(R1501) Rotational and Hall Current Effects on a Free Convection MHD Flow with Radiation and Inclined Magnetic Field

Rotational and Hall current effects on a free convection MHD flow with Radiation and inclined magnetic field are studied here. Electrically conducting, viscous, and incompressible fluid is taken. The flow is modelled with the help of partial differential equations. The analytical solutions for the velocity, concentration, and temperature are solved by the Laplace integral transform method. The outcomes acquired have been examined with the help of graphs drawn for different parameters like Hartmann number, Hall current parameter, inclination of magnetic field, angular velocity and radiation parameter, etc. The variation of the Nusselt number has been shown graphically. It is observed that Hall current parameter and inclination of magnetic field reduces the resistive effect of the applied external magnetic field. Such a study assumes importance because both rotation and Hall current induce secondary flow in the flow-field. The conclusion of the study may be useful in the field of solar physics, rotating magnetic stars, rotating MHD induction machine energy generator and many industrial applications

The genus Isoetes from India: An overview

The information regarding the Indian quillwort is reviewed herewith to highlight the taxonomy, history, distribution, phytogeography, morphology, phenology, chromosome count, numerical taxonomy and present taxonomic scenario of Indian species. Authors also reviewed the opinions of different researchers on doubtful species of Indian Isoetes.&nbsp

Review on the genus Tectaria Cav. from India

The fern genus Tectaria Cav. (Tectariaceae) is one of the largest, morphologically diverse and more complex genera having difficulties in identifying the species and their groups. Since its description, a number of new genera had been separated from it or merged within it created considerable ambiguity. Thus, the main aim of the present review is to provide comprehensive information of the taxonomy, cytology, anatomy, palynology and molecular research carried out so far on the genus Tectaria. Present work is not merely compilation but includes personal observations and is presented here after critical evaluation

Distribution and diversity of Polyporaceae in Western India: An overview and addition to mycoflora of the Gujarat state

Extensive fieldwork in different climatic regimes of Gujarat state during last four years resulted in the collection of more than 349 fungal species. Out of these, 37 species from 20 genera were found to be from the family Polyporaceae. Among these, five species are being reported for the first time here as new distribution records. The highest number of species is represented by the genus Trametes while, Cerrena unicolo, Neolentinus kauffmanii, Dichomitus squalens, Panus conchatus and Laetiporus sulphureus possessed single species each

Genus Athyrium Roth (Athyriaceae: Pteridophyta) from Gujarat State

Present study deals with the diversity, distribution and conservation status of the genus Athyrium Roth in different climatic regimes of Gujarat state. Five species of Athyrium viz., A. hohenackerianum T. Moore, A. falcatum Bedd., A. micropterum Fraser-Jenk., A. parasnathense (C.B.Clarke) Ching ex Mehra & Bir and A. schimperi subsp. biserrulatum (Christ) Fraser-Jenk., were collected form the Gujarat state, of which A. hohenackerianum T. Moore is documented earlier. Therefore, occurrence of A. falcatum, A. micropterum, A. parasnathense, and A. schimperi subsp. biserrulatum, stands as a new distribution records and reported for the first time from Gujarat state. A detailed taxonomic description, photo plates, morphological characters, distribution and comparison of species is provided here for their identification

Status of <i>Isoetes coromandeliana</i> L.f. and <i>Equisetum debile</i> Roxb. ex Voucher in Gujarat State, Western India

Occurrence of Isoetes coromandeliana L.f. in natural ponds of Harni, Savali and Tuwa (India) is known since 1956 by earlier workers. Equisetum debile Roxb. ex Voucher was also reported in 1962 growing as wild at Savali. Available literature indicates that I. coromandeliana falls under the category of ‘near threatened’ in Asian continents and as an ‘endangered species’ at national (India) level. In the current field work study, the authors could not locate the investigated species from the locations earlier documented by researchers. Few saplings of I. coromandeliana were observed at Talod and Vaktapur near Gandhinagar, a new location for the species. In contrast, E. debile appeared to be lost in wild from Gujarat. Their extinction from earlier reported locations is associated with anthropogenic pressure and thus legal action for their protection is needed. The present paper suggests further survey and habitat based studies and recommends conservation and management action plans based upon the ecology of the habitat.</p

