Barley for Food and Health: Science, Technology, and Products

MORPHOLOGY AND ANATOMY 23
Primary leaf
Soil surface
Coleoptile
Seminal
roots
Grain
FIGURE 2.3
Percival 1902.)
Barley seedling with emerged shoot and primary leaf. (Adapted from
Leaves
A barley leaf consists of a sheath, ligule, auricles, and blade. The blade is
lanceolate-linear or gradually tapered with a prominent middle nerve or rib,
flanked by 10 to 12 or more parallel side nerves. The uppermost blade, called
the flag leaf , is often the smallest leaf, other than the seedling leaf, which is the
first leaf to show and is also the smallest. Foliage leaves consist of the dermal
system, ground tissue, and a vascular system and contain green photosynthetic
mesophyll covered by the epidermis on both surfaces. Stomata, providing avenues
for oxygen intake and carbon dioxide removal, are located on the underside of
the leaves. Stomata numbers vary with environment and genotype. Between five
and 11 single leaves arise as a semicircular ridge at alternating points on opposite
sides of the stem. Leaves will differ in size and shape and position on the stem
in different barleys. Leaf size is also influenced by environmental growing conditions,
especially day length. The leaf is attached to the stem by the leaf sheaf at
the node. The sheaf surrounds the stem, being split to the base on the opposite
side from the blade with the two edges overlapping each other. The auricles,