Regulation of vascular differentiation in leaf primordia during the rhythmic growth of Gnetum africanum

Abstract

The growth of the principal axis of Gnetum africanum Welw. is achieved by successive growth and rest periods. During the phase of growth arrest, the terminal bud produces a single pair of leaf primordia containing no vascular tissue whereas observation of the terminal bud of the vinelike stem reveals that the oldest of the leaf primordia do contain vascular tissue before emerging. The differentiation of vascular bundles in the leaf primordia of the principal axis begins only with the return of the growth period during which time new young leaves are formed. The rhythm of formation of the leaves and their vascularization can be accelerated by removal of the young leaves. A prolonged exogenous treatment with abscisic acid after removal of the young leaves reestablishes the inhibition and prevents initiation of vascularization. It seems, therefore, that in the principal axis young leaves inhibit vascular differentiation of the leaf primordia, which may partly explain the inhibition of growth.

Physical Features and Nutritional Value of the Traditional Picking Vegetable, <em>Cuervea isangiensis</em> (De Wild.) N. Halle in Congo-Brazzaville

“…The Gnetum africanum is a vegetable-leaf much consumed in Congo-Brazzaville (Makosso-Vheiye et al, 2008). It is the family of Gnetaccae answered in the tropical regions of Asia, of South America (Mialoundama and Paulet, 1986). Results of the Table 4 show that the leaves of Cuervea isangiensis (De Wild.)…”

Gnetum africanum: A Wild Food Plant from the African Forest with Many Nutritional and Medicinal Properties

“…Gnetum is the sole genus in the family Gnetaceae and comprises about 30 species, most of them lianas distributed in the tropical regions of Asia, South America, 1 and Central Africa. 2 The plants are dioecious: the males produce catkins of stamens, and the female produce catkins of ovules barely protected by an envelope.…”

Nursery substrates and provenances influence rooting performance of juvenile, single-node vine cuttings of Gnetum africanum Welw. (Gnetaceae)

“…(Gnetaceae) is an understorey liana found in the humid tropical forests of Nigeria, Cameroon, Central African Republic, the Republic of Congo, Gabon, Democratic Republic of Congo and Angola (Mialoundama, 1980). Some thirty species of the genus Gnetum occur in the tropics, but only two of these, G. africanum and G. buchholzianum, are found in Africa (Mialoundama & Paulet, 1986). In Cameroon, G. africanum is often found in fallow farmlands and secondary and closed forests.…”