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Kingdom Plantae: It's Definition, Characteristic and Classifications
Kingdom Plantae is one of the major groups of organism that comprises about 266,000 known species of ferns, mosses, herbaceous and woody plants, liverworts, vines, bushes, trees and other forms of plants that dominate and mantle the earth. Plants have varied sizes and intricacy from small nonvascular mosses to giant redwood trees that draw minerals and water through their vascular system and may rise more than 330 feet.
Plants dominate the earth, but only a few percentages of plant species are being properly used by humans for food, drugs, shelter, construction materials, raw materials and fibers. And the plant species where economies and nation depends are wheat, rice, legumes, leafy vegetables, tobacco and conifers.
Plant Kingdom has been producing and sustaining life on earth since the beginning of life forms. They manufacture food for other organisms and provide energy to sustain life. Fossilized plants provide fossil fuels for industrial power plants and throughout history, the plant kingdom has been supplying sufficient oxygen to the atmosphere to maintain the evolution of higher animals.
Over the years, plants have altered into a complex group which allows them to utilize every habitat with enough light for the process of photosynthesis. Plants are autotrophic organism which means they produce their own food through the aid of sunlight.
Today the world’s biomass comprise an enormous number of plants, which not only support nearly most of food webs but also change climate and make and grip soil to avoid erosion, make would the earth habitable for life.
General Characteristic of Plants
Here are some of the characteristics of plant kingdom:
- Plants cells have cellulose walls that uphold their size
- They contain chlorophyll A and B and carotenoid pigment, to utilize sun’s energy.
- Plants store their food in the form of starch
- Plants are multicellular organism with cells that are specialized to form tissues and organs
- They possess reproductive organs that are shielded by non-reproductive cells to avoid gametes or sex cells from drying up.
- The female reproductive structure of plants supplies nutrients and water to the developing embryo.
- They have a life cycle that display an alternation of two generation:
(1) A diploid sporophyte that make spores by meiosis
(2) A haploid gametophyte that create gametes and eventually produces a sporophyte by fertilization.
Classification of Plants
The classifications of plants are based on vascular tissue and reproductive tissues. However, some plants that do not have true roots, stems and leaves because of the absence of vascular tissue belong to Phylum Bryophyta.
Tracheophytes are plants with vascular tissues that aid the transportation of food, water and minerals. Fern (spores-producing plants) and seed-producing plants are placed together in Phylum Tracheophyta. The name comes from the Greek word “Tracheis” which means “windpipe” and “Phyton” which means “plant”. Its name refers to xylem tracheids. Vascular plants have approximately about 212,000 species.
The major groups of tracheophytes are:
(1) Phylum Filicinophyta – ferns (Pterophyta)
(2) Phylum Cycadophyta – cycads
(3) Phylum Coniferophyta – pines
(4) Phylum Angiospermophyta – flowering plants (Anthophyta)
These plants are likely the same in the following ways:
- They contain vascular tissues
- Their bodies are can be identified into true roots, stems and leaves
- They have chlorophyll
References; Science and Technology by Lilia M. Rabago Ph. D , Crescensia C. Joaquin Ph.D, Catherine B. Lagunzad , PH. D, Encarta