Types Of Plant Cell Overview
Definition of a plant cell
Plant cells are the multicellular eukaryotic cells that make up a plant (a cluster of eukaryotes related to the kingdom Plantae that can synthesise their own sustenance from water, sunlight, and carbon dioxide). As eukaryotic cells, they contain a unique nucleus and distinctive structural organelles, which allow them to work in an organised way.
The plant cell has a cell wall composed of cellulose elements, plastids that perform photosynthesis and hold carbohydrates in the form of starch, central vacuoles for restricting the cell’s turgor pressure, as well as a nucleus that controls the cell’s general mechanisms, such as plant cell reproduction. Plant cell-definition, labelled diagram, structure, components, organelles, has a number of well-defined and documented plant cell organelles.
General features of plant cell
The two structural systems that make up a plant are the root system and the shoot system. The root system is composed of structures that are under the earth, whereas the shoot system is built up of structures that are above the earth, such as leaves, stems, fruits, and flowers, such as roots, tubers, and rhizobial structures, and it is where plants first begin to grow.
These systems are built in a different manner and are composed of mature groupings of specialised cells that carry out a variety of tasks, including support, protection, metabolism, reproduction, and growth and development of the plant. For instance, at the meristem, plant cells are created, multiply, and develop into plant tissues. The following tissues:
Dermal tissue, which is composed of epidermal cells and covers the surface of plants, serves to prevent water loss by the plants.
Ground tissue: The ground tissue, the parenchyma, collenchyma, as well as sclerenchyma cells, are responsible for photosynthesis, water and food storage, and make up the vast majority of the root vascular and epidermal system, as well as the support structure of the plant.
Vascular tissue: The xylem, phloem, parenchyma, and cambium cells that make up vascular tissue are responsible for transporting minerals, hormones in plants, water (through xylem), and food (via phloem).
Plant cells divide into new cells, a process known as mitosis, which happens inside the nucleus. This begins at the meristem, which may be positioned at the root or shoot apex of a vascular plant. The meristems found at the tips are known as apical and lateral meristems. The lateral meristems encourage secondary stem wood and cork development, whereas the apical meristems are in charge of developing the roots.
Other plant cell properties are essential for plant growth and metabolism, in addition to cell division, which results in the production of tissues and, ultimately, a plant.
- A cell wall and a plasma membrane are present. It is composed of pectin, cellulose, and hemicellulose. The cell wall provides the cell with its form, its defence, and the means of mediating cellular connections.
- They feature water-filled, dynamic single-membrane central vacuoles that store nitrogen and phosphorus, control the flow of cellular molecules within the cytosol, and facilitate the digestion of proteins that have been stored inside the cell.
- They possess plasmodesmata, a porous layer that constantly extends from the endoplasmic reticulum and allows cell-cell interaction.
- Plant cells also include plastids. Chloroplasts, the most common type of plastid, are made of chlorophyll, a green pigment which collects light energy and converts it to chemical energy that plants use during photosynthesis. The elaioplast is another kind of plastid which stores lipids; chromoplasts, which synthesise and store colours; and amyloplast, which stores starch.
- Plant cells divide by creating the phragmoplast template, which is used to construct cell plates during cytokinesis.
- Plant cells, in contrast to animal cells, conspicuously lack centrioles, cilia, and flagella.
List of Types of Plant Cell
- Parenchyma cells
- Collenchyma cells
- Sclerenchyma cells
- Xylem cells
- Phloem cells
- Meristematic cells
- Epidermal cells
As previously described, plant cells develop at the root tip. The first multiplication that happens at the tip of undifferentiated meristematic cells to form additional specialised cells and cell tissues promotes the development of other cells.
Parenchyma cell definition
These are live, undifferentiated living cells distributed throughout the plant’s body.
They participate in the several mechanisms of the plan, including photosynthesis, food storage, and waste material secretion.
They appear green, according to the experimental observation.
Structure of parenchyma cells
They are undifferentiated living cells with thin, porous membranes.
Since they have no specific structure, they are able to rapidly modify and differentiate into a variety of cells that perform varied functions. There are two kinds of parenchyma cells.
- Palisade parenchyma
- Ray parenchyma
Palisade parenchyma cells contain columnar, enlarged, and organised cells that reside under the epidermis in a number of plant species. In leaf cells’ mesophyll cell layers, chloroplasts are located, palisades are a group of interconnected cells.
Both radial and horizontal patterns of ray parenchyma are mostly found in the plant’s stem wood.
Functions of the Parenchyma cells
- Surface epidermal cells, which greatly participate in light penetration and absorption as well as regulate gas exchange, are responsible for these processes and are closely related to parenchymal cells.
- Small molecules can move freely between cells and the cytoplasm thanks to the porous wall.
