The concentration of carbon dioxide (CO2) has risen continuously in atmosphere due to human induced activities, and has been considered the predominant cause of global climate change. Paulowina tomentosa Steud. (P. tomentosa), a multipurpose tree is popular around global market for its timber and its potential role in CO2 sequestration. In this study, the total biomass carbon of five years old and newly planted P. tomentosa has been estimated. The results indicated that the average total biomass carbon of five years old plant was found to be 4.52±0.53Kg C Year-1 per tree i.e. 9.04±1.06-ton C ha-1 Year-1 (assuming 2000 plants per hector). Likewise, the average total biomass carbon of newly planted P. tomentosa within 4 months was found to be 6.07±0.38 Kg in remote village area in Nepal. The estimated biomass carbon in one year of newly planted plants was found to be 18.21±1.14 Kg Year-1 i.e. 0.36-ton C ha-1 Year-1. These findings reveled that short rotational trees like P. tomentosa can be implemented in agroforestry system to reduce the green house emission in cities and emphasizes the carbon storage potential of agroforestry. In vitro micro propagation technique could be implemented to produce genetically uniform clone of P. tomentosa and can be applied in agroforestry system for the adaptation and to mitigate global climate change.Int. J. Appl. Sci. Biotechnol. Vol 6(3): 220-226

Paulownia tomentosa Steud is a fast growing multipurpose tree. In vitro propagation using nodal explants of P. tomentosa was performed by manipulating amount of cytokinin and auxin in culture media. Shoot bud proliferation from explants were assessed in Murashige and Skoog (MS) medium supplemented with various amounts of hormones such as a) 0.5-2.5 mg/l benzylaminopurine (BAP) and 0.1 mg/l naphthalene acetic acid (NAA), b) 0.5-2.5 mg/l BAP and 0.5-2.5 mg/l kinetin (KN) and c) 0.5-2.5 mg/l BAP and 0.1 mg/l indole-3-acetic acid (IAA). In the present study, we found that hormone combination of BAP and NAA gave optimum growth results. MS medium enriched with 2.0 mg/l BAP and 0.1 mg/l IAA resulted a similar outcome but took 3-4 weeks with respect to the same medium enriched with 1.0 mg/ml BAP and 0.1 mg/ml NAA, which showed response within 2-3 weeks. Shoot length of 2.5-3.5 cm with 3-4 nodes and 8-12 leaves were obtained on MS medium supplemented with 1.0 mg/l BAP and 0.1 mg/l NAA. The acclimatization of explants was done in a polyhouse at 20±5 o C for 2-6 weeks. Rooting was induced in sterile sand. Rooted plants were transferred to plastic bags containing mixture of soil, sand and compost in the ratio of 1:1:1.Besides aforementioned issues, there are several other challenges associated with in vitro propagation of P. tomentosa. Tissue culturing of the plant was established (90%) on MS medium enriched with BAP and NAA and adapted ex vitro with surviving up to 80%. People received an opportunity with this plant because it grows fast and can generate income in 10 years in comparison with others, but at the same time people also have been facing the challenges for plantation of P. tomentosa as government of Nepal does not formulate necessary national policies, legislations and regulatory frameworks in its favor. Thus, system should be developed to set royalty rate of P. tomentosa recognizing its lifetime value.

Realizing myxobacteria as a potential source of antimicrobial metabolites, we pursued research to isolate myxobacteria showing antimicrobial properties. We have successfully isolated three strains (NR-1, NR-2, NR-3) using the Escherichia coli baiting technique. These isolates showed typical myxobacterial growth characteristics. Phylogenetic analysis showed that all the strains (NR-1, NR-2, NR-3) belong to the family Archangiaceae, suborder Cystobacterineae, and order Myxococcales. Furthermore, 16S rRNA gene sequence similarity searched through BLAST revealed that strain NR-1 showed the closest similarity (91.8 %) to the type strain Vitiosangium cumulatum (NR-156939), NR-2 showed (98.8 %) to the type of Cystobacter badius (NR-043940), and NR-3 showed the closest similarity (83.5 %) to the type of strain Cystobacter fuscus (KP-306730). All isolates showed better growth in 0.5-1 % NaCl and pH around 7.0, whereas no growth was observed at pH 9.0 and below 5.0. All strains showed better growth at 32° C and hydrolyzed starch, whereas casein was efficiently hydrolyzed by NR-1 and NR-2. Besides, preliminary antimicrobial tests from crude extracts showed activities against Gram-positive, Gram-negative bacteria, and fungi. Our findings suggest that the arcane soil habitats of Nepal harbor myxobacteria with the capability to produce diverse antimicrobial activities that may be explored to overcome the rapidly rising global concern about antibiotic resistance.