Sap is a fluid transported in xylem cells or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from resin, or cell sap. Saps may be broadly divided into two types: xylem sap and phloem sap. Xylem sap consists of a watery solution of hormones, mineral elements and other nutrients. Transport of sap in xylem is characterized by movement from the roots toward the leaves. Over the past century, there has been some controversy regarding the mechanism of xylem sap transport. Xylem sap transport can be disrupted by cavitation—an "abrupt phase change from liquid to vapor"—resulting in air-filled xylem conduits. In addition to being a fundamental physical limit on tree height, two environmental stresses can disrupt xylem transport by cavitation: "increasingly negative xylem pressures associated with water stress, freeze-thaw cycles in temperate climates. Phloem sap consists of sugars and mineral elements dissolved in water, it flows from where carbohydrates are stored to where they are used.
The pressure flow hypothesis proposes a mechanism for phloem sap transport. Although other hypotheses have been proposed. Phloem sap is thought to play a role in sending informational signals throughout vascular plants. "Loading and unloading patterns are determined by the conductivity and number of plasmodesmata and the position-dependent function of solute-specific, plasma membrane transport proteins. Recent evidence indicates that mobile proteins and RNA are part of the plant's long-distance communication signaling system. Evidence exists for the directed transport and sorting of macromolecules as they pass through plasmodesmata." A large number of insects of the order Hemiptera, feed directly on phloem sap, make it the primary component of their diet. Phloem sap is "nutrient-rich compared with many other plant products and lacking in toxins and feeding deterrents, it is consumed as the dominant or sole diet by a restricted range of animals"; this apparent paradox is explained by the fact that phloem sap is physiologically extreme in terms of animal digestion, it is hypothesized that few animals take direct advantage of this because they lack two adaptations that are necessary to enable direct use by animals.
These include the existence of a high ratio of non-essential/essential amino acids in phloem sap for which these adapted Hemiptera insects contain symbiotic microorganisms which can provide them with essential amino acids. A much larger set of animals do however consume phloem sap by proxy, either "through feeding on the honeydew of phloem-feeding hemipterans. Honeydew is physiologically less extreme than phloem sap, with a higher essential:non-essential amino acid ratio and lower osmotic pressure," or by feeding on the biomass of insects that have grown on more direct ingestion of phloem sap. Maple syrup is made from reduced sugar maple xylem sap; the sap is harvested from the Sugar Maple, Acer saccharum. In some countries harvesting the early spring sap of birch trees for human consumption is common practice. Certain palm tree sap can be used to make palm syrup. In the Canary Islands they use the Canary Island Date Palm while in Chile they use the Chilean Wine Palm to make their syrup called miel de palma.
The plastid is a membrane-bound organelle found in the cells of plants and some other eukaryotic organisms. Plastids were discovered and named by Ernst Haeckel, but A. F. W. Schimper was the first to provide a clear definition. Plastids are the site of manufacture and storage of important chemical compounds used by the cells of autotrophic eukaryotes, they contain pigments used in photosynthesis, the types of pigments in a plastid determine the cell's color. They have a common evolutionary origin and possess a double-stranded DNA molecule, circular, like that of prokaryotic cells. Plastids that contain chlorophyll are called chloroplasts. Plastids can store products like starch and can synthesize fatty acids and terpenes, which can be used for producing energy and as raw material for the synthesis of other molecules. For example, the components of the plant cuticle and its epicuticular wax are synthesized by the epidermal cells from palmitic acid, synthesized in the chloroplasts of the mesophyll tissue.
All plastids are derived from proplastids, which are present in the meristematic regions of the plant. Proplastids and young chloroplasts divide by binary fission, but more mature chloroplasts have this capacity. In plants, plastids may differentiate into several forms, depending upon which function they play in the cell. Undifferentiated plastids may develop into any of the following variants: Chloroplasts: green plastids for photosynthesis; each plastid creates multiple copies of a circular 75–250 kilobase plastome. The number of genome copies per plastid is variable, ranging from more than 1000 in dividing cells, which, in general, contain few plastids, to 100 or fewer in mature cells, where plastid divisions have given rise to a large number of plastids; the plastome contains about 100 genes encoding ribosomal and transfer ribonucleic acids as well as proteins involved in photosynthesis and plastid gene transcription and translation. However, these proteins only represent a small fraction of the total protein set-up necessary to build and maintain the structure and function of a particular type of plastid.
