An efficient and improved method for in vitro propagation of mature tree of Dalbergia sissoo, an ecologically and commercially important timber yielding species, has been developed through axillary shoot proliferation. Bud breaking occurred from nodal shoot segments derived from rejuvenated shoots produced during early spring from a 20-25-year-old lopped tree, on MS medium containing 8.88 μM benzylaminopurine (BAP). Multiple shoots differentiated (20-21shoots/node) on re-culture of explants on halfstrength agar gelled amended MS medium with a combination of 2.22 μM of BAP and 0.002 μM of thidiazuron (TDZ) with 1.0 mM each of Ca(NO 3 ) 2 , K 2 SO 4 , KCl, and NH 4 (SO 4 ) 2 . The maximum shoot multiplication (29-30 shoots/node) was achieved on subculturing in the above mentioned but liquid medium. Furthermore, the problem of shoot tip necrosis and defoliation observed on solid medium were overcome by the use of liquid medium. Ex vitro rooting was achieved on soilrite after basal treatment of microshoots with 984 μM of indole-3-butyric acid (IBA) for 2 min. About 90 % microshoots were rooted on soilrite within 2-3 weeks under the greenhouse conditions. From 20 nodal shoot segments, about 435 hardened plants were acclimatized and transplanted. This is the first report for rapid in vitro propagation of mature trees of D. sissoo on liquid medium followed by ex vitro rooting.

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Increased level of antioxidants and enzymatic activity protects the plants from oxidative damage under stress conditions. In the present study antioxidants involved in the ascorbate–glutathione (ASC–GSH) cycle (APX, GR, ascorbate and dehydroascorbate) were investigated under salt stress in two species of genus Prosopis (P. cineraria and P. juliflora). Both these species are economically very important in arid and semi-arid regions of Rajasthan. For the experimentation one-week-old seedling were treated with different salt concentrations ranging from 0 to 200 mM (0, 25, 50, 75, 100, 150 and 200). The leaves were harvested after 15 and 30 days. The ascorbate content of both the species increased under salt stress. But dehydroascorbate content decrease. The activity of enzymes ascorbate peroxidase (APX) and glutathione reductase (GR) were also found to be increased under salt stress. The increase was comparatively more prominent in P. juliflora which indicates the upregulation of ascorbate-glutathione cycle is higher in P. juliflora and it plays a great role in making P. juliflora more tolerant under high salinity conditions.