V. A. Parthasarathy

Plant regeneration from embryo-derived callus of oil palm – the effect of exogenous polyamines

Regeneration in oil palm was achieved through somatic embryogenesis/organogenesis from embryo-derived callus. Callus was induced from mature embryos of the cross 281 (D)×18 (P) on modified MS medium supplemented with 2,4-D (113.12 μM) and 2-iP (14.76 μM). The embryogenic calluses obtained were transferred to Blaydes medium supplemented with 2,4-D (0.045 μM) and one of the following growth regulators: TDZ (4.54 μM), zeatin riboside (2.85 μM), putrescine (1 mM) and spermine (100 μM). Secondary somatic embryogenesis was found to occur in media supplemented with polyamines. The efficiency of formation of somatic embryos, secondary somatic embryos and shoot meristemoids were significantly higher in putrescine containing medium. Histological studies were also undertaken.

Comparative effectiveness of inter-simple sequence repeat and randomly amplified polymorphic DNA markers to study genetic diversity of Indian Garcinia

A study to compare the effectiveness of inter-simple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD) profiling was carried out with a total of 65 DNA samples using 12 species of Indian Garcinia . ISSR and RAPD profiling were performed with 19 and 12 primers, respectively. ISSR markers generated a total number of 156 bands with 92 polymorphic bands, while RAPD markers produced a total of 134 bands with 80 polymorphic bands. Percentage of polymorphic loci in RAPD profiling was 60.4% while in ISSR profiling, it was 59.3%. Heterogeneity index was similar for the markers, 0.86 for ISSR and 0.89 for RAPD, indicating that both the marker systems are effective in determining polymorphism in Garcinia . ISSR markers showed clear distinction among the species whereas RAPD markers showed segregation based on geographical location as well as species based. Key words : Garcinia , genetic diversity, inter-simple sequence repeats, randomly amplified polymorphic DNA, principal component analysis.

Familiar route retrieval for multicasting in MANETs

In the recent days, Mobile ad hoc networks (MANETs) are used extensively for applications that require mobility while routing, more importantly for emergency and military operations. Routing information to nodes without a fixed infrastructure and with dynamically changing infrastructure is one of the greatest challenges. Multicasting is a more frequent requirement for such defense operations, which adds on to the level of difficulty while routing. In order to overcome this challenge, a couple of protocols exist in the literature providing various solutions to delivering data to multiple destinations at mobility. However, these strategies are either of greater complexity or the cost is high. In this paper, we propose Familiar Route Retrieval for Multicasting (FRRM) in MANETs to use the route familiarity of nodes efficiently to construct routes to destinations. The performance of this algorithm is analyzed using the simulations in the network simulator.

A new supportive opportunistic routing scheme in Mobile Ad-hoc Networks

All the data transmission over the wireless medium in the wireless networks is by broadcasting in nature, which is different from the Internet. Because of the broadcast nature, many opportunities based on overhearing can be used to enhance the data transmission ability in wireless network. Ex-OR is the first practical data forwarding scheme which tries to promote the data transmission ability by utilizing the broadcast nature in wireless mesh networks and the opportunistic data forwarding becomes a well-known term given by Ex-OR to name this kind of new data forwarding scheme. The basic idea in ExOR has triggered a great deal of derivations. However, almost all these derivations are proposed for wireless mesh networks or require the positioning service to support opportunistic data forwarding in the Mobile Ad-hoc Networks (MANETs). In our system, we propose a series of solutions to implement opportunistic data forwarding in more general MANETs, which is called Supportive Opportunistic Routing Scheme in Mobile Ad-hoc Networks (SORS). We propose the small-scale retransmission to utilize the broadcast nature one step further than ExOR, and furthermore it helps us to enhance the efficiency and robustness of the opportunistic data forwarding in MANETs. We run computer simulations in Network Simulator 2 (ns-2), and the simulation results indicate that the proposed solutions work well to support opportunistic data forwarding in MANETs.