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Plants, whilst also having an ornamental role, are also a source of beneficial, bioactive compounds, and in vitro cultures are helpful in finding and obtaining them. Streptocarpus ×hybridus can be a source of antioxidants. The effect of different LED light qualities on the growth, development and metabolite composition of Streptocarpus multiplied in vitro on Murashige and Skoog medium was investigated. The used spectra were: 100% blue (B), 100% red (R), red and blue in 7:3 proportion (RB), 50% RB + 50% ultra violet (RBUV), 50% RB + 50% green (RBG), 50% RB + 50% yellow (RBY), 50% RB + 50% far red (RBfR), and white (WLed). A fluorescent lamp served as the control (Fl). For the best morphological quality of multiplied plants, the use of RBY light is recommended. Fl light reduced the antioxidant properties of extracts compared to LEDs. The most recommended spectrum in this aspect is RBfR, WLed, RBG and R light. These lights (except for R) stimulated the polyphenol content. RBY and R light influenced the highest content of free amino acids and reducing sugars. Studies showed that a selected LED light spectrum can influence the production of plant biomolecules with antioxidant properties and, compared to Fl light, improves the growth and development of multiplied plants. [ABSTRACT FROM AUTHOR]

Streptocarpus is a very popular houseplant with colorful flowers, and has thus piqued the curiosity of plant enthusiasts and breeders. In this study, "Natalie" and "Bristol's Gum Drop" were artificially hybridized to study the influence of the parental reciprocal crosses (P1×P2 and P2×P1) on vegetative and generative morphological traits of F1 progeny. Mean comparisons for morphological characters of parents and F1 plants from both crosses revealed that F1 plants were able to express hybrid vigor for several valuable morphological characteristics. Pearson correlations showed both significant negative and positive correlations between morphological traits of F1 plants from P1×P2 cross, while in the case of P2×P1 no significant negative correlations were observed (p < 0.05). The Start Codon Targeted (SCoT) genetic profiles of the F1 plants with the identifiers P1×P2.19 and P1×P2.35 were remarkably similar, and they grouped with the maternal parent in a small group, supporting the findings of clustering based on morphological data. The parental combination P2×P1 revealed the presence of closely related progenies to the paternal parent, namely P2×P1.16 and P2×P1.5. Two F1 plants named P1×P2.33 and P2×P1.21 were selected based on their phenotypic characteristics and SCoT molecular fingerprinting. These selected genotypes will be tested in our future breeding programs with the aim to create and promote new valuable Streptocarpus cultivars. [ABSTRACT FROM AUTHOR]

Plants, whilst also having an ornamental role, are also a source of beneficial, bioactive compounds, and in vitro cultures are helpful in finding and obtaining them. Streptocarpus ×hybridus can be a source of antioxidants. The effect of different LED light qualities on the growth, development and metabolite composition of Streptocarpus multiplied in vitro on Murashige and Skoog medium was investigated. The used spectra were: 100% blue (B), 100% red (R), red and blue in 7:3 proportion (RB), 50% RB + 50% ultra violet (RBUV), 50% RB + 50% green (RBG), 50% RB + 50% yellow (RBY), 50% RB + 50% far red (RBfR), and white (WLed). A fluorescent lamp served as the control (Fl). For the best morphological quality of multiplied plants, the use of RBY light is recommended. Fl light reduced the antioxidant properties of extracts compared to LEDs. The most recommended spectrum in this aspect is RBfR, WLed, RBG and R light. These lights (except for R) stimulated the polyphenol content. RBY and R light influenced the highest content of free amino acids and reducing sugars. Studies showed that a selected LED light spectrum can influence the production of plant biomolecules with antioxidant properties and, compared to Fl light, improves the growth and development of multiplied plants.

Streptocarpus is a very popular houseplant with colorful flowers, and has thus piqued the curiosity of plant enthusiasts and breeders. In this study, “Natalie” and “Bristol’s Gum Drop” were artificially hybridized to study the influence of the parental reciprocal crosses (P1×P2 and P2×P1) on vegetative and generative morphological traits of F1 progeny. Mean comparisons for morphological characters of parents and F1 plants from both crosses revealed that F1 plants were able to express hybrid vigor for several valuable morphological characteristics. Pearson correlations showed both significant negative and positive correlations between morphological traits of F1 plants from P1×P2 cross, while in the case of P2×P1 no significant negative correlations were observed (p < 0.05). The Start Codon Targeted (SCoT) genetic profiles of the F1 plants with the identifiers P1×P2.19 and P1×P2.35 were remarkably similar, and they grouped with the maternal parent in a small group, supporting the findings of clustering based on morphological data. The parental combination P2×P1 revealed the presence of closely related progenies to the paternal parent, namely P2×P1.16 and P2×P1.5. Two F1 plants named P1×P2.33 and P2×P1.21 were selected based on their phenotypic characteristics and SCoT molecular fingerprinting. These selected genotypes will be tested in our future breeding programs with the aim to create and promote new valuable Streptocarpus cultivars.