Plant nuclear genes encode the vast majority of plastid proteins, the expression of plastid genes and nuclear genes is co-regulated to coordinate proper development of plastids in relation to cell differentiation. Plastid DNA exists as large protein-DNA complexes associated with the inner envelope membrane and called'plastid nucleoids'; each nucleoid particle may contain more than 10 copies of the plastid DNA. The proplastid contains a single nucleoid located in the centre of the plastid; the developing plastid has many nucleoids, localized at the periphery of the plastid, bound to the inner envelope membrane. During the development of proplastids to chloroplasts, when plastids convert from one type to another, nucleoids change in morphology and location within the organelle; the remodelling of nucleoids is believed to occur by modifications to the composition and abundance of nucleoid proteins. Many plastids those responsible for photosynthesis, possess numerous internal membrane layers. In plant cells, long thin protuberances called stromules sometimes form and extend from the main plastid body into the cytosol and interconnect several plastids.
Proteins, smaller molecules, can move within stromules. Most cultured cells that are large compared to other plant cells have long and abundant stromules that extend to the cell periphery. In 2014, evidence of possible plastid genome loss was found in Rafflesia lagascae, a non-photosynthetic parasitic flowering plant, in Polytomella, a genus of non-photosynthetic green algae. Extensive searches for plastid genes in both Rafflesia and Polytomella yielded no results, however the conclusion that their plastomes are missing is still controversial; some scientists argue that plastid genome loss is unlikely since non-photosynthetic plastids contain genes necessary to complete various biosynthetic pathways, such as heme biosynthesis. In algae, the term leucoplast is used for all unpigmented plastids, their function differs from the leucoplasts of plants. Etioplasts and chromoplasts are plant-specific and do not occur in algae. Plastids in algae and hornworts may differ from plant plastids in that they contain pyrenoids.
Glaucophyte algae contain muroplasts, which are similar to chloroplasts except that they have a peptidoglycan cell wall, similar to that of prokaryotes. Red algae contain rhodoplasts, which are red chloroplasts that allow them to photosynthesise to a depth of up to 268 m; the chloroplasts of plants differ from the rhodoplasts of red algae in their ability to synthesize starch, stored in the form of granules within the plastids. In red algae, floridean starch is stored outside the plastids in the cytosol. Most plants inherit the plastids from only one parent. In general, angiosperms inherit plastids from the female gamete, whereas
Chloroplasts are organelles that conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in plant and algal cells. They use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, the immune response in plants; the number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like Arabidopsis and wheat. A chloroplast is a type of organelle known as a plastid, characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are dynamic—they circulate and are moved around within plant cells, pinch in two to reproduce.
Their behavior is influenced by environmental factors like light color and intensity. Chloroplasts, like mitochondria, contain their own DNA, thought to be inherited from their ancestor—a photosynthetic cyanobacterium, engulfed by an early eukaryotic cell. Chloroplasts cannot be made by the plant cell and must be inherited by each daughter cell during cell division. With one exception, all chloroplasts can be traced back to a single endosymbiotic event, when a cyanobacterium was engulfed by the eukaryote. Despite this, chloroplasts can be found in an wide set of organisms, some not directly related to each other—a consequence of many secondary and tertiary endosymbiotic events; the word chloroplast is derived from the Greek words chloros, which means green, plastes, which means "the one who forms". The first definitive description of a chloroplast was given by Hugo von Mohl in 1837 as discrete bodies within the green plant cell. In 1883, A. F. W. Schimper would name these bodies as "chloroplastids".
In 1884, Eduard Strasburger adopted the term "chloroplasts". Chloroplasts are one of many types of organelles in the plant cell, they are considered to have originated from cyanobacteria through endosymbiosis—when a eukaryotic cell engulfed a photosynthesizing cyanobacterium that became a permanent resident in the cell. Mitochondria are thought to have come from a similar event, where an aerobic prokaryote was engulfed; this origin of chloroplasts was first suggested by the Russian biologist Konstantin Mereschkowski in 1905 after Andreas Schimper observed in 1883 that chloroplasts resemble cyanobacteria. Chloroplasts are only found in plants and the amoeboid Paulinella chromatophora. Cyanobacteria are considered the ancestors of chloroplasts, they are sometimes called blue-green algae though they are prokaryotes. They are a diverse phylum of bacteria capable of carrying out photosynthesis, are gram-negative, meaning that they have two cell membranes. Cyanobacteria contain a peptidoglycan cell wall, thicker than in other gram-negative bacteria, and, located between their two cell membranes.
