Lavender is a good source of essential oils and phenolic metabolites for food, medicine, and cosmetic applications. Due to cross-pollination, lavender has substantial plant to plant variation and therefore a high degree of genetic inconsistency in the level of phytochemicals produced for diverse applications. Tissue culture methods, using benzyladenine-induced shoot organogenesis, were used to isolate clonal lines originating from individual heterozygous seeds among a heterogeneous seed population to exploit the genetic heterogeneity. Subsequently, in a two-step method, clonal shoots of each clonal line were evaluated for the ability to tolerate Pseudomonas inoculation and various levels (0-200 microM) of proline analogue, azetidine-2-carboxylate. On the basis of tolerance to Pseudomonas and proline analogue treatments, multiple shoot forming ability, biomass, rosmarinic acid, total phenolics, and total chlorophyll, 20 separate clonal lines were screened and isolated for further vegetative propagation and evaluation. From the clonal lines isolated, lines LH-14, LH-15, LH-17, and LH-11 showed the best potential for overexpression of phenolic metabolites in response to Pseudomonas and proline analogue.

1999) Screening of high biomass and phenolic producing clonal lines of spearmint in tissue culture using pseudomonas and azetidine-2 carboxylate., Food Biotechnology, 13:3, 227-253, AbstractRosmarinic acid (RA) and related phenolics are natural antioxidants found as secondary metabolites in spearmint (Mentha spicata). These phenolic-secondary metabolites have diverse food processing and nutraceutical applications. Since natural cross-pollination results in plant to plant variation in the level of phenolic metabolites, tissue culture-based techniques are essential to isolate elite antioxidant-producing clonal lines. The objective of this research is to develop tissue culture-based selection techniques to isolate high rosmarinic acid and phenolic-producing clonal lines from a heterogenous bulk seed population of spearmint. Multiplied clonal shoots of each line were screened for tolerance to azetidine-2-carboxylate (A2C). Individual shoot apex of each line were also screened for Pseudomonas tolerance. Rosmarinic acid and total phenolics were assayed in 4 Corresponding author

Callus induction was studied for three cultivars of leek (A. ampeloprasum var. porrum L.). Compact and friable callus was induced on embryo, leaf, and root explants on 16 different media. The highest frequency of compact or friable callus formation (up to 71.4%) was obtained when mature, zygotic embryos were cultured on BDS medium, containing 30-g/L sucrose, 1.0 mg/L 2,4-D and 0.5 mg/L BA. In this paper the characterization of a friable, embryogenic callus of leek is described. This callus type was initiated on immature embryos and differed in appearance from formerly induced compact, embryogenic callus. The friable callus was comprised of numerous globular embryoids. The genotype of the donor and the different explants were important parameters in the initiation of this callus type. The basal media did not influence the friable callus production.

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