Skip to main content
Fig. 2 | EvoDevo

Fig. 2

From: Linking the evolution of development of stem vascular system in Nyctaginaceae and its correlation to habit and species diversification

Fig. 2

Development of interxylary phloem (ontogeny 1). A Colignonia glomerata, young stem showing polycyclic eustele and the transition from primary to secondary growth. B Guapira pernambucensis, stem in early secondary growth; note the vascular bundles (ellipse) formed by the CCP, whose phloem will be the first phloem island. C Pisonia aculeata, irregular activity of the cambium which results in phloem islands (double arrows) after the development of the coalescent (arching) cambium (thick arrows). Note that the coalescent cambium is originated from the axial phloem parenchyma in continuity with the original cambium. D, E Guapira pernambucensis. D Arching cambium enclosing two phloem islands. E Two phloem islands formed by secondary conducting phloem and sheathing axial parenchyma. The red arrow indicates a sieve-tube element. Scale bars: 200 μm (A–C); 100 μm (D, E). ca cambium, mb medullary bundles, pa axial phloem parenchyma, pe pericyclic fibers, sap sheathing axial parenchyma, sph secondary conducting phloem, sxy secondary xylem. A, B Stained with astra blue and safranin. C, E Stained with toluidine blue

Back to article page