Leaf vasculature in Zea mays L.

Abstract

The vascular system of the Zea mays L. leaf consists of longitudinal strands interconnected by transverse bundles. In any given transverse section the longitudinal strands may be divided into three types of bundle according to size and structure: small, intermediate, large. Virtually all of the longitudinal strands intergrade structurally however, from one bundle type to another as they descend the leaf. For example, all of the strands having large-bundle anatomy appear distally as small bundles, which intergrade into intermediates and then large bundles as they descend the leaf. Only the large bundles and the intermediates that arise midway between them extend basipetally into the sheath and stem. Most of the remaining longitudinal strands of the blade do not enter the sheath but fuse with other strands above and in the region of the blade joint. Despite the marked decrease in number of longitudinal bundles at the base of the blade, both the total and mean cross-sectional areas of sieve tubes and tracheary elements increase as the bundles continuing into the sheath increase in size. Linear relationships exist between leaf width and total bundle number, and between cross-sectional area of vascular bundles and both total and mean cross-sectional areas of sieve tubes and tracheary elements.

Genetic Control of Carbon Partitioning in Grasses: Roles of Sucrose Transporters and Tie-dyed Loci in Phloem Loading

“…Collectively, the intermediate and small veins are referred to as minor veins, while the largest veins are known as lateral or major veins. Minor veins intergrade into the lateral veins (Russell and Evert, 1985). Transverse veins with anatomy similar to the small veins connect adjacent longitudinal veins.…”

tie-dyed1Functions Non-Cell Autonomously to Control Carbohydrate Accumulation in Maize Leaves

“…We hypothesize that the transport function of veins may be responsible for their association with tdy1 phenotypic region boundaries. Two explanations for this association are that lateral veins have the greatest transport capacity due to their larger amount of phloem tissues (Russell and Evert, 1985), and they have hypodermal sclerenchyma fibers between the bundle sheath and epidermis that form a barrier to apoplastic solute movement (Esau, 1977). Intermediate veins have limited hypodermal sclerenchyma, which might also explain the occasional boundary occurring at these veins.…”

Maize YABBY Genes drooping leaf1 and drooping leaf2 Regulate Plant Architecture

“…The medial-lateral axis is defined by the medial midvein and two lateral margins, with lateral veins running parallel between them (Sharman, 1942;Bosabalidis et al, 1994;Scanlon et al, 1996). Patterning along the adaxial-abaxial axis produces distinct epidermal characters, such as adaxial macrohairs and bulliform cells (Kiesselbach, 1949), and internal tissue arrangements such as polarized vascular bundles where xylem and phloem are positioned adaxially and abaxially, respectively (Russell and Evert, 1985).…”