Somatic Embryogenesis and Plantlet Regeneration of Melia azedarach L (Ghora Neem) from Cotyledonary Segments

Embryogenic calli were obtained within 3–4 weeks on MS medium supplemented with 3% sucrose, 200 mg I-1 caseinhydrolysate, and 3 mg l^?1 each of 2,4-D and NAA from 3–4 days imbibed seeds. Heart-shaped embryos differentiated when growth regulators were withdrawn gradually. Quantification of somatic embryo formation showed a direct relationship between initial response, somatic embryo formation and its subsequent germination. The somatic embryos germinated into emblings with 90% conversion frequency on MS medium containing 2% sucrose.     

Novel expression system for Corynebacterium acetoacidophilum and Escherichia coli based on the T7 RNA polymerase-dependent promoter

The industrially important species of corynebacteria viz. Corynebacterium acetoacidophilum appear to be alternative hosts for recombinant protein production; despite many efforts, a strong promoter-based system in corynebacteria has not been established so far. Described here is a T7 promoter-based expression system which was functional in both gram-positive C. acetoacidophilum and gram-negative Escherichia coli in an external inducer independent manner. This is the very first report of a T7 expression system for Corynebacterium sp. Also, it is a useful addition in the existing T7 expression systems of E. coli.     

Self-diffusion of zinc and iron in soils as affected by pH,CaCO3, moisture,carrier and phosphorus levels

Summary Self-diffusion coefficients of zinc and iron were determined in acid soil of Palampur and alluvial soil of Ludhiana under varying pH, CaCO₃, moisture, carrier and phosphorus levels. Increase in pH caused tremendous reductions in self-diffusion coefficients (D_a) of both zinc and iron in soil. The selfdiffusion coefficients of both these elements were drastically reduced as a result of CaCO₃ application. The D_a values of zinc and iron increased with the decrease in moisture tension and increase in carrier and phosphorus levels. The decrease in D_a values were associated with increase in capacity factor.     

The impact of climate change on the distribution of two threatened Dipterocarp trees

Two ecologically and economically important, and threatened Dipterocarp trees Sal (Shorea robusta) and Garjan (Dipterocarpus turbinatus) form mono‐specific canopies in dry deciduous, moist deciduous, evergreen, and semievergreen forests across South Asia and continental parts of Southeast Asia. They provide valuable timber and play an important role in the economy of many Asian countries. However, both Dipterocarp trees are threatened by continuing forest clearing, habitat alteration, and global climate change. While climatic regimes in the Asian tropics are changing, research on climate change‐driven shifts in the distribution of tropical Asian trees is limited. We applied a bioclimatic modeling approach to these two Dipterocarp trees Sal and Garjan. We used presence‐only records for the tree species, five bioclimatic variables, and selected two climatic scenarios (RCP4.5: an optimistic scenario and RCP8.5: a pessimistic scenario) and three global climate models (GCMs) to encompass the full range of variation in the models. We modeled climate space suitability for both species, projected to 2070, using a climate envelope modeling tool “MaxEnt” (the maximum entropy algorithm). Annual precipitation was the key bioclimatic variable in all GCMs for explaining the current and future distributions of Sal and Garjan (Sal: 49.97 ± 1.33; Garjan: 37.63 ± 1.19). Our models predict that suitable climate space for Sal will decline by 24% and 34% (the mean of the three GCMs) by 2070 under RCP4.5 and RCP8.5, respectively. In contrast, the consequences of imminent climate change appear less severe for Garjan, with a decline of 17% and 27% under RCP4.5 and RCP8.5, respectively. The findings of this study can be used to set conservation guidelines for Sal and Garjan by identifying vulnerable habitats in the region. In addition, the natural habitats of Sal and Garjan can be categorized as low to high risk under changing climates where artificial regeneration should be undertaken for forest restoration.