Like chloroplasts, they have thylakoids within. On the thylakoid membranes are photosynthetic pigments, including chlorophyll a. Phycobilins are common cyanobacterial pigments organized into hemispherical phycobilisomes attached to the outside of the thylakoid membranes. Somewhere around 1 to 2 billion years ago, a free-living cyanobacterium entered an early eukaryotic cell, either as food or as an internal parasite, but managed to escape the phagocytic vacuole it was contained in; the two innermost lipid-bilayer membranes that surround all chloroplasts correspond to the outer and inner membranes of the ancestral cyanobacterium's gram negative cell wall, not the phagosomal membrane from the host, lost. The new cellular resident became an advantage, providing food for the eukaryotic host, which allowed it to live within it. Over time, the cyanobacterium was assimilated, many of its genes were lost or transferred to the nucleus of the host. From genomes that originally contained over 3000 genes only about 130 genes remain in the chloroplasts of contemporary plants.
Some of its proteins were synthesized in the cytoplasm of the host cell, imported back into the chloroplast. Separately, somewhere around 500 million years ago, it happened again and led to the amoeboid Paulinella chromatophora; this event is called endosymbiosis, or "cell living inside another cell with a mutual benefit for both". The external cell is referred to as the host while the internal cell is called the endosymbiont. Chloroplasts are believed to have arisen after mitochondria, since all eukaryotes contain mitochondria, but not all have chloroplasts; this is called serial endosymbiosis—an early eukaryote engulfing the mitochondrion ancestor, some descendants of it engulfing the chloroplast ancestor, creating a cell with both chloroplasts and mitochondria. Whether or not primary chloroplasts came from a single endosymbiotic event, or many independent engulfments across various eukaryotic lineages, has long been debated, it is now held that organisms with primary chloroplasts share a single ancestor that took in a cyanobacterium 600–2000 million years ago.
It has been proposed. The exception is the amoeboid Paulinella chromatophora, which descends from an ancestor that took in a Prochlorococcus cyanobacterium 90–500 million years ago; these chloroplasts
In cell biology a centriole is a cylindrical organelle composed of a protein called tubulin. Centrioles are found in most eukaryotic cells. A bound pair of centrioles, surrounded by a shapeless mass of dense material, called the pericentriolar material, makes up a structure called a centrosome. Centrioles are present in the cells of most eukaryotes, for example those of animals. However, they are absent from conifers, flowering plants and most fungi, are only present in the male gametes of charophytes, seedless vascular plants and ginkgo. Centrioles are made up of nine sets of short microtubule triplets, arranged in a cylinder. Deviations from this structure include crabs and Drosophila melanogaster embryos, with nine doublets, Caenorhabditis elegans sperm cells and early embryos, with nine singlets; the main function of centrioles is to produce cilia during interphase and the aster and the spindle during cell division. Edouard van Beneden made the first observation of centrioles in 1883. In 1895, Theodor Boveri named the organelle a "centriole".
The pattern of centriole duplication was first worked out independently by Etienne de Harven and Joseph G. Gall c. 1950. Centrioles are involved in the organization of the mitotic spindle and in the completion of cytokinesis. Centrioles were thought to be required for the formation of a mitotic spindle in animal cells. However, more recent experiments have demonstrated that cells whose centrioles have been removed via laser ablation can still progress through the G1 stage of interphase before centrioles can be synthesized in a de novo fashion. Additionally, mutant flies lacking centrioles develop although the adult flies' cells lack flagella and cilia and as a result, they die shortly after birth; the centrioles can self replicate during cell division. Centrioles are a important part of centrosomes, which are involved in organizing microtubules in the cytoplasm; the position of the centriole determines the position of the nucleus and plays a crucial role in the spatial arrangement of the cell.
Sperm centrioles are important for 2 functions: to form the sperm flagellum and sperm movement and for the development of the embryo after fertilization. In flagellates and ciliates, the position of the flagellum or cilium is determined by the mother centriole, which becomes the basal body. An inability of cells to use centrioles to make functional flagella and cilia has been linked to a number of genetic and developmental diseases. In particular, the inability of centrioles to properly migrate prior to ciliary assembly has been linked to Meckel-Gruber syndrome. Proper orientation of cilia via centriole positioning toward the posterior of embryonic node cells is critical for establishing left–right asymmetry during mammalian development. Before DNA replication, cells contain two centrioles; the older of the two centrioles is termed the other the daughter. During the cell division cycle, a new centriole grows at the proximal end of both mother and daughter centrioles. After duplication, the two centriole pairs will remain attached to each other orthogonally until mitosis.
