Martinii Var Research Articles

Chemical Composition of Cymbopogon martinii (Roxb.) Wats. var. martinii

ABSTRACT Fourteen constituents have been identified in an oil of Cymbopogon martinii var. martinii (palmarosa) produced in Madhaya Pradesh. The main components were geraniol (79.19%), geranyl acetate (9.15%), and linalool (3.64%).

In vivo and in vitro instability of B chromosomes in palmarosa grass (Cymbopogon martinii var. motia)

Meiotic and mitotic instability and elimination of B chromosomes was observed in diploid palmarosa (Cymbopogon martinii var. motia) with 2n = 20 + 1–2 B under in vivo and in vitro conditions. Under in vivo conditions B chromosomes were totally absent from the roots but preferentially transmitted in the germ line tissues. When present as a pair, the B chromosomes formed bivalents showing almost regular orientation, congression, and disjunction. When present singly, the B chromosome formed a univalent and did not pair with any of the A chromosomes and showed nonalignment on the metaphase plate during metaphase I. Immature inflorescences of a race of palmarosa with 2n = 20 + 2 B were cultured on Murashige and Skoog's medium containing 1 mg/L of 2,4-dichlorophenoxyacetic acid to produce embryogenic callus. The cytological analysis of the callus revealed only 20 A chromosomes in nearly all the cells, both the B chromosomes being eliminated. From this callus, plantlets without B chromosomes were regenerated on MS medium without growth regulators and established in the soil. The regenerated plants exhibited 20 A chromosomes with normal meiosis.Key words: Cymbopogon martinii, chromosome instability, palmarosa grass, B chromosomes, tissue culture, plant regeneration.

Chemosystematics of terpenoids in Cyrnbopogon martinii

Cymbopogon martinii var. sofia possesses cis- and trans-forms of each of p-mentha-2,8-dien-1-ols, piperitols, pmentha-1(7),8-dien-2- ols and carveols, and limonene and carvone. Dominant presence of p-menthadienols is characteristic of the oll. The composition and chemotaxonomic significance is discussed.

Cytogenetical studies of accessory chromosomes in the genus Cymbopogon Spreng.

The B-chromosomes were detected in two species (C. martinii var. motia and C. jwarancusa) out of the 9 species of genus Cymbopogon investigated. The supernumerary chromosomes were found in both the root-tip meristematic cells as well as the PMCs. Investigations with respect to nature and behaviour of the accessary chromosomes were made in the two parental B-chromosomes carrying species, their F1 hybrids with other Cymbopogon species and in the F2 population raised from one of the partially fertile F1 hybrids. The above study clearly shows that the B-chromosomes have a direct effect on the total chromatin length and the chiasma frequency of A-chromosomes. However, no effect on the general morphology or chemical composition of the oil of the plants has been noticed in presence of the accessary chromosomes. The significance of the data on accessary chromosomes is discussed.

Cytogenetical studies in the genus Cymbopogon spreng II. Meiotic studies in six species and their varieties.

Meiotic studies in six Indian Cymbopogon species and their varieties/chemotypes were made from pollen mother cells. The investigated taxa included 5 diploids (2n=20), one tetraploid (2n=40) and two hexaploids (2n=60). Both diploids as well as hexaploids exhibited fairly normal meiosis with ten and thirty bivalents formation, respectively. However, the tetraploid species (C. martinii var. sofia, 2n=40) showed peculiar meiosis by forming multivalent configurations like quadrivalents and hexavalents, suggesting a segmental polyploid nature.

Origin and Taxonomy of Castilleja montigena (Scrophulariaceae)

Based on data from chromosome numbers, comparative morphology, geographic distribution, and floral nectar amino acids, a narrow endemic of the eastern San Bernardino Mountains of Southern California that has been recognized under the name Castilleja ewanii (or C. martinii ssp./var. ewanii) is interpreted as an allopolyploid (n = 24, 36) derived from diploid races (n = 12) of C. chromosa and C. martinii var. martinii. Morphological evidence indicates that introgression from C. martinzi var. martinzi into C. chromosa has occurred either on the diploid level or via backcrossing to the allopolyploid derivatives in the same mountains. Thus both dip- loid introgressants and allopolyploids derived from the same parents are postulated. The type specimen of C. ewanii falls within the diploid introgressants and that name is placed in synonymy under C. chromosa. A new name, C. montigena, is proposed for the polyploids. Castilleja montigena, which possesses recombinant morphological features of the two diploid parental species, had an additive nectar amino acid com- plement of the other two species when they were sampled in several regions at some distance from the San Bernardino mountains. Thus glutamic acid is lacking in C. chromosa and valine is lacking in C. martinii var. martinii while both amino acids are present in the polyploids. In the San Bernardino Mountains, however, diploids of both parental species also possess the additive amino acid complement, thus corrob- orating morphological evidence for limited gene exchange between the diploids in this area.