Morphology of Rice Plant
The Rice Plant.
Fig 1 1
Fig 2. Rice plant is a freely tillering annual grass,
which can grow both on flooded field and dry field
under rainfed condition.
Fig 2. A germinating rice seed.
Roots: (Fig. 2 & 3)
On germination the primary root emerges, followed by two
additional roots. Adventitious roots are then produced
from the basel nodes of the primary stem and tillers. The
young roots are white, thick, short and relatively
unbranched. They elongate with age, branch freely and
become thin flaccid and brown.
1
Fig. 3. Developed rice root system
Stem: (Fig 4 & 5)
Culm is more or less erect, although lodging may occur,
cylindrical, smooth, 35 to 150 cm long, but up to 5 m in floating
rices, 6 to 10 mm in diameter, with solid nodes and hollow
internodes. Internodes are shortest at base, becoming
progressively longer, 10 to 20 in number, but being fewer in
japonica and most in early cultivars. Culm is green or whitish
in colour and on ripening turned to dull yellow. Nodes or
internodes may be pigmented from pink to deep purple. Buds
in axils of leaves at lowest nodes grow out to produce tillers
which appear within 10 to 14 days after germination. Late
tillers may not produce inflorescence and may die.
Fig 4
Fig 2
Leaves: (Fig. 6)
Leaves are found in alternate in two ranks with a
single leaf at each node. The number of nodes and
leaves greatest on the main culm and number
declines progressively with the rise in tillers. The
first leaf at base of main culm and each tiller a
bladeless prophyll; all the others have a sheath and
lamina. Sheath split down whole length and
encircles internodes; those at base longer than
internodes, thus overlapping sheath above; after
10th node sheath become progressively shorter
than internodes. Ligule, a triangular membrane, 1.0
to 1.5 cm long, usually colourless, tending to split
with age. Auricles, when present, falcate, 2 to 4 mm
long, usually fringed with long hairs. Leaf blade
long, narrow, 30 to 50 cm by 1.2 to 2.5 cm,
somewhat pubescent, often with spiny hairs on Fig 3
margins. Laminas of uppermost leaf (flag leaf) is
wider and shorter than others, vertical at flowering, subsequently drooping in indica cultivars, but staying
more erect in japonica cultivars.
Inflorescence: (Fig. 7)
Terminal panicle, 14 to 42 cm long, each with 50 to 500
spikelets, usually about 100, may be open or compact,
erect or drooping. Base of peduncle enclosed in sheath of
flag leaf; at base a ciliate ring at junction with rachis;
distance from top of leaf sheath and ciliate ring determines
the degree of exsertion. Main axis or rachis bears a
variable number of primary branches, and from which bear
number of secondary branches. The one or more spikelets
are borne on the secondary branches.
Fig. 4
The Spikelet: (Fig. 8)
Spikelet of rice consists of one flower. It bears at the
base two empty glumes, a little higher up a flowering
glume called lemma. Opposite to the lemma a
somewhat smaller glume is known as the palea. The
flower remains enclosed by the lemma and the palea
and it is bisexual. The two minute scales called the
lodicules are found near the base of the ovary. The
flower has 6 stamens, anthers versatile and pendulous.
It has one carpels, ovary superior with one ovule. It has
two styles with feathery stigmas.
Fig. 5
The Fruit:-
Hull is the hard cover of the seed. Endosperm is made
up mostly of starch, sugar, protein and fats. It is the
storehouse of food for the embryo. The embryo
develops into the shoot and the root.
Fig. 6
The shape of rice is found in various form. The grain
is usually white or translucent, but red, brown and
blackish forms are known, in which the pigment is
confined to the pericarp. The red in the rice is
dominant. The size of grain varies from 5 to 14.5 mm
long and 1.9 to 3.7 mm broad, and the length of awn
varies..
Fig.7
Chemical Composition of Rice
The chemical composition of rice depends upon the method and degree of milling and polishing and
whether or not it has been parboiled. It is also influenced to some extent by genetic and environmental
factors.
Raw Rice
Husked
Water
Protein
Fat
Carbohydrate
Fibre
Ash
9.7
7.7
1.8
78.1
1.1
1.6
Home
pounded
9.6
7.3
1.2
80.1
0.7
1.1
Undermil
led
9.5
7.2
0.9
81.0
0.5
0.9
Milled
9.7
6.9
0.5
82.1
0.2
0.6
Parboiled Rice
Home
Milled
pounded
12.6
13.3
8.5
6.4
0.6
0.4
77.4
79.1
0.9
0.8