At that point the mother and daughter centrioles separate dependently on an enzyme called separase. The two centrioles in the centrosome are tied to one another; the mother centriole has radiating appendages at the distal end of its long axis and is attached to its daughter at the proximal end. Each daughter cell formed. Centrioles start duplicating; the last common ancestor of all eukaryotes was a ciliated cell with centrioles. Some lineages of eukaryotes, such as land plants, do not have centrioles except in their motile male gametes. Centrioles are absent from all cells of conifers and flowering plants, which do not have ciliate or flagellate gametes, it is unclear if the last common ancestor had two cilia. Important genes required for centriole growth, like centrins, are only found in eukaryotes and not in bacteria or archaeans; the word centriole uses combining forms of centri- and -ole, yielding "little central part", which describes a centriole's typical location near the center of the cell.
Typical centrioles are made of 9 triplets of microtubules organized with radial symmetry. Centrioles can vary the number of microtubules and can be made of 9 doublets of microtubules or 9 singlets of microtubules as in C. elegans. Atypical centrioles are centrioles that do not have microtubules, such as the Proximal Centriole-Like found in D. melanogaster sperm, or that have microtubules with no radial symmetry, such as in the distal centriole of human spermatozoon
The phragmoplast is a plant cell specific structure that forms during late cytokinesis. It serves as a scaffold for cell plate assembly and subsequent formation of a new cell wall separating the two daughter cells; the phragmoplast can only be observed in Phragmoplastophyta, a clade that includes the Coleochaetophyceae, Zygnematophyceae and Embryophyta. Some algae use another type of a phycoplast, during cytokinesis; the phragmoplast is a complex assembly of microtubules and endoplasmic reticulum elements, that assemble in two opposing sets perpendicular to the plane of the future cell plate during anaphase and telophase. It is barrel-shaped and forms from the mitotic spindle between the two daughter nuclei while nuclear envelopes reassemble around them; the cell plate forms as a disc between the two halves of the phragmoplast structure. While new cell plate material is added to the edges of the growing plate, the phragmoplast microtubules disappear in the center and regenerate at the edges of the growing cell plate.
The two structures grow outwards. If a phragmosome was present in the cell, the phragmoplast and cell plate will grow through the space occupied by the phragmosome, they will reach the parent cell wall at the position occupied by the preprophase band. The microtubules and actin filaments within the phragmoplast serve to guide vesicles with cell wall material to the growing cell plate. Actin filaments are possibly involved in guiding the phragmoplast to the site of the former preprophase band location at the parent cell wall. While the cell plate is growing, segments of smooth endoplasmic reticulum are trapped within it forming the plasmodesmata connecting the two daughter cells; the phragmoplast can be differentiated topographically into two areas, the midline that includes the central plane where some of the plus-ends of both anti-parallel sets of microtubules interdigitate, the distal regions at both sides of the midline. After anaphase, the phragmoplast emerges from the remnant spindle MTs in between the daughter nuclei.
MT plus ends overlap the equator of phragmoplast at the site. The formation of the cell plate depends on localized secretory vesicle fusion to deliver membrane and cell-wall components. Excess membrane lipid and cell-wall components are recycled by clathrin/dynamin-dependent retrograde membrane traffic. Once the initial cell plate forms at its center, the phragmoplast begins to expand outward to reach the cell edges. Actin filaments localize to phragmoplast and accumulate at late telophase. Evidence suggests that actin filaments serve phragmoplast expansion more than initial organization, given that disorganization of actin filaments via drug treatments lead to the delay of cell-plate expansion. Many microtubule-associated proteins have been localized to the phragmoplast, including both constitutively expressed ones and those expressed during M-phase, such as EB1c, TANGLED1 and augmin complex proteins; the functions of these proteins in the phragmoplast are similar to their functions elsewhere in the cell.