- Below the layer of epidermal tissue, in the palisade parenchyma, are spongy mesophyll cells that help absorb light for photosynthesis.
- Ray parenchyma cells are found in wood rays, which transport material up the plant stem.
- The xylem and phloem of vascular plants also include a significant number of parenchyma cells, which aid in the movement of water and nutrients throughout the plant.
- Some additionally produce secondary components that serve as defences against herbivore eating and secrete nectar in a biochemical manner.
- Additionally, the parenchyma cells present in leguminous plants’ root tubers, like potatoes, aid in the storage of food.
Collenchyma cell definition
- These cells are elongated and can be discovered beneath the epidermis or on the outermost layers of juvenile plant stems and leaves.
- They are meristem derivatives that become alive after developing and can be found in the vascular system or on the corners of plant stems.
- They don’t exist in the plant roots; they only appear on the plant’s periphery.
- Upon experimental observation, they seem to be red.
Structure of collenchyma cells
- These cells are long and have a thick cell wall. Cellulose and pectin molecules make up the usually wavy cell wall.
- They resemble parenchyma cells at some stage as they mature before becoming collenchyma cells. The Golgi bodies and endoplasmic reticulum unite to create the main cell wall when a number of cells assemble. A thin primary wall is created when two cells unite; this wall doesn’t develop into collenchyma cells.
- Therefore, the more the cells gather and meld together, the stronger and more irregularly shaped the main cell wall becomes. These freshly generated cells are lengthened to provide the plant with support as it grows. Lignin, a polymeric organic complex that creates strong structural tissues in vascular plants and provides them with solid support, notably in wood and bark, is absent from the main wall, which makes it susceptible to rot.
Types of collenchyma cells
collenchyma Tangential collenchyma is (B). Annular collenchyma (C). lacunar collenchyma, in (D). The size of the intercellular gaps in this type can range from tiny spaces (1) to enormous cavities surrounded by collenchymatous walls, and it frequently appears as an intermediate type with angular and lamellar collenchyma (2). NLM (National Institutes of Health) website: PMC3478049
Depending on the wall thickness and the positioning of the cells, there are four different forms of collenchyma.
- Angular collenchyma
- Annular collenchyma
- Lamellar collenchyma
- Lacunar collenchyma
- The cells have an apparent angle and a polygonal form.
- At the cell’s corners, the cells have thicker walls.
- Considering how densely the cells are packed together, they lack intracellular gaps.
- They are present as hypodermis beneath the epidermis.
- The majority of collenchymas are these.
- The walls have thickened consistently.
- It seems like the cells are round in form.
- The cells seem to be tangentially organised into rows because the edges of the cells are thicker.
- They lack intracellular gaps because of how densely they are grouped together.
- They frequently form and are located on the petioles of leaves.
- These cells are created in a manner that leaves intracellular gaps between them.
- The intracellular compartments are encircled by a thicker cell wall.
- They seem to be spherical in form.
- They develop and are located in the fruit’s walls.
Functions of the Collenchyma cells
- They provide assistance to the plant regions that are lengthening and maturing since they are the live cells in plant tissues. The absence of lignin in the cell wall keeps it flexible, supporting immature plant elements like stems, roots, and leaves with plastic (stretchable) support.
- They give plant tissues elasticity and tensile strength, enabling the plants to bend.
- Additionally, they enable the plant sections to enlarge and expand.
- The chloroplast and collenchyma can cooperate to carry out photosynthesis.
- 3. Sclerenchyma cells
Sclerenchyma cell definition
- These collenchyma cells include a component of the cell wall that significantly contributes to the hardness of the cell wall.
- These cells are grown Collenchyma cells, signifying that the secondary cell wall has developed over the primary cell wall. Every plant root contains them, and they are essential for fastening and sustaining plant roots.
Structure of sclerenchyma cells
- They have a lignified cell wall, which makes them quite tough.
- These characteristics make them more stiff than parenchyma and collenchyma cells.
- Additionally, suberin and cutin render them waterproof.
- They do not survive long due to their stiffness and water resistance, since there is no material exchange for cellular metabolisms to support their lifespan.
- Therefore, once they have reached functional maturity (a period of cytoplasm production), they are dead.
Types of sclerenchyma cells
- Two kinds of sclerenchyma cells exist.
- sclerenchyma fibre cells
- Sclereid cells of sclerenchyma
Functions of the sclerenchyma cells
- They provide protection and support to other plant tissues, particularly the tree trunks and fibres of big herbaceous trees, due to their thicker cell walls.
- The thickened cell wall prevents herbivory. Insect larvae, particularly those that feed on peach fruits, suffer damage to their digestive tracts as a result of ingesting the tough cell wall.
- Sclerenchyma fibres are utilised in the production of fabric, thread, and yarns.
4. Xylem Cells
Xylem cell definition
The majority of xylem cells are located in the vascular tissues of woody plant species.
