Journal article

Publication year: 1979

Pages: 329-343

Journal: Flora

Volume number: 168

Issue number: 4

ISSN: 0367-2530

eISSN: 1618-0585

Publisher: Elsevier

Abstract: 
Histological observations in epidermis, stomata, stomata-groups and hypodermis of Begonia leaves are reported in this paper. The nodal conditions of all species as well as cultivars of Begonia so far yet investigated are tri- to multilacunary; only few species possess trilacunary nodes. A network of vascular tissue (vascular plexus) is in almost every species distinctly developed in the transitional section between leaf base and petiole, and between petiole and lamina, too. In several species of Begonia there is in the upper plexus (below the leaf blade) a "ventral transversal anastomosis" clearly observable, whereas the other species a distinct "circular connection" is formed in which all bundles passing ghrough this section are involved. The possible significance of both structures for the development of subpeltate/peltate laminae is discussed. Adaxial vascularization of the axillary buds is in only few species achieved by vascular strings which simply depart from the edges of the median lacune (type A). In all other species without medullary bundles the axillary buds are adaxially supplied by bundles transversing the nodal pith which originate from stelar bundles of the main stem (type B to D). In all species which possess meduallary vascular bundles within the internodes, these medullary bundles contribute to the formation of both the nodal plexus and the adaxial vascularization of the axial buds; in certain species even in such a way, that a so-called "nodal basket" comes into being depending on the number of bundles involved (type E). The presumable mechanical implication of such networks in the implantation and stability of axillary buds/branches as well as likely physiological advantages for balanced distribution of sap is also discussed.

Harvard Citation style: NEUBAUER, H. (1979) NODAL ANATOMY, PETIOLAR AND AXILLARY BUD VASCULARIZATION IN BEGONIA, Flora, 168(4), pp. 329-343

APA Citation style: NEUBAUER, H. (1979). NODAL ANATOMY, PETIOLAR AND AXILLARY BUD VASCULARIZATION IN BEGONIA. Flora. 168(4), 329-343.