One leaf disc with known area was detached from each leaf, avoiding major veins and the midrib .
In both 30 mm and 300 mm long leaves, cell lines close to the midrib were nearly parallel to it, while cell lines closest to the leaf edge had an angle up to 60° with the midrib .
Before measurement the proximal four leaflets were removed and the leaf midrib was inserted into the pressure chamber.
The weight on the opposite side kept the leaf midrib in a straight position.
In brief, approximately midway along the length of the leaf an incision was made into the midrib .
Each leaf has many pinnae and a leaf axis that is subdivided into a midrib and a petiole.
The middle branch leaves the stem and forms the midrib of a leaf, while the other two branches join with their neighbors to reform a full-sized vascular bundle.
The bulk of axial water movement through the elongation zone occurs through xylem elements in the midrib and large lateral veins.
Large sectors or patches which extend from the midrib to the leaf margin are much less frequent, with approximately only one in 100 shoots having such leaves.
During plant culture, the diameter of the hypocotyl and the length of the midrib of primary and subsequent leaves was measured.