The science of crop farming requires a substantive understanding of the plant structure of the angiosperms, specifically the morphology and anatomy of the plant body and the functions of the different parts. The angiosperms or flowering plants, also called Angiospermae, Magnoliophyta, and Anthophyta, should be given prime attention because they comprise most of the living plants (more than 95%) and food crops (Simpson 2010).
By knowing how each part participates in plant growth and development, it will be possible to make necessary manipulations of the plant and of the environment for improved crop production. Familiarity with the different morphological and anatomical terms will likewise enhance understanding and become useful in the identification of crop plants.
The parts of the plant body of the angiosperms are divided into two distinct systems: the root and shoot. In the terrestrial plants, the root system is the plant organ that is normally underground (descending) while the shoot system is above ground (ascending). The root system consists of the primary root and its branches, or a mass of fibrous roots. The plant shoot system consists of the stem, leaves, and the reproductive structures.
The parts of the plant body are also differentiated into two kinds of functional plant organs: vegetative and reproductive. The vegetative structures include the root, stem, and leaves; the reproductive parts consist of the flower, fruit and seed.
The functions of the different plant structures are interrelated. In general, it is the root that provides anchorage and absorbs water, oxygen and other nutrients which are transported to the leaves via the stem (trunk, branches and twigs). At the same time, the leaves absorb carbon dioxide from the air which is utilized in the production of carbohydrate through the process of photosynthesis. This carbohydrate is in turn transported, again via the stem, to the different parts of the plant, including the roots and the reproductive structures. At certain periods of organ development, the stored photosynthate may again be retransported to other plant organs.
Of course, the entire growth processes are more complicated and requires an intimate look into the internal plant structures, biochemistry, and the various plant growth factors. But the starting point is the familiarization of the external parts of the plant body and the gross internal structure of the various plant organs. As in humans, the education of a child always starts with the identification of the different parts of the body.
(Ben G. Bareja, edited May 2011)