16 research outputs found

    Hydroponic and in vitro screening of wheat varieties for salt-tolerance

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    Salt-tolerant wheat cultivars are essential for sustainable wheat production and global food security. The present study aimed to establish a reliable screening protocol as well as successfully isolated the potential salt-tolerant wheat varieties by discerning morpho-physiological parameters with multivariate analysis. Seventeen wheat varieties were evaluated at 0, 12, 15 and 18 dSm-1 salinity levels in a hydroponic culture system at the seedling stage. Moreover, in vitro callusing responses of four selected varieties were determined to clarify the salt tolerance capability at 0, 9, 12 and 15 dSm-1 salt treatments. The seedling growth of most wheat varieties was highly interrupted and reduced by the toxic effects of salinity, however, some varieties such as BARI Gom-32, BARI Gom-33, BARI Gom-31, BARI Gom-30, and BARI Gom-28 showed the lowest reduction under all salinity stress conditions. The total salt tolerance index (TSTI) showed that the cultivar BARI Gom-33 was the most salt-tolerant followed by BARI Gom-32 and BARI Gom-30 whereas BARI Gom-25 was identified as the most sensitive. These results were strongly supported by the principal component analysis (PCA) and Wardā€™s Methods Euclidean based clustering. In vitro results revealed that the lowest reduction of callus induction was recorded in BARI Gom-33 which might show the greatest tolerance to salinity by improving morpho-physiological characteristics against salt stress. Therefore, the identified genotypes might be employed as donor parents to develop salt-tolerant and high-yielding cultivars in the wheat breeding programme

    AN ENGINEERING GEOLOGICAL ANATOMY OF THE PADMA RIVER BANK FAILURE AND EROSION, 2018: A CASE STUDY OF NARIA BANK SECTION, BANGLADESH

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    The Naria town of Bangladesh is developed on the right bank of the Padma River. The bank is an old natural levee of Meghna River. The Holocene-Recent geology of Naria is actively dominated by the fluvial processes of Ganges-Brahmaputra-Meghna River system where the deltaic sediments are characterized as unconsolidated fine sand and silt, covered by thin veneer of clayey silt and loam. The annual volume of water discharge and flow dynamics are dependent on the intensity of the rainfall, runoff and the length of dry winter. Excessive river bank erosion, channel avulsion, renewed submergence of floodplains, and formation of natural levees and channel-bars are due to natural geomorphological processes that impact the area by inevitable ground failures. The geological attributes of ground condition and drastic variations in water levels make the area extremely vulnerable to severe bank failures and erosion. A unique erosion phenomenon prevailing in this part of Bengal delta prompted this study. During Aug-Sept, 2018 a sudden complex attenuation of current, wave and vortex in the Padma water flow caused an extraordinary disaster and made more than 5000 people homeless overnight by devouring away houses including concrete buildings, factories and markets. It is observed that geologically the Padma River remained confined within a width of 5 miles striking NW-SE trend following the margins of older alluvium and Faridpur Trough. The river tends to a meandering pattern consisting of deep vertical trenches along the Naria curvature. The deep trenches form along right bank and render the ground increasingly more vulnerable to subaqueous slope failure due to presence of thick (~200 ft.) alternating cross-bedded silt and micaceous fine sand of very high dilatancy and low angle of friction. The present study identifies some application of technological advancement for developing real-time engineering geological mapping systems for monitoring and managing complex river bank erosion. Large scale 3D engineering geological map coupled with air-borne photogrammetric and radar inferrometry methods can be applied for real-time monitoring and prediction of differential settlements, subaqueous failures and ground movement. The point cloud maps developed using data from these systems can refine engineering geological maps for decision makers and improve the design of protective measure and sustainable engineering structures

    Dicopper(I) Complexes Incorporating Acetylide-functionalized Pyridinyl-based Ligands::Synthesis, Structural and Photovoltaic Studies

