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Facts about the Rice Plant - A Detailed Description
Rice is a food crop that is included as an essential part of a meal across the world. Rice is used for making desserts, puddings or ground and used in the form of rice flour.
The rice plant is a member of the grass family called Poaceae. It is cultivated as an agricultural crop and has an annual yield of 535 million tons. In Asia alone, over 300 million acres of land is used for cultivation of rice.
History of Rice
The first evidence of rice being grown was traced back to China. From China, the cultivation of rice spread to South Asia during 2000 B.C. The knowledge of rice cultivation spread to Indonesia around 1,500 B.C and Japan in 1000 B.C. Rice was introduced to India in 2500 B.C and SriLanka in 1000 B.C.
The growing of rice spread to Europe, Africa, and America when the Moor’s invaded Spain in 700 A.D. In the United States rice was cultivated since the seventeenth century.
Latest archaeological evidence has revealed that an area along the Yangtze River in Central China was the region where rice was first domesticated.
Varieties of Rice
The rice plant is an annual grass that belongs to the genus Oryza. The genus Oryza has two cultivated varieties of rice and 22 wild species of rice. The rice plant belongs to the Gramineae family. The Gramineae family is also referred to as Poaceae.
The two varieties of rice that are widely cultivated for consumption are Oryza sativa (Asian rice) and the Oryza glaberrima (African rice).
What is a tiller?
The tiller is the rice seedling that arises from the seed after germination. The young seedling has three main parts - root, shoot and the leaf.
When the seedling has developed a stem and sprouted about five leaves, more shoots grow out from the main stem. This process is called tillering, and each new stem is called a tiller. At the top of each tiller, there are flat leaves.
At first, the tiller is attached to the main plant and after sometime the tiller separates from the main plant and develops roots of its own.
Description of the Rice Plant
Rice is a plant that has a short lifespan of 3 – 7 months. The height of the rice plant ranges from 0.4 meters to 5 meters. The wild varieties of rice are more than 7 meters tall.
Rice plants grow as a tuft of culms (stems) with long flat leaf blades. The stem of the rice plant has joints that are made up of nodes and internodes. The node is the part of the stem from which a leaf grows. The internode is part of the stem that lies between two nodes.
The root system of the rice plant is shallow, and more than 95% of the roots are found in top 8 inches of the soil.
The roots of the rice plant are fibrous and have many secondary and tertiary branches. The surface of the roots has thin root hairs. The root hairs absorb moisture and nutrients from the soil.
The leaves are arranged in alternate order on the culm in opposite directions. The leaf of the rice plant is complex in structure.
- Leaf sheath originates from the node of a culm (stem) and partially encloses the node.
- Leaf blade also originates from the node and is joined with the sheath.
- The uppermost part of the leaf is called the Flag Leaf and is just below the panicle.
- There are small appendages at the base of the leaf blade called auricles.
- A thin papery structure present above the auricle called the ligule.
Structure of the Flower
The rice flowers are small and are arranged in a panicle-type of an inflorescence. A panicle inflorescence is borne on the uppermost internode of the culm. The spikelet is the floral part of the plant that has the reproductive organs.
The male part of the rice plant is the stamen. It is made up of two parts the anther and the filament. The filament is long, thin and supports the anther at the tip. Each anther has four elongated sacs that hold the pollen grains. The flower of the rice plant has six stamens.
The female part of the rice plant is made up of the stigma, style, and ovary. The pollen grains land on the stigma and these are transported to the ovary where fertilization takes place. The ovary, stigma, and style together make up the carpel.
The lemma and palea are the structures that protect the floral organs. The pedicel is the small stalk that arises from the node and bears the spikelet.
The wind pollinates the flowers of the rice plant.
Structure of the Kernel
Each rice plant bears hundreds of kernels. A rice kernel measures 6-10 mm in length.
The rice kernel has four parts –
- hull – the hard outermost covering
- bran - layers that protect the inner parts of the kernel
- endosperm - found beneath the bran layers
- embryo - the innermost part from which a new rice plant grows
The bran layers are rich in protein, dietary fiber, Gamma Oryzanol and trace minerals, The endosperm (white rice) has protein, carbohydrate, and starch.
The embryo also known as the germ is rich in protein, antioxidants, minerals and phytonutrients.
Harvesting Rice Grains
Rice grows well in heavy soils and is rich in water content. Farmers grow rice in paddies. Paddies are fields with dirt walls around them that help to keep the water inside.
The fields are flooded with water and the seeds, or small rice plants are planted in the soil.
Two or three weeks before the harvest all the water from the field is pumped out, and the rice plants are cut, and the kernels are separated from the rest of the plant. The wet kernels are dried out in the sun. After the harvest, rice is processed in the rice mills.
Why brown rice is more healthy than white rice?
Brown rice is more healthy than white rice because the milling process that produces the brown rice removes only the outermost layer (hull) of the rice grain and does not destroy the nutritious inner layers of the rice grain such as the bran, endosperm and the embryo.
The milling and polishing processes that produce white rice destroy the nutritional inner layers of the rice grain.
The milling and polishing process that produces white rice destroys the following -
- 67 % of Vitamin B3
- 80 % of Vitamin B1
- 90 % of Vitamin B 6
- 60 % of iron
- Half the Manganese
- Half the Phosphorus
- All of the dietary fiber and fatty acids
Brown rice is a healthy choice that contributes to overall good health in the long run.