The effects of cadmium on the anatomical structures of different vegetative parts, namely root, stem and leaf of chickpea, Cicer arientinum L. was studied. Four different concentrations of CdCl2 e.g. 250, 500, 750 and 1000 μM were considered as treatments alongside non treated samples (control). In case of root anatomy decrease of root diameter, root cortex area, thick walled endodermal layer and reduced number of metaxylem vessels were observed compared to control. Similarly, stem diameter, cortical area, size and number of xylem vessels were decreased in Cd treated stem. However, large and increased number of trichomes had been found in Cd treated stem samples with deposition of phenolic compounds in vessels with increasing concentration of Cd. Considerable less toxic effects were observed in leaf anatomy except decrease in leaf thickness, reduced vascular area and closure of stomata in comparison to control sample. All such plant anatomical alterations indicated adverse effects as well as tolerance of chickpea up to certain concentrations of heavy metal to cope up with the changing environment. Dhaka Univ. J. Biol. Sci. 29(1): 45-52, 2020 (January)

To investigate the integration of chitinase gene in lentil (Lens culinaris Medik.) namely, BARI masur-4 (BM-4), BARI masur-5 (BM-5) and BARI masur-6 (BM-6) through Agrobacterium-mediated genetic transformation was performed using Agrobacterium strain EHA 105 harboring bar (resistant to phosphinotrycin) and chitinase (gene of interest) gene. Selection of transformed shoots was carried out by gradually increasing the concentration of phosphinotrycin (PPT) up to 2.0 mg/l. Transgenic lentil shoots were produced with an overall frequency of 0.36 in case of BM-4 and BM-6 and 0.34 in case of BM-5, respectively. Most of the selected shoots developed in vitro flowers and pods following their sub-culture on half strength of MS supplemented with 20 mg/l IBA, 0.5 mg/l NAA with 50 mg/l ticarcillin. Seedlings germinated from the seeds were successfully transferred to soil for the development of further progeny. Stable integration of target gene was confirmed through PCR analysis. Plant Tissue Cult. & Biotech. 29(1): 99-109, 2019 (June)

Genetic transformation system was developed for two microsperma varieties of lentil (Lens culinaris Medik.), namely Bari Masur-4 (BM-4) and Bari Masur-5 (BM-5) using Agrobacterium tumefaciens strain LBA4404 harbouring binary plasmid pBI121, containing GUS and nptII genes. Three different types of embryo explants, namely cotyledonary node (CN), decapitated embryo (DE) and cotyledone attached decapitated embryo (CADE) were used. Highest GUS positive expression was found in DE followed by CADE as detected by transient assays. Following Agrobacterium infection CADE showed better response in developing multiple shoots on MS supplemented with 2.22 μM BAP, 2.32 μM Kn, 0.29 μM GA3 and 30.35 μM tyrosine. Selection of the transformed shoots was carried out by gradually increasing the concentration of kanamycin up to 200 mg/l. Transgenic lentil shoots were produced with an overall frequency of 1.009%. In vitro rooting appeared to have a limitation in obtaining complete plantlets in lentil, therefore in vitro flowering and seed formation were induced in transformed shoots of lentil with a view to recovering of the transgenic progenies. GUS positive shoots were found to produce in vitro flowers and pods on half-strength MS containing 98.4 μM IBA and 2.69 μM NAA. Expression of gene was detected in various tissues of the transformed shoots. Stable integration of GUS gene was also confirmed through PCR analysis.

Investigation on leaf anatomical adaptation of 18 mangrove plant species was carried out. Among the 18 species 13 were dorsiventral and five were isobilateral type. All the species had special stomatal structure and variable cuticle layer to minimize transpiration. Most of the species had succulent leaves with leaf thickness ranging from around 232 to 1363 μm. As an indication of salt secretion, both glandular and non-glandular trichomes were observed in several species. Although presence of single to multilayered hypodermis might effectively function as water storage tissue, several studied mangrove plant species e.g. Cynometra ramiflora L., Phoenix paludosa Roxb., Pongamea pinnata (L.) Pierre, Sonneratia apetala Buch. - Ham., S. caseolaris (L.) Engl. and Xylocarpus moluccensis (Lamk.) M. Roem. showed complete absence of hypodermis. This might be due to moderate saline condition. In addition, marked terminal tracheids in mesophyll tissue of a number of species might help with capillary water storage within the leaf. To enhance mechanical support several species were found to develop considerable amount of diverse sclereids within the mesophyll tissue and surrounding vascular bundle. Although maximum anatomical adaptations are common for plants growing in saline habitat it may be suggested that these features were differentially developed in plants specifically grown in mesohaline zone.

Recent investigation on the root, stem, leaf and petiole anatomy of Momordica charantia L. completed the detailed anatomical study of the genus Momordica from Bangladesh. Root has tetrach vascular bundles where thick patches of sclerenchyma cells encompassed the vessel cells. Five angular ridges and furrows are visible through stem transverse section typical to Cucurbitaceae. Total nine open, bicollateral fibro-vascular bundles are observed in stem crosssection where three large are in the center and others each are under the ridges. Midrib of the leaf is characterized by several double and scarcely seated stalkless globular cystoliths in the lower epidermis. Configuration of petiole is octagonal in shape with eight ridges where seven fibro vascular bundles situated as a ring. Stem and leaf has multicellular, unisireate blunt ended conical shaped trichomes where petiole has similar trichomes with both blunt and pointed head. Dhaka Univ. J. Biol. Sci. 27(1): 69-74, 2018 (January)

No abstract

Not Available Dhaka Univ. J. Biol. Sci. 29(2): 245-252, 2020 (July)

The present study explores detailed morphoanatomical features of five species of Piper L., viz. P. betle L., P. longum L., P. nigrum L., P. retrofractum Vahl and P. sylvaticum Roxb. Each species is supplemented by detailed updated nomenclature, vernacular names, diagnostic characters, phenology, ecology and representative specimens. Maximum number of cortical and medullary vascular bundles have been observed in P. nigrum and P. retrofractum, respectively. In contrast, minimum number of cortical and medullary vascular bundles have been found in P. sylvaticum. Glandulartrichomes are found on the midrib of P. betle, P. longum, and P. sylvaticum, whereas trichomes are lacking in P. nigrum and P. retrofractum. The highest number of collateral vascular bundles have been found in P. retrofractum followed by P. nigrum, while P. betle and P. longum contain single collateral vascular bundle. P. betle can easily be distinguished from other species by its oval stem, non-glandular multicellular trichome with pointed tip, and presence of idioblasts and oil droplets. P. longum is distinct from remaining species by its diacytic stomata. Keys to the species based on morphological and anatomical characters are provided for easy identification of the studied species.