Most research into phragmoplast MAPs have been focused on the midline because it is, where most of the membrane fusion takes place and, where the two sets of anti-parallel MTs are held together. The discovery of an important variety of molecules that localize to the phragmoplast midline is shedding light on the complex processes operating in this phragmoplast region. Two proteins that have critical functions for antiparallel MT bundling at the phragmoplast midline are MAP65-3 and kinesin-5; the kinesin-7 family proteins, HINKEL/AtNACK1 and AtNACK2/TES, recruit a mitogen-activated protein kinase cascade to the midline and induce MAP65 phosphorylation. Phosphorylated MAP65-1 accumulates at the midline and reduces MT-bundling activities for cell-plate expansion; the essential mechanism of MAPK cascade for phragmoplast expansion is suppressed by cyclin dependent kinase activity before telophase. Certain phragmoplast midline-accumulating MAPs are essential proteins for cytokinesis; the kinesin-12 members, PAKRP1 and PAKRP1L, accumulate at the midline and double loss-of-function mutants have defective cytokinesis during male gametogenesis.
PAKRP2 accumulates at midline and in puncta throughout the phragmoplast, which implies that PAKRP2 participates in Golgi-derived vesicle transport. Moss homologs of PAKRP2, KINID1a, KINID1b localize to the phragmoplast midline and are essential for phragmoplast organization. RUNKEL, a HEAT repeat-containing MAP accumulates at the midline and cytokinesis is aberrant in lines with the loss-of-function mutations in this protein. Another midline-localized protein, “two-in-on”, is a putative kinase and is required for cytokinesis as shown by defects in a mutant. TIO interacts with PAKRP1, PAKRP1L, NACK2/TES according to the yeast two hybrid assays. TPLATE, an adaptin-like protein, accumulates at the cell plate and is essential for cytokinesis
A plant cuticle is a protecting film covering the epidermis of leaves, young shoots and other aerial plant organs without periderm. It consists of lipid and hydrocarbon polymers impregnated with wax, is synthesized by the epidermal cells; the plant cuticle is a layer of lipid polymers impregnated with waxes, present on the outer surfaces of the primary organs of all vascular land plants. It is present in the sporophyte generation of hornworts, in both sporophyte and gametophyte generations of mosses The plant cuticle forms a coherent outer covering of the plant that can be isolated intact by treating plant tissue with enzymes such as pectinase and cellulase; the cuticle is composed of an insoluble cuticular membrane impregnated by and covered with soluble waxes. Cutin, a polyester polymer composed of inter-esterified omega hydroxy acids which are cross-linked by ester and epoxide bonds, is the best-known structural component of the cuticular membrane; the cuticle can contain a non-saponifiable hydrocarbon polymer known as Cutan.
The cuticular membrane is impregnated with cuticular waxes and covered with epicuticular waxes, which are mixtures of hydrophobic aliphatic compounds, hydrocarbons with chain lengths in the range C16 to C36. The primary function of the plant cuticle is as a water permeability barrier that prevents evaporation of water from the epidermal surface, prevents external water and solutes from entering the tissues. In addition to its function as a permeability barrier for water and other molecules, the micro and nano-structure of the cuticle confer specialised surface properties that prevent contamination of plant tissues with external water and microorganisms. Aerial organs of many plants, such as the leaves of the sacred lotus have ultra-hydrophobic and self-cleaning properties that have been described by Barthlott and Neinhuis; the lotus effect has applications in biomimetic technical materials. Dehydration protection provided by a maternal cuticle improves offspring fitness in the moss Funaria hygrometrica and in the sporophytes of all vascular plants.
In angiosperms the cuticle is not always thicker. The leaves of xerophytic plants adapted to drier climates have more equal cuticle thicknesses compared to those of mesophytic plants from wetter climates that do not have a high risk of dehydration from the under sides of their leaves. "The waxy sheet of cuticle functions in defense, forming a physical barrier that resists penetration by virus particles, bacterial cells, the spores and growing filaments of fungi". The plant cuticle is one of a series of innovations, together with stomata and phloem and intercellular spaces in stem and leaf mesophyll tissue, that plants evolved more than 450 million years ago during the transition between life in water and life on land. Together, these features enabled upright plant shoots exploring aerial environments to conserve water by internalising the gas exchange surfaces, enclosing them in a waterproof membrane and providing a variable-aperture control mechanism, the stomatal guard cells, which regulate the rates of transpiration and CO2 exchange
Chlorophyta or Prasinophyta is a taxon of green algae informally called chlorophytes. The name is used in two different senses, so care is needed to determine the use by a particular author. In older classification systems, it refers to a paraphyletic group of all the green algae within the green plants and thus includes about 7,000 species of aquatic photosynthetic eukaryotic organisms. In newer classifications, it refers to the sister of the streptophytes/charophytes; the clade Streptophyta consists of the Charophyta. In this sense the Chlorophyta includes only about 4,300 species. Like the land plants, green algae contain chlorophyll a and chlorophyll b and store food as starch in their plastids; the Chlorophyta contains both multicellular species. Some members of the group form symbiotic relationships with protozoa and cnidarians. Others form symbiotic relationships with fungi to form lichens, but the majority of species are free-living; some conduct sexual reproduction, oogamous or isogamous.
