The central cylinder is composed of parenchymatous uniseriate pericycle and alternate bundles of primary xylem and phloem (Figure 2D).
In the root and collet region, each primary xylem bundle breaks into a median protoxylem and a pair of metaxylems, and in this portion a pith begins to appear (Figure 2E, F).
Functional (water-conducting) tracheary elements of all anthesis flower parts, including the pedicel, had helical bands and thus were part of the primary xylem
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.
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).
Torus-bearing pit membranes are present in secondary xylem (wood) and largely or completely absent from primary xylem
diversifolia has a peripheral ring of 24-36 collateraL vascular bundles each with a conspicuous crescent-shaped bundle cap and a strip of densely stained cambial cells between the primary phloem and the primary xylem
Central cylinder is composed of uniseriate parenchymatous pericycle and three strands of primary xylem
and phloem (Figure 2A and B).