VOIP WITH ADAPTIVE RATE IN MULTI- TRANSMISSION RATE WIRELESS LANS

“Voice over Internet Protocol (VoIP)” is a popular communication technology that plays a vital role in term of cost reduction and flexibility. However, like any emerging technology, there are still some issues with VoIP, namely providing good Quality of Service (QoS), capacity consideration and providing security. This study focuses on the QoS issue of VoIP, specifically in “Wireless Local Area Networks (WLAN)”. IEEE 802.11 is the most popular standard of wireless LANs and it offers different transmission rates for wireless channels. Different transmission rates are associated with varying available bandwidth that shall influence the transmission of VoIP traffic

Enhancement of callus induction and regeneration efficiency from embryo cultures of Datura stramonium by adjusting carbon sources and concentrations

Carbon source in the medium is considered to be an essential component for the high production costs of callus and plantlets in tissue culture. We report here the establishment of an efficient tissue culture cycle (callus induction and plant regeneration) for Datura stramonium by adjusting carbon sources and concentrations. Embryo explants of D. stramonium L. were cultured in vitro with six different carbon sources (sucrose, glucose, fructose, galactose, maltose and lactose) and four concentrations (1, 2, 3 and 4%) for callus induction. After that, the best carbon sources for regeneration were investigated with four different carbon sources (sucrose, glucose, fructose and sorbitol) and four concentrations (1, 2, 3 and 4%). The best sugar for callus induction was 2% lactose. The medium containing 3% glucose shows the higher regeneration.Key words: Datura stramonium L., carbon source, callus induction, plant regeneration and embryo culture

Plant tissue culture study on two different races of purslane (Portulaca oleracea L.)

This study was performed on two races of purslane; agronomic purslane and wild one. All the explants were cultured on MS basal medium supplement with 30 g/l sucrose, 8 g/l agar and different plant growthregulator. Petioles, shoot tips and leaves of wild purslane and also leaves of agronomic purslane were cultured in different concentrations and combinations of IBA and BAP (Both in the same four levels, 0, 1, 5 and 10 ìM; collectively 16 treatments). On the other hand, nodal segments and shoot tips of agronomic purslane were cultured in different concentrations (4.44, 8.88 and 13.32 ìM) of BAP or kinetin. The regenerated were rooted in the media containing three levels of IBA or IBA (0.0, 2.5 and 5ìM). Results showed that the treatments containing10 ìM IBA in combination with 10 or 5 ìM BAP are suitable for callus induction from leaves of wild purslane. Direct shoot regeneration from shoot tips orpetiole explants of wild purslane was observed only in 10 ìM IBA alone. Also, BAP at level 8.88 ìM was found to be the best treatment to shoot regeneration from nodal segments of agronomic purslane andIBA at level 2.5 ìM was found to be the best treatment for rooting of regenerated shoots in both races of purslane

In vitro propagation of walnut - A review

<i>In vitro</i> propagation of walnut has played a very important role in rapid multiplication of cultivars with desirable traits and production of healthy and disease-free plants. During the last several years, different approaches have been made for in vitro propagation of walnut. Micropropagation using apicale bud, nodale segement, leaves, petioles, cotyledons, embryos and understanding the specific requirement at different stages has been comprehensively covered in literature. New challenges for refinements of protocols for high rate of shoot multiplication and development of cost effective methods has gained importance in the recent past. Importance of liquid and solid static culture for callus induction, embryogenesis, shoot proliferation and root induction for walnut is also discussed in the present review. Further, the development of protocols for in vitro propagation, culture nodal segment from seedling, somatic embryogenesis and plant regeneration which is considered the most important step for successful implementation of various biotechnological technique used for plant improvement programmes has been adequately addressed in literature. In walnut, there are severalreports which indicate rapid regeneration and multiplication through organogenesis or somatic embryogenesis. On the whole, the present review gives a consolidated account of in vitro propagation in walnut.Key words: Walnut, <i>Juglans</i> spp. L, root induction, shoot multiplication, regeneration, medium culture, micropropagation, somatic embryogenesis

A comparative study on Acorus calamus (Acoraceae) micropropagation and selection of suitable population for cultivation in Iran

In addition to various medicinal properties, Acorus calamus (sweet flag) is used in health, food, and perfume industries. Since this species is a rare plant in Iran, its propagation and cultivation are of the great importance. The aim of this study was to investigate the effects of different plant growth regulators on micropropaga-tion of this plant and to select the appropriate population. The root, the rhizome and the leaf explants of three populations (Arzefon, Pelesk, and Alandan) were cultured on MS medium supplemented with different concentrations of α-naphthalene acetic acid (NAA) and 6-benzylaminopurine (BAP) for callus induction and plant regeneration. The results showed that only rhizome explant resulted in direct plant regeneration. Among different treatments, the 1 mg/l treatment of BAP and NAA - with the highest mean number of regenerated plants (3.75 ± 0.85), the highest percentage of grown explants (91.6%) and maximum average length of regenerated plants (12.06 ± 0.32 cm) - was the best treatment for regeneration of sweet flag. The highest mean number of root (6.6 ± 0.1) was observed in Alandan population in 1 mg/l treatment of indole-3-butyric acid (IBA). According to the present study, Alandan population is suitable for cultivation purposes in Iran