 1:1 mixture, Gs2) and perlite and peat (Per/Pea, 1:1, Gs3 mixture) were used. From the combination of genotypes with growth substrates, 15 experimental variants were obtained. The experiment was organized in a protected space, with 15 leaf cuttings on each variant, in three repetitions. The number of rooted shoots (Sn) and the length of the roots (Rl) were evaluated. Compared to the experience average, there were positive differences in statistical safety conditions for variants V2, V7, V8 and V14 (for LSD0.1%). Negative differences in statistical safety conditions were recorded in variants V3, V4, V6 and V15 (for LSD0.1%), and in variants V10 and V12 (for LSD1%). According to the PCA, PC1 explained 85.684% of the variance, and PC2 explained 14.316% of the variance. Cluster analysis led to the grouping of variants based on Euclidean distances, in relation to the values generated for Sn and Rl, in statistical safety conditions (Coph.corr = 0.784). The result was two distinct clusters, with several subclusters each. The analysis of SDI values found the highest level of similarity between variants G1-Gs1 and G4-Gs1 (SDI = 0.3607), followed by variants G2-Gs2 and G4-Gs1 (SDI = 0.4000), respectively by variants GG4-Gs2 with G5-Gs2 (SDI = 0.5900). [ABSTRACT FROM AUTHOR]

Saintpaulia ionantha is propagated by adventitious buds in horticulture, and periclinal chimeral cultivars are usually difficult to propagate. However, some periclinal chimeral cultivars can be propagated with adventitious buds, and the mechanism of which has been unknown. Striped flower cultivars “Kaname,” “Concord,” and “Monique” were used to investigate what causes flower color separation in adventitious shoot-derived plants by tissue culture. These cultivars were revealed to have mutated flavonoid 3′, 5′ hydroxylase (SiF3′5′H), WDR1 (SiWDR1), or flavonoid 3 hydroxylase (SiF3H), respectively, in their L1 layer. From our previous study using “Kaname,” all flowers from adventitious shoots were colored pink, which was the epidermal color of mother plants' flowers. We used “Concrd” and “Monique” from which we obtained not only monochromatic-colored plants the same as the epidermal color of mother plants, but also plants with a monochromatic colored plants, same as the subepidermal color, and a striped flower color the same as mother plants. Histological observations revealed that epidermal cells divided actively at 14 d after culture and they were involved in the formation of adventitious shoots in the cultured leaf segments of “Kaname.” On the other hand, in “Concord” and “Monique,” the number of divided cells in the subepidermis was rather higher than that of epidermal cells, and subepidermal cells were sometimes involved in shoot formation. In addition, the plant and leaf size of L1-derived plants from “Concord” and “Monique” were non-vigorous and smaller than those derived from the subepidermal layer. In conclusion, periclinal chimeral cultivars of Saintpaulia can be divided into two types. One type has a high cell division activity in the L1 layer, from which only single flower-colored plants derived from L1 can be obtained as adventitious shoots. Another type has a low cell division activity in the L1 layer, from which striped flower-colored plants the same as mother plants derived from several layers including L1 can be obtained as adventitious shoots. In the periclinal chimeral cultivar capable of propagation with adventitious shoots, the possibility was shown that cells in the L2 layer could form shoots by involving cells of the L1 layer with a low division activity.

Abstract: The presence of introduced or non‐native bacteria in river water can create a selective pressure due to their ability to overcome fluctuations in physicochemical conditions and carbon source availability. The carbon source concentrations (monosaccharides and polysaccharides), physicochemical parameters (turbidity, total dissolved solids, biochemical oxygen demand, temperature and pH) and metabolic activity of Salmonella Oranienburg and Saintpaul were determined in water from the central Sinaloa state rivers. This study's results revealed that the carbohydrate availability and physicochemical conditions of river water make it a suitable niche for the establishment of Salmonella serotypes. Metabolic profiles showed that Salmonella Typhimurium could consume a wide variety of carbon sources but only at moderate levels; in contrast, Salmonella Oranienburg and Salmonella Saintpaul demonstrated intense carbon source utilization of a limited diversity of carbon sources. Carbohydrates, amino acids and carboxylic acids were the metabolites most utilized by the environmental Salmonella strains, demonstrating their superior ability to adapt to and survive in river water. [ABSTRACT FROM AUTHOR]

In this study, we revealed how the petals of Saintpaulia fuse into a corolla by using pinwheel phenotype cultivars. Striped patterns in petal, called pinwheel in Saintpaulia , are attractive phenotypes and thought to be the result of periclinal chimerism. For the selection of a genuine periclinal chimeric cultivar from three pinwheel cultivars, adventitious shoots were induced from leaf lamina. Shoot regeneration was observed from the epidermis in all cultivars by microscopic observation. All regenerated shoots from ‘Kaname’ flowered as monochromatic pink flowers, corresponding to an L1 phenotype of the cultivar. From the other two cultivars, many shoots flowered not only as an epidermal phenotype but also as a phenotype of the inner layer. In addition, shoot regeneration was induced from epidermis-peeled petioles from these three cultivars. All shoots from ‘Kaname’ flowered as monochromatic blue flowers, corresponding to an L2 phenotype. On the other hand, many shoots from ‘Kilauea’ flowered not only as monochromatic flowers, corresponding to an L2 phenotype, but also as bi-colored flowers. ‘Innocent Pink’ did not produce shoots from epidermal-peeled petioles. These results suggested that ‘Kaname’ is a genuine periclinal chimera, while the other two cultivars have other mechanisms for pinwheel expression. Genomic PCR using primers that amplifies almost the full length of flavonoid 3′,5′-hydroxylase ( F3 ʹ 5 ʹ H ) revealed the gene to be non-functional in pink flowers from L1 of ‘Kaname’. From monochromatic pink plants and pink portions of the corolla of ‘Kaname’, full-length F3 ʹ 5 ʹ H was not amplified. Similar results were obtained by quantitative PCR. Finally, we observed the fused portion of the petals and revealed that the petal fusion did not occur by postgenital fusion but by “connection”. The process, in Saintpaulia , comprises periclinal cell division in L1 during petal development, active cell division at the edge of the petal, adhesion to the next petals, and fusion. These steps create a striped flower color in Saintpaulia . [ABSTRACT FROM AUTHOR]

