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A rapid system for micropropagation of Swertia chirata Buch-Ham. ex Wall.: an endangered medicinal herb via direct somatic embryogenesis

100%

Balaraju K., Saravanan S., Agastian P., Ignacimuthu S.

Acta Physiologiae Plantarum

2011

tom 33

nr 4

An improved method of direct somatic embryogenesis (SE) was developed in Swertia chirata for the first time using leaves and roots of in vitro-grown young seedlings. In the present study, 2,4-dichlorophenoxyacetic acid (2,4-D) was assessed individually and in combination with other auxins, as well as with cytokinin for its effectiveness to induce somatic embryos. Leaf explants with abaxial side in the medium produced maximum number of somatic embryos. This system omits the callus stage and thus reduces the process of SE in S. chirata by 35–45 days. Embryos at different stages of development were observed. Maturation of heart stage embryos were observed on Murashige and Skoog (MS) medium containing 1 mg L⁻¹ 2,4-D. Upon transfer to the germination medium, they were converted to cotyledonary stage and then plantlets of 33% and 68% of them were converted to cotyledonary stage and then plantlets on MS medium supplemented with 0.05 and 0.1 mg L⁻¹ GA₃ respectively. The 2,4-D alone at 1.0 or 1.5 mg L⁻¹ was found to be better for embryogenic tissue initiation than 2,4-D in combination with indole-3-acetic acid or a-naphthalene acetic acid. For further embryo development, 2,4-D was combined with cytokinins such as 6-benzylaminopurine (BAP) and kinetin or plant growth regulator free medium or medium with 50% reduced concentration of the same hormone while subculturing. Mean germination and percentage of survival were maximum in the medium containing 1.0 mg L⁻¹ 2,4-D in combination with 0.1 mg L⁻¹ BAP. Regenerated plantlets were morphologically and genetically identical. This method offers a vast scope for the clonal propagation of endangered plants.

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Appraisal of tsunami inundation and run-up along the coast of Kanyakumari District, India - GIS analysis

88%

Chandrasekar N., Immanuel J. L., Sahayam J. D., Rajamanickam M., Saravanan S.

Oceanologia

2007

tom 49

nr 3

On 26D ecember 2004, a tsunami severely affected almost all the coastal villages of Kanyakumari District, India. It was one of the worst affected coastal sectors of South India. An attempt has been made here to assess the impact of the tsunami hazard on coastal landforms and the level of inundation using GIS techniques. The areas of inundation were surveyed and mapped by fixing regular transects along the coastal regions. The percentage of inundated area in the total area was estimated. It was found that inundation was higher on low-lying coasts and relatively less on elevated coasts. In some cases, the extent of inundation was a few kilometres in relation to other coasts, but the percentage of inundated area in the total coastal area was high. The extent of inundation along the study area varied from 50 m to 450 m. Inundation was minimal in coastal villages like Kanyakumari, Agastheeswaram, Madhysoodhanapuram and Dharmapuram, but extensive at Colachel. The percentage of inundated area in the total area ranges from 8% (Dharmapuram) to 39% (Colachel). The degree of inundation was controlled by coastal geomorphological features such as sand dunes, cliffs, coastal vegetation, nature and configuration of the beach, not to mention the angle and velocity of the invading tsunami surge.

Ograniczanie wyników

1 Acta Physiologiae Plantarum

1 Oceanologia

2 Saravanan S.

1 Agastian P.

1 Balaraju K.

1 Chandrasekar N.

1 Ignacimuthu S.

1 Immanuel J. L.

1 Rajamanickam M.

1 Sahayam J. D.

1 2011

1 2007

Wyniki wyszukiwania

A rapid system for micropropagation of Swertia chirata Buch-Ham. ex Wall.: an endangered medicinal herb via direct somatic embryogenesis

Appraisal of tsunami inundation and run-up along the coast of Kanyakumari District, India - GIS analysis