Streptocarpus formosus (Hilliard & B.L. Burtt) T.J. Edwards is a flowering herbaceous perennial indigenous to South Africa and is part of the rosulate group of herbaceous acaulescent plants within the Gesneriaceae family. According to the National Assessment database for the Red List of South African Plants version 2020.1., the plant is listed as rare. The ornamental use of S. formosus has untapped commercial potential as a flowering indoor pot plant, an outdoor bedding plant for shade and as a cut flower for the vase, all of which are limited by a five-month eco-dormancy period during the late autumn and all through the cold season in the short-day winter months. Viable commercial production will require cultivation techniques that produce flowering plants all year round. This study investigated the effectiveness of applying root zone heating to S. formosus plants grown in deep water culture hydroponics during the eco-dormancy period in preventing abscission layer formation and in encouraging flowering and assessed the growth activity response of the plants. The experiment was conducted over eight weeks during the winter season in the greenhouse at Kirstenbosch Botanical garden in water reservoirs, each maintained at five different experimental temperature treatments (18, 22, 26—control, 30 and 34 ◦C) applied to 10 sample replicates. The results showed that the lowest hydroponic root zone temperature of 18 ◦C had the greatest effect on the vegetative growth of S. formosus, with the highest average increases in fresh weight (1078 g), root length (211 cm), overall leaf length (362 cm) and the number of newly leaves formed (177 = n), all noted as statistically significant when compared with the other water temperature treatments, which yielded negative results from reduced vegetative growth. Findings from the study also revealed that while all heated solutions significantly prevented the formation of abscission layers of S. formosus, they had a less significant effect on inflorescence formation, with only 18 ◦C having the greatest positive effect on flower development. [ABSTRACT FROM AUTHOR]

Streptocarpus x hybridus is a very popular houseplant with colourful flowers arousing thus the interest of plant breeders. Its potential value is even higher since different chemical compounds could be identified and used for food and pharmaceutical industries. Therefore, the objectives of this study were: to determine genetic relationships between twelve F1 Streptocarpus hybrids and their genitors; to determine the total phenolic and flavonoid content; to evaluate the antioxidant activity of the analysed individuals. Although 12 out of the 24 RAPD primers detected polymorphism among the individuals, the UPGMA dendrogram did not show a very clear grouping pattern for flower colour. In contrast, the phytochemical dendrogram shed more light on the dissimilarities among Streptocarpus flowers in terms of their polyphenolic content. The total phenolic and flavonoid content of the flower extracts determined by the Folin-Ciocalteau and aluminium chloride colorimetric methods ranged from 680.02 to 2360.57 mg of GAE/100 g FW and from 12.52 to 78.36 mg QE/100 g FW. The radical scavenging activity against ABTS ranged from 27.17 to 130.35 µM Trolox/g FW. Due to its ornamental value, H12 was screened by HPLC-PDA-ESI-MS to identify and quantify the chemical compounds involved in flower colour. Among the six compounds that were identified and quantified ( i.e. cyanidin-3-O-galactoside, cyanidin-3-O-xyloside, cyanidin-3-O-glucoside, cyanidin-3-O-arabinoside, peonidin-3-O-glucoside and apigenin-6-C-glucoside), isovitexin reached the highest concentration 4183 µg rutin/100 g FW. These preliminary results, showing high total polyphenolic content and ABTS antioxidant activity, suggest that Streptocarpus flowers could be a valuable source of antioxidants. [ABSTRACT FROM AUTHOR]

A micropropagation protocol via direct shoot organogenesis from Streptocarpus x hybridus Voss. leaf explants was established in this study. The shoot induction of three Streptocarpus cultivars (‘Snow White’, ‘Black Panther’ and ‘Slumber Song’) was successfully achieved on Murashige and Skoog (MS) medium supplemented with 0.2 mg L-1 -indole-3-acetic acid (IAA) and 0.2 mg L-1 thidiazuron (TDZ). In proliferation stage, the effects of two combinations of plant growth regulators -PGR- (V1-0.2 mg/L-1 IAA + 0.5 mg/L-1 BAP and V2-1.0 mg L-1 NAA + 0.2 mg L-1 TDZ) on shoot number and length were examined. The results suggest that PGRs combinations significantly influenced shoot proliferation and root induction in all Streptocarpus cultivars. Among the treatments, 0.2 mg L-1 (IAA) in combination with 0.5 mg L-1 6-benzylaminopurine (BAP) were the most effective for in vitro shoot multiplication and rooting. The in vitro rooting percentage was also determined before subjecting the plantlets to the acclimatization process. Due to acclimatization, Streptocarpus plantlets showed a very high rate of survival (90%). The generated PCR-RAPD profiles for the selected in vitro-raised plants and donor plants were similar which indicates the clonal or true-to-type nature of the progenies.

