An experiment was conducted at the Plant Biotechnology Laboratory, Department of Horticulture, Patuakhali Science and Technology University during the period from August 2016 to April 2017 to standardize the protocol for in vitro propagation of banana. The experiment was laid out in completely randomized design with four replications. Three to four months aged field grown rhizome attached shoots were used as explants and cultured on MS medium with different concentrations and combinations of BAP (6-benzylamino purine), BAP + KIN (Kinetin) + NAA (Naphthalene Acetic Acid) and IBA (Indole-3-Butyric Acid) + IAA (Indole-3-Acetic Acid) to observe their efficacy on single shoot initiation, shoot multiplication and root formation respectively. Minimum number of days required for shoot initiation (9.07) with highest shoot initiation percentage (91.14) and the longest shoot (2.23 cm) was found in MS medium supplemented with 5.0 mg/L BAP. On the other hand, highest shoot multiplication percentage (80.99) with maximum number of shoots per explant (4.47), the highest length of shoots (4.17 cm) and maximum number of leaves (4.04)was observed in MS medium supplemented with 4.0 mg/L BAP + 2.0 mg/L KIN + 2.0 mg/L NAA. In case of root regeneration, the best results on days required for root initiation (9.00), the highest root initiation percentage (85.05), maximum number of roots per plantlet (5.83) and the highest length of roots (4.17 cm) was obtained in MS medium supplemented with1.5 mg/L IBA + 0.5 mg/L IAA. After 5-7 days of hardening in room temperature, established plantlets were ready for planting.

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Background Sucrose non-fermenting-1 (SNF1)-related protein kinase 2 (SnRK2), a plant-specific serine/threonine kinase family, is associated with metabolic responses, including abscisic acid signaling under biotic and abiotic stresses. So far, no information on a genome-wide investigation and stress-mediated expression profiling of jute SnRK2 is available. Recent whole-genome sequencing of two Corchorus species prompted to identify and characterize this SnRK2 gene family. Result We identified seven SnRK2 genes of each of Corchorus olitorius (Co) and C. capsularis (Cc) genomes, with similar physico-molecular properties and sub-group patterns of other models and related crops. In both species, the SnRK2 gene family showed an evolutionarily distinct trend. Highly variable C-terminal and conserved N-terminal regions were observed. Co- and CcSnRK2.3, Co- and CcSnRk2.5, Co- and CcSnRk2.7, and Co- and CcSnRK2.8 were upregulated in response to drought and salinity stresses. In waterlogging conditions, Co- and CcSnRk2.6 and Co- and CcSnRK2.8 showed higher activity when exposed to hypoxic conditions. Expression analysis in different plant parts showed that SnRK2.5 in both Corchorus species is highly expressed in fiber cells providing evidence of the role of fiber formation. Conclusion This is the first comprehensive study of SnRK2 genes in both Corchorus species. All seven genes identified in this study showed an almost similar pattern of gene structures and molecular properties. Gene expression patterns of these genes varied depending on the plant parts and in response to abiotic stresses.

The experiment was carried out during the period from June 2016 to January, 2017 at the Plant Biotechnology Laboratory, Department of Horticulture, Patuakhali Science and Technology University (PSTU) for in vitro regeneration of sweet potato. In this study, the nodal segment explants and different combinations of growth regulators were used for in vitro regeneration of sweet potato. BAP (6-benzylamino purine) and KIN (Kinetin) were used for in vitro shoot regeneration and IBA (Indole-6- Butyric Acid) with NAA (Naphthalene Acetic Acid) were used for in vitro root regeneration. The highest percentage of shoot initiation (91.30), the minimum number of days (9.00) for shoot initiation, the highest number of shoot/plantlet (11.00) and the highest shoot length (4.38 cm) was observed when nodal segment explants cultured on MS medium supplemented with BAP 1.5 mg/L + KIN 0.1 mg/L. On the other hand, the highest root initiation percentage (94.12), the minimum number of days (6.00) for root initiation, the highest number of root/plantlet (9.33) and the highest root length (11.13 cm) was observed in the MS medium supplemented with IBA 0.5 mg/L + NAA 0.1 mg/L. Regenerated plantlets were acclimatized for 5 days and adopted in soil by 6-7 days of transplantation.J. Bangladesh Agril. Univ. 16(2): 178-181, August 2018

Nowadays, there is an emergent public concern about trace elements accumulation in surface soils of banana fields around the industrial area of Bangladesh. This work firstly assessed contamination of metal(loid)s (Cr, Cu, Ni, As, Zn Cd, Mn, Fe, and Pb,) in soils of banana fields, sources and ecological risks of trace elements using various indices, their bioaccumulation in banana plant tissues and probable health risk using chemometric approach. Soils and different tissues of banana (Musa spp.) were collected from long time cultivated banana fields around the industrial area and capital of old Pundranagar, Bangladesh and samples were measured by ICP-MS. Experimental data showed that concentrations range of Cr, Cr, Ni, Cu, As, Cd, Pb, Fe, Mn and Zn in soil were 1.50–61.7, 2.42–87.4, 2.00-100.8, 0.25–31.2, 0.10–12.7, 0.60–91.8, 11330–23782, 8.69–105.9, and 7.50-125.9 mg/kg, respectively. Average level of trace elements in plant parts followed the descending order of roots > leaves > stems > fruits. As a whole, abundances of the examined trace metal(loid)s varied with elements species as well as samples, which occurred apparently due to the variations of parent materials of soil and the excessive use of agrochemicals and pesticides for banana cultivation. Trace elements in soils exhibited moderate to high degree of contamination where Cr, Pb, Zn, Cd and As in soils were mainly originated from anthropogenic activities. Considering health risks of measured metal(loid)s owing to the consumption of banana fruit, both non-cancer and cancer risks were perceived due to As contamination in the study area.