Bunches in both types of secondary xylem narrowed towards the primary xylem
. Sclerenchymatic cells in this part, formed from trache and tracheids in both types, created regular rows in a radial direction.
Xylem in cross section is located radially and has a star-like shapes, its strands go in rays from primary xylem
elements located in the root center and surrounded by sclerenchyma cells.
The central cylinder is composed of parenchymatous uniseriate pericycle and alternate bundles of primary xylem
and phloem (Figure 2D).
Functional (water-conducting) tracheary elements of all anthesis flower parts, including the pedicel, had helical bands and thus were part of the primary xylem
. Sections of embedded material, macerations and SEM provided complementary images of these cells.
Are there monocots in which primary xylem
and early metaxylem are vesselless but metaxylem contains vessels?
The primary xylem
varied the number of diarch, triarch and tetrarch poles (Figure 1c, e, g).
The provascular tissues give rise to the primary vascular system of the plant--the primary xylem
and primary phloem.
The roots were either diarch with two primary xylem
strands or triarch with three primary xylem
strands cleaving into two or three wide secondary xylem lobes.
Deshpande and Vishwakarma (1992), and Rao and Dave (1984) carried out a detailed analysis of the occurrence of crystals at fusiform and at radial/axial parenchyma cells in the secondary phloem and primary xylem
The primary vasculature is non-sympodial, and primary xylem
only occurs as the downward extension of mesarch leaf traces (Fig.
Cell wall development was most pronounced in collenchyma, primary phloem, and primary xylem
vessels at the first sampling date, while other tissues such as epidermis, chlorenchyma, and pith parenchyma had only thin primary walls (Fig.
In this region, tracheary elements of each primary xylem
strand deviate and are distributed on the parenchymatic pith periphery (Figure 4A).