Thin Cell Layer (TCL) Culture System for Herbal Biomass Production and Genetic Transformation of Bacopa monnieri L. Wettst.

Bacopa monnieri (L.) Wettst. (Scrophulariaceae) is a highly sought after medicinal plant with therapeutic properties as cognition enhancer as well as for other brain and body functions. Research was conducted to optimize a thin cell layer explant based micropropagation system to assist mass propagation. Thin cell layers (TCL) derived from leaf and internode segments were used as explants. Murashige and Skoog medium was used to formulate shoot induction, elongation, and rooting media. Shoot induction media were prepared by supplementing three concentrations (0.1, 1.0, and 10.0 μM) of four cytokinins 6-benzylaminopurine, 2-isopentenyl-adenine, 6-3-Hydroxybenzylaminopurine, and thidiazuron to study adventitious shoot bud induction response. An optimum shoot bud induction response was observed on MS medium supplemented with 10.0 μM 6-benzylaminopurine for both leaf and stem transverse thin cell layer (tTCL) explants. The average number of shoot buds from leaf tTCL explants was 59, whereas, on an average, 33 shoot buds were regenerated from internode tTCL explants. Elongation of adventitious shoot buds was achieved best in a liquid medium using Liquid Lab Rocker® system. Elongated shoots recorded 100% rooting in MS medium supplemented with 5 μM indole butyric acid. Bacopa micropropagation employing tTCL explants for initial shoot bud induction and using LLR® boxes in subsequent elongation step can achieve cost effective way to regenerate high volume of plantlets and biomass required for herbal industry. Leaf and stem tTCL explants both were suitable for Agrobacterium tumefaciens (EHA105) mediated genetic transformation. Successful transformation was scored within three days of co-cultivation with Agrobacterium suspension on the basis of Enhanced Green Fluorescent Protein (EGFP) expression as an early and non-destructible screening device. Transformation frequencies of 83% and 76% were accomplished for leaf and stem tTCL explants, respectively. Greenhouse grown Bacopa plants were analyzed as fresh and dry methanolic extracts for total polyphenol content (811.93 ± 7.98 and 814 ± 17.64 GAE mg g-1) and the Trolox Equivalent Antioxidant Capacity values were 1918.25 ± 173.12 and 3163.14 ± 403.25 μmol/g, respectively.

A Review of <i>Paulownia</i>Biotechnology: A Short Rotation, Fast Growing Multipurpose Bioenergy Tree

Paulownia is a genus of fast-growing and multipurpose tree species that is native to China. Due to their rapid growth and value in the timber market, many Paulownia species are cultivated in several temperate zones worldwide. Economic importance of Paulownia is increasing as new uses and related products are developed. It is also suitable as a lignocellulosic feedstock crop for the bioethanol industry in the Southeastern USA. A number of Paulownia species are valuable sources of secondary metabolites including flavonoids with high antioxidant activities. A high demand for planting material in domestic and international markets for afforestation and bioenergy production has necessitated the development of efficient micropropagation protocols for rapid and mass propagation of Paulownia. Over the past several decades, research on Paulownia species has been conducted to develop micropropagation, somatic embryogenesis and genetic transformation protocols for use in agroforestry and reforestation programs. Given the economic importance and current and potential future uses of Paulownia, this paper reviews the development of biotechnological approaches for plant propagation and genetic improvement, and antioxidant potential of secondary metabolites occurring in species.

Cytokinin, Carbon Source, and Acclimatization Requirements for <i>in Vitro</i>Propagation of <i>Scutellaria barbata</i>D. Don and <i>Scutellaria racemosa</i>Pers.

Micropropagation protocols to minimize hyperhydricity were optimized for medicinal Scutellaria barbata and Scutellaria racemosa. Six cytokinins and eight different carbon sources at two different incubation periods of 14 and 21 days were studied for adventitious shoot bud induction using nodal explants. In S. barbata, 5 μM meta-Topolin and 0.1 μM NAA supplemented shoot induction medium produced four shoots each after 14 and 21 day incubation. Observation of S. racemosa nodal explants recorded four and five shoots after 14 and 21 day incubation. In both species, control explants (no plant growth regulators in the medium) consistently resulted in the bud break with two shoots in both 14 and 21 day incubation. The effect of carbon source on shoot regeneration was studied by supplementing eight different sugars at 0.1 M concentration to the optimized shoot induction medium (5 μM meta-Topolin and 0.1 μM NAA). S. barbata nodal explants cultured on shoot induction medium supplemented with fructose and glucose for 14 days produced 10 and nine adventitious shoots respectively;and after 21 day incubation adventitious shoot count reached 19 in glucose supplemented medium. S. racemosa explants in the same experiment produced five shoots in maltose and four shoots in sorbitol supplemented medium after 14 day incubation;whereas after 21 day incubation, sucrose and maltose produced five shoots;fructose, glucose, and sorbitol produced four shoots. Regenerated plants were successfully acclimatized and Scanning Electron Microscopy of the leaf surface revealed differences in stomatal behavior and cuticle deposition between in vitro and acclimatized plants. The antioxidant assay conducted on both Scutellaria species showed considerable total polyphenol content, TEAC activity and flavonoid content in fresh and dried leaf samples attributing to their medicinal potential.

Potential Use of Multipurpose <i>Paulownia elongata</i>Tree as an Animal Feed Resource

Paulownia is known as an economically important multipurpose tree genus due to its fast growth and short-rotation harvesting for timber. There is interest in growing Paulownia species as a woody biofuel crop. There are reports on its leaves being rich in nitrogen and double as good fodder, as well as fertilizer (green manure). Nutritional properties of Paulownia elongata leaves collected at monthly intervals from Paulownia Demonstration Plot, Fort Valley State University (FVSU), Fort Valley, Georgia, USA, from April to November, 2011, were studied. The leaves were dried and analyzed for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), fat, gross energy, and ash content. The CP, NDF, ADF, ADL, fat and ash content ranged from 14% - 23%, 29% - 55%, 18% - 42%, 10% - 22%, 2% - 4%, and 6% - 9%, respectively, indicating that Paulownia leaves have potential as a feed resource for livestock. Forage potential research was followed up by developing protocols to manufacture feed pellets with 75% and 95% leaf component and assessing their physical properties. There is an economic market potential for the by-products of Paulownia, which is usually grown for timber.