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    Heteroaryl incorporated acetylide-functionalized pyridinyl ligands (<b>L1ā€“L6</b>) with the general formula Py-Cī—¼C-Ar (Py = pyridine and Ar = <i>thiophene-2-yl</i>, 2,2ā€²<i>-bithiophene]-5-yl</i>, 2,2ā€²<i>:5</i>ā€²,2ā€³<i>-terthiophene]-5-yl</i>, <i>thienoĀ­[2,3-<i>b</i>]Ā­thiophen-2-yl</i>, <i>quinoline-5-yl</i>, <i>benzoĀ­[c]Ā­[1,2,5]Ā­thiadiazole-5-yl</i>) have been synthesized by Pd(0)/CuĀ­(I)-catalyzed cross-coupling reaction of 4-ethynylpyridine and the respective heteroaryl halide. Ligands <b>L1ā€“L6</b> were isolated in respectable yields and characterized by microanalysis, IR spectroscopy, <sup>1</sup>H NMR spectroscopy, and ESI-MS mass spectrometry. A series of dinuclear CuĀ­(I) complexes <b>1</b>ā€“<b>10</b> have been synthesized by reacting <b>L1ā€“L6</b> with CuI and triphenylphosphine (PPh<sub>3</sub>) (<b>R1</b>) or with an anchored phosphine derivative, 4-(diphenylphosphino) benzoic acid (<b>R2</b>)/2-(diphenylphosphino)Ā­benzenesulfonic acid (<b>R3</b>), in a stoichiometric ratio. The complexes are soluble in common organic solvents and have been characterized by analytical, spectroscopic, and computational methods. Single-crystal X-ray structure analysis confirmed rhomboid dimeric structures for complexes <b>1</b>, <b>2</b>, <b>4</b>, and <b>5</b>, and a polymeric structure for <b>6</b>. Complexes <b>1</b>ā€“<b>6</b> showed oxidation potential responses close to 0.9 V vs Fc<sup>0/+</sup>, which were chemically irreversible and are likely to be associated with multiple steps and core oxidation. Preliminary photovoltaic (PV) results of these new materials indicated moderate power conversion efficiency (PCE) in the range of 0.15ā€“1.56% in dye-sensitized solar cells (DSSCs). The highest PCE was achieved with complex <b>10</b> bearing the sulfonic acid anchoring functionality

    Efficient Plant Regeneration in Garlic through Somatic Embryogenesis from Root Tip Expiants

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    The present study was conducted to establish an efficient protocol of plantlet regeneration through somatic embryogenesis in garlic (Allium sativum L.). Root tips measuring 2 to 3 mm were excised and cultured on agar-solidified MS medium containing various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) for callus and embryo formation. The optimum concentration of 2,4-D was 0.5 Ī¼M. At a concentration higher than 1.0 Ī¼M, 2,4-D had an inhibitory effect on callus and embryo formation. Embryos germinated and formed rooted plantlets on MS solid medium containing 5.0 Ī¼M kinetin. The number of plantlets regenerated per root tip expiant depended on the concentration of 2,4-D in the callus initiation medium. The plantlets were established in the soil after acclimatization in a growth cabinet. Somatic embryos were morphologically characterized by scanning electron microscopy (SEM)

    Anatomical Changes during in Vitro Direct Formation of Shoot Bud from Root Tips in Garlic (Allium sativum L.)

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    In vitro direct shoot bud organogenesis from garlic (Allium sativum L. cv. White roppen) root tips was studied under a light microscope. In root tips cultured on the shoot induction medium that consisted of Murashige and Skoog basal salts and vitamins with 1 Ī¼M NAA and 10 Ī¼M BA, periclinal cell divisions were initiated in epidermal cells in the formative part or the distal elongation zone of the root apical meristem 6 to 8 days after the start of culture (day 6āˆ¼8). The periclinal cell divisions continued to form tiers of cells until day 12. Some of the cells divided anticlinally and formed protrusions of shoot primordia. Several shoot bud primordia developed within 16 days. Organized shoot apical meristems with leaf primordia were evident by day 20. The shoot bud formation in this study did not involve callus formation. The in vitro shoot bud formation from root tips could be efficientiy used for the rapid clonal propagation of garlic without changing the genetic fidelity. The implications of developmental pattern in direct bud regeneration are relevant in developing suitable regeneration systems and conducting critical physiological experiments

    Anatomical Changes during in Vitro

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