Srivastava Shyam C.; Banerji Jayasri: Pentoxylon plant: a reconstruction and interpretation. In: Plant cell biology and development, (13). pp. 11-18. (2001)
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Considering the constant association of vegetative and fertile organs: Pentoxylon (stem), Nipaniophyllum (leaf), Sahnia (pollen organ) and Carnoconites (seed cone), it has been tempting to envisage as to how the whole Pentoxylon plant might have looked like by piecing together. Also it is speculated in what kind of possible habitation or surrounding it could have been thrived. However, it seems very likely that this branched shrubby plant could have attained the height of possibly a small tree possessing supposedly a robust crinkled stem devoid of leaf bases probably thrown off with the maturity. Further, the branches presumably have been portrayed arising and dichotomizing at the extremity of stem whereas the branch scars due to shedding are shown at lower level. The dichotomized branches bear long and short shoots. The long shoots demonstrate sparsely placed leaf cushions while the short shoots have closely placed leaf cushions. The foliage and fertile organs are borne on different kinds of short shoots. However, the attachment on short shoots is indicative of these diverse plant organs belonging to the same plant. The woody short shoots having spirally arranged persistent rhomboid leaf base-cushions depict terminally dichotomizing branchlets each bearing broadly conical head. The female cone Carnoconites containing spirally arranged seeds possessed their micropyles pointing outwards. The outer fleshy and inner stony layer are well developed and nucellus is free from the integument. The short shoots of thick parenchymatous cells terminate into pollen cone Sahnia borne on a collar like structure formed by the raised margin of receptacle. The pollen organ consists of persistent microsporangiophores bearing short branch with several stalked rounded sporangia containing oval monocolpate pollen grains showing longitudinal dehiscence. The slender short shoots which are borne in the axils of long shoots generally bear in apical portion bunch of simple rather stiff, coriaceous, strap-shaped leaves of Nipaniophylium. The plants were deciduous dropping off the leaves in their entirety. Whether the Pentoxylon plant was monoecious or dioecious, for the present, it has been taken as to be monoecious because Sahnia though very rare has always been found intimately associated with Carnoconites which generally occurs detached enormously among other plant remains. Further, the occurrence of Pentoxylon plant has been noted in overwhelming majority in the floral assemblage of Nipania, Rajmahal Hills, India, wherein the representation of phycophytes, mycophytes, pteridophytes, and cycadophytes are less frequent. However, the conifers are quite common. The advent of pentoxylopsids mark a floral change, thereby confirming the younger age for Nipania deposits among the various fossil sites of Rajmahal Hills. Taking the floral composition of Nipania as a whole, it appears, that the vegetation flourished along the lake margins on volcanic terrain under subtropical humid climate. Besides, the discovery of Pentoxylon plant from Australia, New Zealand and Antarctica is quite significant, keeping in view the free dissemination of plant all over the Gondwana countries until the breakup of this supercontinent.
| Mű típusa: | Cikk, tanulmány, mű |
|---|---|
| Befoglaló folyóirat/kiadvány címe: | Plant cell biology and development |
| Dátum: | 2001 |
| Kötet: | 13 |
| ISSN: | 0866-5443 |
| Oldalak: | pp. 11-18 |
| Nyelv: | angol |
| Kiadás helye: | Szeged |
| Befoglaló mű URL: | http://acta.bibl.u-szeged.hu/46862/ |
| Kulcsszavak: | Palinológia, Paleobotanika, Sejtbiológia - molekuláris |
| Megjegyzések: | Bibliogr.: p. 17-18. ; ill. ; összefoglalás angol nyelven |
| Szakterület: | 01. Természettudományok 01. Természettudományok > 01.06. Biológiai tudományok |
| Feltöltés dátuma: | 2017. júl. 07. 08:26 |
| Utolsó módosítás: | 2026. jan. 19. 10:25 |
| URI: | http://acta.bibl.u-szeged.hu/id/eprint/47897 |
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