North Eastern Hill University

About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Ruthenium. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.

High frequency plantlet regeneration from rhizomatous buds in Mantisia spathulata Schult. and Mantisia wengeri Fischer and analysis of genetic uniformity using RAPD markers.

Abstract: A protocol has been devised for enhanced in vitro regeneration of critically endangered Mantisia spathulata Schult. and Mantisia wengeri Fischer. Highest Bud Forming Capacity (BFC) of 6.10 +/- 0.55 with an average of 19.93 +/- 3.19 roots was obtained for M. spathulata within 5-6 weeks in Murashige and Skoogs (MS) medium supplemented with a combination of 10.0 microM of N6-benzyladenine (BA) and 2.5 microM of alpha-naphtalene acetic acid (NAA). For M. wengeri, BFC of 7.82 +/- 0.73 and 20.86 +/- 1.65 roots was achieved in MS media supplemented with a combination of 5.0 microM BA and 2.5 microM of NAA RAPD markers were used to evaluate the genetic stability of in vitro raised hardened plantlets. Similarity coefficient among the regenerated plants ranged between 0.85-0.98 for M. spathulata and 0.83-0.98 for M. wengeri. Maximum of 88 and 90% genetic similarity were obtained between in vitro raised hardened plantlets and mother stock of M. spathulata and M. wengeri, respectively through RAPD analysis. The hardened plantlets after RAPD analysis on being transferred to soil of experimental garden showed no marked phenotypic variations in vegetative or floral characteristics.

Compatible fungi, suitable medium, and appropriate developmental stage essential for stable association of Dendrobium chrysanthum

Abstract: Establishment of symbiotic association at the appropriate developmental stage helped maintain continued growth which is vital for the long-term ex vitro survival of the orchid. In the present study, symbiotic association was carried out using different developmental stages of Dendrobium chrysanthum and pathogenic Rhizoctonia isolates (obtained from orchids and non-orchid hosts) in different culture media. Isolate 2162 supported highest symbiotic germination on OMA-S (oat meal agar medium without nutrients + sucrose), whereas, stable symbiotic association with plantlets was obtained with isolate 4634 on OMA-NC (oat meal agar medium + cellulose). Isolate Dc-2S2 obtained from the host plant did not promote seed germination nor did it form association with protocorms or plantlets. This study, for the first time identifies a combination of compatible fungal isolate, suitable culture medium, and appropriate developmental stage at which symbiotic association in vitro can be deemed successful for the medicinally important orchid, D. chrysanthum.

Micropropagation of Ilex khasiana, a critically endangered and endemic holly of Northeast India

Abstract: Background and aims Ilex khasiana is a rare and critically endangered holly endemic to the Khasi Hills of Meghalaya, India, and confined to a small number of pocket areas. In addition to conventional methods of propagation, endemic and threatened plants such as this could be more effectively multiplied and conserved using in vitro methods. Such techniques have the additional advantage of having a low impact on wild populations because they require a minimum of starting material. Our objective was to develop methodologies for the successful in vitro mass propagation of I. khasiana. Methodology Seedlings were germinated in vitro under sterile conditions and nodal explants from these were transferred to Murashige and Skoog (MS) medium supplemented with 8.88 mM 6-benzyladenine and 4.64 mM kinetin. Principal results This generated � 10 shoots per explant. In a second approach, callus was obtained from seedling-derived leaf discs cultured on MS medium supplemented with 2,4-dichlorophenoxyacetic acid and 6-benzyladenine. Approximately 12 adventitious shoots per callus were regenerated from 83.33 % of the calli after transfer to MS medium supplemented with 6.63 mM 6-benzyladenine. The most effective treatment for inducing root formation on the shoots was transfer of shoots to half-strength MS medium with 9.84 mM indole-3-butyric acid. Regenerated plantlets with well-developed shoots and roots were hardened and transferred to open soil with 70 % survival after 4 weeks. Conclusions Both the methods described here are well suited for the mass multiplication of this critically endangered tree species.

Nano-ferrite supported glutathione as a reusable nano-organocatalyst for the synthesis of phthalazine-trione and dione derivatives under solvent-free conditions

Abstract: Nano-organocatalyzed one-pot four-component reactions for the synthesis of phthalazine-trione/dione derivatives have been devised for the first time from easily accessible starting materials under solvent-free conditions. This methodology showed very good substrate scope and high degree of tolerance for a variety of aldehydes (including aliphatic and heteroaromatic aldehydes) and active methylene compounds. Moreover, the catalyst can be easily separated from the reaction mixture because of its highly paramagnetic nature, by using an external magnet, and can be reused in five more consecutive runs without much decrease in catalytic activities. Other significant advantages of this method are shorter reaction time, good yield, simple work-up procedure, easy catalyst handling etc.