Development of successive cambia and structure of the secondary xylem in some members of the family Amaranthaceae

Young stems of Aerva javanica (Burm.f.) Juss. ex Schult., A. lanata (L.) Juss. ex Schult, A. monsonia Mart., A. sanguinolenta (L.) Blume, Alternanthera bettzickiana (Regel) G. Nicholson, A. philoxeroides (Mart.) Griseb., Gomphrena celosioides Mart., G. globosa L. and Telanthera ficoidea (L.) Moq., showed the renewal of small sectors of cambium by replacing with new segments. Therefore, the secondary phloem formed by earlier cambial segments form isolated islands of phloem enclosed within conjunctive tissues became embedded in the secondary xylem. As the stem grows older, complete ring of cambium is renewed; sometimes an anastomosing network of successive cambia may be seen due to the renewal of larger segments of the cambium. Renewal of the cambium takes place by repeated periclinal division in the parenchyma cells positioned outside to the phloem formed by the previous cambium. Functionally the cambium is bidirectional and exclusively composed of fusiform cambial cells. Differentiation of conducting elements of the secondary xylem and phloem remains restricted to the certain cambial cells while rest of the segments exclusively produce conjunctive cells. Accumulation of starch along with the presence of nuclei in the xylem fibers even after deposition of the secondary wall is consistent in all the species and it seems to be associated with the absence of rays in the secondary xylem and phloem of nine species from four genera. The significance of successive cambia, rayless xylem and nucleated xylem fibers were correlated with plant habit

Assessment of Pteridophyte Diversity and their Status in Gujarat State, Western India

An intensive field survey was carried out from the hilly regions, plains of different climatic regimes and agricultural land of Gujarat state. About 23 species were collected from Gujarat state, from which eight species viz., Actiniopteris radiata (Sw.) Link, Adiantum caudatum L., A. incisum Forssk., Lygodium flexuosum (L.) Sw., Pteris vittata L., Selaginella ciliaris (Retz.) Spring, S. delicatula (Desv. ex Poir.) Alston, and S. repanda (Desv. ex Poir.) Spring. were added as new distributional record for the Gujarat state. Increasing anthropogenic pressure, destruction of forest ecosystem and development of infrastructure facilities including road widening and rainwater harvesting program by deepening of the natural ponds are additional reasons for declining terrestrial and aquatic pteridophyte diversity respectively. Our survey concludes that E. debile is regionally extinct in the wild while Isoetes coromandeliana, will be lost from its natural habitat in short time if not conserved properly. Therefore, there is an urgent need of in situ conservation by developing action plans in collaboration with the state forest department

Formation of medullary phloem in Argyreia nervosa (Burm. f.) Bojer

Histologically, family Convolvulaceae is characterised by the presence of successive cambia, medullary (internal/intraxylary) and interxylary phloem in majority of the species, whereas some of the members are devoid of successive cambia and medullary bundles. The present study on Argyreia nervosa (Burm. f.) Bojer showed the presence of medullary bundles while internal phloem was absent during the primary growth. As the secondary growth progressed, successive cambia initiated from the pericyclic parenchyma. Development of medullary bundles began along with the regular protoxylem and protophloem while formation of intraxylary phloem was observed only after the initiation of secondary growth. Medullary/intraxylary sieve elements began to develop from the marginal pith cells. In thick stems, small segments of internal cambium initiated between the protoxylem and internal phloem. This internal cambium was functionally unidirectional and produced internal phloem centripetally. Developmental particulars are described in details along with its significance