We explain what the plantae kingdom is, what its characteristics and classification are. How is its nutrition, reproduction and examples.
What is the kingdom plantae?
It is called the Kingdom plantae (from the Latin “plants”) or the Vegetable Kingdom. one of the main groups in which biology classifies known living things. Along with the Animal Kingdom (animalia), the Kingdom of mushrooms (fungi), the Protist Kingdom (protistae) and the Moneras Kingdom (monera), constitute the traditional categories of classification of life.
The plant kingdom is of the oldest that the human being has studied, despite the fact that there is no strict and universal criterion regarding what to consider as a plant and what not. Generally speaking, this group is considered to be all forms of terrestrial plant life (trees, shrubs, grass, etc.) and all aquatic algae, as long as they carry out some form of photosynthetic nutrition.
The members of this kingdom are descended, in theory, from a group of living beings called Primoplantae or Archaeplastida: the first eukaryotes capable of photosynthesis, and whose appearance on the primitive Earth is estimated about 1,200 million years ago, during the Proterozoic Eon.
Characteristics of the Kingdom plantae
The individuals of the plant kingdom share the following fundamental characteristics:
- Cell wall and chloroplasts. Plant cells have chlorophyll deposits known as chloroplasts, which gives them their green color and is essential for photosynthesis. In addition, their cells have a rigid cell wall outside the plasma membrane, which gives them structural resistance but conditions their growth.
- They lack mobility. Plants, even aquatic plants, lack their own mobility, that is, they are immobile. They can move as a result of natural agents such as water or wind, in some cases, and they also have a minimal orientation of their bodies that allows them to actively seek the sun, known as positive phototropism, but they cannot move in a habitat to another, or flee from animals that consume them as food.
- Cellulose compound bodies. Cellulose is a type of colorless, odorless, amorphous biopolymer insoluble in water, alcohol and ether, which constitutes the basic building material of the bodies of plants and of some protists.
Classification of the kingdom plantae
The members of this kingdom can be classified into two sub-kingdoms:
- Biliphytas. It is a set of algae endowed with water-soluble pigments that help them capture sunlight, just as cyanobacteria do. In turn, it is divided into two divisions or edges:
- Glaucophytes. About 13 species of freshwater single-celled algae, often considered to belong to the protista kingdom.
- Rhodophytes. Around 7,000 species of red algae.
- Chlorobiotes. Also called Viridiplantae or simply green plants, where there are green algae and terrestrial plants of all kinds, which is why more than 300,000 different species are included here. It is in turn divided into two infra-kingdoms:
- Chlorophytas. It contains about 8,200 species of green algae, both unicellular and multicellular.
- Streptophytas. It contains the total set of terrestrial plants in their enormous variety of habitats, morphologies, growth patterns and defense mechanisms, as well as the algae that are evolutionarily closest to it: the so-called carophytes.
Plant nutrition
The members of the vegetable kingdom are all autotrophs, that is, capable of generating their own food from inorganic matter. This is carried out through the synthesis of sunlight or photosynthesis, and the absorption of nearby inorganic resources: water, minerals and other elements, through the roots. Then an energetic chemical reaction is carried out, which requires atmospheric CO2, water and sunlight as an energy source, to produce complex glucose molecules, which then serve for cellular respiration, that is, for its oxidation and obtaining chemical energy or ATP. This process by-produces oxygen molecules that are released into the air, and responds to the general formula of: H2O → 2H + + 2e- + ½ O2.
There are also certain plants capable of feeding on the organic matter of other living beings, like the famous “carnivorous” plants, which after attracting and capturing insects, proceed to digest them to take advantage of their nutrients.
Reproduction of the kingdom plantae
Plants reproduce in two very different ways, sexual and asexual, depending on their species and sometimes on the environmental conditions in which each individual is found.
- Sexual reproduction or pollination. It occurs thanks to the action of the wind or insects and other animals, which unknowingly carry the dust or pollen generated by the flowers of plants, equivalent to their sexual organs, directly towards the pistils of some other, thus facilitating the exchange of material genetic. The flowers are then fertilized and give rise to a fruit, in which there are seeds: embryos of a new individual with a genome different from the paternal one. The fruit ripens and falls, or is eaten by animals, and its seeds are scattered. Each one will touch the ground and germinate, producing a new plant.
- Asexual or rhizomatic reproduction. It does not involve pollination, nor flowers, but other invisible parts of the plant such as its roots, stolons or rhizomes. These parts grow as the plant has reached maturity and gathers the necessary nutrients to reproduce, thus generating an individual genetically identical to the previous one, but young, who is often physically linked to the parent for a time.
Importance of the Kingdom plantae
Plant life is the mainstay of most of the world’s organisms, and not only for taking care of the production of oxygen that we breathe and serving us as food in the form of fruits, leaves, stems, tubers, etc. Plants also help to control dispersed greenhouse gases in the atmosphere, such as CO2, and to absorb water in various types of soil, preventing their uncontrolled accumulation. Without plant life, the world would not be what it is, and for that very reason it is so important to maintain its variety, presence, and abundance.
Examples of Kingdom plantae
Examples of plants in everyday life are easy to find. In this kingdom enter both the trees, the grass, the weeds and the bushes that we find in any public square or park, as well as the home ferns and the water plants that we use as home decoration. Also the marine or lake algae, the palm trees on the beach, or the cacti and thistles of the deserts.
Botany
The branch of biological sciences dedicated to the study of plants is known as botany and its practitioners as botanists. And just as zoologists study animals in their various aspects, botanists focus on understanding the relationships between plants or between plants and animals, in addition to the internal dynamics of the plant organism, and the particular evolution that gave rise to the emergence of this kingdom of creatures.
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