Yoshida - 1981 - Fundamentals of Rice Crop Science

GROWTH AND DEVELOPMENT OF THE RICE PLANT 55
1.45. How to read the distance between the auricle of the flag leaf and that of the immediate
lower leaf (Matsushima 1970).
penultimate leaf, the distance is zero (0). And when the flag leaf auricle is still in
the sheath of the penultimate leaf, the distance is given a minus (–) sign (Fig.
1.45).
The most active reduction division stage starts when the distance between the
auricles is –3 cm and ends when the distance is + 10 cm. In other words, when the
flag leaf auricle appears from the sheath of the penultimate leaf, the panicle
undergoes the most active period of reduction division.
1.10. HEADING AND ANTHESIS
1.10.1. Morphology of a spikelet
The spikelet is borne on the pedicel, a short stalk that is an extension of the panicle
axis and the primary or secondary branch (Fig. 1.46).
There are two short rudimentary glumes at the upper end of the pedicel. A pair of
sterile lemmas and the rachilla are located between the rudimentary glumes and the
spikelet. The flower is enclosed in the lemma and palea, which may be either
awned or awnless.
The flower consists of the pistil, stamens, and lodicules. The components of the
pistil are the stigmas, styles, and ovary. The stigma is plumose, on to which pollen
grains are shed. The ovary is thick, smooth, and bears two styles.
There are six well-developed stamens, composed of anther and filament. Two
small, oval, thick, and fleshy bodies, called the lodicules, are situated at the base
of the ovary. The lodicules become distended with water and assist in separating
the lemma and palea at flowering.