Kingdom Plantae: Definition, Characteristics, Classification, and Example
What is classification?
What is plant classification?
Characteristics of Kingdom Plantae
Multicellular: They are eukaryotic and multicellular organisms.
Cell wall present: They have a cell wall in their cells, made up of cellulose, hemicellulose, and pectin.
Variety of reproductive structures: They reproduce in a variety of ways, such as vegetative, sexual, and asexual methods.
Autotrophs in nature: They are autotrophs, which means they can make their own food through the process of photosynthesis.
Sedentary: They are non-motile organisms.
Kingdom Plantae is classified based on:
- The plant body and its distinct components: Presence or absence of distinct components, i.e., stem, leaves, and roots.
- Vascular system: Presence or absence of vascular tissues like xylem and phloem to transport water, minerals, nutrients, and organic compounds.
- ability to produce seeds and flowers If they bear seeds, whether the seeds are naked or enclosed in a fruit.
What is Plant Kingdom Classification?
- Thallophytes do not have a well-defined body structure, lacking distinct organs such as stems, leaves, or roots.
- They are also referred to as thallus-bearing plants. Thallophytes include algae, fungi, and lichens.
- They are aquatic and non-motile. They can be found in fresh water as well as saline water.
- They make their own food through photosynthesis, as they contain chlorophyll. Thus, these are autotrophic plants.
- They are multicellular, eukaryotic, non-vascular plants.
- Some common examples of thallophyta are Volvox, Fucus, Polysiphonia, Ulothrix, Chara, and Spirogyra.
- Bryophytes are known as the amphibians of the plant kingdom because they grow in moist soil but need water for the fertilization process.
- Bryophytes are multicellular and autotrophic.
- They do not have true roots, stems, or leaves. Instead, they have stem-like or leaf-like parts and root-like rhizoids.
- They are non-vascular plants. They absorb water and nutrients from the air through the surface of the plant body, such as the leaves.
- Their haploids produce gametes and are thus called gametophytes. The male sex organ is called antheridium, and the female sex organ is called archegonium.
- Bryophytes reproduce through the production and dispersal of spores instead of seeds.
- Mosses, hornworts, and liverworts are examples of bryophytes.
- Pteridophyta are known as the first terrestrial plants. They have well-defined plant bodies that are differentiated into roots, leaves, and stems.
- They do not bear flowers or seeds.
- Pteridophytes are vascular plants, meaning they possess specialized tissues for the transport of water, nutrients, and sugars throughout their bodies.
- They reproduce via spores rather than seeds. Spores are dispersed into the environment and can germinate into gametophytes under suitable conditions.
Spores are formed along the back surface of the leaves.
- They are mostly found in tropical rainforests and thrive in areas with high humidity and consistent moisture.
- True ferns, horsetails, whisk ferns, clubmosses, and quillworts are some examples of Pteridophytes.
- They are further divided into four categories: psilopsida, lycopsida, sphenopsida, and pteropsida.
- Gymnosperm is derived from the Greek words Gymno, which means “naked,” and Sperms, which means “seeds.”
- Gymnosperms are vascular plants, which means they have specialized tissues for the transport of water throughout their bodies.
- They possess well-developed xylem and phloem, allowing efficient conduction of fluids and nutrients.
- Gymnosperms produce seeds that are exposed and not enclosed within a fruit. They do not form fruits and are therefore called gymnosperms.
- Gymnosperms are typically wind-pollinated, relying on the dispersal of pollen through the air.
- Cycas, picea, thuja, and pinus are some examples of gymnosperms.
- Angiosperms = Angio means covered + Sperma means seed.
- Angiosperms, also known as flowering plants, are the most diverse and widespread group of plants on Earth.
- They have well-defined plant bodies that are differentiated into the root system, shoot system, and leaves.
- Angiosperms produce fruits, which are mature ovaries that develop after fertilization.
- They have well-developed vascular tissues, including xylem and phloem.
- Angiosperms are further divided into monocots and dicots based on the number of cotyledons present in the seeds.
- Monocots, short for monocotyledons, are a group of flowering plants that belong to the family Monocotyledonae.
- They have a single cotyledon in their seeds. This cotyledon serves as a nutrient storage organ during germination.
- Monocot leaves often have long, narrow veins that run parallel to one another. The leaves of grasses, lilies, and orchids are examples of monocots.
- Monocots possess a fibrous root system.
- Monocot stems have dispersed vascular bundle arrangements. These vascular bundles in monocots are dispersed throughout the stem without having a distinct ring-like pattern.
- Monocots have pollen grains with a single furrow or pore.
- Monocots typically have flower parts in multiples of three. This means their flowers often have three or multiples of three petals, sepals, stamens, and pistils.
- Some examples of monocots are bananas, palm trees, sugar cane, ginger, rice, and wheat.
- They have two cotyledons in their seeds. These cotyledons act as organs for storing nutrients during germination.
- Taproot systems are a common feature of dicots’ root systems. A taproot system is made up of a primary root that penetrates the soil deeply and produces smaller lateral roots.
- Dicot leaves often come in a wider variety of shapes compared to monocot leaves. Rose, maple, and sunflower leaves are a few examples of dicots.
- Vascular bundles are arranged in a circular pattern, with the xylem on the inside and the phloem on the outside. These vascular bundles are responsible for the transport of water and nutrients throughout the plant.
- Dicot flowers commonly have their parts in multiples of four or five. This means their flowers have four or five petals, sepals, stamens, and pistils.
- Dicot pollen grains usually have three furrows, or pores. This distinguishes them from monocots, whose pollen grains typically contain a single pore or furrow.
- Some examples of dicots are mangoes, blackberries, almonds, papaya, peas, and oak.