Structure of Xylem cells
- Tracheids and vascular elements are their two conduction components.
- Tracheids, which are vessels, are present and transfer water and nutrients from the plant’s roots to its leaves.
- Tracheids are elongated, thin, lignified vessels; as a result, they contain a secondary cell wall that has hardened and is designed specifically to transport water from the roots.
- Additionally, the tracheid includes overlapping tap terminals that are arranged in an angle to provide connection and communication between cells.
- The vessel’s components enable water transportation. They are lined to produce a consistent, hollow tube that is three metres in length, hollow, shorter and wider than the tracheids but lacks the angled endplates.
- The xylem cells are additionally associated with fibres and parenchyma cells in order to build ring and looping networks with pits called “bordered pits for transmission.” As a result, they possess both a primary cell wall and a lignified cell wall.
- Water can pass between the xylem cells through the bordered pits, which are places in the cell wall where the major cell wall components are deposited.
- Tracheids are found in gymnosperms, ferns, and pteridophytes, whereas vessel components are found in flowering plants.
Functions of the xylem cells
The primary function of xylem cells is to move water, soluble nutrition, minerals, and inorganic ions upstream from the roots of the plant and its constituents. These compounds pass readily through the xylem tracheids as well as vessel elements with the aid of xylem sap.
5. Phloem Cells
Phloem cell definition
- These cells are located outside the xylem layer of the cell. While they attain maturity and need energy to transport materials, they come to life.
- They function to transport nutrients from plant leaves towards various plant parts.
- Additionally, because of their flaccid cell walls, they are unable to transfer materials under high pressure due to a lack of tensile strength.
Types of phloem cells
Phloem cells are of two different types:
- Sieve cells
- Sieve tubesmembers and companion cells
Sieve tube and companion cells
- Large numbers of plasmodesmata connect these cells, which regulate the metabolism of other cells.
- They are continuously spread from one extreme of the sieve to the other, where they are firmly packed and are shorter and broader than sieve tube members.
- The solute materials can pass more quickly through the sieve cells and tubes because of this concentration. At maturity, the nucleus, ribosomes, and vacuole membrane of the sieve tube members all break down.
- Materials are moved into and out of the sieve tube members with the help of the partner cells. The Phloem (P)-proteins at the cell wall and the callose, which are exclusive to sieve tubes, work in concert to repair wounds on the sieve tubes.
- They are the earliest kind of phloem that is present in ferns and conifers.
- They have tapering, overlapping ends and are structurally lengthy. Their cell walls are covered with pores, and callose is all around them (a carbohydrate that repairs the pores after an injury).
- To assist in transferring materials into the phloem, they collaborate with albuminous cells.
- This is where food that has been dissolved, such as sugar, flows.
Functions of the phloem cells
According to the growth of the plant, it can transmit nutrients in all channels, allowing it to transport dissolved nutrients and organic compounds all through the entire plant.
6. Meristematic cells
Meristematic cell definition
- The meristems are another name for them.
- These are the plant cells that continually divide during the course of a plant’s existence.
- They can self-renew and have fast metabolisms, which helps them manage the cells.
Structure of the meristematic cells
- The Parenchyma, Collenchyma, and Sclerenchyma cells are produced as these cells divide.
- They don’t have a central vacuole, a thin wall, and are composed of undeveloped plastids.
- They have a tightly packed protoplast.
- They feature a big nucleus and a cubic form.
- They work their metabolism hard.
- They have no intercellular gap since they are tightly packed together.
- They have a significant impact on the breadth and length of the plant.
Types of meristematic cells
According to the tissue they are found in, meristematic cells may be divided into three categories.
Apical meristems: which may be seen at the tips of roots and stems that have begun to grow, help to extend the plant’s length.
Lateral meristems: The radial portion of the stem and roots includes lateral meristems, which contribute to the thickness of the plant.
Intercalary meristems: At the base of the leaves are intercalary meristems, which contribute to the variation in leaf size.
Functions of the meristematic cells
- They have a significant impact on the length and width of the plants, as well as the variation in leaf size.
- They develop into the plants’ permanent tissues after differentiating.
7. Epidermal Cells
Epidermal cell definition
- These are the plant’s outer cells that provide defence against harmful invaders like fungus and water loss.
- There are no intracellular gaps, and they are arranged closely together.
- To prevent water loss, they have a waxy cuticle layer covering them.
- Plant stems, leaves, roots, and seeds are all covered in these cells.
Types of epidermal cells
The plant is primarily protected by three different types of epidermal cells against environmental hazards, including high temperatures, infections, and chemical exposures like radiation. They consist of:
- Pavement cells
- Stomatal guard cells
Structure and Functions of Epidermal Cells
- These epidermal cells are the most prevalent kind that all plants have. They are not highly specialised, lack a clearly defined shape, and do not perform any specific tasks.
