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Open access

Soumen Saha, Tulsi Dey and Parthadeb Ghosh

Micropropagation of Ocimum kilimandscharicum Guerke (Labiatae)

An efficient plant regeneration protocol has been developed from nodal explants of Ocimum kilimandscharicum Guerke, a medicinally important herbaceous plant species belonging to the family Lamiaceae. Axillary shoot bud proliferation was initiated from nodal explants cultured on MS medium supplemented with various concentrations of 6-benzyladenine (BA) (0.5-3.0 mg/l), kinetin (KN) (0.5-3.0 mg/l) and 2-isoPentenyladenine (2-iP) (0.5-3.0 mg/l). The maximum number of shoots (6.09±0.05), with average length 3.83±0.11 cm, was achieved with medium containing 1.0 mg/l BA. Shoot culture was established by repeated subculturing of the original nodal explants on shoot multiplication medium after each harvest of newly formed shoots. In this way, 20-30 shoots were obtained from a single nodal explant after 5 months. Rooting of shoots was achieved on half-strength MS medium supplemented with 1.5 mg/1 Indole-3-butyric acid (IBA) and 2% sucrose. Well-developed plantlets transferred to plastic pots containing soil and vermiculite (1:1) showed 81.13% survival. The genetic fidelity of in-vitro-raised field-grown plants to the donor plant was ascertained from random amplified polymorphic DNA (RAPD) markers. This protocol can be used for commercial propagation and for future genetic improvement studies.

Open access

D. Barman, D.K. Kundu, Soumen Pal, Susanto Pal, A.K. Chakraborty, A.K. Jha, S.P. Mazumdar, R. Saha and P. Bhattacharyya

Abstract

Soil temperature is an important factor in biogeochemical processes. On-site monitoring of soil temperature is limited in spatiotemporal scale as compared to air temperature data inventories due to various management difficulties. Therefore, empirical models were developed by taking 30-year long-term (1985-2014) air and soil temperature data for prediction of soil temperatures at three depths (5, 15, 30 cm) in morning (0636 Indian standard time) and afternoon (1336 Indian standard time) for alluvial soils in lower Indo-Gangetic plain. At 5 cm depth, power and exponential regression models were best fitted for daily data in morning and afternoon, respectively, but it was reverse at 15 cm. However, at 30 cm, exponential models were best fitted for both the times. Regression analysis revealed that in morning for all three depths and in afternoon for 30 cm depth, soil temperatures (daily, weekly, and monthly) could be predicted more efficiently with the help of corresponding mean air temperature than that of maximum and minimum. However, in afternoon, prediction of soil temperature at 5 and 15 cm depths were more precised for all the time intervals when maximum air temperature was used, except for weekly soil temperature at 15 cm, where the use of mean air temperature gave better prediction.