Figure 2 shows the internode cross sectional area and the distribution of bundles in cortex (the para-epidermal zone 1 is 19% of the total cross sectional area) and pith (89%) in four Ohio43/KYS plants at the stage of silking. The numbering system adapted places the top ear above the internode #12 (Fig. 2a). The tassel begins above internodes #2-3 and the top crown roots initiate at the node above internodes #19-20. The results indicate a maximum bundle number at the ground level (#19) and demonstrate a general exponential reduction in the number of vascular bundles and cross-section area toward the apex of the plant. However, a shoulder in the curve was observed around the ear-bearing node (internodes 12-16) as the large number of vascular bundles supplying the ear (Fig. 2b-e).
This article is part of a report by WYC for Siemens Westinghouse Science and Technology Competition (Semi Finalist) and Intel Science Talent Search (2001).
Figure 1. Vascular bundles below and through a node. Note the branching before the vasculatures enter the node (black arrow). V: vascular bundles, White Arrow: Direction of Apex.
2. (a) Diagrammatic representation of the using internode numbering
system used in this article, (b) number of vasculatures in zone 1, (c)
number of vasculatures in pith (core), (d) number of total vasculatures,
(e) cross sectional area.
Return to the MNL 76 On-Line Index
Return to the Maize Newsletter Index
Return to the Maize Genome Database Page