- The shape of pavement cells varies from plant to plant; for example, the dicots’ leaves resemble jigsaw puzzle pieces, providing them with mechanical strength.
- Pavement cells seem to be rectangular and have an axis parallel to the direction of plant growth when seen on the stem and other lengthy plant components.
- The activities that the pavement cells carry out are connected to the various morphologies. For instance, during the embryogenesis of plant seeds, epidermal cells are generated.
- The cells are tightly packed together to provide a protective layer that shields the underlying cells from excessive water loss.
- The functions of the pavement cell include:
- keep the plants’ internal temperature constant.
- They serve as a physical barrier against external toxins like radiation and infections.
- They divide the stomata of the leaves.
Stomatal Guard cells
- Depending on the type of plant, stomatal guard cells are accessible.
- They have a distinct shape and are extremely specialised, enabling them to carry out a range of tasks.
- The structure distinguishes between two different types of guard cells: those that control water availability by keeping the turgor pressure constant while opening and shutting the stomata; and those that control the flow of gases into and out of the leaves’ stomata.
- Chloroplasts are also present in the stromal guard cells. They thereby affect photosynthesis in a useful way.
- These are also referred to as epidermal hairs since they grow on the epidermis. They are a specific class of cells with clearly discernible forms.
- They are huge, with a diameter of roughly 300 um.
- By serving as traps and poisons for animal predators, they significantly contribute to the protection of the plants against infections and predators.
- These cells go through endoreplication rather than cell division to increase their cell population.
References and Source
- <1% – https://www2.estrellamountain.edu/faculty/farabee/BIOBK/BioBookPLANTANAT.html
- <1% – https://www.youtube.com/watch?v=MWz4ptP_QEU
- <1% – https://www.thoughtco.com/what-is-a-plant-cell-373384
- <1% – https://www.thoughtco.com/cell-wall-373613
- <1% – https://www.studyblue.com/notes/note/n/bio-1500-study-guide-2014-15-turchyn/deck/12773783
- <1% – https://www.researchgate.net/publication/260736170_The_Plant_Vascular_System_Evolution_Development_and_FunctionsF
- <1% – https://www.oldbridgeadmin.org/cms/lib/NJ02201158/Centricity/Domain/1066/chapter-29-plant-structure-and-function.pdf
- <1% – https://www.ncbi.nlm.nih.gov/books/NBK9889/
- <1% – https://www.britannica.com/science/xylem
- <1% – https://www.britannica.com/science/parenchyma-plant-tissue
- <1% – https://www.britannica.com/science/meristem
- <1% – https://www.britannica.com/science/bacteria
- <1% – https://www.biologynotes.site/components-of-the-cell/
- <1% – https://www.bbc.co.uk/bitesize/guides/z2kmk2p/revision/3
- <1% – https://www.answers.com/Q/What_made_up_of_phloem_tissue_and_a_cork_cambium_that_protect_the_stem
- <1% – https://study.com/academy/lesson/collenchyma-cells-function-definition-examples.html
- <1% – https://sciencing.com/cells/
- <1% – https://quizlet.com/9615589/bio-exam-1-flash-cards/
- <1% – https://quizlet.com/31673504/whats-stomata-with-you-flash-cards/
- <1% – https://quizlet.com/19629366/tissues-flash-cards/
- <1% – https://quizlet.com/17179233/mastering-biology-plant-growth-flash-cards/
- <1% – https://quizlet.com/123462152/plant-kingdom-quiz-1-flash-cards/
- <1% – https://en.wikipedia.org/wiki/Tracheid
- <1% – https://en.wikipedia.org/wiki/Lignin
- <1% – https://en.wikipedia.org/wiki/Ground_tissue
- <1% – https://courses.lumenlearning.com/boundless-biology/chapter/stems/
- <1% – https://courses.lumenlearning.com/boundless-biology/chapter/leaves/
- <1% – https://bmmgizmo.wordpress.com/2013/09/21/types-of-epidermal-cells/
- <1% – https://biologydictionary.net/xylem/
- <1% – https://answers.yahoo.com/question/index?qid=20081011194035AAp3jk5
- <1% – http://www.biologyreference.com/A-Ar/Anatomy-of-Plants.html
- <1% – http://preuniversity.grkraj.org/html/3_PLANT_ANATOMY.htm
- <1% – http://facweb.furman.edu/~lthompson/bgy34/plantanatomy/plant_cells.htm
- <1% – http://brilliantpublicschool.com/files/documents/Doc-1164-XI-Biology-Support-Material-HOTS-and-OTBA-2014-15.pdf
- <1% – http://bio1520.biology.gatech.edu/growth-and-reproduction/plant-development-i-tissue-differentiation-and-function/