Effect of activated charcoal and ascorbic acid on in vitro morphogenesis and o-dihydroxyphenols content in Paphiopedilum insigne

Phenolic compounds limit micropropagation of many orchids in vitro. The aim of the study was to estimate the effect of activated charcoal (AC);1, 2 or 4 g/L) or ascorbic acid (AA; 10, 20 or 30 mg/L) added to the half strength MS medium on the growth and o-dihydroxyphenols content in Paphiopedilum insigne in vitro. A positive effect of AC on the shoot and root formation has been found. The highest multiplication rate (5.6 shoots/explant) and rooting frequency were obtained on medium containing 2 g/L of AC. However, AC reduced the leaf number as compared to the control. The lowest content of o-dihydroxyphenols was marked in Paphiopedilum insigne leaves when the shoots were grown on medium with 10 mg/L AA, followed by AC at 1 or 2 g/L.

BA and TDZ in the Morphogenesis in Vitro of Passiflora Setacea

Passiflora setacea DC (Passifloraceae) is considered an important species in the genetic breeding of passion fruit. However, its use is limited due to low seed germination. This paper aimed to study the effect of cytokinins 6-benzyladenine (BA) and thidiazuron (TDZ) on the in vitro morphogenesis of P. setacea using three explants: hypocotyl, nodal segment, and root segment. The explants were induced to morphogenesis in MS medium modified and with different concentrations of BA and TDZ. After 55 days, the percentage of calluses and shoots were evaluated, and anatomical characterization was performed. The three explants used in the in vitro morphogenesis of P. setacea showed callus and shoots formation, but in greater numbers in the nodal segments treated with BA. TDZ isolated affected equal to or less than BA on callus and shoots formation for the three explants. Direct and indirect organogenesis was observed in the three types of explants. From the results obtained for plant regeneration via in vitro morphogenesis of P. setacea, it is recommended to use a nodal segment in MSM medium and supplemented with 2.22 μmol L-1 of BA.

In vitro germination of Abricó-de-Macaco (Couroupita guianensis aubl.)zygotic embryos in different culture media and light spectra

ABSTRACT: Couroupita guianensis Aubl. is an Amazonian forest species with important medicinal and ornamental value. This study evaluated the effect of different culture media and light spectra on the in vitro germination and development of the zygotic embryos of C. guianensis. The culture media, MS and WPM, were evaluated without the addition of plant growth regulators and were associated with four LED light spectra: white (CW), 70% red + 30% blue (R2B), 100% red (R), and 100% blue (B). One hundred percent of the seeds successfully underwent in vitro germination, and the culture media did not interfere with embryo development. In addition to this, the different light spectra induced in vitro morphogenesis and R2B treatment significantly promoted the production of secondary roots. This effect may aid in the rooting and acclimatization of seedlings of this species.

Dolutegravir impairs stem cell-based 3D morphogenesis models in a manner dependent on dose and timing of exposure: an implication for its developmental toxicity

Dolutegravir is an anti-retroviral drug of the integrase strand transfer inhibitor class used to treat HIV infection. It is the recommended first-line regimen for most people, including women of childbearing age. However, some human and animal studies have suggested that dolutegravir causes birth defects, although its developmental toxicity remains controversial. Here, we investigated the adverse effects of dolutegravir using pluripotent stem cell-based in vitro morphogenesis models that have previously been validated as effective tools to assess the developmental toxicity of various chemicals. Dolutegravir diminished the growth and axial elongation of the morphogenesis model of mouse pluripotent stem cells at exposures of 2 μM and above in a concentration-dependent manner. Concomitantly, dolutegravir altered the expression profiles of developmental regulator genes involved in embryonic patterning. The adverse effects were observed when the morphogenesis model was exposed to dolutegravir at early stages of development, but not at later stages. The potency and molecular impact of dolutegravir on the morphogenesis model were distinct from other integrase strand transfer inhibitors. Lastly, dolutegravir altered the growth and gene expression profiles of the morphogenesis model of human embryonic stem cells at 1 μM and above. These studies demonstrate that dolutegravir impairs morphological and molecular aspects of the in vitro morphogenesis models in a manner dependent on dose and timing of exposure through mechanisms that are unrelated to its action as an integrase strand transfer inhibitor. This finding will be useful for interpreting the conflicting outcomes regarding the developmental toxicity of dolutegravir in human and animal studies.

The Effect of Trifluralin on Post-in vitro Morphogenesis of Five Genotypes of Head Cabbage (Brassica oleraceae var. capitata)

Six genotypes of head cabbage (‘Flexima’, ‘Mutsuma’, ‘Septima’, ‘Zeus’, DC6, ‘Ancoma’) have been studied to find an effective method of obtaining polyploids using trifluralin. The effect of various trifluralin concentrations (0.5, 1.0, 1.5, and 2.0 mg·L−1) and treatment conditions (24 °C/24 h, 24 °C/48 h, 30 °C/24 h, and 30 °C/48 h) on organogenesis of organogenic callus, hypocotyl, and seeds was tested. Ploidy level was detected using a flow cytometer. As a result, low survival of hypocotyls and calli was obtained. The shoots induced from calli and hypocotyls failed to develop quality plantlets and most calli and hypocotyls remained recalcitrant for further differentiation. Treated seeds seemed to be promising objects basing on a considerable percentage of plant regeneration. With the increased concentration of trifluralin and increasing press of treatment conditions, the seed germination rate was significantly reduced. Shoot induction from germinated seeds varied among genotypes and treatments. The root induction was independent of treatments but also reduced considerably compared to the control. Under tested conditions, none of the polyploids resulted. Further studies are required to be successful in protocol development.

In vitro morphogenesis of Physalis ixocarpa Brot ex. Horm

ABSTRACT Physalis ixocarpa Brot. ex Horm. is considered the most economically important species of the genus. Tissue culture is pointed out as a strategy for its propagation, but researches indicate that in vitro responses are genotype-dependent. This study aimed to evaluate the in vitro morphogenesis of the P. ixocarpa green and purple varieties, in view of the massive propagation of the species. The morphogenic capacity of the explants cotyledonary node, hypocotyl and cotyledon was evaluated in Murashige & Skoog medium supplemented with benzylaminopurine - BAP (0.00, 2.5, 5.0, 7.5 or 10.0 μM) and naphthaleneacetic acid - NAA (0.00 or 2.5 μM), using a completely randomized experimental design, in a 3 x 5 x 2 factorial scheme, with 30 treatments for each variety. The number of shoots per direct and indirect organogenesis and the percentage of explants with callus were analyzed. The in vitro morphogenetic expression of P. ixocarpa is influenced by the type of explant and by the plant regulators BAP and NAA. The cotyledonary node explant is efficient for the production of shoots via direct organogenesis in the two varieties studied.