All members of the clade have motile flagellated swimming cells. While most species live in freshwater habitats and a large number in marine habitats, other species are adapted to a wide range of land environments. For example, Chlamydomonas nivalis, which causes Watermelon snow, lives on summer alpine snowfields. Others, such as Trentepohlia species, live attached to rocks or woody parts of trees. Monostroma kuroshiense, an edible green alga cultivated worldwide and most expensive among green algae, belongs to this group. Species of Chlorophyta are common inhabitants of marine and terrestrial environments. Several species have adapted to specialised and extreme environments, such as deserts, arctic environments, hypersaline habitats, marine deep waters and deep-sea hydrothermal vents; some groups, such as the Trentepohliales are found on land. Several species of Chlorophyta live in symbiosis with a diverse range of eukaryotes, including fungi, forams and molluscs; some species of Chlorophyta are either free-living or parasitic.
Two common species of the heterotrophic green alga Prototheca are pathogenic and can cause the disease protothecosis in humans and animals. Characteristics used for the classification of Chlorophyta are: type of zoid, cytokinesis, organization level, life cycle, type of gametes, cell wall polysaccharides and more genetic data. A newer proposed classification follows Leliaert et al. 2011 and modified with Silar 2016, Leliaert 2016 and Lopes dos Santos et al. 2017 for the green algae clades and Novíkov & Barabaš-Krasni 2015 for the land plants clade. Sánchez-Baracaldo et al. is followed for the basal clades. Simplified phylogeny of the Chlorophyta, according to Leliaert et al. 2012. Note that many algae classified in Chlorophyta are placed here in Streptophyta. Viridiplantae Chlorophyta core chlorophytes Ulvophyceae Cladophorales Dasycladales Bryopsidales Trentepohliales Ulvales-Ulotrichales Oltmannsiellopsidales Chlorophyceae Oedogoniales Chaetophorales Chaetopeltidiales Chlamydomonadales Sphaeropleales Trebouxiophyceae Chlorellales Oocystaceae Microthamniales Trebouxiales Prasiola clade Chlorodendrophyceae prasinophytes Pyramimonadales Mamiellophyceae Pycnococcaceae Nephroselmidophyceae Prasinococcales Palmophyllales Streptophyta charophytes Mesostigmatophyceae Chlorokybophyceae Klebsormidiophyceae Charophyceae Zygnematophyceae Coleochaetophyceae Embryophyta A possible classification when Chlorophyta refers to one of the two clades of the Viridiplantae is shown below.
Class Prasinophyceae T. A. Chr. ex Ø. Moestrup & J. Throndsen Class Chlorophyceae Wille Class Trebouxiophyceae T. Friedl Class Ulvophyceae Division Chlorophyta Subdivision Chlorophytina Class Chlorophyceae Order Chlamydomonadales Order Sphaeropleales Order Oedogoniales Order Chaetopeltidales Order Chaetophorales Incertae Sedis Class Ulvophyceae Order Ulotrichales Order Ulvales Order Siphoncladales/Cladophorales Order Caulerpales Order Dasycladales Class Trebouxiophyceae Order Trebouxiales Order Microthamniales Order Prasiolales Order Chlorellales Class Prasinophyceae Order Pyramimonadales Order Mamiellales Order Pseudoscourfieldiales Order Chlorodendrales Incertae sedis Division Charophyta Class Mesostigmatophyceae Class Chlorokybophyceae Class Klebsormidiophyceae Class Zygnemophyceae Order Zygnematales Order Desmidiales Class Coleochaetophyceae Order Coleochaetales Subdivision Streptophytina Class Charophyceae Order Charales Class Embryophyceae Classification of the Chlorophyta, treated as all green algae, according to Hoek and Jahns 1995.
Class Prasinophyceae Class Chlorophyceae Class Ulvophyceae Class Cladophorophyceae Class Bryopsidophyceae Class Dasycladophyceae Class Trentepohliophyceae