Several photographs of different varieties of African violets are presented including Sierra Sunrise, Jersey Little Devil, and Rob's Sarsparilla.

The taxonomy of the African, Madagascan and Comoro Island (Afro-Malagasy) Gesneriaceae attracts a large amount of interest given the horticultural importance of Cape Primroses (Streptocarpus) and African Violets (Saintpaulia). Earlier studies indicated that the Afro-Malagasy genera form a strongly supported clade, and recent classifications have included some of the genera within an expanded Streptocarpus. Given the global importance of this group, we carried out a comprehensive molecular phylogenetic analysis of all Afro-Malagasy genera in subfamily Didymocarpoideae, tribe Trichosporeae, subtribe Streptocarpinae, to investigate species relationships in these genera as the basis for a new classification. Phylogenetic analyses of the nuclear ribosomal spacer (ITS, 5S NTS) and chloroplast intron and spacer regions (rp120-rps12 spacer, trnL intron, trnLF spacer) of 226 samples were performed, including all Streptocarpinae genera, except the monotypic Nodonema. The molecular phylogenies demonstrate that the genera with non-twisted fruits are nested within Streptocarpus which has twisted fruits. Two main clades were found, one comprising herbaceous caulescent Streptocarpus that also included Saintpaulia, the caulescents Hovanella and Schizoboea, and the unifoliates Acanthonema and Trachystigma. The second clade comprises the woody caulescents and acaulescent Streptocarpus, Colpogyne and Linnaeopsis. Altogether, twelve well-supported subclades can be recognized, each with a combination of distinct morphological characteristics. A new classification of tribe Streptocarpinae, de facto Streptocarpus, is presented, retaining the two subgenera, Streptocarpus and Streptocarpella, and dividing them into five and seven sections respectively. Nodonema is attributed to subg. Streptocarpus for morphological reasons. The former genus Saintpaulia is classified as Streptocarpus subg. Streptocarpella sect. Saintpaulia with ten species recognized. [ABSTRACT FROM AUTHOR]

Saintpaulia (African violet) leaves are known to be damaged by a rapid temperature decrease when cold water is applied to the leaf surface; the injury is ascribed to the chloroplast damage caused by the cytosolic pH decrease following the degradation of the vacuolar membrane in the palisade cells. In this report, we present evidence for the involvement of Ca2+ in facilitating the collapse of the vacuolar membrane and in turn in the temperature sensitivity of Saintpaulia leaves. In the presence of a Ca2+ chelator (EGTA) or certain Ca2+ channel inhibitors (Gd3+ or La3+) but not others (verapamil or nifedipine), the pH of the vacuole, monitored through BCECF (20,70-bis(carboxyethyl)-4 or 5-carboxyfluorescein) fluorescence, did not increase in response to a rapid temperature drop. These pharmacological observations are consistent with the involvement of mechanosensitive Ca2+ channels in the collapse of the vacuolar membrane. The high level of expression of an MCA- (Arabidopsis mechanosensitive Ca2+ channel) like gene, a likely candidate for a mechanosensitive Ca2+ channel(s) in plant cells, was confirmed in the palisade tissue in Saintpaulia leaves by using a newly developed method of gene expression analysis for the specialized small tissues. [ABSTRACT FROM AUTHOR]

In order to estimate the correlation between pollen viability, germination and the morphological traits, 15 Saintpaulia genotypes were analysed. Pollen viability was obtained by staining with potassium iodide (25%) and germination was estimated using solid nutrient medium (15% sucrose, 85% humidity, 22 °C temperature). Several morphological traits such as number of flowers, diameter of leaves rosette, number of leaves, length and width of leaves and petiole length were evaluated to determine growth indices. The results obtained indicated that 'Hot Pink Bell' genotype achieved the highest number of flowers and the largest diameter of leaves rosette. Genotypes 'Tomahawks' and S. grotei recorded the highest number of leaves. Higher width of leaves values was obtained in 'Aloha Orchid', while genotype 'Park Avenue Blue' was noted for a high length of leaves. Positive correlations were recorded among viability and germination in S. jonantha, S. rupicola and S. grotei. Significant positive correlation was registered between pollen viability and the number of flowers, but also between germination and the number of flowers per plant. The results indicated a possible correlation between viability, germination capacity and the morphological traits in most genotypes studied. [ABSTRACT FROM AUTHOR]