Streptocarpus formosus (Hilliard & B.L. Burtt) T.J. Edwards is a flowering herbaceous perennial indigenous to South Africa and is part of the rosulate group of herbaceous acaulescent plants within the Gesneriaceae family. According to the National Assessment database for the Red List of South African Plants version 2020.1., the plant is listed as rare. The ornamental use of S. formosus has untapped commercial potential as a flowering indoor pot plant, an outdoor bedding plant for shade and as a cut flower for the vase, all of which are limited by a five-month eco-dormancy period during the late autumn and all through the cold season in the short-day winter months. Viable commercial production will require cultivation techniques that produce flowering plants all year round. This study investigated the effectiveness of applying root zone heating to S. formosus plants grown in deep water culture hydroponics during the eco-dormancy period in preventing abscission layer formation and in encouraging flowering and assessed the growth activity response of the plants. The experiment was conducted over eight weeks during the winter season in the greenhouse at Kirstenbosch Botanical garden in water reservoirs, each maintained at five different experimental temperature treatments (18, 22, 26—control, 30 and 34 °C) applied to 10 sample replicates. The results showed that the lowest hydroponic root zone temperature of 18 °C had the greatest effect on the vegetative growth of S. formosus, with the highest average increases in fresh weight (1078 g), root length (211 cm), overall leaf length (362 cm) and the number of newly leaves formed (177 = n), all noted as statistically significant when compared with the other water temperature treatments, which yielded negative results from reduced vegetative growth. Findings from the study also revealed that while all heated solutions significantly prevented the formation of abscission layers of S. formosus, they had a less significant effect on inflorescence formation, with only 18 °C having the greatest positive effect on flower development.

The genetic relationship among three Streptocarpus parents and twelve F1 hybrids was assessed using sequence-related amplified polymorphism (SRAP) molecular markers and Fourier-transform infrared (FT-IR) spectroscopy. Both methods were able to discriminate F1 hybrids and parents as revealed by cluster analysis. For hybrid identification, the type III SRAP marker was the most effective due to the presence of male-specific bands in the hybrids. Different behaviors in the biochemical variability of DNA samples have been observed by FT-IR spectral analysis, which might be attributed to the inherent nature of the genomic DNA from parents and their F1 progenies. Mantel test was also carried out to compare morphological, SRAP, and FT-IR results based on genetic distances. The highest correlation coefficient was found between morphological and SRAP marker distances (R = 0.607; p ≤ 0.022). A lower correlation was observed between the morphological and FT-IR distance matrix (R = 0.231; p ≤0.008). Moreover, a positive correlation was found between the distances generated with SRAP and FT-IR analyses (R = 0.026) but was not statistically significant. These findings show that both SRAP and FT-IR techniques combined with morphological descriptions can be used effectively for nonconventional breeding programs for Streptocarpus to obtain new and valuable varieties.

A micropropagation protocol via direct shoot organogenesis from Streptocarpus x hybridus Voss. leaf explants was established in this study. The shoot induction of three Streptocarpus cultivars ('Snow White', 'Black Panther' and 'Slumber Song') was successfully achieved on Murashige and Skoog (MS) medium supplemented with 0.2 mg L-1 -indole-3-acetic acid (IAA) and 0.2 mg L-1 thidiazuron (TDZ). In proliferation stage, the effects of two combinations of plant growth regulators -PGR- (V1-0.2 mg/L-1 IAA + 0.5 mg/L-1 BAP and V2-1.0 mg L-1 NAA + 0.2 mg L-1 TDZ) on shoot number and length were examined. The results suggest that PGRs combinations significantly influenced shoot proliferation and root induction in all Streptocarpus cultivars. Among the treatments, 0.2 mg L-1 (IAA) in combination with 0.5 mg L-1 6-benzylaminopurine (BAP) were the most effective for in vitro shoot multiplication and rooting. The in vitro rooting percentage was also determined before subjecting the plantlets to the acclimatization process. Due to acclimatization, Streptocarpus plantlets showed a very high rate of survival (90%). The generated PCR-RAPD profiles for the selected in vitro-raised plants and donor plants were similar which indicates the clonal or true-to-type nature of the progenies. [ABSTRACT FROM AUTHOR]

The genetic relationship among three Streptocarpus parents and twelve F1 hybrids was assessed using sequence-related amplified polymorphism (SRAP) molecular markers and Fourier-transform infrared (FT-IR) spectroscopy. Both methods were able to discriminate F1 hybrids and parents as revealed by cluster analysis. For hybrid identification, the type III SRAP marker was the most effective due to the presence of male-specific bands in the hybrids. Different behaviors in the biochemical variability of DNA samples have been observed by FT-IR spectral analysis, which might be attributed to the inherent nature of the genomic DNA from parents and their F1 progenies. Mantel test was also carried out to compare morphological, SRAP, and FT-IR results based on genetic distances. The highest correlation coefficient was found between morphological and SRAP marker distances (R = 0.607; p ≤ 0.022). A lower correlation was observed between the morphological and FT-IR distance matrix (R = 0.231; p ≤0.008). Moreover, a positive correlation was found between the distances generated with SRAP and FT-IR analyses (R = 0.026) but was not statistically significant. These findings show that both SRAP and FT-IR techniques combined with morphological descriptions can be used effectively for nonconventional breeding programs for Streptocarpus to obtain new and valuable varieties. [ABSTRACT FROM AUTHOR]